OPERATING MANUAL
HANDHELD AUDIO AND
ACOUSTIC ANALYZER
XL2
Made in
Switzerland
Contact NTi Audio at
Headquarter
France +33 4 78 64 15 68 [email protected]
Germany +49 201 6470 1900 [email protected]
www.nti-audio.com
Firmware V4.84
Version 4.84.00 / Aug 23
All information subject to change without notice.
© All rights reserved.
® XL2, XL2-TA, EXEL, M2230, M2340, M2211, M2215, M4261, MA220, MA230,
™ M2230-WP, M2340-WP, M4261-WP, WP30-90, WP30-150, WP61 and Minirator are trademarks
of NTi Audio.
NTi Audio AG
Im alten Riet 102, 9494 Schaan
Liechtenstein, Europa
is an ISO 9001:2015 and ISO 14001:2015 certified company.
3
Table of Contents
Table of Contents
5. Acoustic Analyzer .......................................................... 64
FFT Analysis + Tolerance ..............................................64
Reverberation Time ...................................................... 74
Polarity .........................................................................86
Delay Time ...................................................................90
1/12 Octave + Tolerance (optional) ............................... 96
Noise Curves (optional) ..............................................108
Speech Intelligibility STIPA (optional) ......................... 118
6. Audio Analyzer ............................................................135
RMS / THD+N ............................................................ 135
Oscilloscope ..............................................................138
7. Vibration Meter ............................................................139
VibMeter / Spectrum .................................................139
FFT Analysis + Tolerance ............................................ 146
Oscilloscope ..............................................................150
1/12 Octave + Tolerance (optional) .............................151
8. Calibration ...................................................................156
9. Profiles .........................................................................163
10. Spectral Limits Option (Capture + Tolerances) .......170
11. System Settings ........................................................183
Settings ......................................................................183
1. Introduction .....................................................................5
2. Overview .......................................................................... 7
Operation .......................................................................9
The Screen Display ...................................................... 11
3. Getting Started .............................................................14
Power Supply .............................................................. 14
Attaching the Hand Strap .............................................17
Unfolding the Stand ..................................................... 18
Connecting the XL2 ....................................................18
Switching the XL2 On and Off .....................................20
Select Measurement Function .....................................20
Calibration prior Measurement ....................................21
4. Sound Level Meter ........................................................ 22
Overview .....................................................................26
Sound Level Meter - Getting Started ...........................34
RTA Measurement - Getting Started ...........................39
Reporting .....................................................................43
Wav-File Recording ......................................................46
Events (optional) ..........................................................49
Limits ...........................................................................56
Correction Value KSET .................................................58
Locked Run Mode ........................................................62
4
Table of Contents
Vibration .....................................................................186
Scheduler ................................................................... 187
Options ......................................................................189
Information ................................................................190
12. Data Management ....................................................191
Record Voice Notes .................................................... 197
Recall Measurements ................................................ 203
Append Measurements ............................................205
13. XL2 Projector PRO Software .................................... 210
14. Data Explorer (optional) ........................................... 212
15. Building Acoustics (optional) ...................................214
16. Room Acoustics (optional) .......................................216
17. Sound Power (optional) ............................................ 218
18. Unattended Noise Monitoring .....................................220
19. Time Synchronization...............................................226
20. Remote Measurement ..............................................230
21. Microphones .............................................................232
22. Further Information ..................................................246
My NTi Audio .............................................................246
Firmware Update .......................................................249
Options ......................................................................250
Warranty Conditions ..................................................271
Service and Repairs ...................................................272
Calibration Certificate .................................................272
Declaration of Conformity .......................................... 274
23. Technical Data XL2 .................................................... 276
24. Technical Data Microphones ....................................288
25. Technical Data PreAmplifier ......................................298
Appendix .........................................................................299
Appendix 1: Standard - Optional Features .................299
Appendix 2: Factory Default Profiles .........................303
Appendix 3: Description Sound Levels ......................308
Appendix 4: Common Sound Levels ..........................313
Appendix 5: Vibration Meter Functions ......................319
Details IEC 61672 & IEC 61260 ....................................... 320
General Information ...................................................322
Class 1 Sound Calibrator ............................................ 325
Accessory ..................................................................325
Level Linearity ............................................................326
Level Linearity of Octaveband-Spectrum ................... 328
Level Linearity of Third-Octaveband-Spectrum ..........329
Self-generated Noise with Microphone .....................330
Frequency Response Corrections .............................. 332
Frequency Weighting .................................................336
Directional Response (dB) .........................................337
Information for Calibration ............................................342
5
Introduction
- Room Acoustics
- Building Acoustics
- Reverberation Time
- Noise Curves
• Industrial Quality Control
• Condition Monitoring
How to Read this Manual
The XL2 push buttons are displayed as icons
, , , ,
, , , , . A detailed description of the push buttons is
listed in the chapter Overview - Operation.
Menu items displayed on the XL2 page screens are shown in
this user manual by a bold font, e.g., SLMeter, Parameter, ...
1. Introduction
Thank you for purchasing the XL2 Audio and Acoustic Analyzer.
The XL2 Analyzer forms the unique combination of a state-of-
the-art Sound Level Meter, a comprehensive Acoustic Analyzer
as well as a powerful Audio Analyzer. The wide range of func-
tionalities is tailored for:
• Evacuation Systems
- Speech Intelligibility
• Electroacoustic Installations
- Installed Sound
- AV Installations
- Cinemas
• Noise Measurement
- Unattended Noise Monitoring
- Environmental Noise
- Occupational Health
- Vehicle Noise
- Sound Power
• Live Sound
- Sound Level Monitoring
- Front of House
- PA Rental
• Broadcast
• Room & Building Acoustics
6
Introduction
Product Configurations
The following items are included with the respective model:
XL2
without
Micro-
phone
• XL2 Analyzer
• USB Flash Drive with test signals
• USB cable
• Li-Po battery
• Hand strap
• Operating manual
XL2 +
M2230
• XL2 Analyzer
• M2230 Measurement Microphone
consisting of
- Microphone PreAmplifier MA220
- Microphone Capsule MC230 or MC230A
• 50 mm Windscreen
• Microphone-holder MH01
with Adapter 5/8“ - 3/8“
• Individual Frequency Response Chart
• USB Flash Drive with test signals
• Li-Po battery
• USB cable
• Hand strap
• Operating manual
XL2 +
M2211
• XL2 Analyzer
• M2211 Measurement Microphone
consisting of
- Microphone PreAmplifier MA220
- Microphone Capsule 7052
• 33 mm Windscreen
• Microphone-holder
with Adapter 5/8“ - 3/8“
• USB Flash Drive with test signals
• Li-Po battery
• USB cable
• Hand strap
• Operating manual
XL2 +
M4261
• XL2 Analyzer
• M4261 Measurement Microphone
• 33 mm Windscreen
• Microphone-holder
with Adapter 5/8“ - 3/8“
• USB Flash Drive with test signals
• Li-Po battery
• USB cable
• Hand strap
• Operating manual
7
Overview
8
9
7
Headphone
Output
SD Card
TOSLink Output
1
2
3
4
5
6
Voice Note Input
RCA Input
XLR Input
Digital I/O
USB Connector
DC Power Socket
10
Speaker
11
Tripod Mount
2. Overview
XL2 interfaces:
8
Overview
1
XLR Signal Input
Either a balanced audio signal, an NTi Audio measure-
ment microphone or the microphone pre-amplifier MA220
plug directly into the XLR input. The Automated Sen-
sor Detection (ASD) technology reads the electronic
data sheet of any connected NTi Audio device after the
48 V microphone phantom power is activated.
2
RCA Input
Unbalanced audio signal input.
3
Voice Note Input
Internal microphone for recording voice notes and measur-
ing polarity and delay time. For polarity measurements, an
external microphone may also be used.
4
DC Power Socket
Socket for mains power adapter. Further details in the chap-
ter Power Supply in this manual.
5
USB Connector
Mini-B USB connection, for accessing the SD Card.
6
Digital I/O
Programmable digital inputs/outputs.
7
SD Card
For storing data, screenshots, voice notes, wav-files -
required to power on and run the instrument.
8
TOSLink Output
24 bit linear PCM audio signal output. For future use; not
active at this time.
9
Headphone Output
The XLR/RCA input signals are routed to the headphone
connector (3.5 mm Minijack; mono monitor wired to both
channels of stereo jack). Connecting headphones mutes the
internal speaker. To connect the headphone output direct-
ly to a line input, a load impedance < 8 kOhm is required
for proper operation. This can be achieved by inserting a
1 kOhm resistance between tip and ground of the output
jack.
10
Speaker
The XLR/RCA input signals are routed to the speaker. Press
the speaker button
to toggle the speaker on/off. Press
and hold the speaker button to access the volume control.
Set the speaker level with the rotary wheel
.
11
Tripod Mount
Mechanical mount for attaching the XL2 to a tripod or mi-
crophone stand.
9
Overview
Operation
9 8 7
6
5
4
3
2
1
1
Page Control
Switches among various screens depending on the menu
function selected.
2
Volume of Speaker and Headphone Output
• Press the button
briefly to enable or disable the
speaker.
The speaker is activated and the speaker or headphone
icon appears in the upper menu bar.
• Press and hold the speaker button .
A pop-up window for volume is displayed.
10
Overview
• FFT + Tol: The limit button lights up green for results
within tolerance and red for out-of-tolerance results.
• Polarity: The limit button lights up green at positive polar-
ity and red at negative polarity.
• 1/12 Oct + Tol: The limit button lights up green for results
within tolerance and red for out of tolerance results.
5
Pause
Pauses the current measurement. Press the pause button
or the start/stop button to continue the measure-
ment. The data logging is continued in the function SLMe-
ter/RTA during the pause period and listed in the log file.
6
Start/Stop
Starts and stops a measurement.
7
Enter
Confirms a selection.
8
Rotary Wheel
Selects the required measurement function or the individu-
al measurement parameter.
9
ESC
Terminates an entry, returns to the top menu level or closes
an open window.
• Hold the speaker button
down and adjust the level
of the speaker and headphone outputs with the rotary
wheel
. Digital gain control prevents gain increases be-
yond a level that will cause signal clipping. The maximum
gain setting depends on the connected input signal.
• The headphone output provides a linear output signal us-
ing the SLMeter function over a measurement range of
57 dB. The minimum Z-weighted sound pressure level at
reference sensitivity is:
- M2230, M2340: 58 dB
- M2211: 64 dB
- M4261: 66 dB
3
Power & Backlight
The power button switches the instrument on. The XL2 is
immediately ready for operation. Holding down the power
button
for one second switches the XL2 off. Additionally,
a brief press of the power button
toggles the backlight
during operation.
4
Limit
• SLMeter: The limit button lights up green, yellow or red
according to the settings in the Limit page. Press the
limit button
to access the Limit page. For more details
visit the chapter Sound Level Meter: Limits.
11
Overview
The Screen Display
The XL2 displays the actual sound levels also in case of no
measurement has been started. Any displayed averaged level
refers to the previous measurement period. The XL2 shows
four lines in case of no previous measurement period is ap-
plicable.
Display Contrast Setting
• Hold down escape
and turn the rotary wheel until the
desired contrast is reached.
Updating of display
• Numeric values
Updated every 500ms independent of the measurement
function. The maximum time span between the end of
the measurement period and the first test result display is
500ms.
• Graphs and spectra
Updated every 50ms
1
2 3 4 75 986
The display is updated continuously during measurement.
12
Overview
1
Measurement Results
Individual level measurement results.
2
Main Menu
SLMeter/RTA SPL & RTA Measurement
FFT + Tol FFT Analysis with optional Tolerance
Management
RT60 Reverberation Time
Polarity Polarity
Delay Time Delay Time
RMS/THD+N RMS Level and Distortion
Oscilloscope Scope
1/12 Oct + Tol Spectral Analysis with Tolerance Man-
agement (optional)
Noise Curves Noise Curves
STIPA Speech Intelligibility (optional)
Cinema Meter Calibration and verification of cinema
loudspeaker systems (optional)
Calibrate Calibration Menu for microphone
Profile ... Store and load measurement profiles
System System Settings
3
Page Selector
Toggles between available measurement and result pages
within the same function menu. Alternatively use the page
button
.
4
Input Selector
Select XLR or RCA input connectors as the source.
5
Memory Menu
The memory menu is used for data storage management.
One of the following symbols flashes before or after start-
ing the measurement:
9-8-7 Time in seconds until instrument is settled and
measurement will start.
RUN Indicates the ongoing measurement.
LOG Indicates the ongoing measurement with data
logging.
AUD Indicates the ongoing measurement with data
logging and audio recording.
Evt Indicates an ongoing triggered-event recording.
13
Overview
After a completed measurement, the memory symbol
indicates a non-saved measurement report. Your measure-
ment needs to be stored manually. For more details visit
the chapter Data Management.
6
Speaker/Headphone
Indication of enabled rear speaker or headphone output.
7
Phantom Power Supply
48V The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.
ASD An NTi Audio measurement microphone with
automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of
the microphone and switches the 48 V Phan-
tom power automatically on
48V Phantom power is switched off.
8
Real-Time Clock
The real-time clock is set in the System menu.
9
Battery Symbol
The battery symbol indicates the battery status as follows:
Using rechargeable Li-Po battery:
Level indication 100% (U > 4.0 Volt).
(Battery charges when mains adaptor connected)
Level indication:
75%: U = 3.9 - 4.0 Volt
50%: U = 3.8 - 3.9 Volt
25%: U = 3.7 - 3.8 Volt
Level indication 0% (U < 3.7 Volt). The battery is
almost empty and must be recharged.
The battery is being recharged by the mains
power adapter.
The XL2 is connected via USB to a computer.
The battery charge level decreases slowly dur-
ing XL2 usage.
Using standard AA batteries:
No level indication as long as U > 4.5 Volt.
Level indication 0% (U < 4.5 Volt). The batteries
are almost empty and should be replaced.
Using mains or supply:
No indication of battery status.
14
Getting Started
3. Getting Started
Power Supply
The XL2 offers flexible power management options and can be
operated either by
• Replaceable, rechargeable lithium-polymer (Li-Po) battery
(included with the XL2 Analyzer)
• 4x AA-batteries
• Mains Power Adapter
The new battery is charged to approximately 50% and should
be fully charged before use with:
Battery Charger
(optional)
Charging Time: approx. 3 hours
NTi Audio #: 600 000 332
Mains Power
Adapter
(optional)
Charging Time: approx. 6 hours
Leave the battery inside and switch off
the XL2
. Running the XL2 during
charging prolongs the charging time.
NTi Audio #: 600 000 333
USB Power
from PC
Charging Time: approx. 6 hours
Switch off the XL2
for charging. The
charging power is equal or less than the
power consumption.
Operation using Mains Power Supply
You can also operate the XL2 with the optional NTi Audio Mains
Power Adapter. During such operation it is recommended to
leave the batteries inside the instrument.
Mains Power Adapter
• Electrically-isolated, linear DC power supply
• A decreased THD+N performance will oc-
cur with unbalanced input signals when us-
ing switching-type power supplies (approx.
3 dB).
• Non-NTi Audio power supplies may have fur-
ther negative effects on measurements.
• Damage caused by using an inappropriate ex-
ternal DC supply is not covered by warranty.
DC Power supply specifications
• Voltage: 7.5 - 20.0 Volt
• Power: minimum 6 Watt
• Connector type: 2.1 x 5.5 x 9.5 mm
• Polarity:
.
15
Getting Started
Rechargeable Li-Po Battery
• Open the battery cover at the rear of the instrument.
• Insert the rechargeable battery with the contacts edge first.
• Close the battery cover.
Switch off the XL2 for faster recharging by
mains power adapter or USB connection.
Caution
• Switch the XL2 off prior opening the battery
cover in order to prevent any electronic dis-
charges.
• Avoid short-circuits.
• Operate and charge the battery between 0°C
and 45°C (32°F - 113°F).
• Do not heat the battery above 60°C.
• Do not place the battery in or near fire.
• Do not solder directly on to the battery.
• Do not disassemble the battery.
• Do not insert the battery in reverse polarity.
• Remove the battery for applications with a
connected mains power adapter over mul-
tiple weeks.
1.
3.
2.
16
Getting Started
AA-Batteries
Alternatively, the XL2 can be powered by AA type batteries
• Open the battery cover.
• Insert 4 fully-charged AA batteries, observing correct polarity
of the +/- indications in the battery compartment.
The polarity alternates with successive batteries.
• Close the battery cover.
• Switch the XL2 off prior opening the battery
cover in order to prevent any electronic dis-
charges.
• Use only similar batteries from the same
manufacturer.
• Replace discharged batteries with new ones.
• Do not mix used and new batteries.
• During operation, the battery temperature
may increase noticeably. This is not a defect.
• Remove all batteries if the XL2 is not to be
used over a long period of time.
1.
2.
17
Getting Started
Attaching the Hand Strap
To avoid accidentally dropping the XL2, a hand strap is supplied
with the instrument.
• Pull the loop of the hand strap through the opening.
• Pull the other end of the hand strap through the loop.
• Pull the hand strap tight.
2.1. 3.
18
Getting Started
Unfolding the Stand
A convenient table stand is attached to the rear of the instru-
ment.
• Unfold the stand and rest the XL2 on a flat surface.
Connecting the XL2
Acoustic Measurements
Connect an NTi Audio measurement microphone to the XLR
input connector of the XL2.
19
Getting Started
Audio Measurements: XLR Connection
• Connect the source to the XL2 with an XLR cable.
• Select the XLR input in the menu.
Audio Measurements: RCA Connection
• Connect the source to the XL2 with an RCA (cinch) cable.
• Select the RCA input in the menu.
20
Getting Started
Switching the XL2 On and Off
Switching On the XL2
Press power
to switch on the XL2.
There is a brief sound of relays and the display illuminates.
Switching Off the XL2
Press power
and hold it down for one second to switch off
the XL2.
Select Measurement Function
• Navigate with the rotary wheel to the main menu bar.
• Confirm with enter
to select the measurement function.
The main menu window opens
Main menu with enabled options
• Scroll up/down with the rotary wheel to select the re-
quired function and confirm with enter
.
The measurement function is selected.
21
Getting Started
Setting the Parameters with the Rotary Wheel
• Turn the rotary wheel
to navigate within the display
screen.
The selected parameter is highlighted with a black back-
ground.
• Confirm with enter .
The parameter display flashes and/or available parameters
or settings are shown.
• Turn the rotary wheel to set the parameter or toggle with
enter
through the settings.
• Confirm with enter
.
Now the parameter is set.
Calibration prior Measurement
We recommend the daily calibration of the XL2 Analyzer with
the Sound Calibrator. This ensures accurate measurement re-
sults.
For more details see chapter Calibration.
22
Sound Level Meter
4. Sound Level Meter
The XL2 provides, together with the measurement micro-
phone, a precise sound level meter for monitoring live sound
events and/or environmental noise.
The Type Approval Option upgrades the instrument to the
XL2-TA, the sound level meter dedicated to certified measure-
ments. The XL2 with the M2230 microphone forms a type ap-
proved sound level meter offering class 1 performance accord-
ing IEC61672 (see chapter Options and Accessories)
For example, Actual, Lmin, Lmax, Leq with frequency weight-
ing A, C and Z and time weighting F and S can be measured
at the same time. All measurement results are simultaneously
available. You may log all acquired level information, including
real-time information, onto the removable SD Card. To com-
plete the documentation of the measured sound pressure lev-
els, the XL2 offers wav-file recording, as well as the facility
to add voice notes for each measurement. The XL2 measures
correction values between the loudest point of the live event
and the actual measurement positions in accordance with DIN
15905-5 and V-NISSG. In parallel with the wide band param-
eters, the XL2 measures the real-time spectrum either in 1/1 or
1/3 octave-band resolution. The RTA perfectly suits tasks such
as optimization of sound systems
Extended Acoustic Pack (optional)
The Extended Acoustic Pack offers the following additional fea-
tures for sound-level and acoustic measurements:
• SLMeter/RTA function
- Recording of linear wav-files (24 bit, 48 kHz)
- Percentiles for wide band and spectrum with flexible set-
ting from 0.1% to 99.9%
- Sound Exposure Level L
AE
- 100 ms logging
- RTA logging of Lmin and Lmax
- Event-triggered audio and data recording
- Time weighting: Impulse (LxI, LxIeq with x= A, C, Z)
- True peak level in 1/1 and 1/3 octave resolution
- Clock-impulse maximum level (TaktMax) in accordance
with DIN 45645-1 and DIN 45657
- Impulsiveness detection in accordance with BS4142:2014
and NordTest ACOU 112
• FFT function
- High-resolution Zoom-FFT with selectable frequency
ranges and resolution up to 0.4 Hz in the range of 5 Hz to
20 kHz
• RT60 function
- Reverberation time in 1/3 octave resolution
• 1/12 octave Spectral Analyzer
(requires Spectral Limits Option)
- Recording of linear wav-files (24 bit, 48 kHz)
23
Sound Level Meter
The sound level meter offers different pages:
Page Selection using the Page Button
• Press page to toggle between the 123 SLMeter page
and the RTA page.
Page Selection using the Rotary Wheel
• Select the page 123 SLMeter with the rotary wheel .
• Confirm with enter
.
Menu with enabled options
You have selected the individual sound level meter page.
123 SLMeter: Sound Level Meter
Displays the selected broadband sound level results. You can
change the font size of the result. Depending on the font size
chosen, the XL2 shows 3 or 5 results simultaneously. Individual
frequency weighting, time weighting, actual, minimum, maxi-
mum and correction values can be chosen for each displayed
result.
RTA: Real-Time Spectrum
Displays the 1/3 or 1/1 octave spectrum of the selected sound
level within the audio band. Additionally the wide band result is
shown graphically by a bar.
Reporting: Report Setting
Here you set which sound pressure levels shall be stored in a
.txt file after the completed measurement. Choose between:
ALL Stores all sound pressure levels.
Selected Stores up to 10 different individually-defined
sound pressure levels.
For details refer to the chapter Reporting.
24
Sound Level Meter
Logging: Setup of Data Logging
The XL2 features a powerful sound level meter data logger,
which allows you to record all required sound level values dur-
ing the measurement. In the logging page you set which sound
pressure levels shall be logged over time. For details refer to
the chapter Logging. Choose between:
ALL Logs all sound pressure levels.
Selected Logs up to 10 different individually-defined sound
pressure levels.
Event Trigger: Event Setting (optional)
The event function is available with the optional Extended
Acoustic Pack. The XL2 event feature offers the following func-
tionalities:
• Automated event triggered at noise levels above/below a
preset value including setting markers for specific noise cat-
egories. Application example: Recording the noise level for
L
AF
> 80 dB.
• Event triggered by external key press of the XL2 Input Key-
pad. You can utilize four keys (1-4) to categorize any noise of
interest or noise to be later excluded in the post-processing.
A typical application is categorizing any annoying industrial
noise by persons living in the neighborhood.
Limit LED: Limit Setting
H
ere you set the function
of the limit LED , thereby highlight-
ing any sound level that exceeds the pre-set limits in orange
or red color. Further, external peripherals are controlled by the
optional Serial I/O Interface based on the sound level, such as
displaying sound levels on a large external red-orange-green
lamp. For details refer to the chapter Limits.
K
SET Correction: Setup of Correction Values
This page provides a wizard to measure correction values,
which could be helpful for compliant sound level monitoring
of live events. It measures the correction values between
the actual measurement position and the loudest posi-
tion accessible by the audience. The XL2 displays and logs
the selected sound pressure levels including the correction
values, allowing the sound engineer to monitor the sound
level at the loudest position in the audience. The measure-
ment meets the requirements of the standards DIN15905-5
and V-NISSG. For details refer to chapter Correction Value
K
SET.
25
Sound Level Meter
Set EQt, L%: Selection of measured levels
This page allows setting the following levels:
• Moving Time-average Sound Level
Gliding Leq with selectable time window from one second to
one hour. Four individual levels can be configured. This level
is also called “running Leq,T” or “sliding Leq,T”.
• Percentile Sound Level
- Allows the individual configuration of seven statistic lev-
els from 0.1% to 99.9% (optional with Extended Acoustic
Pack).
- The Broadband Source for the calculation of the level sta-
tistics can be chosen from a set of different levels with
either a frequency weighting A, C or Z. The time weight-
ings F, S and the moving time-averaged sound level for one
second are supported.
26
Sound Level Meter
Overview
Numeric Result Page
The numeric result page 123 SLMeter displays the selected
broadband sound level results. You can change the font size of
the result. Depending on the font size chosen, the XL2 shows
three or five results simultaneously. Individual frequency
weighting, time weighting, actual, minimum, maximum and
correction values can be chosen for each displayed result.
8
4 5
6
7
1
2
3
Real-Time Analyzer Page
The real-time analyzer page
RTA measures and displays
the 1/3 or 1/1 octave spectrum from 6.3 Hz to 20 kHz including
wideband results. The real-time spectrum RTA is measured in
parallel with the A and Z-weighted wideband levels.
14
13
11
12
16
9
10
15
17
27
Sound Level Meter
1
Sound Level Result 1
All sound levels are measured and logged simultaneously.
You select which sound levels should be displayed.
Change Parameter
• Turn the rotary wheel
to select the parameter Lxx.
• Press enter
to open the selection menu and choose
the wideband sound pressure level to be displayed.
• Turn the rotary wheel
to select the required test result
parameters and confirm with enter
.
Change Font Size
• Turn the rotary wheel to select the actual test result.
• Press enter
1x, 2x or 3x to set the font size to small,
medium or large.
The XL2 shows 3 sound levels on the display if a large font
is chosen, otherwise it shows 5 sound levels.
2
Sound Level Result 2 & 3
Follow the setting instructions for sound level result 1.
3
Sound Level Result 4 & 5
To display sound level results 4 & 5, choose a smaller font
for all results. Follow the setting instructions for sound level
result 1.
4
Input Range
The XL2 Analyzer provides three input ranges to accom-
modate the wide range of input signals. The individual rang-
es are based on the microphone sensitivity setting in the
calibration menu of the XL2. For example, at a sensitivity
S=20mV/Pa the input ranges are
• Low: 10 - 110 dBSPL
• Mid: 30 - 130 dBSPL
• High: 50 - 150 dBSPL
Select the lowest possible input range according to the
maximum level expected during the measurement; e.g., if
the sound pressure will always be below 110 dBSPL, then
select the lowest input range 10 - 110 dBSPL.
5
Run Indication
The run indication shows the measurement status running,
paused or stopped. Various measurement settings are
locked during ongoing measurements, such as changing
the input ranging or the preset measurement time.
28
Sound Level Meter
6
Actual Measurement Time
Counts actual measurement time in hrs:min:sec. Supports
time modes: continuous, single and (synchronized) repeat.
Timer Mode Continuous
(applicable for standard measurements)
All values are recorded and monitored continu-
ously after starting a measurement with start
.
The actual measurement time is shown.
Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement
.
The actual measurement time counts back to zero and
the measurement ends.
• All measurement results may be recalled.
Timer Mode Repeat
Provides automated repeated measurements with
user-defined, preset measurement time cycles.
• Set the required measurement time.
• Press start
.
The actual measurement time counts back to
zero. When the preset measurement time has
elapsed, the measurement time and the mea-
surement results are reset and a new mea-
surement is started. All measurement results
of the previous cycle are reset.
• Press stop
to complete the measurement.
29
Sound Level Meter
8
Phantom Power Supply
48V The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.
ASD An NTi Audio measurement microphone with
automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of
the microphone and switches the 48 V Phan-
tom power automatically on
48V Phantom power is switched off.
9
Result Symbols / Capture
This field offers two functions:
• Symbols for measurement results
15
Upper RTA parameter displayed as line.
Lower RTA parameter displayed as bargraph.
Timer Mode Repeat Synchronized
Provides automated repeated measure-
ments synchronized to the XL2 real-time clock.
Press start
to begin the measurement.
In order to align the selected preset measurement
time with the real-time clock, the XL2 shortens
the first cycle to match the real-time clock syn-
chronization. All following measurement cycles
are synchronized to the real-time clock.
For example, the cycle time setting is 30 minutes
and the measurement starts at 7.50 a.m. -> the
first test cycle measures from 7.50 - 8.00 a.m.
Thereafter a new test cycle starts automatically
for 30 minutes. The 30-minute cycles repeat until
the measurement is stopped.
The measurements in the synchronized repeat
timer mode start exactly on the half or full hour in
accordance with DIN 15905.
7
Preset Measurement Time
Adjustment of preset measurement time for single and re-
peat timer setting.
30
Sound Level Meter
11
Y-Scale setting
• Select the Y-Axis with the rotary wheel
and confirm
with enter
.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter
.
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter
.
12
RTA Measurement Result
Real-time analyzer results in 1/1 octave or 1/3 octave band
resolution. Adjust the resolution at
17
.
13
X-Scale setting
Toggles X-scale range between
20 Hz - 20 kHz RTA levels including wide band results
6.3 Hz - 8 kHz RTA levels including wide band results
6.3 Hz - 20 kHz RTA levels
• Select the X-Axis with the rotary wheel
and confirm
with enter
.
• Toggle with the rotary wheel
between the ranges.
• Confirm with enter
.
• Capture
One of the displayed RTA readings may be captured. Any
measurement data can then be compared with this cap-
tured reference live on the XL2 Analyzer. For example,
compare the RTA spectrum of the left and right speakers.
• Select the parameter to be captured.
• Confirm with enter
, to capture the reading.
• Select the upper RTA parameter
15
and choose
Capt.
• Confirm with enter
.
The lower RTA reading can be compared with the previ-
ously-captured reference data.
10
Measurement Result
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band pointed to by the arrow.
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
31
Sound Level Meter
The cursor readout may be set manually to any
frequency band or wide band level. The readout re-
mains at the selected frequency.
• Select the frequency with the rotary wheel
.
• Press enter
.
• Select the frequency of interest.
• Confirm with enter
.
The cursor readout
11
displays the measure-
ment results of the selected frequency band.
16
Setting of Test Result Resolution
Set the RTA result display to 1/1 octave or 1/3 octave band
resolution as follows:
• Turn the rotary wheel
to select the parameter
17
.
• Press enter
to toggle between 1/1 OCT and 1/3 OCT
and set this parameter.
14
Broadband Results
Actual sound level.
The broadband sound pressure level Leq, Lmin, Lmax and
Live are displayed here. The Live level is displayed with
time weighting Fast.
A A-weighted broadband sound pressure level
Z Broadband sound pressure level without any fre-
quency weighting
15
Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the highest level,
e.g. tracing feedback frequencies at live sound.
• Select the frequency with the rotary wheel
.
• Press enter
.
• You may readout any individual frequency.
• Return to auto frequency with enter
.
The cursor returns to the frequency with high-
est level bar.
32
Sound Level Meter
17
Measurement Unit
Select the measurement unit as follows:
dB Sound level in dBSPL
This measurement unit is permanently selected
when an NTi Audio measurement microphone
with electronic data sheet is connected.
dBu Input level in dBu
dBV Input level in dBV
V Input level in Volt
LOW - Indication
The low indicator for an individual level “<” is displayed when:
• The measured sound pressure level is below the selected
linear measurement range. In this case the results shown
are most likely higher than the actual sound pressure level ->
choose the next lower measurement range.
• The measured sound pressure level is just above the residual
noise of the connected NTi Audio measurement microphone.
This reduces the measurement accuracy -> choose another
microphone designed for low level measurements.
The low condition is registered in the log and report files in the
column “Low(eq/peak)“ individually for all frequency weight-
ings, the RMS and the peak levels.
33
Sound Level Meter
Overload Indication
In case the measurement result exceeds the preset measure-
ment range, then limit arrows indicate this overload condi-
tion. The arrows
are displayed for as long as the overload
exists, and at least for a minimum of 1 second. Furthermore,
such an overload condition triggers the OVR indication in the
bottom line, which remains displayed for the complete mea-
surement period. These overload indications are reset at the
start of a new measurement. All overload conditions are regis-
tered in the log and report files.
Possible causes for exceeding measurement ranges are
• The measured sound pressure level exceeds the pre-set
measurement range during the measurement period. Once
this happens, the OVR indication remains displayed for the
complete measurement period -> select the next higher
measurement range or reduce the input signal level as ap-
plicable.
• The input level is near the maximum level of the connected
NTi Audio measurement microphone.
34
Sound Level Meter
Sound Level Meter - Getting Started
Test Preparations
• Connect the measurement microphone to the XL2.
• Switch on the XL2
.
The XL2 reads the electronic data sheet of any connected NTi
Audio ASD microphone and switches the 48 V phantom power
automatically.
The 48 V phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
• Position the XL2 at the measurement location using a micro-
phone stand or a tripod.
• Select the SLMeter function in the measurement menu and
toggle with page
to the numeric result page .
All wideband and RTA levels are measured and
logged simultaneously. You select which sound
levels should be displayed.
Select Displayed Test Result
This example describes the setting of the commonly-used ac-
tual sound pressure level L
AF
(level L, frequency weighting A,
time weighting F).
• Select the first parameter setting with the rotary wheel
.
• Confirm with enter
.
Press start to measure and display the
sound levels results indicated with ----.
35
Sound Level Meter
Select Frequency Weighting
The pop-up window FREQ WEIGHTING appears.
• Select the frequency weighting A.
Installation of the Extended Acoustic Option
adds more items to the pop-up window
• Confirm with enter .
Select Time Weighting
The pop-up window extends with TIME WEIGHTING.
• Select the required time weighting; e.g.
(=Fast).
• Confirm with enter .
36
Sound Level Meter
Select Parameter
The pop-up window extends with PARAMETER settings.
• Select the parameter live.
• Confirm with enter .
Select Correction Value
The pop-up window extends with CORRECTION settings.
• Select the parameter off.
• Confirm with enter .
The pop-up window closes and the measured sound pres-
sure level L
AF
is displayed.
37
Sound Level Meter
Select further Sound Levels
• Select further sound pressure levels as described above;
e.g., L
Aeq
and L
AFmax
Select Input Range
• Select the lowest possible input range based on the maxi-
mum level expected during the measurement. Wrong input
ranges are indicated by a “<” in front of the measurement
value or a flashing OVR message in the lower menu bar.
• Select the input range RNGE and press enter
.
• Turn the rotary wheel
to set the applicable input range and
confirm with enter
.
The numeric result page and the real-time ana-
lyzer page use the same input range.
38
Sound Level Meter
Start Measurement
• The XL2 is ready to measure the sound levels L
AF
, L
Aeq
and
L
AFmax
.
• Press start
.
The run indication switches to running . The integrated
sound pressure level over time L
Aeq
and the maximum lev-
el in the measurement period L
AFmax
are displayed. The
parameter RUN, LOG (logging is enabled) or AUD (audio
recording is configured) flashes in the memory menu.
Stop Measurement and Data Saving
• Press stop
.
The XL2 stores the broadband sound pressure levels and
the real-time analyzer results simultaneously.
• Press enter to confirm. The measurement data is stored
on the SD Card in ASCII format.
The sound pressure level measurement is completed.
39
Sound Level Meter
Data Post-Processing
The XL2 stores all data and audio onto the SD card for direct
transfer to a computer. Audio data is stored as .wav files. Data
reports and log files are stored in plain text format, which can
be opened with any text editor (Notepad, Wordpad, etc.). The
data is tab-delimited, so dropping the .txt file into a spreadsheet
application will conveniently show the results in columns.
Furthermore, a series of free MS Excel application templates pro-
vide a convenient way to view the measurement results of specific
tasks and create simple reports. They are available as free down-
load for all registered XL2 customers on the support website at
https://my.nti-audio.com. (Enable all macros when opening the
document.)
For the most comprehensive analysis of logged noise monitor-
ing data, use the XL2 Data Explorer software. The data import
into the software is enabled by the Data Explorer Option, which
needs to be installed in the XL2 Sound Level Meter. More de-
tails in chapter XL2 Data Explorer.
RTA Measurement - Getting Started
Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
phantom power automatically on as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2
.
The 48 V phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
• Position the XL2 at the measurement location using a micro-
phone stand or tripod.
• Select the SLMeter function in the measurement menu and
toggle with page
to the real-time analyzer (RTA) page
.
All wideband and RTA levels are measured and
logged simultaneously. You select the sound
levels to be displayed.
40
Sound Level Meter
RTA Configuration
The XL2 displays two different sound pressure levels at the
same time. You configure which test results to display; e.g.,
L
ZFmax
and L
ZF
live
.
• Ensure no other measurement is going on. The run indication
should display the stop symbol
.
• Select the LZF value with the rotary wheel
.
• Confirm with enter .
Select RTA Frequency Weighting
The pop-up window FREQ WEIGHTING appears.
• Select the frequency weighting Z.
• Confirm with enter .
Press start to measure and display the
sound levels results indicated with ----.
41
Sound Level Meter
Select Upper/Lower RTA Parameter
• Select the parameter shown to the right of the upper LZF
value with the rotary wheel
; e.g. max.
• Press enter
.
The pop-up window PARAMETER appears.
• Select the parameter max.
• Confirm with enter .
• Follow the same instruction and select the lower RTA pa-
rameter live.
Select RTA Time Weighting
The pop-up window extends with TIME WEIGHTING.
• Select the required time weighting; e.g.,
(=Fast).
• Confirm with enter .
42
Sound Level Meter
Select Input Range
• Select the lowest possible input range according to the maxi-
mum level expected during the measurement. Wrong input
ranges are indicated by a < in front of the measurement val-
ue or a flashing OVR message in the lower menu bar.
• Select the input range RNGE and press enter
.
• Turn the rotary wheel
to set the applicable input range and
confirm with enter
.
The numeric result page and the real-time ana-
lyzer page use the same input range.
Start RTA Measurement
• The XL2 is ready to display the measured sound pressure
levels L
ZFmax
and L
ZF
live
.
• Press start
.
The run indication switches to running . The actual sound
level L
ZFlive
and the maximum level L
AFmax
are displayed.
The parameter RUN , LOG (logging is enabled) or AUD (au-
dio recording is configured) flashes in the memory menu.
43
Sound Level Meter
Stop the Measurement and Data Saving
• Press stop
.
The XL2 stores the broadband sound pressure levels and
the real-time analyzer results simultaneously.
• Press enter to confirm. The measurement data is stored
on the SD Card in ASCII format.
The RTA measurement is completed.
Reporting
A report saves the conducted measurements onto the installed
SD Card. The XL2 Supports setting the individual levels to be
stored in the report after the measurement is completed.
1
2
3
1
Add Spectra
No No RTA measurement reporting.
Leq The RTA Leq level is stored in the report.
44
Sound Level Meter
Leq, Lmax,
Lmin
The RTA Leq, Lmin, Lmax levels are stored
in the report.
All All RTA levels are stored in the report.
2
Report Values
Choose between the following result reporting:
ALL Records all available sound pressure levels
without correction values.
Selected Records a subset of up to 10 different levels,
including correction values if you require.
• Select Report Values with the rotary wheel
.
• Press enter
to toggle between All or Selected.
3
Selected Report Values
• By setting Selected at
2
up to 10 individual report val-
ues can be chosen. Select the first value Lxx with the
rotary wheel
and press enter .
The pop-up window for level selection appears.
• Select the reporting level with the rotary wheel
and
confirm with enter
.
Logging
The XL2 features a powerful sound level meter data logger,
which allows you to record all required sound level values dur-
ing the selected period of time. All results are logged onto the
SD Card. The measurement results can be loaded to a PC for
documentation and visualization. The LOG menu offers the de-
tailed setup of the log report.
1
2
3
4
5
6
7
45
Sound Level Meter
1
Logging
Select Logging with the rotary wheel
and press enter
to enable the automated logging of test results.
On The XL2 logs measurement data every interval
dt
2
.
Off No Logging
2
Interval Dt
Adjust the logging interval. The optional Extended Acoustic
Pack offers the additional 100 ms logging.
3
Add Spectra
Set the RTA logging for each logging interval here.
No No RTA spectrum is logged.
Leq The Leq spectrum is logged.
Leq, Lmax,
Lmin
The Leq, Lmax and Lmin spectrum is
logged simulatenuously (requires optional
Extended Acoustic Pack).
4
Log Audio
The XL2 logs audio data as a wav-file. Choose among the
following settings:
Off Audio logging is off
On Audio logging is activate from mea-
surement start to stop.
Events Only Audio logging of triggered events
only.
For more details read the chapters Wav-File Recording and
Events.
5
Format
Choose among the following audio recording settings:
Compressed Compressed audio logging
Compressed+AGC Compressed audio logging with
automated gain control
24Bit_48kHz Linear audio logging in 24 bit,
48 kHz resolution (optional with
Extended Acoustic Pack)
46
Sound Level Meter
6
Log Value Setting
Choose between the following settings:
ALL Logs all available sound pressure levels with-
out correction values.
Selected Logs a subset of up to 10 different sound
pressure levels, including correction values if
you require.
• Select Log Values with the rotary wheel
.
• Press enter
to toggle between All and Selected.
7
Selected Log Values
By setting Selected at
5
up to 10 individual log values can
be chosen.
• Select the first value Lxx with the rotary wheel
and
press enter
.
The pop-up window for level selection appears.
• Select the logging level with the rotary wheel
and con-
firm with enter
.
At 100ms Logging is the log value selection limited to five
different parameters.
Wav-File Recording
The XL2 records a wav-file of the measured input signal and
stores it on the SD Card. The available formats are:
• Compressed (default, using ADPCM compression). A new
wav-file is started automatically after 12 hours of recording
(typical maximum wav-file size = 512 MByte)
• Compressed+AGC, compressed with automated gain con-
trol. The gain control increases the level of low-level signals,
so that the wav-file is well-leveled during playback on the
PC.
• 24Bit_48kHz, linear wav-file logging in 24 bit, 48kHz resolu-
tion with the optional Extended Acoustic Pack. A new wav-
file is started automatically after 1 hour of recording (typical
maximum wav-file size = 512 MByte)
Broadcast Wave Format BWF
The XL2 stores scaling factor, serial number,
date, time and time zone within the wav-file (ac-
cording to EBU TECH 3285). This information is
available through professional audio/video tools
typically used in broadcast.
47
Sound Level Meter
Sample name of wav-file:
1
MyTest_SLM_000_Audio_FS133.0dB(PK)_00.wav
2 3 4
5
1
MyTest
File name defined by user.
2
SLM
Measurement function.
3
000
Automatically incrementing file number.
4
Audio_FS133.0dB(PK)
Audio file with full scale peak level. In case of a Com-
pressed + AGC recording, the file name reads “AGC”; this
file contains corrected level information only.
5
00
For wav-file recording over longer periods, the XL2 splits
the audio data into individual wav-files with about 500 MB
(compressed audio: 12 hours; linear: 1 hour), keeping the
file size small for easier handling on the PC. The number
5
increments for each successive wav-file.
The advantage of wav-file recordings is to identify and docu-
ment sound sources after the measurement. For example, at
a live event an excessive peak level may have been measured
and logged. Actually, this peak level was caused by people
shouting nearby the measurement microphone, and not by the
audio system being monitored. The recorded wav-file assists in
verifying this and the test results can then be post-processed.
Pausing Measurement
If any ongoing measurement is paused
, the
XL2 continues the recording of wav-files during
the paused period. The logged data and audio
data can be synchronized using the stored real-
time information.
Events
The wav-files are stored in a folder, named, for
example,
2011-11-30_SLM_000_AudioEvent_0001-0200.
The actual wav-files are named for example, as
xxxx_FS133.0dB(PK).wav (xxxx = incrementing
number)
48
Sound Level Meter
Another example is environmental noise monitoring: Listening
to the recorded wav-file after the measurement may help to
determine the predominant sound source. The XL2 Analyzer
preserves the original absolute test signal level in the recorded
wav-file.
The XL2 Analyzer provides three input ranges to accom-
modate the wide range of input signals. The dynamic range
of the recorded wav-file is set according to the selected in-
put range. For example, at a microphone sensitivity of
S= 20 mV/Pa, the full-scale peak level is:
Range Name Range Level Full-scale peak level
Low 10 - 110 dBSPL 117.8 dBSPL
Mid 30 - 130 dBSPL 135.9 dBSPL
High 50 - 150 dBSPL 159.9 dBSPL
Select the lowest possible input range accord-
ing to the maximum level expected during the
measurement; e.g., If the sound pressure will
always be below 110 dBSPL, select the lowest
input range 10 - 110 dBSPL.
49
Sound Level Meter
Events (optional)
The event function is available with the XL2 Extended Acoustic
Pack Option. The XL2 Analyzer may be configured to record
wav-files and additional noise levels only when triggered, in-
stead of the complete measurement duration.
Advantages
Reduces the data volume acquired, thereby
• Simplifying data post-processing
• Saving memory for long-term measurement applications.
Events
Events are triggered either automatically by sound levels above/
below a preset value or manually by external key press using
the XL2 Input Keypad.
Data Logging
The XL2 Analyzer logs the data specified in the
LOG setting for the complete measurement du-
ration into a log file. The markers and triggered
events results are added to the same log file.
The XL2 Input Keypad is available as an acces-
sory. Please see chapter Options and Accesso-
ries for details.
Recommendation
With the large storage capacity of the XL2, NTi Audio recom-
mends logging at a 1 second or faster interval. This allows the
accurate collection of event data; one event will be stored with-
in a logged interval. If results for reporting are required at lon-
ger intervals, e.g. one hour, the XL2 Data Explorer software is
recommended. It easily combines logged data into longer audit
intervals. An additional advantage of a faster logging interval is
that only an entire logged interval can be excluded from the
average. This is useful when a qualified noise consultant judges
that a sound is not caused by the object under test or is not a
normal sound for a measurement location.
Functions
The XL2 event feature offers the following functionalities:
• Automated event triggered at noise levels above/below a
preset value including setting markers for specific noise cat-
egories. Application example: Recording the noise level for
L
AF
> 80 dB.
• Event triggered by external key press of the XL2 Input Key-
pad. You can utilize four keys (1-4) to categorize any noise of
interest or noise to be later excluded in the post-processing.
A typical application is categorizing any annoying industrial
noise by persons living in the neighborhood.
50
Sound Level Meter
Trigger Events: on level above/below
100
90
80
70
60
Time [seconds]
3
Event Duration
2
14
13 12
Level [dB]
Features:
• The levels L
Aeq
, L
Zeq
and L
CPeak
are recorded for the event
duration.
• Audio data is recorded for the triggered event duration only,
thus simplifying data post-processing and saving memory
space for long-term measurements.
• Setting markers by external key press of the XL2 Input Key-
pad.
14
1
2
3
5
6
7
11
4
8
9
10
13
12
51
Sound Level Meter
1
Trigger Events
Choose from the following settings:
Off No event triggering
on level
above
Events are triggered at noise levels above the
preset value
2
for the start duration
13
.
on level
below
Events are triggered at noise levels below the
preset value
2
for the start duration
13
.
on ext.
key
press
Events are triggered by external key press.
2
Start [dB]
Set the level at which the triggered event is started.
Start Duration
13
The event start is triggered when the noise level is higher
(or lower) than the preset value and continues for the pre-
set duration.
3
Stop [dB]
Set the level at which the triggered event is stopped.
on level
above
Stop level = Start level
2
- Hysteresis
14
on level
below
Stop level = Start level
2
+ Hysteresis
14
Stop Duration
12
The event stop is triggered when the noise level is lower (or
higher) than the preset value and continues for the preset
duration.
Hysteresis
14
Set the hysteresis to an appropriate value to prevent rapid
switching on and off as the level drifts around the Start
level.
4
Level Selection
Define the level type to be monitored.
52
Sound Level Meter
5
Log Audio
The XL2 logs audio data as a wav-file. Choose from the fol-
lowing settings:
Off Audio logging is off
On Audio logging is activated from
measurement start to stop.
Events Only Audio logging of triggered events
only.
For more details read the chapter Wav-File Recording.
6
Format
Choose from the following audio recording formats:
Compressed Compressed audio logging
Compressed+AGC Compressed audio logging with
Automated Gain Control (AGC)
24Bit_48kHz Linear audio logging in 24 bit,
48 kHz resolution. (Required for
post-processing on the PC with
Extended Acoustic Pack)
7
Audio Logging Period
If Log Audio
5
is set to Events Only, then the duration
for the audio recording may be further specified:
Recording
whole event
Records a wav-file for the whole trig-
gered event duration.
Stop recording
after
Records a wav-file for the specified
period after the event start is trig-
gered.
8
Status Information
Displays current trigger status:
• Waiting for trigger
• Armed (during start duration
13
)
• Audio + data recording
• Completing log cycle
9
Actual Level
Measurement result of the defined level
4
.
10
Event Counter
Counts the number of triggered events that have occurred
during the ongoing measurement.
53
Sound Level Meter
11
Trigger and Marker Monitor
Answers the question: What caused the triggered event?
Lvl Event automatically triggered by level.
1 Event triggered or marker added by pressing key 1
of the XL2 Input Keypad.
2 Event triggered or marker added by pressing key 2
of the XL2 Input Keypad.
3 Event triggered or marker added by pressing key 3
of the XL2 Input Keypad.
4 Event triggered or marker added by pressing key 4
of the XL2 Input Keypad.
12
Stop Duration
See
3
.
13
Start Duration
See
2
.
14
Hysteresis
See
3
.
Trigger Events: on external key press
Trigger Events by pressing a button on the external input key-
pad with automated or manual stop of the event.
100
90
80
70
60
Time [seconds]
Event Duration
15
Event Duration
15
key press
Level [dB]
key press
Features:
• The levels L
Aeq
, L
Zeq
and L
CPeak
are recorded for the event
duration.
• Audio data may be recorded for the user-defined event dura-
tion
15
after the key press.
• Retrigger with every repeated key press within the event
duration.
54
Sound Level Meter
15
16
15
Event Stop Mode and Event Duration
on key release The event is recorded as long as the
button of the input keypad is kept
pressed; the Event period is at least
Min. Event Duration long.
on ext. key-
press
The event is stopped by pressing a but-
ton on the external input keypad; the
Event period is at most Max. Event
Duration long.
16
Button Functionality of Input Keypad
treat each key
separately
All four buttons operate individually.
For example pressing the button 2
will be recorded as button 2 in the
measurement report. This allows you
to distinguish different acoustic noise
sources.
treat all keys as
Key 1
All four buttons operate in parallel and
any button press will be recorded as
button 1 in the measurement report.
55
Sound Level Meter
How to Setup the XL2 for Triggered Event Measurements
• Select the logging page, set Logging On, Interval dt:
00:00:01 and choose the required log values.
• Setup the event page. For example, the screenshot below
starts the event recording after L
AF
exceeds 80 dB for 2 sec-
onds and stops after L
AF
is lower than 70 dB for 3 seconds.
• Select the memory menu and create a new folder. This folder
will then be displayed in the memory menu. All log data and
event wav-files are stored in this folder.
The XL2 is ready for the triggered event measurement.
Logging Enabled
Triggered-event recording requires the activa-
tion of sound level logging. Using the default
Interval dt: 1 second is recommended.
Auto Save
If Log Audio
5
is set to Events Only, then
the XL2 sets per default Naming+Saving: auto
in the memory menu. This ensures that the re-
corded triggered event data is stored on the SD
Card.
For convenience, in case more than 20 triggered
events have been recorded, the Autosave ->
Delete function is disabled, as deleting such
multiple wav-files on the XL2 is time-consum-
ing.
Wav-files
All triggered-event wav-files are stored in an in-
dividual folder. For details see chapter Logging.
56
Sound Level Meter
Limits
The limit page offers two functions:
• Setup of limit LED
function; enabling the XL2 to highlight
any sound levels that exceed the pre-set limit in orange or
red color. The default color is green.
• Limit parameter setup for external connected accessories,
such as the Digital I/O Adapter PCB, the Limit Light or the
Stack Light. These accessories connect to the digital I/O in-
terface of the XL2.
1
2
3
8
4
5
6
7
1
Limit LED On/Off
Select Limit LED with the rotary wheel
and press enter
to enable/disable the limit function.
2
LED - Level 1
Select one sound level for the limit LED indication
.
• Select the soun
d level field with the rotary wheel .
• Press enter
and select the sound level for the limit
LED indication.
3
Selected Level Values
To set the level values for the limit LED
,
• Select the Red or Orange soun
d level with the rotary
wheel
and press enter .
• Set the level value with the rotary wheel
and confirm
with enter
.
4
Digital I/O On/Off
Select Digital I/O with the rotary wheel
and press enter
to enable/disable the operation of externally connected
accessories.
57
Sound Level Meter
5
I/O - Level 1
Setup of the level type 1, which is used to trigger externally
connected accessories.
• Select the
level field with the rotary wheel .
• Press enter
and select the level for the control of the
external accessory.
6
Selected Sound Level Values
To set the level values for the control of the externally con-
nected accessory.
• Select the Out 1, Out 2, Out 3 or Out 4
level with the ro-
tary wheel
and press enter . The Limit Light and the
Stack Light use Out 1 for red, Out 2 for yellow and Out
3 for green light.
• Set the level value with the rotary wheel
and confirm
with enter
.
7
I/O - Level 2
Follow the setting for I/O - Level 1. The I/O level 1 may be
combined with I/O level 2 using and/or combinations, pro-
viding indications in level ranges. Alternatively, other levels
can be selected for the control of the externally connected
accessories.
8
LED - Level 2
Follow the setting for LED - Level 1.
I/O Limits with Triggered Events
If event recording is enabled, the digital output
4 (Out 4) is utilized, e.g. as confirmation feed-
back to the XL2 Input Keypad. Therefore the
limit setting of Out 4 is disabled.
58
Sound Level Meter
Correction Value KSET
The correction value page offers a measurement wizard for live
event monitoring, applicable in case the measurement location
differs from the loudest position in the live event area.
Measurement Position
The goal at live event monitoring is to measure the sound level
at the loudest position accessible by the audience. Setting up
any sound level measurement at this loudest location is typi-
cally not practical, thus an alternative measurement position is
chosen. The recommended measurement position in order to
minimize the influence that audience noise has on the mea-
surement:
• Mount the measurement microphone in front of the main
speakers
• Position the XL2 Analyzer at front of house (FOH)
• Connect the XL2 Analyzer and measurement microphone
using a professional audio cable
Positioning the measurement microphone at
front of house (FOH) may result in audience
noise interfering with the measurement results.
The audience noise will be further amplified by
the measured k-values.
2
1
1
Correction k1
The correction k1 is based on the LAeq.
2
Correction k2
Select the level type for correction k2.
LCpeak
for Germany DIN15905-5;
correction is based on LCpeak measurement
LCeq correction is based on LCeq measurement
59
Sound Level Meter
Level Difference
Prior to the start of the live event, the level difference between
the loudest and the measurement position is measured. The
XL2 Analyzer calculates the level difference automatically based
on the individual sound level measurements at both locations.
This level difference is included in the sound level reading dur-
ing the live event, and the XL2 thereby displays and records the
sound pressure level of the loudest point.
XL2 positioned at FOH
Loudest
Audience
Position
Level difference
Measurement
Position
(Microphone)
audience area
How to Measure the Correction Value
• Play a Pink noise signal at the typical sound level of the live
event (signal source: Minirator or NTi Audio Test CD or or
USB Flash Drive)
• Select the correction page
.
• Search the audience area for the location with the highest
sound pressure level and position the XL2 Analyzer.
• Turn the rotary wheel
to select the parameter RUN next
to Audience, select LA, LC or LA&LC and press enter
.
The XL2 measures the sound level at the loudest position
for 15 seconds. The timer counts down to zero.
60
Sound Level Meter
• Wait until the measurement is completed.
• Position the XL2 at the measurement position.
• Turn the rotary wheel
to select the parameter RUN next
to Measure, select LA, LC or LA&LC and press enter
.
The XL2 measures the sound level at the measurement
position for 15 seconds. The timer counts down to zero.
• Wait until the measurement is completed.
• The correction values k1 and k2 are calculated and displayed
including date and time.
61
Sound Level Meter
Manual Setting of Correction Values
You may fine-tune the correction values k1 and k2 manually.
Such fine-tuning adds the remark “Manually Adjusted” in the
log file.
2
3
1
• Turn the rotary wheel to select the correction value
3
and press enter
.
The selected correction value starts flashing.
• Set the correction value with the rotary wheel .
The note “Manually Adjusted” is displayed at
2
.
• To undo the manual setting turn the rotary wheel
to select
the parameter UNDO at
2
.
• Confirm with enter
.
Reset Correction Values
You may clear all correction values back to zero
by pressing the Clear All
1
and confirm with
enter
.
Display k1 and k2 during Measurement
The correction values k1 and k2 can be dis-
played in the numeric result page during the on-
going sound level measurement instead of any
other sound levels.
Correction Values in Profiles
The correction values k1 and k2 can optionally
be stored within profiles. Loading the profile,
sets the stored correction values.
62
Sound Level Meter
Locked Run Mode
The Locked Run Mode simplifies sound level monitoring. You
just need to power up the XL2 and the measurement starts
automatically. The measurement continues until you switch off
the instrument using the power button
. The measurement
data is stored by default.
Start Locked Run Mode
• Set the required parameters in the sound level meter for
your noise monitoring application.
• Press and hold the start/stop button
for 3 seconds.
The Locked Run Mode is now activated. The Run Indicator
1
displays L. The Info window is displayed at the same
time.
• Switch off the instrument.
The measurement is stopped and the data is saved.
• Switch on the instrument.
The sound level measurement starts automatically and
continues as long as the device is powered on.
• The page button
allows toggling between the sound lev-
el meter and real time analyzer window. All other buttons are
deactivated during Locked Run Mode.
1
End Locked Run Mode
• Press and hold the start/stop button
for 3 seconds during
the ongoing measurement.
The measurement is stopped and the Locked Run Mode
deactivated.
63
Sound Level Meter
64
FFT Analysis + Tolerance
5. Acoustic Analyzer
Besides the comprehensive sound level meter functions, the
XL2 Audio and Acoustic Analyzer offers the following acoustic
measurement functions:
• FFT Analysis with optional tolerance function
• Reverberation Time
• Polarity
• Delay time
• 1/12 Octave + Tolerance Analysis (optional)
• Noise Curves (optional)
• Speech intelligibility STIPA (optional)
FFT Analysis + Tolerance
The FFT measurement is the ideal tool for visualization of comb
filters and narrow band effects. It allows a detailed frequency
response investigation of audio and acoustic systems. The XL2
includes an extremely fast, real-time FFT. Optional features
are
• High-resolution Zoom-FFT up to 0.4 Hz steps in the fre-
quency range 5 Hz - 20 kHz provided with optional Extended
Acoustic Pack or the Spectral Limits Option
• Capture and tolerance function provided with Spectral Limits
Option; thus the main menu function reads FFT + Tol.
65
FFT Analysis + Tolerance
13
2
4
11
1
5 7
8
9
6
12
14
10
3
1
Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:
• Symbols for measurement results
2
Upper result displayed as line.
Lower result displayed as bargraph.
• Capture & Start Tolerance Mode
The displayed readings may be captured as reference
reading C1 to C8 for
• Comparing measurement results against captured
traces with relative or absolute curve display.
• Creating tolerance masks based on captured refer-
ence curves for passed / failed measurements.
Capture EQ Captures the upper parameter
Capture Live Captures the lower parameter
66
FFT Analysis + Tolerance
3
Y-Scale setting
• Select the Y-Axis with the rotary wheel
and confirm
with enter
.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter
.
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter
.
4
Measurement Result
Displays the actual and averaged measurement results.
5
Input Range
The XL2 Analyzer provides three input ranges to accom-
modate the wide range of input signals. The individual rang-
es are based on the microphone sensitivity setting in the
calibration menu of the XL2. For example at a sensitivity
S=20mV/Pa the input ranges are
• Lower range: 10 - 110 dBSPL
• Middle range: 30 - 130 dBSPL
• Upper range: 50 - 150 dBSPL
Select the lowest possible input range according to the
maximum level expected during the measurement; e.g., if
the sound pressure will be always below 110 dBSPL, then
select the lowest input range 10 - 110 dBSPL.
Manage
captures
Allows to rename captures, clear re-
corded captures, save captures to the
SD Card for export from the XL2 or
load captures from the SD Card for im-
port to the XL2.
Start tolerance
mode
Starts the tolerance mode for passed/
failed measurements comparing the
actual measurement results against a
tolerance band.
2
Measurement Result
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band indicated by the arrow.
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
67
FFT Analysis + Tolerance
6
Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 sec-
ond as well FAST (125 ms) and SLOW (1 second). Applica-
tions:
Short Time
Weighting
High-resolution in time with minimum
averaging
Long Time
Weighting
Low resolution in time with longer aver-
aging
7
Run Indication
The run indication shows the measurement status running,
paused or stopped. Various measurement settings are
locked during ongoing measurements, such as changing
the input ranging or the preset measurement time.
For passed/failed measurements with the Spectral Limits
option the run indication may display A for a preset auto-
mated level trigger.
8
Actual Measurement Time
Counts actual measurement time in hrs:min:sec. Supports
setting of time modes: continuous and single.
Timer Mode Continuous
(applicable for standard measurements)
All values are recorded and monitored continu-
ously after starting a measurement with start
.
The actual measurement time is shown.
Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement
.
9
Preset Measurement Time
Adjustment of preset measurement time for single timer
setting.
68
FFT Analysis + Tolerance
10
Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the highest level,
e.g. tracing feedback frequencies at live sound.
• Select the frequency with the rotary wheel
.
• Press enter
.
• You may readout any individual frequency.
• Return to auto frequency with enter
.
The cursor returns to the frequency with high-
est level bar.
The cursor readout may be set manually to any
frequency. The readout remains at the selected fre-
quency.
• Select the frequency with the rotary wheel
.
• Press enter
.
• Select the frequency of interest.
• Confirm with enter
.
The cursor readout
2
displays the measure-
ment results of the selected frequency band.
11
Zoom Mode
(optional, applicable with the Extended Acoustic Pack or
the Spectral Limits Option)
• Select the readout frequency
10
and press enter
.
• The zoom mode is displayed above the flashing arrow.
• Select the zoom-in frequency with the rotary wheel
.
• Press limit
and zoom the linear frequency scale in or
out with the rotary wheel
.
• Release limit
and scroll the linear frequency scale left
or right with the rotary wheel
.
12
Phantom Power Supply
48V The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.
ASD An NTi Audio measurement microphone with
automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of
the microphone and switches the 48 V Phan-
tom power automatically on
48V Phantom power is switched off.
69
FFT Analysis + Tolerance
13
Measurement Unit
Select the measurement unit as follows:
dB Sound level in dBSPL
This measurement unit is permanently selected
upon connecting a NTi Audio measurement mi-
crophone with electronic data sheet.
dBu Input level in dBu
dBV Input level in dBV
V Input level in Volt
14
Page Selector X-Scale and Parameter Setting
20k Shows FFT result of the frequency band range.
484.38 Hz - 20.453 kHz in a resolution of
140.62 Hz with 143 bins shown on the display.
1k7 Shows FFT result of the frequency band range.
58 Hz - 1.722 kHz in a resolution of 11.72 Hz with
143 bins shown on the display.
200 Shows FFT result of the frequency band range.
7 Hz - 215.01 Hz in a resolution of 1.46 Hz with 143
bins shown on the display.
Usr User Range
(applicable with optional Extended Acoustic Pack
or Spectral Limits Option)
5 Hz - 20 kHz in zoom mode with a minimum reso-
lution of 0.366 Hz and 143 bins displayed.
Set Selection for FFT Windowing:
• Hann: Default for acoustic measurements
• Dolph-Chebyshev: for analyzing small signals
(e.g. harmonics) close to a dominant signal.
The page button
switches these display modes.
70
FFT Analysis + Tolerance
FFT Analysis - Getting Started
Test Preparations
• Connect the measurement microphone to the XL2.
• Switch on the XL2
.
The 48 V Phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
• Position the XL2 at the measurement location using a micro-
phone stand or tripod.
Configuration
The XL2 displays two different sound pressure levels at the
same time. You configure to display either the levels Live,
Max, Min, EQ or captured results.
• Select the upper result parameter with the rotary wheel
.
• Confirm with enter .
71
FFT Analysis + Tolerance
Select Upper/Lower Reading
The pop-up window Select reading appears.
• Select the integrated averaged reading EQ. All available se-
lections are Z-weighted (= no weighting).
• Confirm with enter .
The pop-up window Select reading mode appears.
• Select EQ for normal absolute display of measurements.
• Follow the same instruction and select the lower FFT read-
ing Live.
Press start to measure and display the
sound levels results indicated with ----.
72
FFT Analysis + Tolerance
Select Input Range
• Select the lowest possible input range according to the maxi-
mum level expected during the measurement.
• Select the input range RNGE and press enter
.
• Turn the rotary wheel
to set the applicable input range and
confirm with enter
.
Start Measurement
• The XL2 measures the selected sound pressure lev-
els Live and EQ. All available sound levels are
Z-weighted (= no weighting).
• Press start
.
The run indication switches to running . The actual sound
level Live and the averaged level EQ are displayed. The pa-
rameter RUN flashes in the memory menu.
73
FFT Analysis + Tolerance
Stop Measurement and Data Saving
• Press stop
.
The XL2 stores the measurement data automatically.
• Press enter to confirm. The measurement data is stored
on the SD Card in ASCII format.
The measurement is completed.
Audio Recording
The XL2 Analyzer may record a linear audio file (48 kHz, 24 Bit)
of the measurement period together with the FFT data. Just
load a txt-file named “fftaudio.txt” in the root directory of the
XL2. This requires the installed option Extend Acoustic Pack.
Capture References and Create Tolerances
The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high-
resolution 1/12 Oct + Tol spectral analysis.
Features:
• Captures multiple traces in the internal memory
• Comparing measurement results against captured traces
with relative or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captured reference
curves for passed / failed measurements
• Export and import of tolerance and capture files
• True peak level in 1/1 and 1/3 octave resolution
• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequen-
cy range 5 Hz - 20 kHz
Read the detailed description in the separate chapter
Capture + Tolerance.
74
Reverberation Time RT60
Reverberation Time
The XL2 measures the energy decay from 63 Hz to
8 kHz using the Schroeder method in 1/1 octave resolution. The
optional Extended Acoustic Pack enables 1/3 octave band reso-
lution from 50 Hz to 10 kHz. Use either an impulse source (e.g.,
a starter pistol) or an interrupted pink noise as the test signal.
What is Reverberation Time?
Reverberation time is the time required for the sound pres-
sure level to decrease by 60 dB after the sound stimulus signal
is stopped. For simple practical measurements the applicable
standard ISO 3382 and ASTM E2235 specifies the following
two measurement methods:
• T20
- The measurement requires just a small dynamic measure-
ment range of ~35 dB above the ambient noise level for
each frequency band.
- RT60 (T20) = 3 x decay time of 20 dB
• T30
- The measurement requires a dynamic measurement
range of ~45 dB above the ambient noise level for each
frequency band.
- RT60 (T30) = 2 x decay time of 30 dB
In detail, the reverberation time is based on a linear least-
squares regression of the measured decay curve. If the
overall reverberation time is short (e.g. < 0.3 seconds)
the room acoustic is referred to as being “dead”; for ex-
ample, a heavily furnished room with thick carpets, cur-
tains and upholstered furniture may have such an acous-
tic character. If the overall reverberation time is long (e.g. >
2 seconds) the room acoustic is referred to as being “live” and
echoic; for example, a large empty room with painted plaster
walls and a tiled floor may have such an acoustic character.
Level [dB]
0 dB
-5 dB
-25 dB
-35 dB
Time
distance to
noise floor
20 dB level range to
obtain the reverbera-
tion time
Reverberation Time Measurement with T20 method
75
Reverberation Time RT60
RT60 Run Test Page
2
7
1112
5
4
3
1
6
8
9
10
RT60 Result Page
13
15
16
18
17
14
76
Reverberation Time RT60
RT60 Cycle Result Page
20
22
21
19
1
Set Level Markers
Prior to conducting a reverberation time measurement, the
environmental noise is measured, and the required energy
level of the test signal is determined.
• Select SET and press enter
to measure the actual en-
vironmental noise.
The required level markers appear in grey color.
2
Input Range
Select between the lower, mid and upper input range. The
exact ranges depend on the microphone sensitivity setting
in the calibration menu of the XL2.
3
Run Indication
This icon displays the running and stop status of the rever-
beration time measurement. It is controlled by start/stop
.
77
Reverberation Time RT60
4
Measurement Status STAT
Displays the actual measurement status. Start and stop the
reverberation time measurement with start/stop
. The
following status information is displayed:
ARMED Measurement is waiting for the test signal
to exceed at least one measurement trigger
marker, then the measurement is triggered
automatically.
NOISE A sound stimulus signal above the trigger
marker is being received.
DECAY Decay is being measured.
PAUSE The measurement has been paused by press-
ing pause
.
STOP No Reverberation time measurement is pres-
ently being performed.
5
Average AVRG
Counts the measurement cycles. When using an interrupt-
ed noise test signal, a minimum of 3 sequential cycles is
recommended.
6
Actual Real-Time Spectrum
The black bars indicate the actual signal, including back-
ground noise. While setting up the reverberation time mea-
surement you should increase the test signal level until the
black bars exceed the grey bars completely and the status
4
displays NOISE.
7
Level Marker
The grey bars indicate the signal level required for effective
reverberation time measurements in each octave band.
The marker has a length of 35 dB, and can be set by
• Selecting SET
1
with the rotary wheel
.
• Press enter
to measure the environmental noise in
the silent room.
8
Band Status
Indicates a successful reverberation time measurement
above each octave band with a tick
.
9
Measurement Method
Select between the measurement methods T20 and T30.
T20 requires just a small dynamic measurement range of
~35 dB above the ambient noise level for each frequen-
cy band. T30 requires a dynamic measurement range of
~45 dB.
78
Reverberation Time RT60
12
Page Selector
Select between the RT60 run test page and the result page.
The page button
toggles between these displays.
RT60 run test page
RT60 result page. Toggle with the measurement
result selection
18
among
AVRG RT60 result page showing average
of all cycles and uncertainty factor
CYC xx RT60 result page for each cycle
Last RT60 result page for last cycle
14
Y-Axis Reverberation Time
Reverberation time in seconds. The scaling is automatically
adjusted.
10
Measurement Resolution
Reverberation time measurement selectable in 1/3 oc-
tave or 1/1 octave band resolution. The optional Extended
Acoustic Pack enables 1/3 octave band resolution from
50 Hz to 10 kHz.
11
Phantom Power Supply
48V The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.
ASD An NTi Audio measurement microphone with
automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of
the microphone and switches the 48 V Phan-
tom power automatically on
48V Phantom power is switched off.
79
Reverberation Time RT60
14
Uncertainty Factor
The uncertainty factor is displayed in the RT60 average re-
sult page. It indicates the uncertainty of the averaged mea-
surement results, reduces as more cycles are measured,
and depends on the measured reverberation time and the
bandwidth of the individual frequency band; lower bands
show a higher uncertainty factor. The number of measure-
ment cycles is displayed at
5
.
15
Overall Reverberation Time Test Result
Readout of reverberation time and uncertainty factor.
Uncertainty factor. For more details see
14
.
Reverberation time measurement results.
16
X-Axis
Octave Bands 63 Hz - 8 kHz
17
Cursor Readout
Select the individual frequency band and read out the fol-
lowing numeric measurement results
• Uncertainty factor in % or correlation in %.
• Reverberation time RT60 (T20), of the selected frequen-
cy band, in seconds (s).
18
Measurement Result Selection
The reverberation time measurement function allows con-
secutive measurements within one test sequence. An
averaged test result of all measurements is automatically
calculated.
Select CYC and scroll with the rotary wheel
through the
individual test result cycles showing
Last Last Test Result
Displays the result of last measurement cycle.
xx Single Test Cycle Results
The individual single test results are marked
with CYC xx, where xx is an incriminating num-
ber. You may delete individual test results. The
averaged reverberation time result uses only the
remaining valid measurements. To delete results
in a cycle,
• Select DEL with the rotary wheel
• Confirm with enter .
AVRG Averaged Test Result
The averaged test results of all cycles are calcu-
lated and displayed.
80
Reverberation Time RT60
19
Correlation Factor in %
The correlation factor is 100% for perfectly linear sound
pressure level decay after the sound source has ceased.
The natural deviation from this linearity results in lower
correlation values. The correlation factor is typically 80 -
100%.
20
Cycle Reverberation Time Test Result
Readout of cycle reverberation time and correlation factor
19
when selection
18
is CYC xx or Last.
Correlation Factor. Scale is on the right Y-axis. For
more details see
19
.
Reverberation time measurement result of individ-
ual displayed cycle. Scale is on the left Y-axis.
21
Y-Axis Correlation Factor
The right Y-axis shows the correlation factor in %. The cor-
relation factor Y-axis is displayed when test result selection
18
is CYC xx or Last.
22
Delete Cycle Results
Individual cycle results may be deleted, thereby excluding
them from the calculation of the AVRG result.
Test Signals
Use either an interrupted pink noise or an im-
pulse source as the test signal.
• Interrupted pink noise
Precision measurements require an omni-di-
rectional speaker with identical radiation char-
acteristic in all directions. Various interrupted
pink noise test signals with different on/off
times are offered on the NTi Audio Test CD
or USB Flash Drive (included with the XL2) or
the Minirator signal generator. Test signals are
available for download at https://my.nti-audio.
com/support/xl2. A minimum of three mea-
surement cycles shall be performed. The XL2
averages these readings automatically.
• Impulse
The trigger signal is an impulse source, such
as a starter pistol, starter clap or bursting bal-
loon. Individual measurements, or test se-
quences with repeated trigger signals, can be
carried out.
81
Reverberation Time RT60
RT60 Measurement - Getting Started
Test Signal: Pink Noise
Play a pink noise signal through an omnidirectional speaker
in the room under test. The sound source should be played
for a long enough time period to ensure that a balance be-
tween injected and absorbed acoustic energy has been
reached. For example the sound reflections should be given
enough time to reach all reflective surfaces in the room. As
a rule of thumb, ensure that the pink noise is played for at
least the time period of the estimated reverberation time
test result. If in doubt, play the Minirator MR-PRO, the Test
Signal CD or or USB Flash Drive as sound source for at least
5 seconds for each cycle. Each time the source signal stops,
the XL2 recognizes this interruption, triggers, measures the
decay time and calculates the reverberation time automatically.
A minimum of three measurement cycles shall be performed.
Test Signal: Impulse
Fire an impulse sound source in the room under test, e.g. use
a starter pistol, starter clap or bursting balloon. The XL2 mea-
sures the decay time and calculates the reverberation time au-
tomatically.
Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
Phantom power automatically on as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2
.
The 48 V Phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
• Position the XL2 at the measurement location using a micro-
phone stand or tripod.
• Select the RT60 function in the measurement menu and
toggle with page
to the run page RUN.
• Prepare the environment for the measurement. For example
mute all sound sources to establish silence.
82
Reverberation Time RT60
Set Level Markers
• Select the parameter SET with the rotary wheel
and
press enter
.
The environmental noise is measured and the grey level
markers are set.
Get Ready for the Reverberation Time Measurement
• Protect the ears against high sound pressure levels, as the
test signals might be very loud.
Setting the pink noise level:
• Start the pink noise test signal with the appropriate on/off
time according to the room. Use an initial low level.
• Increase the test signal level until all level markers for the
minimum test signal level are passed. Use an equalizer to
push individual band levels.
• Switch off the interrupted pink noise signal after you have
finished setting the pink noise level.
83
Reverberation Time RT60
Start the Measurement
• Press start
. The status indication switches to ARMED.
• Enable the test signal; e.g., switch on the interrupted pink
noise signal or fire a starter pistol.
• The black bars have to exceed the grey bars completely.
Continue the Measurement
Using pink noise:
The interrupted pink noise test signal continues with the pre-
set on/off time. The XL2 automatically triggers at each cycle.
Complete a minimum of three test cycles to accurately calcu-
late the uncertainty factor. Perform more cycles to increase the
measurement accuracy (= smaller uncertainty factor).
Using an impulse source:
A single impulse at one measurement location is sufficient. No
further measurements are required to increase the statistical
measurement accuracy.
Confirmation marks indicating success-
ful measurements, are displayed above each
band.
84
Reverberation Time RT60
Stop the Measurement and Read Out the Result
• Press stop
.
• If applicable, switch off the pink noise test signal.
• Select the result page RES with page
.
The average reverberation time for each fre-
quency band is displayed in seconds and the
measurement uncertainty in %.
•
•
•
•
Read Out the Individual Cycle Result
• If multiple cycles have been recorded, then select CYC with
the rotary wheel
, press enter and select the individual
cycle result with the rotary wheel
.
Within each cycle, the reverberation time for
each frequency band is displayed in seconds
and the correlation factor in %.
•
•
•
•
•
•
•
•
•
•
•
•
The reverberation time measurement is completed.
85
Reverberation Time RT60
Measurements with multiple source and microphone posi-
tions
Room resonances may be applicable at individual measure-
ment positions. Thus, perform reverberation time measure-
ments at further positions within the room and average all
readings.
Overload Indication
In case the measurement result exceeds the preset measure-
ment range, then limit arrows
indicate this overload condi-
tion.
Possible causes for exceeding measurement ranges are
• The measured sound pressure level exceeds the pre-set
measurement range -> select the next higher measurement
range or reduce the input signal level as applicable.
• The input level is near the maximum level of the connected
NTi Audio measurement microphone.
In case the level cannot be reduced (e.g. using a gun as signal
source) then the overload condition can be skipped by storing
a text-file with the filename “RT60allowOVLD.txt” on the XL2
main directory.
Error Indications
Various error indications are displayed for unsuccessful rever-
beration time measurements. Corrupt cycles can be deleted
individually. These results are then excluded from the average
calculations.
• LOW LEVL
This is the abbreviation of “low test signal level” during the
measurement. Increase the test signal level until the black
level markers exceed the grey level markers in every fre-
quency band. Also, ensure that the level falls below the grey
level markers, otherwise use a reverberation time test signal
with longer on/off times.
• T>18S
The measured reverberation time exceeds the time limit of
18 seconds. This is commonly caused by either an incorrect
analyzer range setting or environmental noise. In the first
case, choose another range setting. In the second case, en-
sure that the environmental noise remains constant during
the measurement, and/or SET the level markers again while
the environmental noise is high.
86
Polarity
Polarity
Polarity measurement is important in matching the left and
right speakers for a good stereo sound image. The polarity
function measures the polarity of cables, single speakers and
speaker cabinets. For testing, use the polarity signal provided
on the Minirator test signal generator, the NTi Audio Test CD or
USB Flash Drive.
The polarity of individual speakers or speaker cabinets might
change with the frequency. For example, the mid-range speak-
er polarity may differ from the woofer polarity within the same
speaker cabinet. Therefore, the polarity detailed result page of
the XL2 displays the measured polarity of the individual octave
bands from 125 Hz to 8 kHz. This allows in-depth verification of
the polarity - frequency relationship.
• Polarity is a simple test within the very com-
plex science of signal phasing. Drivers, speak-
ers and crossovers all cause phase shifts of
the audio signal.
• The polarity of various speakers within the
same cabinet may differ by design!
• Polarity testing is useful for checking the cor-
rect wiring of similar speaker systems.
Positive/Negative Result Page
1
2
4
3
87
Polarity
Detailed Result Page
6
5
10
9
7
8
Polarity result for Minirator
connected directly to XL2 Analyzer
1
Input Selection
Select the signal source as follows:
• Select Signal Source with the rotary wheel
.
• Press enter
to select either
Voice
Note
Mic
Use the internal voice note microphone of the
XL2 for polarity measurements. This selection
disables the rear speaker.
XLR
Input
Measure the acoustic polarity with a measure-
ment microphone. Alternatively, measure the
polarity of an electrical signal connected with
an XLR audio cable.
RCA
Input
Measure the polarity of an electrical signal con-
nected with an RCA audio cable.
2
Polarity Test Result
Displays either POSITIVE, NEGATIVE or ??? (=undefined).
For further visual indication, the limit button
illuminates
green for POSITIVE and red for NEGATIVE polarity.
3
Level RMS
Measures the absolute level of the input signal. The unit’s
dBu, dBV and V are selectable.
88
Polarity
4
Balance Indicator
Indication of the audio signal balance between pin 2 and 3
on the XLR input for input signals > -34 dBu.
The input signal is balanced.
The signal is unbalanced. The level of pin 2 is
higher than pin 3.
The signal is unbalanced. The level of pin 3 is
higher than pin 2.
5
Relative Level Indicator
The grey area shows the measured signal energy within
the individual frequency bands. The bands with the biggest
energy have the most effect on the actual displayed POSI-
TIVE / NEGATIVE polarity result.
6
Polarity Indication
+ Polarity of frequency band is positive. The polarity re-
sult is in the upper display area; the + area.
- Polarity of frequency band is negative. The polarity
result is in the lower display area; the - area.
7
X-Axis
Seven octave bands with center frequencies from
125 Hz to 8 kHz. SUB displays the polarity of Sub-woofers;
frequency range < 100 Hz.
8
Negative Polarity Area
Measurement results area with negative polarity (-). The
black line in the middle of relative level indicator
5
displays
the measured polarity of the individual frequency band. The
dashed line indicates the lower limit of the measurement
result area.
9
Uncertain Polarity Area ???
Polarity results for frequency bands in this area are uncer-
tain. Therefore, the polarity result ??? is displayed.
10
Positive Polarity Area
Measurement results area with positive polarity (+). The
black line in the middle of relative level indicator
5
displays
the measured polarity of the individual frequency band. The
dashed line indicates the upper limit of the measurement
result area.
89
Polarity
Polarity Measurement - Getting Started
For acoustic polarity measurement you can use the internal
voice note microphone, or an external measurement micro-
phone, plugged into the XLR input. The polarity result for left
and right speaker cabinets should match for a good stereo
sound image.
• Feed the speaker cabinet with the polarity test signal of the
Minirator.
• Adjust the test level (at Minirator or amplifier) until the test
signal is clearly heard.
• Enable the polarity test signal at the left speaker cabinet;
mute the right speaker cabinet.
• To activate the internal microphone, select Signal Source
with the rotary wheel
and choose Voice Note Mic with
enter
.
• Measure the polarity of the left speaker cabinet and save the
screenshot in the memory menu
.
• Enable the polarity test signal at the right speaker cabinet;
mute the left speaker cabinet.
• Measure the polarity of the right speaker cabinet.
• Compare the polarity test result of both speaker cabinets.
The polarity measurement is completed.
The sample result shows the polarity as:
• Sub-woofer: Low energy, no sub installed
• Woofer: Positive
• Mid-range: Negative
• Tweeter: Positive (with small levels)
The major part of the signal energy is measured
in the mid-range frequency bands. Therefore,
the overall displayed polarity is NEGATIVE.
90
Delay Time
Delay Time
The delay time measurement function is suitable for accurate
configuration of delay line setups, by optimizing the direction-
ality of the signal source. The XL2 measures the delay time
between the reference signal and the acoustic signal from the
speaker. The acoustic delay settings are displayed, allowing you
to easily set the measured delay time into the delay device in
the rack. The NTi Audio delay time test signal is provided either
by the Minirator MR-PRO, MR2 or the NTi Audio Test CD / USB
Flash Drive included with the XL2.
2
1
3
4
5
6
7
1
Delay Signal Source
Select the signal source for the delay measurement:
CD Player Using the NTi Audio Test CD; this set-
ting implies the synchronization time bar
is set to 100 seconds = 1 min. 40 sec.;
after 100 seconds the XL2 has to be syn-
chronized to the delay test signal again.
Minirator The Minirator MR-PRO and MR2 provides
a more reliable test signal source than a
CD player. Therefore, the XL2 offers an ex-
tended time range without synchronization.
Only after 300 seconds (5 minutes) does
the XL2 have to be synchronized to the de-
lay test signal again.
2
Store Button
Press the store button to record the actual delay
7
of the
reference speaker.
3
Reference Delay Time
Individually-stored delay time of reference speaker.
91
Delay Time
4
Calculated Distance
Distance from measurement position to speaker in meters
or feet, based on the defined temperature in °C or °F
5
Synchronization Time Bar
The automated synchronization allows delay time mea-
surements without any connected electrical reference
signal for 100 seconds using the NTi Audio Test CD / USB
Flash Drive or 300 seconds using the Minirator, MR2 or
MR-PRO. It displays the time remaining until the next re-
quired synchronization.
6
Calculated Delay Time: Store - Actual
Calculated difference between delay time of speaker A and
speaker B as shown on the next page. The automated dif-
ference calculation simplifies the verification of delay line
arrangements, such as those used in larger halls or audi-
toriums.
7
Actual Delay
Actual measured delay time referring to the electrical refer-
ence signal.
Delay Test utilizes VoiceNote Microphone
The XL2 uses the internal VoiceNote micro-
phone to measure the acoustic delay. Do not
connect any measurement microphone to the
XL2 for the delay time measurement.
Rear Speaker
The rear speaker on the XL2 is disabled during
delay measurements, thereby avoiding mea-
surement failures. The headphone output is ac-
tive.
92
Delay Time
Delay Measurement - Getting Started
The delay time measurement is conducted between the syn-
chronized electrical input signal and the acoustic signal mea-
sured by the built-in voice note microphone. In this example,
the delay between speakers A and B in the illustrated audito-
rium is measured.
lecturer
speaker A
front left
speaker
front right
speaker B
sub left
speaker
sub right
measurement
position
Test Preparations
• Prepare the delay test signal; use either the
• NTi Audio Test CD or USB Flash Drive
• NTi Audio Minirator for analog systems
• NTi Audio Digirator for digital or Dolby/DTS systems
• Start the delay test signal.
• Connect the generated delay test signal with an audio cable
to the RCA or XLR input of the XL2, e.g. take the reference
signal from an auxiliary channel of a mixing console.
• Select XLR or RCA input in the upper XL2 menu
• Set the actual environment temperature, to ensure that the
distance is displayed correctly later.
93
Delay Time
• Wait until the XL2 synchronizes to the incoming delay test
signal, then the synchronization time bar fills up.
• Disconnect the audio cable, with the synchronizing signal,
from the XL2, allowing you to move around freely for the
delay measurement. When selecting Minirator as the delay
signal source, the XL2 has to be synchronized to the signal
source again after 5 minutes. When selecting CD Player as
the delay signal source, the XL2 has to be synchronized to
the signal source every 100 seconds.
Measure Reference Speaker A
• Start the delay test signal at speaker A, mute speaker B.
• Position yourself with the XL2 at the measurement position
next to speaker B sub left as indicated above. This is the
worst-case position in the auditorium with regard to acoustic
delay in the sound field. The XL2 uses the VoiceNote micro-
phone for the delay test; do not connect any measurement
microphone.
The XL2 measures the delay time of speaker A in reference
to the electrical input signal in milliseconds.
94
Delay Time
Store Reference
• Select the displayed 0.0 ms below Act. Delay with the rotary
wheel
and press enter .
The reference result of speaker A is stored for the differ-
ence calculation of delay A - B.
• Stop the delay test signal at speaker A.
Measure Sub Speaker B
• Start the delay test signal at speaker B. Mute speaker A.
• Position yourself with the XL2 at the shown measurement
position. The XL2 uses the VoiceNote microphone for the de-
lay test; do not connect any measurement microphone.
The XL2 measures the delay time of speaker B in reference
to the electrical input signal in milliseconds.
95
Delay Time
Automated Difference Calculation
• The delay time difference between speaker A and B is
automatically calculated and shown below the Act. Delay
result.
The delay time is measured.
Delay Test utilizes VoiceNote Microphone
The XL2 uses the internal VoiceNote micro-
phone to measure the acoustic delay. Do not
connect any measurement microphone to the
XL2 for the delay time measurement.
Measurement Position
Do not position the XL2 too close to reflecting
surfaces, such as walls or floors. The reflections
are likely to prevent accurate measurements.
Result Interpretation
• The resulting time in milliseconds shows
the time difference of the sound signal from
speaker A and B arriving at the measurement
position. Speaker B has to be delayed by the
displayed difference result.
• To optimize directionality, add a further 5 ms
to the calculated difference. The main signal
from speaker A then arrives at the measure-
ment position first. The acoustic signal from
sub speaker B arrives 5 ms later. This im-
proves the subjective directionality percep-
tion of the listeners.
Distance in meter/feet
The distance results in meter/feet are displayed
below for easy verification of the test results
accuracy. The readings are based on 330 m/s
sound speed at 0°C / 32°F.
96
1/12 Octave + Tolerance
1/12 Octave + Tolerance (optional)
The Spectral Limits Option extends the XL2 function range
with an RTA analyzer with spectral resolutions from 1/1 octave
down to 1/12th octave. Trace capturing, relative curve display
and comprehensive tolerance handling are supported in the
FFT Analysis and the high-resolution 1/12 Oct + Tol spectral
analysis.
Features
• High-resolution RTA function “1/12 Oct + Tol” with select-
able 1/1, 1/3, 1/6 and 1/12 octave spectral resolution
• Capturing of multiple readings into the internal memory
• Comparing measurement results against captures with rela-
tive or absolute curve display
• Comprehensive tolerance handling with tolerance masks
based on captures for passed/failed measurements
• Export and import of tolerance and capture files
• Frequency band listening at rear speaker
Applications
• PA-rental: Verifying the frequency response of returned
speakers and microphones against reference records ensur-
ing they are back in stock in good working condition.
• Industrial quality testing: Passed/Failed test in the production
line or during service of any audible quality criteria, such as
with motors, machines, vacuum cleaners, ...
• Cinema: Comparing frequency responses against an ideal
response curve according the X-Curve requirements.
Tolerance Handling
The XL2 Analyzer compares spectral measurements against a
tolerance band and visualizes exceptions in every frequency
band. The passed/failed condition is further visualized by the
limit button
and forwarded to the I/O interface of the instru-
ment in order to drive an external alarm device such the acces-
sory SPL Stack Light.
Tolerance curves can either be imported from txt-files or direct-
ly derived from captured measurements. The XL2 calculates
tolerance bands based on
• Single captured results
• Manually generated txt-files on the PC
• Mean average of multiple captures
• Min/Max curves of multiple captures
97
1/12 Octave + Tolerance
2
4
12
1
5 7
8
9
6
13
11
3
10
14
1
Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:
• Symbols for measurement results
2
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
• Capture & Start Tolerance Mode
The displayed spectral readings may be captured in C1
- C8 for
• Comparing measurement results against captures
with relative or absolute curve display.
• Creating tolerance masks based on captures for
passed / failed measurements.
Capture EQ Captures the upper parameter
Capture Live Captures the lower parameter
Manage
captures
Allows to rename captures, clear record-
ed captures, save captures to the SD
Card for export or load captures from the
SD Card for import to the XL2.
98
1/12 Octave + Tolerance
Start tolerance
mode
Starts the tolerance mode for passed/
failed measurements comparing the
actual measurement results against a
tolerance band.
2
Measurement Result
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band indicated by the arrow.
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
3
Y-Scale setting
• Select the Y-Axis with the rotary wheel
and confirm
with enter
.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter
.
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter
.
4
Spectral Measurement Result
Spectral results in 1/1, 1/3, 1/6 or 1/12 octave band resolu-
tion. Adjust the resolution at
12
.
5
Input Range
The XL2 Analyzer provides three input ranges to accom-
modate the wide range of input signals. The individual rang-
es are based on the microphone sensitivity setting in the
calibration menu of the XL2. For example at a sensitivity
S=20mV/Pa the input ranges are
• Lower range: 10 - 110 dBSPL
• Middle range: 30 - 130 dBSPL
• Upper range: 50 - 150 dBSPL
Select the lowest possible input range according to the
maximum level expected during the measurement; e.g., if
the sound pressure will be always below 110 dBSPL, then
select the lowest input range 10 - 110 dBSPL.
6
Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 second
as well FAST (125 ms) and SLOW (1 second). Applications:
Short Time
Weighting
High-resolution in time with minimum
averaging
Long Time
Weighting
Low resolution in time with longer aver-
aging
99
1/12 Octave + Tolerance
7
Run Indication
The run indication shows the measurement status running,
paused or stopped. Various measurement settings are
locked during ongoing measurements, such as changing
the input ranging or the preset measurement time.
For passed/failed measurements with the Spectral Limits
option the run indication may display A for a preset auto-
mated level trigger.
8
Actual Measurement Time
Counts actual measurement time in hrs:min:sec. Supports
setting of time modes: continuous and single.
Timer Mode Continuous
(applicable for standard measurements)
All values are recorded and monitored continu-
ously after starting a measurement with start
.
The actual measurement time is shown.
Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement
.
9
Preset Measurement Time
Adjustment of preset measurement time for single timer
setting.
10
Broadband Results
User-selectable display of broadband results:
Broadband A A-weighted level
Broadband C C-weighted level
Broadband Z without any frequency weighting
- none
Sum of
bands
Sum of displayed frequency bands (only
available when #HideUnusedBands is
set to True within the tolerance file)
100
1/12 Octave + Tolerance
11
Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor automatically follows the highest level,
e.g. tracing live performance feedback frequencies
• Select the frequency with the rotary wheel
.
• Press enter
.
• You may read out any individual frequency.
• Return to auto frequency with enter
.
The cursor returns to the frequency with high-
est level bar.
The cursor readout may be set manually to any
frequency band or wideband level. The readout re-
mains at the selected frequency.
• Select the frequency with the rotary wheel
.
• Press enter
.
• Select the frequency of interest.
• Confirm with enter
.
The cursor readout
2
displays the measure-
ment results of the selected frequency band.
12
Setting of Test Result Resolution
Set the spectral result display to 1/1, 1/3, 1/6 or 1/12 octave
band resolution as follows:
• Turn the rotary wheel
to select the parameter
12
.
• Press enter
to open the selection window.
• Turn the rotary wheel
to select 1/1 OCT, 1/3 OCT,
1/6 OCT or 1/12 OCT
• Press enter
to confirm.
13
Phantom Power Supply
48V The XL2 provides 48 V Phantom power sup-
ply to the microphone or sensor.
ASD An NTi Audio measurement microphone with
automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of
the microphone and switches the 48 V Phan-
tom power automatically on.
48V Phantom power is switched off.
101
1/12 Octave + Tolerance
14
Measurement Unit
Select the measurement unit as follows:
dB Sound level in dBSPL
This measurement unit is permanently selected
while an NTi Audio measurement microphone
with electronic data sheet is connected.
dBu Input level in dBu
dBV Input level in dBV
V Input level in Volt
Band Listening
The selected frequency band of the input signal
is audible on the rear speaker or at the head-
phone output.
• Press and hold the speaker button
down.
The pop-up window Volume is displayed.
• Keep the speaker button
pressed and
press enter
at the same time.
The band listening is activated.
102
1/12 Octave + Tolerance
1/12 Octave - Getting Started
Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
Phantom power on automatically as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2
.
The 48 V Phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
• Position the XL2 at the measurement location using a micro-
phone stand or tripod.
• Select the 1/12 Oct + Tol function in the measurement
menu.
The displayed wideband and spectral levels are
measured and stored simultaneously.
Configuration
The XL2 displays two different sound pressure levels at the
same time. You configure to display either the levels Live,
Max, Min, EQ, EQ1“, EQ4“ or captured results.
• Select the upper result parameter with the rotary wheel
.
• Confirm with enter .
103
1/12 Octave + Tolerance
Select Upper/Lower Reading
The pop-up window Select reading appears.
• Select the time-averaged sound level EQ. All available selec-
tions are Z-weighted (= no weighting).
• Confirm with enter .
The pop-up window Select reading mode appears.
• Select EQ for normal absolute display of measurements.
• Follow the same instruction and select the lower spectral
reading Live.
Press start to measure and display the
sound levels results indicated with ----.
104
1/12 Octave + Tolerance
Select Input Range
Select the lowest possible input range according to the maxi-
mum level expected during the measurement.
• Select the input range RNGE and press enter
.
• Turn the rotary wheel
to set the applicable input range and
confirm with enter
.
Start Measurement
• The XL2 measures the selected sound pressure lev-
els Live and EQ. All available sound levels are
Z-weighted (= no weighting).
• Press start
.
The run indication switches to running . The actual sound
level Live and the averaged level EQ are displayed. The pa-
rameter RUN flashes in the memory menu.
105
1/12 Octave + Tolerance
Stop Measurement and Data Saving
• Press stop
.
The XL2 stores the measurement data automatically.
• Press enter to confirm. The measurement data is stored
on the SD Card in ASCII format.
The measurement is completed.
Audio Recording
The XL2 Analyzer may record a linear audio file (48 kHz, 24 Bit)
of the measurement period together with the spectral data. Just
load a txt-file named “12audio.txt” in the root directory of the
XL2. This requires the installed option Extend Acoustic Pack.
Capture References and Create Tolerances
The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high-
resolution 1/12 Oct + Tol spectral analysis.
Features:
• Capturing of multiple readings into the internal memory
• Comparing measurement results against captures with rela-
tive or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captures for passed /
failed measurements
• Export and import of tolerance and capture files
• True peak level in 1/1 and 1/3 octave resolution
• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequen-
cy range 5 Hz - 20 kHz
Read the detailed description in the separate chapter
Spectral Limits Option (Capture + Tolerances).
106
1/12 Octave + Tolerance
1/12 Octave - Fast Frequency Response
Measurement
The XL2 provides fast and accurate frequency response mea-
surement within one second using pink noise. For this pur-
pose, the Minirator MR-PRO generates the test signal “Fast
Pink Noise” tailored to this application.
Test Signal
The test signal “Fast Pink Noise” is not “random”; it contains
an absolutely flat spectrum within the cycle time. The frequen-
cy resolution of the test signal is limited to 1 / cycle time; there-
fore you can choose between two different test signals:
Minirator MR-PRO
Test Signal
XL2 Frequency
Resolution
XL2
Measurement
Duration
File -> Signals ->
Fastpnk1
1/1 Octave
1/3 Octave
1 second
File -> Signals ->
Fastpnk4
1/6 Octave
1/12 Octave
4 seconds
Measurement in 1/3 Octave Resolution
• Select the test signal Fastpnk1 on the Minirator MR-PRO.
• Connect the MR-PRO to the input of the device under test.
• Take the XL2 and select the function 1/12Oct.
• Select the one-third octave band frequency resolution.
• Select the measurement parameter EQ, the mode “Single”
and set the measurement duration to one second.
• For higher frequency resolutions use the test signal Fast-
pnk4 and a measurement duration of four seconds.
• Start the measurement
.
You have successfully completed the measurement.
107
1/12 Octave + Tolerance
Optimize the Frequency Response
The fast frequency response measurement with the test sig-
nal “Fast Pink Noise” saves time in optimizing the frequency
response of audio devices or speakers. During your settings
on the equalizer, you will receive a precise result on the XL2
screen within one second.
• Select the test signal Fastpnk1 on the Minirator MR-PRO.
• Connect the MR-PRO to the input of the device under test.
• Take the XL2 and select the function 1/12Oct.
• Select the measurement parameter EQ1”, the mode “Sin-
gle” and set the measurement duration to one second.
• Adjust the settings on the equalizer.
The XL2 displays the actual frequency response within a
second.
Test Signal „Fast Pink Noise“ Advantage
Frequency response measurements often use
the standard Pink Noise in combination with
a 1/n octave analysis. Because of the random-
ness, longer averaging times are necessary to
get accurate results. Too short averaging times
result in “noise” in the result, as shown here:
In comparison, the test signal “Fast Pink Noise”
enables a precise measurement result within
one or four seconds.
108
Noise Curves
Noise Curves (optional)
The Spectral Limits Option extends the XL2 with the Noise
Curves measurement function. A noise curve may be used to
characterize room noise or other environments. Various stan-
dardized international noise curves are the most widely used
means for evaluating background sound in buildings, and other
facilities such as transit facilities, as well as in other indoor/
outdoor spaces. Residual noise in buildings may be generated
from both environmental sources (e.g. outside traffic) and sys-
temic sources (e.g. heating, ventilating, and air-conditioning
(HVAC) systems; or other machinery in use). It is also frequently
necessary to measure residual noise curves prior to expected
changes in advance of construction or prior to other expected
environmental noise changes.
Noise Rating NR
(in accordance with ISO/R 1996-1971)
Noise rating (NR) is a graphical method for assigning a single
number rating to a noise spectrum. It can be used to specify
the maximum acceptable level in each octave band of a fre-
quency spectrum, or to assess the acceptability of a noise
spectrum for a particular application. The method was originally
proposed for use in assessing environmental noise, but it is
now used frequently for describing noise from mechanical ven-
tilation systems in buildings. To make a rating, the measured
noise spectrum is superimposed on a family of NR contours;
the NR of the spectrum corresponds to the value of the first
NR contour that is entirely above the spectrum.
Noise Criteria NC
(in accordance with ANSI S12.2-2019 and -1995)
The NC rating of a spectrum is designated as the value of the
lowest NC curve above the measured octave-band spectrum.
The designating number for any NC curve is, approximately,
its Speech Interference Level (SIL): the average of the levels
in the 500, 1000, 2000 and 4000 Hz octave bands. SIL is a
simple metric, which measures the effects of noise on speech
intelligibility. The XL2 Analyzer includes the tangency method
adaptation in accordance with the standard.
Room Noise Criteria RNC
(in accordance with ANSI S12.2-2019)
The RNC method is used to determine noise ratings when the
noise from HVAC systems at low frequencies is high, and which
is also suspected of containing sizeable fluctuations or surging.
109
Noise Curves
It essentially represents a rumble criterion. The RNC curves
also provide a procedure that reduces the result essentially
back to the NC curves when systems are well designed and
acoustically well-behaved. Following the RNC specification, the
XL2 measures the octave-band sound pressure level every 100
ms, followed by processing to determine the applicable room
noise criterion (RNC) curve. The minimum measurement time
is 20 seconds.
Preferred Noise Criteria PNC
(in accordance with ASA 1971)
PNC curves represent a more stringent method based on an
extension of the basic Noise Criteria system. They have been
used in the past to judge the acceptability of ventilation and
other background broadband noise. PNC curves are less often
used than Noise Criteria curves because they are more strin-
gent at lower frequencies than the Noise Criteria curves, but
also because the latest (2019) version of Noise Criteria curves
also includes an extended frequency range somewhat mitigat-
ing the original reasons for PNC.
Room Criteria RC
(in accordance with ANSI S12.2-1995)
The RC criterion curves are a system for use in the design
of heating, ventilating, and air-conditioning (HVAC) systems in
office buildings, dwelling units, etc., where the desired mid-
frequency levels are in the range of 25 to 50 dB. Each RC crite-
rion curve bears a rating number equal to the level at 1000 Hz.
Spectrum classification
• Neutral spectrum (N): The levels at 500 Hz and below do not
exceed the RC curve corresponding to a sound level spec-
trum by more than 5 dB; and the spectrum levels in Band
1000 Hz and higher do not exceed the corresponding RC
curve by more than 3 dB.
• Rumble (R): Excessive noise in low-frequency band
The level in one or more of the octave bands at and below
500 Hz exceeds the RC curve corresponding to a spectrum
by more than 5 dB.
• Hiss (H): Excessive noise in high-frequency bands
The level in one or more of the octave bands at and above
1000 Hz exceeds the RC curve corresponding to a spectrum
by more than 3 dB.
• Vibration and rattle (RV): The level in one or more of the oc-
tave bands from 16 Hz through 63 Hz exceeds the criterion
for moderately noticeable rattle.
110
Noise Curves
Noise Curves Result Page
4
1
7 8
9
10
3
6
11
2
12
5
The standards list the noise criteria in 5 dB steps. The XL2
measures the noise criteria in detailed 1 dB steps, which are
calculated by linear interpolation between the standardized
5 dB levels.
RNC Information Page
13
14
The RNC information page is available when viewing Noise Cri-
teria and Room Noise Criteria results, in accordance with ANSI
S12.2-2019. It reports any large fluctuations or surging at low
frequencies, e.g. caused by fans.
111
Noise Curves
1
Noise Curve
Selection of the noise curve type and measurement re-
sult.
Noise Curve Types
• Noise Rating NR
• Noise Criteria NC (2019) and (1995)
• Room Noise Criteria RNC
• Room Criteria RC (1995)
• Preferred Noise Criteria PNC (1971)
Measurement Result
The noise rating of a spectrum is designated as the value of
the highest curve “touched” by the measured octave-band
spectrum. The octave band in which this “touching” occurs
is noted along with the curve designation.
2
Measurement Result
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band pointed to by the arrow. With the cursor in auto-
matic mode, the arrow points to the frequency band with
the highest noise rating as shown in
1
.
3
Y-Scale setting
• Auto-Scroll
• Zoom:
- Select the Y-Axis with the rotary wheel
and confirm
with enter
.
- Select the zoom factor between 10, 5, 2.5 dB/div and
confirm with enter
.
4
Noise Measurement Result
Real-time spectrum in 1/1 octave band resolution.
5
Noise Floor
The grey area shows the noise floor of the connected NTi
Audio measurement microphone (provided by the electron-
ic data sheet) in combination with the XL2 Analyzer.
6
X-Scale
X-Scale from 16 Hz to 8 kHz.
112
Noise Curves
7
Live View
Select the LiveView with the rotary wheel
to get an
overview of the current noise level. Alternatively press the
limit button
.
The XL2 measures the noise curve after pressing the start
button . This will provide the noise rating measurement
in accordance with all standards.
8
Run Indication
The run indication shows the measurement status running,
paused or stopped. Various measurement settings are
locked during ongoing measurements, such as the preset
measurement time.
9
Actual Measurement Time
Counts actual measurement time in hrs:min:sec. Supports
time modes: continuous and single.
Timer Mode Continuous
(applicable for standard measurements)
All values are recorded and monitored continu-
ously after starting a measurement with start
.
The actual measurement time is shown.
Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement
.
The actual measurement time counts back to
zero and the measurement ends.
10
Preset Measurement Time
Adjustment of preset measurement time for the timer
mode single.
113
Noise Curves
11
Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the frequency
band with the highest noise rating.
• Select the frequency with the rotary wheel
.
• Press enter
.
• You may read out any individual frequency.
• Return to auto frequency with enter
.
The cursor returns to the frequency with high-
est noise rating.
The cursor readout may be set manually to any
frequency band or wide band level. The readout re-
mains at the selected frequency.
• Select the frequency with the rotary wheel
.
• Press enter
.
• Select the frequency of interest.
• Confirm with enter
.
The cursor readout
2
displays the measure-
ment results of the selected frequency band.
12
SIL Measurement Result
The speech interference level (SIL) result is shown for
noise curve types NC-2019 and NC-1995
1
. It is calcu-
lated by averaging the octave-band sound pressure levels
at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. If the measured
spectrum in any octave band does not exceed any of the
octave bands of that NC(SIL) curve, the spectrum is des-
ignated NC(SIL). If one or more octave-band levels exceed
the NC(SIL) curve, then the NC curve number may differ to
the SIL value, as the NC rating for that spectrum must be
determined using the tangency method.
13
Large Fluctuations
This reports any large fluctuations at low frequencies
for the Room Noise Criteria RNC in accordance with
ANSI S12.2-2019. If one or more displayed measurement
results exceed the limits, then large fluctuations exist.
Concluding the LEQ levels in the octave frequency bands
below 300 Hz are automatically “penalized” at the RNC
measurement.
14
Correction Values
The noise curve type RNC uses these correction values
based on the measured fluctuation results to determine
the RNC curve result.
114
Noise Curves
Recommendations
Type of Room -
Space Type
NC and
RNC
Curve
Level
LAeq
RC curve
Concert and recital
halls
- 15-18 -
Small auditoriums
(≤500 seats)
35-39 25-30 -
Large auditoriums
(>500 seats)
30-35 20-25 -
TV and broadcast stu-
dios
16-35 15-25 -
Live performance the-
aters
25-30 20-25 -
Premier movie theaters 25-30 20-25 -
Normal theater 30 25 -
Private residences
Bedrooms 35-39 25-30 25-30(N)
Apartments 39-48 30-40 30-35 (N)
Type of Room -
Space Type
NC and
RNC
Curve
Level
LAeq
RC curve
Family rooms and living
rooms
39-48 30-40 30-35 (N)
Hotels/Motels
Individual rooms or
suites
39-44 30-35 25-35 (N)
Meeting/banquet
rooms
35-44 25-35 25-35 (N)
Service support areas 48-57 40-50 35-45 (N)
Office buildings
Offices executive 35-44 25-35 25-35 (N)
Offices small 44-48 35-40 25-35 (N)
Offices large 39-44 30-35 -
Conference rooms
large
35-39 25-30 25-35 (N)
Conference rooms
small
39-44 30-35 25-35 (N)
115
Noise Curves
Noise Curves - Getting Started
Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
Phantom power automatically on as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2
.
The 48V Phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
• Select the Noise Curves function in the measurement
menu.
The microphone should be moved slowly to po-
sitions around the entire space at locations that
are near the average normal standing or seated
height of human ears. The recommended mea-
surement period is more than 20 seconds long.
Configuration
• Select the noise curve type with the rotary wheel
.
• Confirm with enter .
The XL2 measures all noise curve types at the
same time, thus you can change the selection
also after the measurement.
116
Noise Curves
Start Measurement
• Press start
.
The run indication switches to running . The actual noise
level LZeq of the selected octave band is displayed. The
parameter RUN flashes in the memory menu. The Y-axis
adjusts automatically according the measurement result.
Stop Measurement and Data Saving
• Press stop
.
The XL2 stores the measurement data automatically.
• Press enter to confirm. The measurement data is stored
on the SD Card in ASCII format.
The measurement is completed.
117
Noise Curves
118
STIPA
Speech Intelligibility STIPA (optional)
The STIPA analyzer option allows reliable measurement
of the speech transmission index (STI) within 15 seconds.
Besides the single value STI or CIS (= common intelligibil-
ity scale) test result, a detailed view of the modulation indi-
ces and individual band level results is provided. The STI-
PA analyzer meets the standard IEC 60268-16, edition 5
released in 2020. The XL2 also supports noise corrections, au-
tomated averaging of measurements and the older standard
editions 2, 3 and 4.
The intelligibility of speech depends on:
• Signal-to-noise ratio
• Psychoacoustic masking effects
• Sound pressure level
• Ambient noise level
• Reverberation time
• Reflections
• Frequency response
• Distortion
The speech intelligibility measurement function STIPA is an op-
tion for the XL2 Audio and Acoustic Analyzer. Ask your local
representative for purchasing details.
Signal Source
Choose the applicable STIPA test signal source:
NTi Audio
TalkBox
The NTi Audio TalkBox simulates a person talking
at a precise acoustic level, enabling the measure-
ment of the complete signal chain including the
microphone.
• Place the NTi Audio TalkBox in front of the mi-
crophone at the typical position of the talking
persons head.
• Select Track 1 for the STIPA test signal.
• Select Output Mode to Speaker; you should
hear the STIPA test signal.
Minirator
MR-PRO
The Minirator MR-PRO is used for electrical signal
injection into public address systems that com-
monly use alarm messages from a hard drive
(systems without a microphone).
Other Audio
Player
Register the XL2 and download the STIPA test
signal at https://my.nti-audio.com/support/xl2.
The maximum tolerable deviation in test signal
playback sample frequency is 0.1%.
The standard STIPA signal is based on random noise limited to
the bands contained in a male speech spectrum.
119
STIPA
STIPA Numeric Result Page
1
2
3
4
5
9
10
6
7
8
Use only the original NTi Audio test signal for
speech intelligibility measurements with the
XL2. Other signals may not seamlessly loop,
thus causing wrong measurement results!
STIPA Table Result Page
14131211
120
STIPA
STIPA Averaging
15
16 17
18
STIPA Ambient Noise Correction
19
20
24
21
22
23
121
STIPA
1
Run Indication
This icon displays the run status of the measurement.
2
Measurement Result
• Single value speech transmission index result.
• Repeatability of measurement result:
Since a dedicated noise test signal is used, the result
may deviate by a of maximum 0.03 STI (=Max-Min) at the
same measurement position.
3
Sound Level L
Aeq
Shows the time-averaged sound level of the 15 seconds
measurement cycle time.
4
Sound Level L
AS
Actual sound pressure level.
5
Analog Test Result Bargraph
Bargraph display and interpretation of the speech intelligi-
bility measurement result
• Exlnt 0.75 - 1.00 STI
• Good 0.60 - 0.75 STI
• Fair 0.45 - 0.60 STI
• Poor 0.30 - 0.45 STI
• Bad 0.00 - 0.30 STI
6
Qualification Scale
The STI value is shown as a letter representing the qualifi-
cation scale below. Listed are also examples of typical ap-
plication environments.
Band STI Range Examples of typical uses
A+ > 0.76 recording studios
A 0.72 - 0.76 theatres, speech auditoria,
parliaments, courts
B 0.68 - 0.72 theatres, speech auditoria,
parliaments, courts
C 0.64 - 0.68 teleconference, theatres
D 0.60 - 0.64 class rooms, concert halls
E 0.56 - 0.60 concert halls, modern churches
F 0.52 - 0.56 PA in shopping malls,
public offices, cathedrals
G 0.48 - 0.52 PA in shopping malls,
public offices
H 0.44 - 0.48 PA in difficult acoustic
environments
I 0.40 - 0.44 PA in very difficult spaces
J 0.36 - 0.40 not suitable for PA systems
U < 0.36 not suitable for PA systems
122
STIPA
7
Measurement Unit
The speech intelligibility result is displayed in STI (Speech
Transmission Index) or CIS (Common Intelligibility Scale),
whereby CIS is calculated as CIS = 1 + log STI.
8
Edition of Standard IEC60268-16
ed5.0 actual edition released in 2020 with continuous
level dependent auditory masking function
ed4.0 old edition released in 2011 with continuous
level dependent auditory masking function
ed3.0 old edition released in 2003 with stepped level
dependent auditory masking function
ed2.0 old edition released in 1998 with fixed masking
function
9
Progress Bar
Measurement status indication; a single speech intelligibil-
ity measurement takes 15 seconds. The actual measure-
ment time and measurement status are indicated here.
10
Page Selector
Select between these pages:
Speech intelligibility measurement result
Table result page with modulation ratio and
sound levels for each octave band
On-site averaging of results.
Ambient Noise Correction
The page button
toggles between the 123 - Ta b - Avr
screens. These pages show the speech intelligibility mea-
surement results. The page Cor offers setting the noise
spectra prior the STI measurement.
11
Octave Bands
Frequencies 125 Hz - 8 kHz in 1/1 octave band resolution.
12
Sound Pressure Level L
eq
Individual time-averaged octave band level L
eq
.
123
STIPA
13
STIPA Modulation Ratio mr1, mr2
For good speech intelligibility it is mandatory that the in-
tegrity of the transmitted voice signal modulations are pre-
served. Therefore, STIPA is based on measuring the MTF
(Modulation Transfer Function). This function quantifies the
degree to which the voice modulations are preserved in
individual octave bands. The STIPA method determines the
MTF by analyzing the seven frequency bands. Each band is
modulated with two frequencies, resulting in the modula-
tion ratio mr1 and mr2. All indexes together combined with
psycho-acoustic models provide the single-value speech
intelligibility result.
Band mr1 mr2
125 Hz 1.60 Hz 8.00 Hz
250 Hz 1.00 Hz 5.00 Hz
500 Hz 0.63 Hz 3.15 Hz
1 kHz 2.00 Hz 10.00 Hz
2 kHz 1.25 Hz 6.30 Hz
4 kHz 0.80 Hz 4.00 Hz
8 kHz 2.50 Hz 12.50 Hz
14
Error Detection
The built in error detection helps identifying faulty measure-
ments caused by the amount of impulsive ambient noise.
Such noise influences the accuracy of any speech intelligi-
bility measurement. The error detection checks the follow-
ing:
• Invalid modulation indices in individual octave bands (mr1
or mr2 > 1.3)
• Changes in ambient noise or any impulsive noise dur-
ing the measurement (by comparing the first half of the
measurement period with the second half)
15
Cycle Reading
The standard IEC 60268-16 recommends measuring the
speech intelligibility two or three times at each measure-
ment position. This reduces potential measurement errors.
The individual cycle readings are listed here.
16
STI-Average
Calculated average of the recorded cycle results.
17
Difference
Difference (Max – Min) of the of the recorded cycle re-
sults.
124
STIPA
18
Start next Cycle Measurement
Start the next cycle measurement at the same measure-
ment position here.
19
Ambient Noise Measure / Load / Save
Measure here the actual ambient noise during an adjust-
able measurement time. You may save this record and re-
load the data set for any later speech intelligibility measure-
ment.
20
Source of Data
Informs about the source of the ambient noise data. The
choices are:
• Default Settings
• Edited manually
• Measured Date Time
This information is documented in the measurement re-
port.
21
LAeq of Ambient Noise
This LAeq is calculated based on the octave band levels;
you may manually set this level in accordance with the typi-
cal noise level as specified for your application. The default
level is 80 dB.
22
Spectral Level of Ambient Noise
Adjustable octave band level from 125 Hz to 8 kHz. The de-
fault spectrum is equals the replayed STIPA test signal at
LAeq = 80 dB.
23
Activation of manual Octave Band Level Setting
Select EDIT with the rotary wheel
to adjust the indi-
vidual octave band levels.
24
Activation of Ambient Noise Correction
On Ambient noise correction is active
Off Ambient noise correction is deactivated
The XL2 Analyzer has been manufactured in
compliance with all specifications as described
in IEC 60268-16. Due diligence has been ob-
served in validating
• the measuring system
• the accuracy of the measured STI across a
range of relevant reference conditions
• the accuracy of the modulation transfer func-
tion matrix.
125
STIPA
Question Mark ? at individual Octave Bands
Individual octave bands are marked with ? in case of a
• Missing test signal level
• Invalid modulation indices (mr1 or mr2 > 1.3)
• Changes in ambient noise or any impulsive noise during the
measurement
Flashing Question Marks ?.?? at
2
The measurement result flashes in combination with the ques-
tion marks ??? in case of a
• Question Mark ? at one or multiple octave bands. See the
STIPA Table Result Page on the XL2 for details.
• Changes in ambient noise or any impulsive noise during the
measurement
In case the question marks ?.?? are flashing,
then the measurement is faulty. Verify possible
causes and repeat the measurement.
For details see the chapter STI Measurement
Hints.
STI Measurement - Getting Started
Test Preparations
The XL2 reads the electronic data sheet of the connected
NTi Audio measurement microphone and switches the 48 V
Phantom power automatically on as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2
.
The 48 V Phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.
• Position the XL2 at the measurement location using a micro-
phone stand or tripod.
• Select the STIPA measurement function in the measure-
ment menu.
• Prepare the environment for the measurement. For example
mute all sound sources to establish silence.
No impulsive noise shall occur during the
speech intelligibility measurement as well no
speaking or other noise sources should be al-
lowed near the measurement microphone.
126
STIPA
Start STIPA Test Signal
Select the STIPA signal source according your application re-
quirements.
• Switch on the STIPA test signal at the signal source.
• Set the acoustic sound pressure level of the PA system to
simulate the typical announcement level; e.g. L
AS
= 85 dB.
Start Measurement
• Press start
.
The progress bar switches to RUNNING. The test result
tendency is shown on the bargraph, marked with Bad,
Poor, Fair, Good and Exlnt.
127
STIPA
Stop Measurement and Data Saving
After the period of 15 seconds the speech intelligibility mea-
surement finishes automatically. The progress bar indications
switches to FINISHED and the final test result is displayed. The
measurement result is stored automatically.
• Switch off the STIPA test signal.
• Press enter to confirm. The measurement data is stored
on the SD Card in ASCII format.
The measurement is completed.
Averaging of STI Results
The standard IEC 60268-16 recommends averaging two or
three subsequent results taken at the same measurement lo-
cation.
The German Standard VDE 0833-4 requires performing mini-
mum three subsequent measurements for one measurement
position in case of STI < 0.63.
The XL2 Analyzer offers automated averaging of two up to
eight speech intelligibility results based on these standard re-
quirements.
128
STIPA
Start Averaging
• Select the averaging page Avr.
• Turn the rotary wheel to select the parameter START
NEW and press enter
.
The first measurement starts automatically. It is labeled
Cyc 1.
Add Cycles
• Press enter
to confirm Add Cycle.
• Repeat the measurement at the same position as required.
The XL2 performs further measurements and adds them to
the list.
129
STIPA
Finish
• Choose Finish to end the averaging.
The speech intelligibility average and the deviation are dis-
played for documentation.
Display of STIPA Numeric Result Page
The symbol
indicates that the averaged STI value is dis-
played.
130
STIPA
Ambient Noise Correction
Measuring the speech intelligibility index under realistic envi-
ronmental conditions is often not feasible; e.g., playing the test
signal in a railway station at emergency levels during peak hours
will irritate passengers. Additionally, at rush-hour the charac-
teristics of ambient noise might be highly impulsive, while a
pre-requisite for accurate speech intelligibility measurements
is a negligible impulsivity in the ambient noise. Under such cir-
cumstances the speech intelligibility measurement should be
shifted to a more suitable time of the day; e.g. night time.
Measurement Sequence
• First measure the ambient noise
• Secondly measure the speech intelligibility
This sequence simplifies the measurement
as follows: The XL2 immediately displays the
speech intelligibility result with ambient noise
correction. This result provides a guideline if
repeated measurements at the same location
with averaging is required. For details see the
chapter STIPA Measurement Hints.
Enable Ambient Noise Correction
• Select the correction page Cor.
• Turn the rotary wheel
to select the parameter Ambient
Noise Correction and press enter
.
The correction enables and the XL2 displays this screen:
You may adjust the ambient noise band levels
and the LAeq.
131
STIPA
Commissioning New PA-Systems
New announcement systems are commissioned e.g. at public
areas prior the grand opening. Thus, the actual ambient noise
caused by the public is not available yet during the speech in-
telligibility measurement. Here you may simulate the real-life
condition with ambient noise data enabled by one of the fol-
lowing modes:
• Utilize a reference noise file, which might be applicable for
the actual project
- Measure the ambient noise at another similar project and
store this as reference noise file.
- Back on the actual project select the parameter Load with
the rotary wheel
and press enter .
- Select the reference noise file, which shall be utilized as
ambient noise correction for your speech intelligibility
measurements.
• Edit actual noise data
- Select the parameter Edit or the LAeq level with the ro-
tary wheel
and press enter .
- Turn the rotary wheel to adjust the noise level.
- Press enter
to continue the setting.
Skip the next step “Measure Ambient Noise” and go to “STI
Measurement”.
Measure Ambient Noise
• Position the microphone at the STIPA measurement point.
• Select Measure (without any test signal presence).
The XL2 measures the ambient noise and displays the LEQ
octave band result.
You may edit the noise data.
132
STIPA
STI Measurement
• Select the STIPA result page 123.
• Perform the speech intelligibility measurement.
The XL2 displays the corrected speech intelligibility result
in large font. The actual measured result is listed below in
smaller font.
Data Post-Processing
In the case when no ambient noise correction has been car-
ried out on-site with the XL2 Analyzer, you may post-process
your measurement data on the PC. The NTi Audio STI Report-
ing Tool combines the speech intelligibility measurement taken
with quiet conditions and the actual ambient noise caused by
the public, e.g. during day-time. This emulates the speech intel-
ligibility expected during real-life conditions.
STI Reporting Tool
The STI Reporting Tool creates measurement reports accord-
ing to the standards
• AS 1670.4
• CEN/TS 54-32:2015
• DIN EN 50849:2017
• IEC 60268-16
• ISO 7240-19:2007
• VDE V 0833-4-32:2016
• VDE 0828-1:2017-11
Import the data directly from your XL2 including the ambient
noise measurements. The corresponding speech intelligibility
STI or CIS values are shown.
133
STIPA
The STI Reporting Tool is free to download on the XL2 Support
website https://my.nti-audio.com for all registered users. (En-
able all macros when opening the document.)
System Requirements:
• PC running Windows OS
• Excel 2010 - 2016
STI Measurement Hints
Ambient Noise
• The ambient noise has to be sufficiently static during the
measurement. A signal-noise ratio of 15 dB or higher is rec-
ommended to achieve best speech intelligibility. Impulsive
ambient noise during the measurement, such as speech,
causes severe measurement errors. The STIPA result is usu-
ally too high.
• Fluctuating noise is detected by measuring the direct STI in
the absence of the test signal. Carry out these measurements
at least at a representative set of locations. If the STI is too
high (e.g. STI > 0,3), the measurement results are likely to
be erroneous. In this case the speech intelligibility measure-
ment should be carried out without the presence of noise.
Utilize the ambient noise correction for such instances.
• At locations with varying conditions (e.g., some public areas
with few people and other areas with crowds) the worst-
case speech intelligibility should be measured. Consult the
local regulations (e.g. the NFPA code in the U.S.) for direc-
tives concerning measurement locations and number of re-
quired measurements under which circumstances.
German Standard VDE 0833-4 Requirements
STI > 0.63 One single measurement is sufficient.
STI < 0.63 Perform three subsequent measurements at this
measurement position.
• If the maximum result deviation of these three
measurements is > 0.03 then a further three
measurements shall be performed.
• If the maximum result deviation of these mea-
surements is > 0.05 then the cause of this in-
stability shall be evaluated and removed.
• The arithmetic average of the performed three
or six measurements has to be reported.
134
STIPA
Utilize the STIPA Reporting Tool for the documentation of your
measurements according the standard.
An STI > 0.63 implies that the speech intelligibility is higher
than 0.5 with a confidence level of 95%.
CD-Player
• Only high-quality CD-Players should be used to reproduce
the STIPA test signal as only limited time-shifts (+/- 20 ppm)
ensure reliable test results. Pitch control and shock protec-
tion should be disabled. We recommend that only profes-
sional CD-Players be used. You can verify the time shift of the
CD-Player using a 1 kHz test signal:
- Insert the NTi Audio Test CD into the CD-Player and start
track 1, which is the 1 kHz test signal.
- Connect the XL2 directly to the audio output of the CD-
Player and measure the signal frequency in RMS/THD+N
mode. The displayed frequency should be in the range
from 0.99998 kHz to 1.00002 kHz
• STIPA test signals from other test system manufacturers
may sound similar but are not compatible. Only the original
NTi Audio STIPA test signal should be used in combination
with the XL2.
Measurement
• Select measurement positions as stipulated by local regula-
tions. As a guideline, typically position the microphone at 1
- 1.2 meters above ground in sitting areas or 1.5 - 1.8 meters
in standing areas. Also, directly in front of the speakers or
very close to a wall are examples of positions that are not
typical.
• The person taking the measurements should be out of the
acoustic field, so as not to affect the measurement results.
For this purpose, the measurement microphone can be
mounted on a microphone stand and connected with the
ASD Cable to the XL2.
• Low speech intelligibility readings can be caused by
- Excessive sound reverberation, echoes or reflections
- Poor speaker directivity or speaker coverage
- Speaker level setting incorrect; e.g. low signal-to-noise ra-
tio.
135
Audio Analyzer
6. Audio Analyzer
The XL2 offers a comprehensive audio analyzer. Broadband
or wideband measurements are offered by the measurement
functions RMS/THD+N and Oscilloscope.
The following measurement functions offer detailed analysis of
the audio spectrum in Volt, dBu and dBV:
• SLMeter/RTA
• FFT
• 1/12 Oct+Tol (optional)
Just change the measurement unit according your require-
ments. See the individual chapters for more details.
• If an NTi Audio measurement microphone
with electronic data sheet is connected,
the XL2 will automatically activate the unit
dBSPL (dB) for sound level measurements.
• A decreased THD+N performance will occur
with unbalanced input signals when using
switching-type power supplies (approx. 3 dB).
Remove such a mains adapter for critical ap-
plications.
RMS / THD+N
The XL2 Audio and Acoustic Analyzer measures the parame-
ters Level RMS, THD+N and frequency simultaneously.
1
2
3
4
5
136
Audio Analyzer
1
Filter
Z-Weighting Frequency Z-weighting with flat frequen-
cy response from 20 Hz to 22 kHz. De-
fault measurement setting.
A-Weighting Frequency A-weighting according
IEC 61672 for low noise levels.
C-Weighting Frequency C-weighting according
IEC 61672 for high noise levels.
HP-100Hz Highpass 100 Hz, -200 dB/dec.,
maximally flat magnitude filter,
e.g. -60 dB @ 50 Hz
HP-400Hz Highpass 400 Hz, -120 dB/dec., maxi-
mally flat magnitude filter, attenuates
50/60Hz components of test signal
HP-19k Highpass 19 kHz; e.g., to measure a
20 kHz pilot tone level of a public address
system without disturbing the public.
22.4-22.4k Bandpass filter 22.4 Hz - 22.4 kHz
(IEC 468-4)
2
Level RMS
Measures the absolute level of the input signal. The unit’s
dBu, dBV, Volt V, dBSPL, Watt W and dBm are selectable.
The Watt and dBm measurement results are calculated
based on a user-defined Load. The unit dBSPL is not avail-
able for the type approved XL2-TA firmware.
3
THD+N
Measures the total harmonic distortion and noise of the
input signal. The distortion measurement, expressed in dB,
linear or in %, is conducted within the bandwidth 10 Hz - 20
kHz. This value is calculated as follows:
THD+N = (Distortion+Noise) / (Signal + Distortion+Noise)
4
Frequency in Hz
The XL2 automatically extracts and measures the frequen-
cy of the fundamental signal. The XL2 frequency counter
technology even reads the frequency correctly for heavily
distorted signals.
137
Audio Analyzer
5
Balance Indicator
Indication of the audio signal balance between pin 2 and 3
on the XLR input for input signals > -34 dBu.
The input signal is balanced.
The signal is unbalanced. The level at pin 2 is
higher than at pin 3.
The signal is unbalanced. The level at pin 3 is
higher than at pin 2.
PreNotch Listening
The input signal is audible at the rear speaker or
headphone output.
• Press and hold down the speaker button
.
The pop-up window volume is dis-
played.
138
Audio Analyzer
PostNotch Listening
The main frequency component is filtered out
by a notch filter, leaving only the remaining sig-
nal audible.
• Press the speaker button
to display the vol-
ume window.
• Additionally, press enter
The post notch listening with auto-gain
function is activated. The maximum gain
setting is 0 dB.
e.g. using a 100 Hz sine test signal connected
to the XL2 input, with the 100 Hz main fre-
quency filtered by the notch filter, the complete
frequency spectrum is available at the speaker
or headphone output. This feature allows you to
listen to the actual distortion signal. You there-
fore hear a noise from the speaker even without
any connected inputs signal!
Oscilloscope
The scope function visualizes the waveform of the electrical in-
put signal. It automatically triggers to the fundamental frequen-
cy and selects the scaling of the X-axis (time) and Y-axis (level)
accordingly. The fundamental, or most dominant, frequency of
the input signals is displayed above the scope screen.
The scope scaling is fixed.
139
Vibration Meter
7. Vibration Meter
The Vibration Option turns the XL2 Audio and Acoustic Analyzer
into a professional vibration meter with broadband measure-
ments and spectral analysis in 1/3 or octave resolution. The
XL2 Vibration Meter determines vibration acceleration, velocity
and deflection with standard-compliant weighting filters in the
frequency range from 0.8 Hz to 2.5 kHz. Detailed recording
of measurement data and audio files allow for comprehensive
evaluation and reporting. In addition, the XL2 Vibration Meter
comes standard with an FFT analysis and an oscilloscope func-
tion. Selectable FFT frequency ranges from 1 Hz to 1.69 kHz
allow a detailed examination of the measured vibrations.
The Spectral Limits Option adds functions to the Vibration Me-
ter including a zoom FFT up to 20 kHz and a 1/12 octave band
analysis from 0.73 Hz to 1.36 kHz. Also, it adds the ability to
record reference spectra and set tolerances for pass / fail qual-
ity control measurements. The Remote Measurement Option
allows the real-time acquisition of measurement data directly
into a computer application via the USB interface. A document-
ed command set is available.
VibMeter / Spectrum
The vibration meter offers different pages:
Page Selection using the Page Button
• Press page to toggle between the 123 VibMeter page
and the CPB page.
Page Selection using the Rotary Wheel
• Select the page 123 VibMeter with the rotary wheel .
• Confirm with enter
.
Page Selection
140
Vibration Meter
123 Values: Vibration Meter
Displays the selected broadband vibration level results. You can
change the font size of the result. Depending on the font size
chosen, the XL2 shows 2 up to 4 results simultaneously. The
display of the actual or maximum level can be selected with
the applicable frequency weighting. The peak levels PK or P-P
are real peak levels.
Spectrum: Constant Percentage Bandwidth CPB
Displays the 1/3 or 1/1 octave spectrum of the selected RMS,
peak or peak-peak vibration level. Additionally, the wide band
result B is shown graphically by a bar.
Reporting: Report Setting
Here you set which vibration levels shall be stored in a .txt file
after the completed measurement. Choose between:
ALL Stores all vibration levels.
Selected Stores up to 10 different individually-defined vi-
bration levels.
For details refer to the chapter Reporting.
Logging: Setup of Data Logging
The XL2 features a powerful vibration level meter data logger,
which allows you to record all required vibration level values
during the measurement. In the logging page you set which
vibration levels shall be logged over time. For details refer to
the chapter Logging. Choose between:
ALL Logs all vibration levels.
Selected Logs up to 10 different individually-defined vibra-
tion levels.
Limit LED: Limit Setting
H
ere you set the function
of the limit LED , thereby highlight-
ing any vibration level that exceeds the pre-set limits in orange
or red color. Further, external peripherals are controlled by the
optional Serial I/O Interface based on the vibration level, such
as displaying vibration levels on a large external red-orange-
green lamp. For details refer to the chapter Limits.
141
Vibration Meter
Overview
Numeric Result Page
The numeric result page 123 Values displays the selected
broadband vibration level results. You can change the font
size of the result. Depending on the font size chosen, the XL2
shows 2 up to 4 results simultaneously. The display of the ac-
tual or maximum level can be selected with the applicable fre-
quency weighting.
1
2
3
Constant Percentage Bandwidth Analyzer Page
The real-time analyzer page
Spectrum measures and dis-
plays the 1/3 or 1/1 octave spectrum in the selected frequency
range including the wideband result.
9
8
5
11 10
7
4
6
142
Vibration Meter
1
Vibration Level Result 1
All vibration levels are measured and logged simultaneous-
ly. You select which vibration levels should be displayed.
Change Parameter
• Turn the rotary wheel
to select the parameter Lxx.
• Press enter
to open the selection menu and choose
the wideband vibration level to be displayed.
• Turn the rotary wheel
to select the required test result
parameters and confirm with enter
.
Change Font Size
• Turn the rotary wheel to select the actual test result.
• Press enter
1x, 2x or 3x to set the font size to small,
medium or large.
The XL2 shows 2 vibration levels on the display if a large
font is chosen, otherwise it shows 4 vibration levels.
2
Vibration Level Result 2
Follow the setting instructions for vibration level result 1.
3
Filter
Select one of the following frequency filters:
FLAT no filter applied
1-80Hz Filter 1 - 80 Hz with decay rate of 12 dB /
octave in accordance with DIN 45669-1
1-315Hz Filter 1 - 315 Hz with decay rate of 12 dB /
octave in accordance with DIN 45669-1
10-1000Hz Filter 10 - 1000 Hz with decay rate of 18 dB /
octave in accordance with ISO 2954
4
Result Symbols / Capture
This field offers two functions:
• Symbols for measurement results
11
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
143
Vibration Meter
• Capture
One of the displayed frequency band readings may be
captured. Any measurement data can then be compared
with this captured reference live on the XL2 Analyzer.
• Select the parameter to be captured.
• Confirm with enter
, to capture the reading.
• Select the upper parameter
15
and choose Capt.
• Confirm with enter
.
The lower reading can be compared with the previously-
captured reference data.
5
Level Type
Select in the System Settings:
• metric or imperial units
• RMS, peak or peak-peak level
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
6
Y-Scale setting
• Select the Y-Axis with the rotary wheel
and confirm
with enter
.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div and
confirm with enter
.
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter
.
7
Measurement Result
Real-time analyzer results in 1/1 octave or 1/3 octave band
resolution.
8
X-Scale setting
Third-octave band resolution
2.5 Hz - 2.5 kHz frequency band levels including wide
band result
0.8 Hz - 1.0 kHz frequency band levels including wide
band result
0.8 Hz - 2.5 kHz frequency band levels
144
Vibration Meter
Octave band resolution
4 Hz - 2.0 kHz frequency band levels including wide
band result
1 Hz - 0.5 kHz frequency band levels including wide
band result
1 Hz - 2.0 kHz frequency band levels
• Select the X-Axis with the rotary wheel
and confirm
with enter
.
• Toggle with the rotary wheel
between the ranges.
• Confirm with enter
.
9
Broadband Results
Displays broadband level B.
10
Filter
Select the preset frequency filter here, which is already
used on the broadband page.
11
Measurement Result
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band pointed to by the arrow.
Select the measurement unit as follows:
Acceleration a • m/s2
• g
• in/s2
• dB
Velocity v • m/s
• in/s
• dB
Displacement d • m
• in
• dB
145
Vibration Meter
Wav-File Recording
The XL2 records a wav-file of the measured input signal and
stores it on the SD Card. The available formats are:
• Compressed (default, using ADPCM compression). A new
wav-file is started automatically after 12 hours of recording
(typical maximum wav-file size = 512 MByte)
• Compressed+AGC, compressed with automated gain con-
trol. The gain control increases the level of low-level signals,
so that the wav-file is well-leveled during playback on the
PC.
• 24Bit_48kHz, linear wav-file logging in 24 bit, 48kHz resolu-
tion with the optional Extended Acoustic Pack. A new wav-
file is started automatically after 1 hour of recording (typical
maximum wav-file size = 512 MByte)
Broadcast Wave Format BWF
The XL2 stores scaling factor, serial number,
date, time and time zone within the wav-file (ac-
cording to EBU TECH 3285). This information is
available through professional audio/video tools
typically used in broadcast.
Sample name of wav-file:
1
MyTest_V_Meter_000_Audio_FS_2.52e2_mps2(PK)_00.wav
2 3 4
5
1
MyTest
File name defined by user.
2
SLM
Measurement function.
3
000
Automatically incrementing file number.
4
Audio_FS_2.52e2_mps2(PK)
Audio file with full-scale peak level based on acceleration
in unit m/s2. In case of a Compressed + AGC recording,
the file name reads “AGC”; this file contains corrected level
information only.
5
00
The number increments for each successive wav-file during
a longer recording.
146
Vibration Meter
FFT Analysis + Tolerance
The XL2 Vibration Meter includes a fast real-time FFT.
The following features are available upon installing the Spectral
Limits Option in the XL2 Analyzer:
• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequen-
cy range 1 Hz - 20 kHz
• Capture and tolerance function provided with Spectral Limits
Option; thus the main menu function reads FFT + Tol.
8
2
4
1
5
9
6
3
7
147
Vibration Meter
1
Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:
• Symbols for measurement results
2
Upper result displayed as line.
Lower result displayed as bargraph.
• Capture & Start Tolerance Mode
The displayed readings may be captured as reference
reading C1 to C8 for
• Comparing measurement results against captured
traces with relative or absolute curve display.
• Creating tolerance masks based on captured refer-
ence curves for passed / failed measurements.
Capture EQ Captures the upper parameter
Capture Live Captures the lower parameter
Manage
captures
Allows to rename captures, clear re-
corded captures, save captures to the
SD Card for export from the XL2 or
load captures from the SD Card for im-
port to the XL2.
Start tolerance
mode
Starts the tolerance mode for passed/
failed measurements comparing the
actual measurement results against a
tolerance band.
2
Measurement Result
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band indicated by the arrow.
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
Select in the System Settings:
• metric or imperial units
• RMS, peak or peak-peak level
148
Vibration Meter
3
Y-Scale setting
• Select the Y-Axis with the rotary wheel
and confirm
with enter
.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter
.
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter
.
4
Measurement Result
Displays the actual and averaged measurement results.
5
Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 sec-
onds as well FAST (125 ms) and SLOW (1 second).
Applications:
Short Time
Weighting
High-resolution in time with minimum
averaging
Long Time
Weighting
Low resolution in time with longer aver-
aging
6
Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the highest level,
e.g. tracing the dominant frequency of a rotating
part.
• Select the frequency with the rotary wheel
.
• Press enter
.
• You may readout any individual frequency.
• Return to auto frequency with enter
.
The cursor returns to the frequency with high-
est level bar.
The cursor readout may be set manually to any
frequency. The readout remains at the selected fre-
quency.
• Select the frequency with the rotary wheel
.
• Press enter
.
• Select the frequency of interest.
• Confirm with enter
.
The cursor readout
2
displays the measure-
ment results of the selected frequency band.
149
Vibration Meter
7
Zoom Mode
(optional, applicable with the Spectral Limits Option)
• Select the readout frequency
10
and press enter
.
• The zoom mode is displayed above the flashing arrow.
• Select the zoom-in frequency with the rotary wheel
.
• Press limit
and zoom the linear frequency scale in or
out with the rotary wheel
.
• Release limit
and scroll the linear frequency scale left
or right with the rotary wheel
.
8
Measurement Unit
Select the measurement unit as follows:
Acceleration a • m/s2
• g
• in/s2
• dBa
Velocity v • m/s
• in/s
• dBv
Displacement d • m
• in
• dBd
The Spectral Limits Option extends the function with cap-
tures and tolerances. All tolerances are specified as accel-
eration.
150
Vibration Meter
Oscilloscope
The scope function visualizes the waveform of the electrical in-
put signal. It automatically triggers to the fundamental frequen-
cy and selects the scaling of the X-axis (time) and Y-axis (level)
accordingly. The fundamental, or most dominant, frequency of
the input signals is displayed above the scope screen.
The scope scaling is fixed.
9
Page Selector X-Scale and Parameter Setting
1k7 Shows FFT result of the frequency band range.
23 Hz - 1.687 kHz in a resolution of
11.72 Hz with 143 bins shown on the display.
400 Shows FFT result of the frequency band range.
5 Hz - 421.02 Hz in a resolution of 2.92 Hz with
143 bins shown on the display.
100 Shows FFT result of the frequency band range.
1 Hz - 105.00 Hz in a resolution of 0.73 Hz with
143 bins shown on the display.
Usr User Range
(applicable with optional Extended Acoustic Pack
or Spectral Limits Option)
1 Hz - 20 kHz in zoom mode with a minimum reso-
lution of 0.366 Hz and 143 bins displayed.
Set Selection for FFT Windowing:
• Hann: Default setting
• Dolph-Chebyshev: for analyzing small signals
(e.g. harmonics) close to a dominant signal.
The page button
switches these display modes.
151
Vibration Meter
1/12 Octave + Tolerance (optional)
The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high-
resolution 1/12 Oct + Tol spectral analysis.
Features:
• Capturing of multiple readings into the internal memory
• Comparing measurement results against captures with rela-
tive or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captures for passed /
failed measurements
8
2
4
1
5
6
3
7
152
Vibration Meter
1
Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:
• Symbols for measurement results
2
Upper result displayed as line.
Lower result displayed as bargraph.
• Capture & Start Tolerance Mode
The displayed readings may be captured as reference
reading C1 to C8 for
• Comparing measurement results against captured
traces with relative or absolute curve display.
• Creating tolerance masks based on captured refer-
ence curves for passed / failed measurements.
Capture EQ Captures the upper parameter
Capture Live Captures the lower parameter
Manage
captures
Allows to rename captures, clear re-
corded captures, save captures to the
SD Card for export from the XL2 or
load captures from the SD Card for im-
port to the XL2.
Start tolerance
mode
Starts the tolerance mode for passed/
failed measurements comparing the
actual measurement results against a
tolerance band.
2
Measurement Result
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band indicated by the arrow.
Upper parameter displayed as line.
Lower parameter displayed as bargraph.
Select in the System Settings:
• metric or imperial units
• RMS, peak or peak-peak level
153
Vibration Meter
3
Y-Scale setting
• Select the Y-Axis with the rotary wheel
and confirm
with enter
.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter
.
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter
.
4
Measurement Result
Displays the actual and averaged measurement results.
5
Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 sec-
onds as well FAST (125 ms) and SLOW (1 second).
Applications:
Short Time
Weighting
High-resolution in time with minimum
averaging
Long Time
Weighting
Low resolution in time with longer aver-
aging
6
Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the highest level,
e.g. tracing the dominant frequency of a rotating
part.
• Select the frequency with the rotary wheel
.
• Press enter
.
• You may readout any individual frequency.
• Return to auto frequency with enter
.
The cursor returns to the frequency with high-
est level bar.
The cursor readout may be set manually to any
frequency. The readout remains at the selected fre-
quency.
• Select the frequency with the rotary wheel
.
• Press enter
.
• Select the frequency of interest.
• Confirm with enter
.
The cursor readout
2
displays the measure-
ment results of the selected frequency band.
154
Vibration Meter
7
Setting of Test Result Resolution
Set the spectral result display to 1/1, 1/3, 1/6 or 1/12 octave
band resolution as follows:
• Turn the rotary wheel
to select the parameter
12
.
• Press enter
to open the selection window.
• Turn the rotary wheel
to select 1/1 OCT, 1/3 OCT,
1/6 OCT or 1/12 OCT
• Press enter
to confirm.
8
Measurement Unit
Select the measurement unit as follows:
Acceleration a • m/s2
• g
• in/s2
• dBa
Velocity v • m/s
• in/s
• dBv
Displacement d • m
• in
• dBd
The Spectral Limits Option extends the function with cap-
tures and tolerances. All tolerances are specified as accel-
eration.
155
Vibration Meter
156
Calibration
8. Calibration
The XL2 Audio and Acoustic Analyzer meets or exceeds the
specifications listed in the chapter Technical Data.
Instrument Calibration
In order to maintain the high accuracy, annual calibration of
the XL2 Analyzer and the measurement microphone is recom-
mended. The calibration service verifies the complete product
specifications, differences to the last calibration and measures
the frequency response of the measurement microphone. To
enquire about calibration service, follow the RMA guide lines
at www.nti-audio.com.
Microphone Sensitivity
NTi Audio’s ASD measurement microphones and the micro-
phone pre-amplifier MA220 include an electronic data sheet.
The Automated Sensor Detection (ASD) of the XL2 recognizes
the sensitivity and calibration data of the connected micro-
phone. The electronic data sheet, including the microphone
sensitivity, is displayed in the menu Calibrte.
Environmental Conditions
The sound level meter and calibrator should be exposed to the
same environmental conditions prior any calibration for the fol-
lowing recommended periods:
• 10 minutes after a temperature change of 10°C.
• 15 seconds after the static air pressure has changed by
5 kPa.
• 10 minutes after a humidity change of 30% without conden-
sation.
The described calibration method and correction data apply for
the following environmental conditions:
• Temperature: -10 °C to +50 °C
• Static air pressure: 65 kPa to 108 kPa
• Humidity: 25 % to 90 % r.H.
without dew from -10 °C to +39 °C
Ambient Noise
Please make sure that, during the calibration with 114 dB, the
ambient noise level is lower than 89 dB.
157
Calibration
Calibration Menu with connected
Measurement Microphone
1
2
7
5
4
6
8
3
Calibration Menu without any connected Sensor
9
158
Calibration
Calibration Menu with connected
ICP Adapter ASD and Accelerometer
10
1
Phantom Power Supply
48V The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.
ASD An NTi Audio measurement microphone with
automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of
the microphone and switches the 48 V Phan-
tom power automatically on
48V Phantom power is switched off.
2
Electronic Data Sheet of Measurement Microphone
Read out data from the connected microphone.
3
Factory Sensitivity
Factory sensitivity of the connected sensor.
4
Level Type
L
ZF
Default setting.
L
HP100F
Suppressing any low frequency noise, for
example wind during outdoor calibrations.
159
Calibration
5
Start Field Calibration
Select RUN and press enter to start the sensitivity setting
using an external calibrator.
6
Level of External Calibrator
The reference calibration level is 114 dB. The XL2 Supports
a level setting between 0 dB and 200 dB.
7
Sensitivity
Applicable microphone sensitivity in the range from
1 µV/Pa to 9.99 V/Pa. The sensor detection of the XL2 reads
the sensitivity automatically from the electronic datasheet
of the connected NTi Audio microphone or preamplifier.
8
Spectral Correction
Select one of the spectral corrections as applicable. This
selection can be activated in the System Settings Set page
at position
11
. The correction data is listed in chapter Tech-
nical Data.
Off no spectral correction.
WP30 1/2”
Community
for horizontal noise incidents using
the WP30 Weather Protection
8
WP30 1/2”
Aircraft
for vertical noise incidents using the
WP30 Weather Protection; no spec-
tral correction applies
WP61 1/4”
Community
for horizontal noise incidents using
the WP61 Weather Protection
WP61 1/4”
Aircraft
for vertical noise incidents using the
WP61 Weather Protection; no spec-
tral correction applies
M22xx DF 1/2” Diffuse-field correction for measure-
ment microphones M2230, M2340,
M2215, M2211
M42xx DF 1/4” Diffuse-field correction for measure-
ment microphone M4261
9
Selection Sound Level Meter / Vibration Meter
Sound Sound Level Meter
Vibration Vibration Meter
160
Calibration
10
Unit Selection Accelerometer Sensitivity
The accelerometer sensitivity is provided in the range of
• 1 µV/(m/s2) - 10.0 V/(m/s2) or
• 10 µV/g - 100 V/g
Field Calibration - With External Sound Calibrator
Field-sensitivity setting for measurement microphones with an
external calibrator.
• Turn the rotary wheel
to select the parameter User Cali-
bration
6
and press enter
.
• Set the calibration level according to the calibrator used.
• Generate the specific reference signal with the calibrator
onto the microphone.
• Turn the rotary wheel
to select the parameter RUN
5
and press enter
.
• The pop-up window Calibration: Calibration running ... ap-
pears and changes to Calibration: Successfully finished!
for a successfully completed calibration.
Field Calibration - Manual Sensitivity Setting
In case no external calibration device is available, set the sensi-
tivity of non-NTi Audio sensors manually according to the prod-
uct specifications as follows:
• Select Sensitivity
7
with the rotary wheel
.
• Press enter
and adjust the sensitivity with the rotary
wheel
.
• Confirm with enter
.
Field Sensitivity
The XL2 writes the field-sensitivity setting onto
the electronic data sheet of the connected NTi
Audio measurement microphone, microphone
preamplifier or ASD Adapter. All subsequent
measurements automatically utilize this field-
sensitivity.
In case the measured sensitivity deviates ±1.5
dB for a class 1 microphone and ±3 dB for a
class 2 microphone to the nominal microphone
sensitivity, then the XL2 displays the following
message: Measured sensitivity to far (xxdB)
from factory settings. Check calibration level
and microphone!
In doubts kindly contact NTi Audio with the de-
tails.
161
Calibration
Free-field Correction
The following free-field correction shall be applied using the
NTi Audio Class 1 Sound Calibrator
• M2230, M2340, M2211, M2215: -0.1 dB
The following correction shall be applied using the NTi Audio
Class 1 Sound Calibrator with 1/4” adapter ADP 1/4-P
• M4260: +0.1 dB
• M4261: +0.2 dB
The NTi Audio microphones are free-field equalized measure-
ment microphone. Thus, they already compensate the in-
creased level by the presence of the microphone body in the
free-field. Pressure conditions apply during the calibration.
Therefore, the level in front of the 1/2” microphone diaphragm
differs by -0.08 dB with reference ambient conditions.
• M2230 with 50 mm Wind Screen
The correction value is +0.12 dB and the XL2 has to be set
to a calibration level of 114.0 dB (=114-0.08+0.12).
• M2230, M2340 with 90 mm Wind Screen
The correction value is +0.19 dB and the calibration level on
the XL2 has to be set to 114.1 dB (=114-0.08+0.19).
• M2230, M2340 with WP30 Wind Screen 90 mm
The correction value is +0.19 dB and the calibration level on
the XL2 has to be set to 114.1 dB (=114-0.08+0.19).
Example - Field Calibration
• Configuration
- XL2 + M2230 Measurement Microphone
- NTi Audio Class 1 Sound Calibrator @ 114.0 dB
• The level
1
at User Calibration shall be set to 113.9 dB
(=114.0 - 0.1).
1
• Select the parameter RUN and press enter .
The field calibration is completed.
162
Calibration
Applying Correction Values @ M2230
The goal is to measure the sound pressure without the influence
of the microphone in the air. However, the presence of the mi-
crophone body in the free-field environment affects already the
sound pressure level at high frequencies. The measurement mi-
crophone acts at high frequencies like a reflector. The sound
pressure increases in front of the microphone capsule mem-
brane. For example, the sound pressure level is 114.0 dB in the
free field prior installing the microphone. Now the measurement
microphone is placed into the free field. The pressure in front of
the capsule is increased by 0.1 dB at 1 kHz. However, since the
sound without microphone influence shall be determined, the
free-field equalization of the M2230 compensates this effect. The
XL2 Sound Level Meter reads the accurate measured value of
114.0 dB and not 114.1 dB.
If the Class 1 Sound Calibrator is placed on the M2230 measure-
ment microphone, then the pressure conditions applies to the
microphone capsule. The pressure in the volume of the calibrator
matches the pressure on the membrane surface of the micro-
phone. Now the free-field equalization and the pressure condi-
tions for the calibration have to be taken into account. Thus, the
XL2 has to be adjusted to a calibration level of 113.9 dB when us-
ing the M2230. This applies for calibrations at reference ambient
conditions and an accurate calibrator output level at the reference
sound pressure level.
163
Profiles
9. Profiles
Profiles are templates of measurement setups. You may define
which profile is loaded at startup, so that the measurements
are carried out always with the same setup and instrument set-
tings.
A remarkable advantage of the XL2 is the flexible user inter-
face. The measurement screens may be personalized and only
a limited subset of the comprehensive functionality enabled
to create simplified operator interfaces. Advanced users may
access all menus, settings and store their preferred measure-
ment configurations. For simplicity the XL2 Audio and Acoustic
Analyzer offers fixed operator interfaces with specific pre-de-
fined settings. The XL2 can boot up with exactly the required
measurement parameters according to the pre-defined instru-
ment configurations. This ensures accurate measurements are
achieved in both advanced and basic usage environments.
Profiles - Getting Started
Activate Profile Selection at Startup
• Select Show profile list
1
in the System menu.
• Press enter
to activate Ye s . This will show the profile list
at startup.
1
The profile list is shown next time you power up the XL2.
164
Profiles
Preset Measurement Function
• Start the XL2 Analyzer in Full mode.
• Select the typically-used measurement function and adjust
the measurement parameters according to the requirements.
For example, measuring the sound levels L
AF
, L
Aeq
and
L
AFmax
for 10 seconds:
Store MyProfile
• Select Profile in the main menu and press enter
.
The profile menu opens.
165
Profiles
• Select Manage and press enter .
The Manage Profile menu opens.
Each stored profile includes all settings of all
measurement functions and pages. Only the
following details are not stored:
• Calibration settings
• System settings
• Temperature unit
• Phantom power on/off
• Select Save Profile and press enter
.
The Save Profile menu opens.
• Select Rename and press enter .
• Set the profile name to MyProfile. The maximum name
length is 20 characters.
166
Profiles
• Select Configure available screens and press enter .
• Select additional available pages/measurement functions for
the profile; e.g. RTA
.
• Press escape
to return to the Save Profile screen.
• Set Append mode available: yes in order to have the ap-
pend data feature available in the memory menu
.
• You may enable manual measurement range setting within
your profile. Select Allow manual ranging: yes.
• The correction values defined in K
SET
may be part of the
profile for selectable profiles with different corrections.
• Select Save and press enter
.
Select Profile at Startup
• Switch on the XL2
The profile selection is shown on the display.
• Select the profile MyProfile and press enter .
The XL2 starts up with the pre-configured settings for
sound level monitoring.
167
Profiles
Select Profile during Operation
• Select Profile in the main menu and press enter
.
The profile menu opens.
• Choose Select and load the required profile.
Run Measurement
The profile name is displayed when a measurement function
is highlighted. The main menu offers only the measurement
functions enabled by the profile, plus the calibration and profile
menu.
• Press start
.
• Wait 10 seconds until the measurement is finished.
• To return to the full mode either switch off the XL2
again
or select EXIT Profile in the main menu.
168
Profiles
Export MyProfile to PC
If you have two or more XL2 Audio and Acoustic Analyzers,
you may like to transfer the same profiles to the other instru-
ments.
• Select Profile in the main menu and press enter
.
• Select Manage and press enter
.
• Select Export to SD-Card and press enter
.
The XL2 generates a folder on the SD Card called “Profiles”.
All available profiles are exported into this folder.
• Connect the XL2 to the PC.
• Copy/paste the profile called MyProfile to the PC.
Import MyProfile from PC
• Connect another XL2 to the PC and generate a folder called
“Profiles” on the SD Card.
• Copy the profile called MyProfile into the folder “Profiles”.
• Start up the XL2, select Profile in the main menu and press
enter
.
• Select Manage and press enter
.
• Select Import from SD-Card and press enter
.
MyProfile is available on the other XL2 Analyzer.
If the profile is exported from an XL2 Analyzer
with activated options to another XL2 Analyzer
without options, then these options have to be
hidden prior to storing the profile for export:
• In the exporting XL2 system menu, select the
individual option and toggle with enter
to
Hidden.
• Store the profile in the XL2 Analyzer.
169
Profiles
The XL2 can store up to 20 individual profiles in the internal
system memory and offers three different profile types:
Types Description
Factory
default
profiles
The XL2 includes factory default profiles, which
are marked with “#” in the beginning of the file
name. Sample filename: #DIN15905-5.prfs
The factory default profiles are a free
download for all registered XL2 cus-
tomers on the support website at
https://my.nti-audio.com. For details see the
chapter My NTi Audio.
For detailed settings of factory default profiles
please see the Appendix 2 in this manual.
User
profiles
User profiles are profiles generated by you on
the XL2 Analyzer.
Sample filename: MyProfile.prfl
Secured
profiles
Secured profiles are locked user profiles with
overwrite protection indicated by the file name
ending in “xxx.prfs”. This file name cannot be
overwritten.
Sample filename: MyProfile.prfs
How to generate secured profiles
• Export the profiles to SD Card according to
the procedure in the chapter Profile - Getting
Started.
• Connect the XL2 to the PC.
• Select the user profile in the folder “Profile”.
• Manually change the ending of the user pro-
file from “xxx.prfl” to “xxx.prfs”
• Disconnect the XL2 from the PC.
• Import the profiles from the SD Card
• Power off/on
the XL2 Analyzer
The secured profile is displayed with a lock-
symbol in the profile selection window on
startup of the XL2.
170
Capture + Tolerances
10. Spectral Limits Option
(Capture + Tolerances)
The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high-
resolution 1/12 Oct + Tol spectral analysis.
Features:
• Capturing of multiple readings into the internal memory
• Comparing measurement results against captures with rela-
tive or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captures for passed /
failed measurements
Capture the EQ Measurement Results
• Select the Capture & Start Tolerance Mode symbol for cap-
turing the measurement result.
• Confirm with enter .
171
Capture + Tolerances
A pop-up window appears.
• Select Capture EQ.
• Confirm with enter
.
The pop-up window ... and store it to appears.
• Select C1.
• Confirm with enter
and set the capture name in the dis-
played letter selection box e.g. to Ref.
The capture has been stored in the internal XL2 memory.
172
Capture + Tolerances
Edit Capture Manually
• Select the Capture & Start Tolerance Mode symbol.
• Confirm with enter
.
• Select Manage captures.
• Confirm with enter
.
• Select Save to SD card.
The pop-up window Save captures appears.
• Select the capture to be exported, e.g. C1.
The pop-up window Save capture C1 to appears.
• Confirm with Save.
The XL2 generates the file MyCapture.txt in a new folder
called Captures.
• Edit the sound level data in the capture file. All frequency
data has to remain the same.
• Load the new capture file with Manage captures back into
the internal XL2 memory.
See the difference between Live Level and Capture
• Blank the upper parameter by setting ----.
• Select the lower parameter with the rotary wheel
.
• Confirm with enter
.
• Select Live and confirm with enter
.
The pop-up window Select reading mode appears.
• Select Live - for displaying the relative difference.
• Confirm with enter
.
• Select Ref and confirm with enter
.
• Set the Y-axis accordingly to show the zero-line.
173
Capture + Tolerances
The relative difference between the Live level and the cap-
tured reference is displayed.
All levels differences (relative levels) are dis-
played in the unit dBr.
Manual Editing of Capture Data
Kindly observe the following rules while manually editing cap-
ture data:
• The spectral level data is Z-weighted, thus the sum of all
bands has to equal the Z-weighted broadband level.
• The A and C-weighted broadband levels are calculated ob-
serving the corresponding correction factors.
• Enter -999 if nothing shall be deducted at certain broadband
levels or frequency bands.
%1/12OctaveAnalyzerCapture
%‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐DONOTEDITTHISSECTION‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
‐
#Capturetime
#Levelunit
dBr
#Octaveresolution
1/1Octave
%‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐EDITONLYLEVELSHERE!‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
‐
#A‐weightedbroadbandlevel
32.74
#C‐weightedbroadbandlevel
‐999
#Z‐weightedbroadbandlevel
33.17
#Columns
Frequency Level
#Spectrum
16 ‐999
31.5 ‐999
63 ‐999
125 10.5
250 20.5
500 25.7
1000 28.6
2000 25.5
4000 23.4
8000 24.5
16000 ‐999
22.04.201513:55
174
Capture + Tolerances
Start Tolerance Mode for Passed/Failed Measurements
• Select the Capture & Start Tolerance Mode symbol with the
rotary wheel
.
• Confirm with enter .
A pop-up window appears.
• Select Start tolerance mode.
• Confirm with enter
.
175
Capture + Tolerances
The pop-up window Make tolerance from appears.
• Select Ref to load the earlier captured reference spectrum.
• Confirm with enter
.
You may press the page button to toggle
between the date and spectral resolution data
of the capture.
Passed Result
The tolerance mode is active for passed/failed measure-
ments.
The passed/failed condition is further visualized by the bicolor
“limit” button and forwarded to the I/O interface of the instru-
ment in order to drive an external alarm device such as the
accessory SPL Stack Light.
2 3
1
176
Capture + Tolerances
1
PASSED / FAILED Result
PASSED The actual measurement result is within the
tolerance band.
The actual measurement result is outside of
the tolerance band. Exceptions are visual-
ized in any out-of-tolerance frequency band.
2
Tolerance Bandwidth
Adjusts the tolerance bandwidth based on the captured ref-
erence spectrum in dB.
3
Level Offset
Provides a level offset in dB to shift the tolerance band up
or down.
Failed Result
The XL2 Analyzer compares spectral measurements against a
tolerance band and visualizes exceptions
1
in every frequen-
cy band.
1
Select another Tolerance File
• Select the tolerance Ref with the rotary wheel
.
• Confirm with enter
.
• Select the new tolerance file from the SD Card or the internal
XL2 memory.
177
Capture + Tolerances
Tolerance Menu
2
1
3
1
Capture & Start Tolerance
Opens capture and tolerance menu.
2
Tolerance Type
Select between high/low, high or low tolerance band based
on the reference data set.
3
Frequency Range
Setting of start and stop frequency of the tolerance band.
Advanced Start Functions
You may start the passed/failed measurement in one of the
following ways:
• Press the XL2 start button
.
• Activate the automated level trigger in the tolerance file.
• Activate the digital input 1 via the external I/O interface; e.g.
a foot switch or a PLC control.
Digital I/O Interface
Result Passed: Output 1
Result Failed: Output 3
Start Measurement: Input 1
Tolerance Management
Tolerance curves can either be imported from txt-files or direct-
ly derived from captured measurements. The XL2 calculates
tolerance bands based on
• Single captured results
• txt-files generated manually on a PC
• Mean average of multiple captures
• Min/Max curves of multiple captures
178
Capture + Tolerances
Create Tolerance Files Manually on PC
• Capture a spectrum on the XL2 Analyzer.
• Enter the tolerance mode and generate a tolerance band for
the capture.
• Select the Capture & Start Tolerance Mode symbol.
• Confirm with enter
.
• Select Save tol. to SD Card to export the capture tolerance
file. This file includes the reference capture and the tolerance
data. The XL2 generates a txt-file in the folder “Tolerances”.
• Open the capture tolerance file with a text editor or MS Ex-
cel.
• Edit the tolerance data according to your requirements.
Change only the Min, Ideal and Max column values. You may
delete rows, but do not change the frequency column val-
ues. Any rows where frequency column values have been
changed will be discarded by the XL2.
• Store your individual tolerance file as a txt-file in the XL2
folder “Tolerances”.
• Start the XL2 tolerance mode and load the new tolerance file
from the SD Card.
• All entries in the customized tolerance file
need to be tab-separated.
• The individual tolerance file entries may be in
any order; no sequential order required.
• Tolerance file templates and standardized tol-
erance files are a free download for all regis-
tered XL2 customers on the support website
at https://my.nti-audio.com. For details see
the chapter My NTi Audio in this manual.
179
Capture + Tolerances
Band-limited Measurement Range
Alternatively to the settings on the XL2, the tolerance may also
be limited to a range of frequency bands or a number of indi-
vidual frequencies on a computer.
• Open the tolerance file on the computer.
• Delete all not required frequency bands.
• Set #Hide UnusedBands to True.
• Save the file changes.
• Load the updated tolerance file in the XL2.
The XL2 shows selectable broadband values with A, C or Z-
weighting on the right-hand side of the spectrum.
Alternatively select the following averaged or summed levels:
• Bands E-Sum: Sum of displayed frequency bands
• Bands E-Mean: Energy-averaged level of displayed frequen-
cy bands, e.g. the bands 80 dB and 70 dB produce 77.4 dB.
• Bands A-Mean: Arithmetically-averaged level of displayed
frequency bands, e.g. the bands 80 dB and 70 dB produce
75 dB.
180
Capture + Tolerances
#Unit
dBr
#Mode
HighLow
#Columns
Frequency Min Ideal Max
#ATolerances
UNDEF 80 unde
f
90
#ZTolerances
UNDEF 80 unde
f
90
#BandTolerances
20 70 unde
f
80
1000 70 unde
f
80
1000 73 unde
f
77
4000 73 unde
f
77
4000 70 unde
f
80
20000 70 unde
f
80
#LevelOffset
0
#HideUnusedBands
false
#nAllowedViolations
0
#Unit dBr (relative), fixed setting
#Mode Describes tolerance type; the XL2 allows set-
ting of the tolerance type independently of the
tolerance file.
HighLow Utilizes upper and lower toler-
ance based on ideal reference.
High Utilizes only upper tolerance
based on ideal reference.
Low Utilizes only lower tolerance
based on ideal reference.
#Columns Column headings for further tolerance data
separated into columns:
Frequency / Min / Ideal / Max
#ATolerances Defines the tolerance band for the
A-weighted wideband level (not mandatory).
#CTolerances Defines the tolerance band for the
C-weighted wideband level (not mandatory).
181
Capture + Tolerances
#ZTolerances Defines the tolerance band for the
Z-weighted wideband level (not mandatory).
#BandSum
Tolerances
Defines the tolerance band for the
sum of displayed frequency bands (not man-
datory).
#Band
Tolerances
• Defines the tolerance band for the individual
frequencies.
• The ideal parameter can be set as “undef”.
• The same frequency value on two succes-
sive rows defines a tolerance step, e.g.:
Frequency Min Ideal Max
100 70 75 80
500 70 75 80
500 75 80 90
1000 75 80 90
#LevelOffset All levels in the tolerance file are relative levels
dBr. Thus, the level offset provides the relation
between the relative level and actual sound
pressure level. (not mandatory)
The XL2 allows setting of the level offset inde-
pendently of the tolerance file.
#Hide
UnusedBands
Defines the way measurement results are
shown.
Tru e Measurement results of fre-
quency bands without any
specified tolerance are not
displayed. The total level of all
shown bands (sum of bands) is
available as a broadband result.
False The measurement result of all
frequency bands are shown.
#nAllowed
Violations
Allows a PASSED result with a maximum
number of n failed frequency bands (not man-
datory)
182
Capture + Tolerances
#FreqScale
Spacing
Defines the frequency scale spacing in the X-
axis for the tolerance data. (not mandatory)
lin Tolerance data displayed with
linear frequency spacing, e.g.
used in the FFT function. (de-
fault setting)
log Tolerance data displayed with
logarithmic frequency spacing
e.g. used in the 1/12 Oct + Tol
function.
#AutoStart Enables auto start function. (not mandatory)
Tru e Auto start is active. The run indi-
cation displays A. The measure-
ment starts automatically after
the trigger level is reached.
Alternatively the measurement
may start manually by pressing
start
.
False No auto start function. (default
setting)
#AutoStartTrig-
gerLevel
Sets the sound level in dBZ for an automated
level trigger; the passed/failed measurement
starts as soon as the set level e.g. 95 dB is
reached or exceeded. The actual input level
can be monitored at the input range bar. (man-
datory if #AutoStart is Tr u e )
#AutoStartSet-
tlingTime
Defines the settling time, after the auto start
trigger level is exceeded, until the start of the
measurement; the time is set in 100 millisec-
ond steps e.g. setting 0.5 equals a settling
time of 0.5 seconds. If the input level drops
below the auto start trigger level during this
period, no measurement is carried out. (not
mandatory)
#MeasTime Defines the measurement time in 100 millisec-
ond steps; e.g. setting 1.5 equals a measure-
ment period of 1.5 seconds. (not mandatory)
#FailDeadTime Defines the delay for a failed condition in sec-
onds; for example, the XL2 triggers “failed” if
the measurement result is beyond the toler-
ance limits for e.g. 60 seconds. This feature
supports condition monitoring applications.
(not mandatory)
183
System Settings
11. System Settings
The various system settings of the instrument can be adjusted
as follows: Turn the rotary wheel
to navigate to the main
menu
1
and select System. Confirm with enter
.
Settings
1
3
4
8
9
2
5
10
6
7
11
2
Page Selector
Toggles with the page button
between
Set System setting
Vib Vibration (applicable only upon installing the Vibra-
tion option and selecting the vibration menu)
Sch Scheduler
Opt Options
Inf System information
3
Auto power off
If no button has been pressed for the defined time period,
then the instrument switches off. The auto power off mode
is disabled when a measurement is running or when an
external mains power supply is used.
• Select Auto power off with the rotary wheel
.
• Confirm with enter
.
• Set the auto power off time with the rotary wheel
.
• Confirm with enter
.
184
System Settings
4
Backlight
Toggle the backlight with the power/backlight button
.
The backlight offers three different conditions:
• On
• Dimmed
• Off
Auto On/Off The backlight switches off if no key is
pressed for 2 minutes.
Auto
On/Dimmed
The backlight dims if no key is pressed
for 2 minutes.
Manual The backlight can be toggled between
On, Dimmed and Off.
• Navigate the cursor to the backlight function.
• Toggle with enter
to set this parameter.
Dimming the backlight reduces the power
consumption.
5
Date and Time Setting
The XL2 includes a real-time clock. All measurements are
logged with a date and time stamp.
Time Zone Select your time zone
DST/ Sum-
mer time
Activate this for daylight saving
Date Date in yyyy:mm:dd
Time Time in hh:mm:ss
Set the real-time clock as follows:
• Select the Date function
5
with the rotary wheel
.
• Confirm with enter
.
• Set the date with the rotary wheel
.
• Confirm each setting with enter
.
• Follow the same procedure for Time.
You have set the real-time clock.
185
System Settings
6
Show Profile List
You may configure the XL2 to start up with individual preset
application profiles. For example, sound level monitoring in
accordance with DIN 15905 or V-NISSG.
Ye s The instrument starts up with default application
profiles. Further details about the application pro-
files are in the chapter Profiles.
No The instrument starts up in the last configuration
without any application profiles.
7
Phantom Power
You can select if the phantom power should be activated or
disabled when the XL2 is powered up.
Off The phantom power is switched off when
the XL2 is powered up; e.g. when it is
common to measure lines.
Remember The XL2 remembers the setting prior to
the last shutdown. (= default setting)
8
Speaker
Enables/disables the rear speaker. For example, it is recom-
mended that the rear speaker be disabled for all acoustic
measurements. This prevents measuring the audio feed-
back sound loop generated through the rear speaker.
9
USB Mode
This defines how the PC recognizes the connected XL2:
Ask on
connect
Select either the Mass storage or COM port
mode after connecting the XL2 to the PC.
Mass
storage
The PC recognizes the XL2 as a mass storage
device automatically, allowing you to down-
load XL2 measurement reports.
COM
port
The PC recognizes the XL2 as a COM port au-
tomatically for application of the XL2 Projector
PRO and the Remote Measurement Option.
186
System Settings
10
Decimal Separator
Set the decimal separator to match the generated mea-
surement reports to the PC settings. This simplifies data
post-processing on the PC.
• Navigate to the Dec. Separator function
8
with the ro-
tary wheel
.
• Toggle between “ . ” and “ , ” with enter
to set this
parameter.
The decimal separator is set.
11
Calibration Menu Setting
Setting of the calibration menu.
Standard The default calibration menu is displayed.
Show
Spec.
Corr.
This setting is required to activate the re-
quired weather protection or diffuse-field
correction in the calibration menu.
Vibration
This page is available upon switching to the vibration menu,
which requires an installed Vibration-Option. Vibration is select-
ed in the calibration menu.
2
1
1
Selection Metrical-Imperial Units
Units selection
2
dB Reference
Definition of the reference parameters for dB results
187
System Settings
Scheduler
1
2
3
4
5
6
7
The XL2 Analyzer offers automated scheduled measurements
without any human interaction. You may schedule a measure-
ment for one or multiple days or ever.
XL2 Actions after pressing Start Schedule
• Selects the preset measurement function.
• Standby until start time
• Starts measurement at start time
• Stops measurement after the preset measurement duration
• Stores measurement data to SD Card (no reconfirmation re-
quired)
• Stops schedule or standby until next start time.
Supported measurement functions:
• SLMeter/RTA
• FFT + Tol
• RT60
• 1/12 Oct + Tol
• STIPA
188
System Settings
1
Function
Select the measurement functions for the scheduled mea-
surements.
2
Start Date and Time
Set the date for the scheduled measurement(s):
• Select Start with the rotary wheel
.
• Confirm with enter
.
• Set the date with the rotary wheel
.
• Confirm each setting with enter
.
Set the time for the scheduled measurement:
• Select the T symbol to the right of the date.
• Confirm with enter
.
• Set the time with the rotary wheel
.
• Confirm each setting with enter
.
3
Scheduled Duration
Set the scheduled duration of the measurement(s). The ac-
tual settings of the selected measurement function apply.
4
Recurrence
Off Schedules a single measurement.
On Schedules a measurement sequence with the
same start and end time for the selected days.
5
Days
Select the week days for the recurrence
6
End
Set the number of occurrences of the scheduled measure-
ment. Each week day is one occurrence. Select between
1 to 99 occurrences or an endless schedule (= never).
7
Start Schedule
Starts the scheduled measurement(s).
The Scheduler active window is displayed.
189
System Settings
Scheduling - Getting Started
After starting the scheduled measurement, the XL2 waits for
the next scheduled start date and time. The instrument buttons
are disabled.
Power Supply
It is recommended that the instrument remains powered on
until the next start time, using the accessory mains power
adapter. If the XL2 is powered off and on again during this time,
then the XL2 Analyzer restarts in the Scheduler function and
continues the countdown. This applies also for any interruption
of mains power supply.
Stopping the Scheduler
Press and hold the start/stop button
to stop the scheduler
prior to the start of the measurement or as an interrupt of any
ongoing scheduled measurement.
Operation with PC
Starting the schedule switches the USB interface automatically
into the COM port mode for remote measurement applications
or using the XL2 Projector PRO software.
Options
Displays the options installed on the XL2.
Every installed option may be temporarily Hidden to generate
a profile for other XL2s without this option installed.
• Select the installed option.
• Toggle with enter
to set this parameter.
190
System Settings
Information
1
2
1
Serial Number
Displays the instrument’s serial number.
2
Firmware
Displays of the firmware version number (to update the
firmware to the latest version see the chapter Firmware
Update of XL2.
191
Data Management
12. Data Management
The XL2 stores all acquired measurement data including real-
time information onto the removable SD Card. Additionally,
wav-files might be recorded and individual voice notes added
for a complete documentation of the measurement.
• Carry out a sound level measurement.
• Select the memory menu
in the upper menu bar.
• Press enter
. The memory menu opens.
1 2
4
3
5
6
7
8
9
10
1
Create New Project Folder
Add a new folder with an individual project name. The maxi-
mum length of the project name is 16 characters. A fast
way for creating new folder names is
• Select an existing folder name with DIR
• Select NEW
• Rename the folder and confirm with start
, thereby
creating a new folder name.
2
Select Project Folder
An overview of all existing project folders is shown. Select
a folder to store the results of the measurements.
3
Project Folder Name
All measurements are stored in this project folder.
4
Autosave
Setting of auto or manual data file naming and saving
On The results are named and stored automati-
cally in the selected project folder.
Off A question mark appears in the upper menu
bar
at the end of the measurement. You
can choose to individually name and store
each single measurement.
192
Data Management
Assisted A pop up menu appears after each measure-
ment. You may select to keep or delete the
stored measurement records.
5
Save Test
Stores the measurement in the selected project folder.
6
Save Screenshot
Stores the XL2 screen in the selected project folder.
7
Load Test
Loads back previously-stored result data from the SD Card
for detailed examination on the instrument screen.
8
Append Mode
The append mode stores one or more results into the same
data file, simplifying data analysis and handling on the PC.
Application example:
When measuring the acoustic spectrum at various loca-
tions within the same venue, the append mode allows you
to store all the measurement results into one single data
file.
9
Free Memory
Displays the remaining available memory on the SD Card.
The XL2 prevents a memory overflow. SD Cards are not de-
signed for a 100% memory usage; the XL2 keeps at least
2% or 50 MB empty.
The XL2 deactivates the audio recording 50 MB before this
limit is reached and reports this on the display.
In the case where only 2% or 50 MB remains, the XL2
• deactivates the data logging and reports this on the dis-
play.
• disables Save Test and Autosave
• saves the report at the end of the current measure-
ment.
193
Data Management
10
Write Cache (available with Extended Acoustic Pack)
A low Write Cache level indicates that the SD Card is per-
forming well. The optional Extended Acoustic Pack with
simultaneous 100ms logging and linear wav-file recording
results in high data volumes being written to the SD Card.
Some non-original SD Cards may overload (OVLD), caus-
ing the loss of some measurement data. Verify the Write
Cache of your SD Card during your measurements. Use
only original SD Cards. We recommend SD Cards from the
manufacturers SanDisk and Transcend.
Original SD Cards ensure that all measurement
data and audio wav-files are stored in good or-
der on the SD Card. Non-original SD Cards may
lead to low performance or errors.
Order information: see chapter Accessories.
In case the SD Card is full, you can insert the
original spare SD Card into the XL2 and contin-
ue with the measurements. The XL2 generates
the projects and system folders automatically.
Memory Structure of SD Card
1
2
3
1
Projects
The folder Projects contains subfolders with the stored
measurement results. The default subfolder name is
“MyProject”. You can create further individual subfolders.
2
XL2.htm
This file opens the XL2 instrument status page, with Serial
Number, Firmware and Installed Options.
The page also provides links for online
• Firmware updates
• Activation of Options
3
XL2_SYS
The XL2 system folder contains a file with serial number,
firmware version and installed options - DO NOT EDIT THIS
FILE.
194
Data Management
Measurement Data - Getting Started
Enable Data Logging
• Select the Log page in the sound level meter function and
set the logging parameters; e.g., as follows:
The data logging is enabled. The sound pressure level will
be logged each second while the measurement is running.
Select Parameters for Measurement Report
• Select the Rep page in the sound level meter function and
set the parameters as follows:
195
Data Management
Complete the Measurement
• Press page
to return to the numeric result page.
• Press start
. The sound level measurement is now run-
ning.
• Press stop
to complete the sound level measurement.
The measurement data is stored automatically using the
factory settings. In the memory menu
„Autosave: As-
sisted” is activated.
Manual Data Saving
• In the case when the instrument is used with the setting
Autosave: Off, a question mark appears after the completed
measurement
.
• Now you may store the measurement data manually.
• Select the memory menu
with the rotary wheel and
confirm with enter
.
• Press enter to confirm Save Test.
The pop-up window Save Test appears.
196
Data Management
Select File Name
• Name the first part of the file name. The maximum length of
the first part is 12 characters. The next part “_SLM_001” is
defined by the XL2 to avoid overwriting of existing measure-
ments, whereby “SLM” is the appendix for the measure-
ment function and “001” is an automatically-incrementing
number.
Predefined Save Names
Generate a text file with user defined save
names, such as “Room1”, “Room2”, ..., and
store it as “savenames.txt” in the root directory
of the XL2. Just use names with letters or num-
bers - special characters are not supported.
The XL2 displays the first line of the txt-file in
the Save Test selection menu at manual data
saving.
197
Data Management
Record Voice Notes
With the internal voice note microphone, record a Voicenote
to save with the test to remind yourself at a later stage where
and/or under which conditions the measurement was done.
• Select Record Voicenote and press enter
.
• Select REC and press enter .
• Record the voice note and press enter
to finish.
The voice note has been recorded.
Save Measurement Data
• Select SAVE and confirm with enter .
The measurement data including test configurations and all
log files are stored on the SD Card.
Overwrite File
Disabling Automatic Numbering allows results
to be overwritten with new results.
198
Data Management
Save Screenshot
• Select the memory menu
with the rotary wheel and
confirm with enter
.
The memory menu opens.
• Select Save Screenshot and press enter
.
• Select the file name and confirm SAVE with enter
.
The screenshot is saved to the SD Card.
Measurement Data Logging:
If the battery runs out while you are measur-
ing with logging and/or repeated-reporting en-
abled, the XL2 creates the folder RESTORE_AF-
TER_POWERFAIL and stores the measurement
data up until the switch-off time. The next time
you switch on the XL2, the following window
informs you that this data exists. Click OK:
There may be invalid data at the end of the file,
which you can delete manually to create a valid
report.
199
Data Management
View Project Folder on the PC
• Connect the XL2 with the USB cable to the PC.
The pop-up window USB Mode appears.
• Select Mass Storage and confirm with enter .
The PC recognizes the XL2 as a mass storage device. The
following SD Card content is shown:
• Open the folder “Projects” and the subfolder “MyProject”.
All stored measurement data files are shown.
If the XL2 is started with USB connection to PC,
then the COM port mode is automatically acti-
vated for remote measurement or the XL2 Pro-
jector PRO software. Therefore, if you want to
access the data in the SD Card, then first start
the XL2 and thereafter connect the USB cable
to the PC.
200
Data Management
Overview of Measurement Data Files
1
2
3
4
5
6
7
1
Test System File
System file for use by XL2 only. It contains the measure-
ment data and test configuration of the last measurement
cycle for later reload and view of measurement results in
the XL2.
2
Sound Level Log File
The XL2 logs sound levels in pre-defined log time intervals.
For more details please see the chapter Sound Level Me-
ter: Logging.
3
Measurement Report File
Final report after the completed measurement. For more
details please see the chapter Sound Level Meter: Report-
ing.
4
Wav-File
The wav-file is the recorded audio file. The index
“FS133.0dB(PK)” in file name represents the full-scale
peak level of the recorded wav-file. For more details please
see the chapter Sound Level Meter: Wav-File Recording.
5
RTA Log File
The XL2 logs the detailed real-time analyzer spectra in pre-
defined time intervals. For more details please see chapter
Sound Level Meter: Logging.
6
Voice Note
A voice annotation can be recorded for each stored mea-
surement or screenshot. For more details please see the
chapter Data Management: Voice Notes.
7
Screenshot
Picture of the actual XL2 display.
201
Data Management
The log data file may become very big during
long-term measurement applications. As soon
the file size reaches 2 GB during the ongoing
measurement, the file is saved with the index 1
and a new data file created with index 2.
XL2 Data Explorer Software combines all these
data files together seamlessly.
Transfer Measurement Data to PC
• Drag and drop the required data files to the PC.
Card Reader
Alternatively the SD Card can be inserted into
a card reader. This offers a faster data transfer
from the SD Card to the PC.
Additional Data Files using Repeat Mode
For sound level measurements with timer mode
Repeat or Repeat Synchronized the following
additional data files are generated:
• MyTest_SLM_000_123_Report_Rep.txt
• MyTest_SLM_000_RTA_Report_Rep.txt
Common xxx_Report.txt files contain the mea-
surement data of the last measurement cycle.
The xxx_Report_Rep.txt file contains the results
of all measurement cycles in the Repeat or Re-
peat Synchronized mode.
Microsoft Excel
The generated .txt files are best viewed on the
PC using “Open with” -> Microsoft Excel.
202
Data Management
Log File Format
File name: e.g. MyTest_SLM_000_123_Log.txt
XL2 Broadband Logging MyProjects\MyTest_SLM_000_123_Log.txt
---------------------
# Hardware Configuration
Device Info:
XL2, SNo. A2A-02673-D1, FW2.20
Mic Type: NTi Audio M4260, S/N: 1486, User calibrated 2011-04-05 13:56
Mic Sensitivity: 27.3 mV/Pa
# Measurement Setup
Timer mode: continuous
Timer set: --:--:--
Log-Interval: 00:00:01
k1: 0.0 dB
k2: 0.0 dB
kset Date: k-Values not measured
Range: 30 - 130 dB
# Time
Start: 201
1-05-15, 17:44:06
End: 2011-05-15, 17:44:16
# Broadband LOG Results
Date Time Timer LAeq_dt LAeq LAFmax_dt LCPKmax_dt
[YYYY-MM-DD] [hh:mm:ss] [hh:mm:ss] [dB] [dB] [dB] [dB]
15.11.2010 17:44:07 00:00:01 97.0 97.0 102.4 119.0
15.11.2010 17:44:08 00:00:02 85.8 94.3 91.9 105.7
15.11.2010 17:44:09 00:00:03 73.8 92.5 85.2 102.4
15.11.2010 17:44:10 00:00:04 79.0 91.4 85.3 103.9
15.11.2010 17:44:11 00:00:05 72.6 90.4 75.9 94.8
15.11.2010 17:44:12 00:00:06 67.3 89.6 71.4 87.3
15.11.2010 17:44:13 00:00:07 91.2 89.9 95.3 112.3
15.11.2010 17:44:14 00:00:08 92.7 90.4 97.1 113.2
15.11.2010 17:44:15 00:00:09 79.3 89.9 81.6 97.9
15.11.2010 17:44:16 00:00:10 78.0 89.5 82.5 98.1
15.11.2010 17:44:16 00:00:10 50.9 89.3 67.4 79.9
# Broadband LOG Results over whole log period
15.11.2010 17:44:16 00:00:10 89.3 89.3 102.4 119
Level LAeq_dt “delta t”
Level within the logging interval. e.g. If the logging
interval is 1 second, then LAeq_dt is the time-
averaged level of each second.
Report File Format
File name: e.g. MyTest_SLM_000_123_Report.txt
XL2 Sound Level Meter Broadband Reporting MyProjects\MyTest_SLM_000_123_Report.txt
-----------------------------------------
# Hardware Configuration
Device Info:
XL2, SNo. A2A-02673-D1, FW2.
20
Mic Type: NTi Audio M4260, S/N: 1486, User calibrated 2010-11-05 13:56
Mic Sensitivity:
27.3 mV/Pa
# Measurement Setup
Append mode: OFF
Timer mode: continuous
Timer set: --:--:--
k1: 0.0 dB
k2: 0.0 dB
kset Date: k-Values not measured
Range: 30 - 130 dB
# Broadband Results
Start Stop
Date Time Date Time LAeq LCPKmax
[YYYY-MM-DD] [hh:mm:ss] [YYYY-MM-DD] [hh:mm:ss] [dB] [dB]
15.11.2010 17:44:06 15.11.2010 17:44:16 89.3 119.0
Data Post-Processing
A Microsoft Excel form generating an automated sound level
measurement report and chart is available as a free download
for all registered XL2 customers on the support website at
https://my.nti-audio.com. (Enable all macros when opening the
document.)
203
Data Management
XL2 File Validator
A check sum is written to the file at the end of every measure-
ment report. The XL2 Analyzer calculates the check sum auto-
matically based on the data content of the file. Using the XL2
File Validator PC-software, the contents of a data file may be
verified at any time. e.g. authorities can verify if the XL2 report
file is original or the data has been manually modified.
The software ”XL2 File Validator” is available for download for
all registered XL2 customers at https://my.nti-audio.com.
Recall Measurements
The straight-forward but powerful Load Test and Save Test
functions serve the dual purpose of conveniently retrieving
standard test setups for repeat testing and also of saving
stored result data for later recall and examination on screen.
The following measurement functions support the recall func-
tion:
• SLMeter, sound level meter
• FFT Analysis
• RT60 Reverberation time
• 1/12 Octave Band Analysis
• Noise Curves
• STIPA, speech intelligibility measurement
204
Data Management
Load Test
• Select the memory menu
with the rotary wheel and
confirm with enter
.
The memory menu opens.
Select File Name
• Select Load Test and confirm with enter
.
The pop-up window Load Test appears.
• Select the project folder and stored data file name with DIR.
• Select LOAD, confirm with enter
.
205
Data Management
View Measurement Data
The previously stored measurement data is displayed.
1
The run indication
1
shows the pause symbol.
You may continue with the measurements di-
rectly, e.g., choose the measurement function,
setup parameters and press start
.
Append Measurements
The append mode stores the results of several individual mea-
surements into the same data file, thus simplifying measure-
ment result analysis and data handling on the PC.
The following measurement functions support the append
mode:
• SLMeter, sound level meter
• STIPA, speech intelligibility measurement
Application example:
The sound level L
Aeq
shall be measured at various locations in
the same venue hall using a pink noise test signal. The append
mode allows to store all individual measurement results into
one single data file.
Backup the stored measurement data from the
XL2 to the PC daily. This prevents any data loss
if data has been deleted from the SD Card by
mistake.
206
Data Management
Start the Append Mode
• Select SLMeter and preselect the sound level L
Aeq
.
• Select the memory menu
with the rotary wheel and
confirm with enter
.
The memory menu opens.
• Select Start Append Mode and confirm with enter
.
The Start Append Mode window opens.
Select Filename
• Name the first part of the file name. The maximum length of
the first part is 12 characters. The next part “_SLM_001” is
defined by the XL2 to avoid overwriting of existing measure-
ments, whereby “SLM” is the appendix for the measure-
ment function and “001” is an automatically-incrementing
number.
• Select START and confirm with enter
.
The append mode is available.
207
Data Management
Take Measurement Results
• Measure the sound level L
Aeq
on the first position.
• Select the memory menu and Append Data.
In append mode, the XL2 does not store:
• Log files
• Wav-files
• Repeated report files generated in timer
mode repeat and repeat synchronized.
Store Measurement Results
The pop-up window Append Data appears.
• Select the location ID and measurement ID, thus each mea-
surement result is stored with an individual description for
later documentation.
• Select Append with the rotary wheel
and confirm with
enter
.
The measurement data is stored on the SD Card.
208
Data Management
Append Further Measurement Results
• Move to the next location in the room, carry out the mea-
surement and follow the described append data procedure.
Exit Append Mode
• Open the memory menu
.
• Select Exit Append after adding the last measurement.
Auto Append
Alternatively the XL2 can append measurement
data to the same report file automatically.
• Start the Append mode and set Auto Append
is ON in the memory menu or in the pop-up
window Start Append Mode.
Skip Append Data
If you select SKIP in the Append Data window,
then no measurement data is appended to the
report file.
Append After Power Up
You can continue to add measurement results into the same
data file at any time later.
• Store the measurements in the append mode and switch the
XL2 off and on again
.
The pop-up window Continue append appears.
• Select Ye s and continue adding measurement results to the
same report file in the append mode.
209
Data Management
Recall Previous Measurements for Append
Any previously stored measurement with the remark for ap-
pend can be recalled and further test records appended.
• Select Load Test and press enter
.
• Select the project folder and stored data file name.
• Select LOAD confirm with enter
.
The pop-up window Load for Append appears.
• Select Continue and add further measurements to the same
report file in the append mode.
210
XL2 Projector PRO
13. XL2 Projector PRO Software
The Projector PRO displays the XL2 screen in real-time via
USB on the connected Windows or Mac computer. The soft-
ware toolbar enables control of the XL2 with the mouse and
keyboard. The background color turns from green to red syn-
chronized with the XL2 limit button color
according to the
user-defined limits.
The “XL View” and the “Sound Level Predictor” display extend
the XL2 Projector PRO for live sound monitoring applications.
• The “XL View” window presents sound levels in large size
on the connected computer screen. Users may select to
view one, two or three sound pressure levels. Exceeding
levels are presented with a pre-warning amber or alarming
red color.
• The “Sound Level Predictor” visualizes the level history of
the current measurement interval and indicates the head-
room for the actual measurement period or the next few
minutes. Green bars confirm that the present level is well be-
low limits. Red bars are a call to action to reduce the sound
level at the mixing desk. This allows the FOH engineer to
optimize dynamic passages of the band for maximum audi-
ence satisfaction while still remaining within the legal limits.
Additionally, the Projector PRO software offers the ability to
retrieve measurement data from the XL2 without interruption
to the measurement process. The entire file system of the XL2
is available while the XL2 is measuring.
The “XL View” and the “Sound Level Predictor” require that
the Projector PRO Option or the Remote Measurement Option
be installed on the XL2.
Projector PRO software is a free download for all registered
XL2 customers on the support website https://my.nti-audio.
com.
Installation Instructions
• Register your XL2 and download the software from the sup-
port page at https://my.nti-audio.com.
• Unzip the file “XL2 Projector PRO Setup Vxx.zip“ on your
computer.
• Start the software installation and follow the instructions
including driver installation.
• Start the XL2 Projector PRO software.
• Start the XL2 Analyzer and connect it to the computer.
211
XL2 Projector PRO
The pop-up window USB Mode appears.
• Select COM port on the XL2.
• Microsoft Windows may recognize the new hardware au-
tomatically and start the hardware installation assistant. If
prompted, select “No connection to Windows Update” and
continue with the installation.
• Complete the installation.
XL2 Projector PRO displays the instrument screen in real-
time.
For more details and features see the XL2 Projector PRO user
manual at ? in the menu.
212
Data Explorer Software
14. Data Explorer (optional)
Data Explorer is a PC-based software application with a pow-
erful data processor for easy and fast analysis of sound level
measurement data. It is dedicated to acoustic consultants and
noise measurement professionals. Data Explorer provides a
convenient way to view, analyze and manage data and quickly
create customized reports.
Features of the Data Explorer software:
• Data visualization
• Fast zoom and pan
• Audio playback synchronized to graph
• Markers with on-the-fly calculations
• Automated tonal and impulsive marker generation
• Percentile levels Ln and Rating level Lr calculation
• Customized Reporting
Download the Data Explorer software from the XL2 Support
Page https://my.nti-audio.com.
XL2 Data Explorer Permanent
The Data Explorer Option enables the import of logged sound
level data into the Data Explorer software, a PC-based soft-
ware application with a powerful data processor for easy and
fast analysis of noise monitoring data.
Data Explorer 365
An annual subscription service for a XL2 Sound Level Meter is
offered alternatively to the permanently installed option.
Supported operating systems
• Windows XP SP3
• Windows Vista SP1 or later
• Windows 7, 8, 10, 11
213
Data Explorer Software
214
Building Acoustics
15. Building Acoustics (optional)
The Sound Insulation Reporter software is a PC-based soft-
ware application that provides all the standard reports for Air-
borne and Impact sound insulation measurements. Designed
for acoustic consultants, this comprehensive tool uses data
gathered by the XL2 Sound Level Meter, and quickly returns
graphical analysis of all measurement positions.
Additionally, the software offers the ability to acquire real-time
data; two or more XL2 Sound Level Meters, may be controlled
directly by the software. This allows simultaneous wireless
measurement in both the sending and receiving room onsite;
saving time. To enable this real-time acquisition of data, the
Sound Insulation Reporter software requires that the connect-
ed XL2s also have an activated Remote Measurement Option
installed.
Features:
• Airborne, Impact and Facade Sound Insulation
• Customized Reporting
• Standards ASTM E336, ASTM E413, ASTM E1007, ASTM
E989, ASTM E966, ASTM E1332, BB93, DIN 4109, Document
E, GB/T 19889, ISO 16283, ISO 140, ISO 717, ISO 10140, NEN
5077:2019, SIA 181:2006, SIA 181:2020
XL2 Sound Insulation Permanent
The Sound Insulation Option enables the import of measure-
ment data into the Sound Insulation Reporter software.
Sound Insulation Reporter 365
An annual subscription service for a XL2 Sound Level Meter is
offered alternatively to the permanently installed option.
Supported operating systems
• Windows Vista SP1 or later
• Windows 7, 8.x, 10, 11
Requirements
The measurement of the reverberation time in 1/3 octave band
resolution requires the optional Extended Acoustic Pack in-
stalled on the XL2 Sound Level Meter.
Download the software from the XL2 Support Page at
https://my.nti-audio.com.
215
Building Acoustics
216
Room Acoustics
16. Room Acoustics (optional)
The Room Acoustics Reporter is a PC software for automati-
cally generating reverberation time measurement reports and
analyzing the RTA frequency response spectrum. The software
supports acousticians and experts in the visualization and de-
tailed evaluation of measurement data recorded with the XL2
Sound Level Meter.
Features:
• Room acoustic simulation according to Sabine or Eyring
• Import of own sound absorber database and tolerances
• Frequency response spectrum and Noise Curves
The following standards are supported
• IEC 61260: Octave-band and fractional-octave-band filters
• GB 50371 - Code for sound reinforcement system design
• ANSI/ASA S12.2-2019 - Noice criteria curves NC
• ANSI/ASA S12.2-2019 - Room noice criterion RNC
• DIN 15996:2020 - Grenzkurven GK
• ISO R 1996-1971 - Noise rating curves NR
• ASR A3.7:2021 - Working Place
• DIN 18041: 2016 - Acoustic quality in rooms
• ISO 3382-1:2009 - Reverberation time in performance spaces
• ISO 3382-2:2008 - Reverberation time in ordinary rooms
• ÖNORM B 8115-3:2015 - Room Acoustics
• ASTM C423-17 - Sound Absorption
• ISO 354:2003 - Sound absorption in a reverberation room
XL2 Room Acoustics Permanent
The Room Acoustics Option enables the import of measure-
ment data into the Room Acoustics Reporter software.
Room Acoustics Reporter 365
An annual subscription service for a XL2 Sound Level Meter is
offered alternatively to the permanently installed option.
Supported operating systems
• Windows Vista SP1 or later
• Windows 7, 8.x, 10, 11
Requirements
The measurement of the reverberation time in 1/3 octave band
resolution requires the optional Extended Acoustic Pack in-
stalled on the XL2 Sound Level Meter.
Download the software from the XL2 Support Page at
https://my.nti-audio.com.
217
Room Acoustics
218
Sound Power
17. Sound Power (optional)
Sound Power Reporter is a PC-based software application that
provides all the standard reports for sound power measure-
ments in accordance with ISO 3744 and ANSI-ASA S12.54.
Designed for industrial professionals, this comprehensive tool
uses data gathered by the XL2 Sound Level Meter, and quickly
returns graphical analysis of all measurement positions.
Features of the Sound Power Reporter software:
• Visualization of all measurement
• Customized Reporting
• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-ASA S12.51,
ANSI-ASA S12.54, ANSI-ASA S12.56
Download the software from the XL2 Support Page at
https://my.nti-audio.com.
XL2 Sound Power Permanent
The Sound Power Option enables the import of measurement
data into the Sound Power Reporter software.
Sound Power Reporter 365
An annual subscription service for a XL2 Sound Level Meter is
offered alternatively to the permanently installed option.
Supported operating systems
• Windows Vista SP1 or later
• Windows 7, 8.x, 10, 11
Requirements
The measurement of the reverberation time in one-third octave
band resolution requires the optional Extended Acoustic Pack
installed on the XL2 Sound Level Meter.
219
Sound Power
220
NoiseScout
18. Unattended Noise Monitoring
NoiseScout provides a comprehensive but easy-to-use 24/7
noise monitoring solution. Noise levels are recorded on-site by
the XL2 Sound Level Meter and are available for remote moni-
toring and download. NoiseScout is aimed at both short-term
noise assessments and long-term monitoring applications. It
offers the freedom to start and stop the remote noise monitor-
ing from your office or mobile device providing total flexibility
in meeting your project requirements.
Noise Monitoring in “Managed Mode”
During acquisition, audio recordings of the loudest periods and
automated email alerts allow noise issues to be addressed be-
fore a non-compliance condition arises. NoiseScout displays
the noise levels measured by the XL2 Sound Level Meter live
in your web browser. The measurement data recorded out in
the field is presented online in charts and dashboards. Multiple
noise level meters can be monitored simultaneously within the
map view, thus providing localized geographic visualization for
all noise levels at a glance. Identified users can access all their
projects, control their monitors or create basic view modes, al-
lowing stakeholders to oversee their noise level data.
XL2
Managed Unattended Noise Monitoring
221
NoiseScout
Noise Monitoring in “Gateway Mode”
Direct access to the XL2 Sound Level Meter is available from
around the world. An internet connection allows SFTP (Secure
File Transfer Protocol) and remote access to the XL2. All data
files can then be retrieved from the remote XL2 Sound Level
Meter even during an ongoing measurement. Also, the spec-
tral data and audio files can be directly downloaded from the
remote XL2.
The remote access allows full control of the XL2 Sound Level
Meter. All remote measurement commands available on the
XL2 are supported. For example, the current measurement
data may be captured in real time into a computer application,
e.g. C#, MS Excel or LabView. You may program a customized
measurement application for remote sound level monitoring,
audio analysis or automated measurement tasks.
NoiseScout operates also in a local network (intranet) without
internet connection.
XL2
Secure FTP Connection
FTP Browser
USB
XL2 Data Explorer
LAN
Mobile
2017-03-16_SLM_000.XL2
2017-03-16_SLM_000_123_Report.txt
2017-03-16_SLM_000_123_Log.txt
2017-03-16_SLM_000_RTA_3rd_Report.txt
2017-03-16_SLM_000_RTA_3rd_Log.txt
2017-03-16_SLM_000_Audio_FS136.0dB(PK)_00.wav
Remote Access to XL2 Sound Level Meter
222
NoiseScout
How to connect?
The NetBox may be connected to the internet via mobile (3G,
4G, 5G; 4G/5G using an external modem), LAN or Wi-Fi.
The LAN connection is established automatically. Setup on the
XL2 is required for the 3G mobile and Wi-Fi connection.
• Insert SIM card (not provided) into the NetBox
• Connect the NetBox to the XL2 Sound Level Meter.
• Select
1
and confirm with enter
.
1
1
Network Status Indication
It replaces the speaker symbol in the top menu.
No network connection
Network connection established
Confirmation check mark indicates success-
ful on-going NoiseScout communication
2
223
NoiseScout
• Select Settings
2
and confirm with enter
.
• Select Mobile Data and confirm with enter
; the minimum
requirement is entering the APN of your provider.
• Set the connection parameters and select Exit.
• Confirm Close.
The XL2 is connected to the network.
224
NoiseScout
Automated System Self-Test
The measurement microphone of a noise monitor is perma-
nently exposed to the weather. This might impair the micro-
phone capsule and its performance. Therefore, NoiseScout
offers an automated system self-test (CIC). The complete sig-
nal chain may be verified periodically, remotely, and without
removing the microphone from site. Thus, precise sound level
measurements are ensured. This test also produces an alarm
in case of any unexpected issues, like cable or microphone
defects.
The automated system self-test is supported by the XL2 Sound
Level Meter with the M2340 Measurement Microphone. The
microphone preamplifier has a built-in dedicated signal genera-
tor for the self-test, which is activated from NoiseScout via the
XL2 Sound Level Meter through the ASD communication. This
generator produces a square wave signal with the fundamen-
tal frequencies 31.25 Hz and 1000 Hz and the corresponding
harmonics for the self-test. The generated test signal spectrum
is measured by the XL2 and stored as a reference. Later on,
NoiseScout repeats the same test, e.g. daily, and the resulting
one-third octave spectrum is compared against the reference.
One-Third
Frequency Band
[Hz]
Description Typical
reference spectrum
[dB]
31.25
100
160
fundamental square wave
harmonic
harmonic
101.5
91.5
87.0
200
315
400
harmonic
harmonic
harmonic
83.4
82.2
79.5
500
630
800
harmonic
harmonic
harmonic
79.9
78.4
77.6
1000
3150
5000
fundamental square wave
harmonic
harmonic
100.9
91.5
87.3
6300
8000
10000
harmonic
harmonic
harmonic
83.2
81.8
83.4
12500
16000
20000
harmonics
harmonics
harmonics
80.8
80.9
79.3
225
NoiseScout
The maximum deviation in each frequency band is specified
at 1 dB supporting the specified range of environmental con-
ditions. Unexpected issues, like cable defects, loose capsule
mounting, or a missing microphone capsule cause a higher de-
viation and trigger an automated alarm.
High ambient noise may affect the self-test. Therefore, the
ambient noise level is measured prior to performing the self-
test. All is fine as long as the ambient noise effect is less than
0.2 dB during the self-test – this requires the ambient noise
to be 13.3 dB below the reference spectrum of the self-test.
High ambient noise levels will be reported in combination with
a failed self-test.
The following workflow is carried out by NoiseScout
• Measure ambient noise level and compare result with refer-
ence spectrum
• Generate 31.25 Hz square wave signal and measure actual
noise spectrum
• Generate 1000 Hz square wave signal and measure actual
noise spectrum
• Compare results with the reference one-third octave spec-
trum
This workflow takes approximately 7 seconds.
Self-Test Method
The sysem self-test uses the charge injection
check method, in short CIC. A dedicated square
wave signal is capacitively coupled to the input
of the MA230 Preamplifier and attenuated by
the capacitance of the microphone capsule.
Physical changes in capsules can influence
their capacitance, which ultimately leads to a
changed level read from the test signal. The test
signal passes through the preamplifier and the
cable to the XL2 Sound Level Meter for evalua-
tion. This allows any changes in the microphone
capacitance, e.g. caused by damages of the mi-
crophone capsule or a loose capsule mounting
to be detected.
Additional periodic manual calibration using a
Sound Calibrator is recommended in combina-
tion with a visual inspection of the noise moni-
tor.
226
Time Synchronization
19. Time Synchronization
The XL2 Analyzer may synchronize the start time precisely with
the GPS signal. The measurement start matches the GPS time
with an accuracy of +/- 0.7 ms (+/- 32 samples @ 48 kHz).
This requires
• a txt-file named “gpssync.txt” stored on the SD card
• a specially adapted GPS Receiver, NTi Audio # 600 000 357
Concept
The measurement start follows these concepts:
• Relative Time
The GPS Receiver generates a square signal with a frequen-
cy of 0.1 Hz. The rising edge is exactly synchronized to full
10 seconds. In other words, the positive edge of the signal
indicates the following: 00 – 10 – 20 – 30 – 40 – 50.
The square wave signal is available at the RCA input of the
XL2 Analyzer. The instrument architecture offers two chan-
nels, so it can simultaneously process the microphone signal
on the XLR input and the time signal on the RCA input.
Thanks to the GPS signal, the XL2 may precisely start every
10 seconds.
• Absolute time
The XL2 receives the absolute time from the connected
NetBox, which synchronizes to the NTP service. The XL2
time is synced every 60 seconds. The communication be-
tween XL2 and NetBox causes an uncertainty in the timing
in the two-digit milliseconds range.
The combination of the relative and absolute timing allows the
XL2 to start the measurement accurately. The GPS time signal
does not have to be permanently present on the XL2 during
the measurement, which accommodates the operation in case
of unfavorable GPS reception. It is important that the time sig-
nal was detected by the XL2 at least once before the start of
the measurement, the XL2 then retains this time information
with an accuracy of typically 0.5 ms per hour.
After repositioning the GPS receiver, the sys-
tem takes about an hour to initialize for the first
time.
After rebooting the XL2, or after changing the
measurement function, the XL2 needs to syn-
chronize with GPS time again.
227
Time Synchronization
XL2 User Interface
The clock delimiter signals the state of GPS time detection.
GPS time signal is synchronized with GPS
(locked).
GPS receiver connected, but time signal not
synced with GPS (unlock).
GPS time signal not found, receiver is not
connected or XL2 not configured for GPS.
When starting a GPS time-synchronous measurement you ob-
serve the following characteristics:
After starting the measurement, the start
counter in the button will remain at 1 for up
to 10 seconds.
Exactly 4 seconds before a full 10 second
time jump, the button changes and the mea-
sured values and the timer value of the pre-
vious measurement are reset.
The measurement begins exactly at the
10-second jump.
Start without GPS
If the XL2 has not received a valid GPS information until the
start time, the internal XL2 time will be used as time. The XL2
time is set by the NetBox.
If the NetBox has connection to the network before the start
time, then the time of NetBox is precisely synchronized via
NTP. The start is precise to about 10 ms. If the NetBox could
not yet be provided with an exact time by NTP at the start, then
the NetBox time deviation is approx. 20 ppm since the last syn-
chronization (this corresponds to one error per day of
24 hours * 3600 * 20 / 1e6 = 1.7 sec.
As soon as the XL2 receives a valid time information via GPS,
the time deviation is logged in the log file.
228
Time Synchronization
Minutes of deviation
The deviation of the time currently used for the measure-
ment from the GPS time is recorded by the XL2 in the log file
(123_Log.txt).
Add_To_Time
[ms]
GPS Status
[]
0.0 2.0
Meaning of the column “GPS Status”:
0.0 No GPS signal detected at the RCA input
1. 0 GPS signal detected but signaled UNLOCKED
2.0 GPS signal LOCKED (OK)
The deviation Add_To_Time can only be determined currently
if the GPS status = 2 (locked). Otherwise, the last known er-
ror is used for the current log line. The Add_To_Time column
indicates “-.-” in case that there was no GPS time recognized
since the start of the device.
Example
The PPS signal is recorded with the XL2. For this, the input of
the XL2 from XLR to RCA can be set. The positive edge of the
recording should always be exactly to multiples of 10 seconds,
but in this case at 00: 35: 00,005:
_123_log.txt:
2017-10-05 09:49:58 00:34:58 -5.00 2.0 ---/---
2017-10-05 09:49:59 00:34:59 -5.00 2.0 ---/---
2017-10-05 09:50:00 00:35:00 -5.00 2.0 ---/---
2017-10-05 09:50:01 00:35:01 -5.00 2.0 ---/---
2017-10-05 09:50:02 00:35:02 -5.00 2.0 ---/---
In the log file, a correction value Add_to_Time of -5ms is re-
corded for this time position, so the corrected position of the
pulse is: 00: 35: 00,005 + (-5ms) = 00:35:00.
The state of the time synchronization can be seen in detail on
the NoiseScout Gateway website.
229
Time Synchronization
Connection Diagram
GPS Receiver Adapter Cable MD6/RCAconnects to XL2 Adapter Cable MD6/USB connects to NetBox - USB 1
230
Remote Measurement
20. Remote Measurement
The Remote Measurement option allows the real-time acquisi-
tion of XL2 measurement data directly into a computer applica-
tion via USB. The option adds a real-time acquisition facility to
the Sound Insulation Reporter software.
Alternatively you can write your own unique measurement ap-
plications for sound level monitoring or automated measure-
ments, e.g. with MS Excel or LabView. A documented com-
mand set for data retrieval via USB is available. The following
XL2 measurement functions are supported:
• Sound level meter and spectrum analyzer SLMeter/RTA
• Vibration Meter VibMeter
• FFT Analyzer + Tol
• RT60 reverberation time
• Audio analyzer RMS/THD+N
• High-resolution RTA function 1/12 Oct + Tol
The functionality of the Projector PRO option is included.
Order information:
Remote Measurement Option
NTi Audio #: 600 000 375
The commands are sent in ASCII format through the virtual
COM port to the XL2 Analyzer.
Example Command Set
INIT START
MEAS:INIT
MEAS:SLM:123? LAF
Result returned to PC: 53.8 dB,OK
The time the XL2 requires for a response depends on the com-
mand and the workload of the XL2 (logging settings). A typical
pattern for querying measurement data is:
xl2.write(‹MEAS:INIT\n›)
xl2.write(‹MEAS:SLM:RTA:dt? EQ\n›)
result = xl2.readline()
This pattern delivers a measurement result within:
• Min: 8 ms
• Mean: 10 ms
• Max: 35 ms
For more details you may download the dedicated Remote
Measurement Reference Manual.
231
Remote Measurement
Auto Start
The XL2 with serial number ending “E0” or higher may power
on automatically upon after a power loss (e.g. mains power dis-
connected or battery pack empty) the power is available again.
Best the instrument is operated by mains power without the
internal battery pack installed. This auto start functionality is
enabled by copying a txt-file with the file name “AutoOn.txt”
onto the SD Card. This allows to remotely control the XL2 as
soon as power supply is available at the instrument.
232
Microphones
21. Microphones
Overview Measurement Microphones
M2230 M2340 M2211 M2215 M4261 M2914
Certified Class 1
measurement
microphone
in accordance with
IEC 61672,
metal diaphragm
Certified Class 1
measurement mi-
crophone according
to IEC 61672, metal
diaphragm, system
self-test (CIC) with
XL2
General purpose
measurement
microphone
class 1 frequency
response,
metal diaphragm
Measurement mi-
crophone for high
sound levels (up to
153 dB),
class 1 frequency
response, metal dia-
phragm
Cost-effective
class 2 measure-
ment microphone
for general sound
level testing and
service of audio-
acoustic installations
High-performance
microphone
for acoustic mea-
surements of
very low sound
pressure levels
consists of MA220
PreAmplifier and
MC230 or MC230A
capsule
consists of
MA230 PreAmpli-
fier and MC230A
capsule
consists of
MA220 PreAmplifier
and 7052 capsule
consists of
MA220 PreAmplifier
and 7056 capsule
with permanently-
installed capsule
requires ICP Adapter
ASD
233
Microphones
Overview Outdoor Measurement Microphones
M2230-WP-90/-150
Outdoor Microphone
M2340-WP-90/-150
Outdoor Microphone
M4261-WP
Outdoor Microphone
Certified outdoor measurement
microphone,
class 1 in accordance with IEC 61672
Certified outdoor measurement
microphone,
class 1 in accordance with IEC 61672,
system self-test (CIC)
Outdoor measurement microphone,
class 2 in accordance with IEC 61672
consists of
M2230 Measurement Microphone
+ WP30 Weather Protection
with 90 mm or 150 mm windscreen
consists of
M2340 Measurement Microphone
+ WP30 Weather Protection
with 90 mm or 150 mm windscreen
consists of
M4261 Measurement Microphone
+ WP61 Weather Protection
with 90 mm windscreen
234
Microphones
Overview Microphone Preamplifier
MA220
PreAmplifier
MA230
PreAmplifier
Microphone preamplifier
compatible with 1/2” pre-polarized capsules
Microphone preamplifier
compatible with 1/2” pre-polarized capsules,
system self-test (CIC) with XL2 or XL3
235
Microphones
The plug-on measurement microphones combined with the
XL2 Analyzer create a powerful sound level meter and a pro-
fessional acoustic analyzer. The microphones are 48 VDC phan-
tom-powered and include an electronic data sheet.
Integrated Preamplifier
The microphone body contains a preamplifier that requires
48 VDC phantom power supply for operation. The microphones
combine high dynamic range and wide frequency range with
low noise. They can also be connected to the XL2 Audio and
Acoustic Analyzer using an ASD Cable for measurements at
remote locations or for reduction of acoustic reflections.
Electronic Data Sheet
The microphones include an electronic data sheet. The Auto-
mated Sensor Detection (ASD) of the XL2 Analyzer reads this
data, i.e. the microphone model and calibration data. This pro-
motes faster setup and ensures accurate measurements.
Connection diagram of measurement microphones
with electronic data sheet
Screen connection used for
ASD technology
XLR M
Pin 2 +
Pin 3 -
Pin 1 Shield
Pin 1
Pin 2
Pin 3
XLR M
1
2
3
1
2
3
2
3
1
Microphone
ASD
Microphone
Capsule
Microphone plugs directly into the XL2
The XL2 automatically reads the electronic data sheet of the
connected microphone as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2.
The XL2 reads the electronic data sheet of the connected
microphone during a brief initialization process prior to the
first measurement.
236
Microphones
Microphone Connection via the ASD Cable
The NTi Audio measurement microphones can be connected
to the XL2 Analyzer using an ASD Cable for measurements
at remote locations or for reducing acoustic reflections. The
electronic data sheet is transmitted via the XLR connector’s
housing. Do not touch this during the brief initialization period
to ensure the complete data sheet is recognized by the XL2.
The automated sensor detection does not disturb any mea-
surements. You may join 5 or 10 meter ASD Cables together in
series. The ASD technology supports accurate data communi-
cation up to a combined cable length of 20 meters (= 65 feet).
Microphone Connection via a professional Audio Cable
For distances longer than 20 meter (= 65 feet) use a high-
quality, low-capacitance standard professional audio cable. The
microphone sensitivity has to be entered manually into the XL2
Analyzer.
Alternatively connect the microphone first directly to the Ana-
lyzer. The XL2 reads the sensitivity and remembers this value.
Afterwards connect the audio cable.
• Use the microphone for the intended
purpose only.
• Protect the microphone from contamination
by always using the supplied windscreen.
• Never use the microphone in a damp or wet
environment.
• Do not jar or drop the microphone.
• Do not remove the microphone protective grid.
• Do not touch the microphone membrane.
• Remove the black dust cap of the 1/2”
measurement microphones prior to use.
• In an outdoor environment, ensure that you
install protection against lightning strikes.
237
Microphones
Outdoor Measurement Microphones
The Outdoor Measurement Microphones offer a weather-pro-
tected measurement solution for the XL2 Sound Level Meter
allowing acquisition of environmental noise data in outdoor ap-
plications. The corrosion-free polymer housing, wind screen,
water-repellent membrane and bird spike provide excellent pro-
tection from rain, wind, dust and perching birds.
Outdoor Measurement Microphone Types
• M2230-WP: M2230 Measurement Microphone +
WP30 Weather Protection
• M2340-WP: M2340 + WP30 Weather Protection
• M4261-WP: M4261 + WP61 Weather Protection
• Do not install the Outdoor Measurement Mi-
crophones in horizontal direction. Raindrops
may damage the measurement microphone.
• The snap mechanism works only at tempera-
tures above -15°C / 5°F (as the O-Ring stiff-
ens). In colder conditions we suggest you
warm up the housing first, e.g. with your
hands.
Bird Spike BS01
#600 040 062
90 mm
Wind Screen
#600 040 061
Upper
Body Part
#150 000 048
Lower
Body Part
#150 000 047
Tripod
Mounting Plate
#600 040 072
Inside:
Measurement
Microphone
Inside:
Protection Cage with
water-repellent
membrane
WP30 #600 040 064
WP61 #600 040 081
O-Ring Replacement Set
#600 040 069
Fixing Screw
M5 x 6 mm
238
Microphones
The Outdoor Measurement Microphones M2230-WP and
M2340-WP fulfill the Class 1 requirements according to
IEC61672 and ANSI S1.4 for vertical sound incidence. For com-
pliance with horizontal sound incidence a spectral correction is
employed in the associated XL2 Sound Level Meter.
Alternatively the Measurement Microphone M2211 or M2215
can be fitted into the Weather Protection WP30. These micro-
phones have to be pushed further into the upper body by 3
mm. The top part of the capsule has to be 13 mm above the
upper body housing of the WP30. This is required because the
M2211 and M2215 capsule is 3 mm shorter than the default
M2230 microphone capsule.
The Outdoor Measurement Microphone M4261-WP fulfills the
Class 2 requirements according to IEC61672 and ANSI S1.4.
It consists of an M4261 Microphone and the WP61 Weather
Protection. For compliance with horizontal sound incidence a
spectral correction is employed in the associated XL2 Sound
Level Meter.
Always activate the applicable frequency cor-
rection filter in the XL2. The filter ensures
that the measurements accuracy meets the
class 1 requirements of IEC 61672 and
ANSI S1.4.
239
Microphones
Assembling
This chapter describes how to install the Measurement Micro-
phone into the weather protection kit:
Install ASD Cable
• Feed the female XLR of the ASD Cable through the bottom
of the lower body tube.
• Attach the footer plate to the lower body tube using the
three allen screws, feeding the cable through the side slot
of the footer plate.
Insert Measurement Microphone
• Connect the measurement microphone to the female XLR
of the ASD Cable.
• Insert the measurement microphone into the upper body
tube so that the bottom end of the microphone is in line
with the bottom end of the upper body tube. Align the fixing
screw hole of the upper body tube with the lower screw of
the measurement microphone (remove the fixing screw to
see the lower screw head through the fixing screw hole).
Fixing Screw Hole
Lower screw of
measurement
microphone
240
Microphones
Attach the Microphone to the Upper Body Tube
Attaching the fixing screw of the upper body tube onto the
lower screw of the measurement microphone ensures that the
microphone housing is not scratched.
• Insert and gently tighten the fixing screw while jiggling the
microphone. You will feel the fixing screw center in the head
of the lower screw of the microphone. Do not over tighten
the fixing screw.
• Again verify that the bottom end of the inserted microphone is
in line with the bottom end of the upper body tube.
In Line
Assemble the Weather Protection Body
Retract the ASD cable through the lower body tube and screw
the lower body tube to the upper tube, ensuring that the cable
does not twist during this operation.
241
Microphones
Mount the Top Section
The top section of the weather protection kit consists of the
wind screen, the enclosed protection cage with water-repel-
lent membrane and the bird spike. Gently slide the top section
over the microphone tip and on to the upper body tube. You will
feel a slight increase in resistance approximately 3 mm before
the top section’s final position. Slightly increase the pressure
until the top section snaps into the final position with an au-
dible click.
You have successfully assembled the Outdoor Measure-
ment Microphone.
Calibration
The design of the Outdoor Measurement Microphone sup-
ports easy calibration of the microphone. To calibrate, follow
the procedure below:
• The top section of the Outdoor Microphone is snapped
on to the body tube. Remove the top section of the Out-
door Microphone by gently pulling the bird spike upwards.
At the same time gently push up on the cage inside the
wind screen with two fingers of your other hand. You will
feel when the snap mechanism is released.
Gently remove the top section.
Push
Pull
242
Microphones
• Calibrate the microphone as described in the XL2 user man-
ual using the NTi Audio Precision Calibrator.
• Snap the top section back into position on the body tube.
You have successfully calibrated the Outdoor Measure-
ment Microphone.
• The outdoor windscreen is recommended to be
replaced annually. The “WP30-90/WP61 Wind-
screen Replacement” includes two 90 mm
spare windscreens, NTi Audio # 600 040 061.
The “WP30-150 Windscreen Replacement”
includes two 150 mm spare windscreens,
NTi Audio # 600 040 095.
• The water-repellent membrane in the top sec-
tion is mounted with two O-Rings. Inspect
these O-Rings (13x1 mm) and the membrane
annually for proper seating and good condi-
tion. Do not touch the water-repellent mem-
brane.
243
Microphones
Disassembling the Top Section
• The top section is snapped on to the body tube. Remove
the top section by gently pulling the bird spike upwards. At
the same time gently push up on the cage inside the wind
screen with two fingers of your other hand. You will feel
when the snap mechanism is released.
• Gently remove the top section and turn the top section up-
side down and hold it by the bird spike.
• Gently unscrew the cage from the hole of the wind screen.
Do not touch the water-repellent membrane!
• Assemble in reverse order.
Capsule Replacement Instruction
The microphones for the XL2 Analyzer include an electronic
data sheet. The Automated Sensor Detection (ASD) of the XL2
Analyzer automatically reads this data, i.e. the microphone
model and calibration data. This promotes faster setup and en-
sures accurate measurements. In case of a capsule replace-
ment, the electronic data sheet needs to be updated with the
data of the new capsule.
Step-by-Step-Instruction
• Install the new capsule on the microphone preamplifier.
• Plug the measurement microphone directly into the XL2.
• Install the latest firmware in the XL2, available at
https://my.nti-audio.com/support/xl2.
• Start the XL2 Projector PRO Software. The computer re-
quires online connection to the web.
• Connect the XL2 with the USB cable to the Projector PRO
software, thus you see the XL2 display live on the computer
monitor. (if prompted select COM-Port on the XL2)
• Press the computer keyboard keys “Ctrl + Shift + F5” at the
same time (alternatively “Ctrl + Alt + F5”)
244
Microphones
• Select Original NTi Audio Microphone or Custom micro-
phone.
• Case: Original NTi Audio Microphone
- Enter the serial number of the new capsule
- Confirm by clicking Write to MA220.
- Now XL2 reads the factory sensitivity of the new capsule
from the NTi Audio server and stores the new data into
the electronic data sheet of the preamplifier. You will be
prompted if all is in good order.
• Case: Custom microphone
- Enter the microphone sensitivity
- Confirm by clicking Write to MA220.
- Now XL2 stores the microphone sensitivity as factory sen-
sitivity in the electronic data sheet of the MA220 PreAm-
plifier.
• Verify the setting in the “CALIBRATE” screen of the XL2 and
perform a user calibration to verify if the new capsule works
in good order.
245
Microphones
246
Further Information
22. Further Information
My NTi Audio
Register your instruments at My NTi Audio and benefit from
the following possibilities:
• Free updates for your instruments
• Activation of optional product functions
• Premium access to downloads
• Receive application and product news
• Faster worldwide support
• Tracing support in case of loss or theft
• Calibration support
How to Register
• Open the web page “https://my.nti-audio.com”.
• You are prompted to login or create your My NTi Audio
account.
• The web page “My NTi Audio Products” opens.
• Select the product type and enter the serial number.
• Confirm with “Register”.
• Now your product is listed in the table “My Products“.
Congratulations, your NTi Audio product is registered
Tips and Troubleshooting
Overview
• Resetting to Factory Default
• XL2 Starts Up with Limited Functions
• Can I use another SD Card?
• Formatting the SD Card
• SD Card Errors
• Error messages on display
• Stored Data or Wav-files not available on SD Card
• Date and Time Lost
Resetting to Factory Default
If the XL2 Audio and Acoustic Analyzer reacts unexpectedly, a
reset to the factory settings might solve the problem.
• Switch off the XL2
.
• Hold down escape
and simultaneously operate On/Off
.
The XL2 starts up and the reset confirmation is displayed.
247
Further Information
XL2 Starts Up with Limited Functions
The XL2 has been operated the last time in one of the sim-
plified application profiles and the system settings have been
changed as follows: Select Profile from Yes to No.
• Follow the above resetting to factory default.
The XL2 will start up with full functionality.
Can I use another SD Card?
Yes, you can use any alternative SD Card, such as offered in the
chapter Further Information: Accessories.
• Switch off the XL2
.
• Insert the SD Card into the XL2 Analyzer.
• Switch on the XL2
.
The XL2 writes the data structure automatically to the in-
serted SD Card.
Formatting the SD Card
In case you need to format the SD Card, then we recommend
doing so utilizing the software SDFormatter. This software en-
sures the best performance of your SD Card. SDFormatter is a
free download at www.sdcard.org/downloads.
SD Card Errors
The XL2 Audio and Acoustic Analyzer writes measurement
data automatically onto the SD Card during ongoing measure-
ments, thus a functioning SD Card has to be inserted at all
times.
Error Messages Actions to do
Missing SD-Card Insert the SD Card.
SD-Card is not FAT
formatted
Format the SD Card on the PC. Follow
the instructions at Formatting the SC
Card in this chapter.
SD-Card is full The memory of the SD Card is full.
Download all data to the PC and emp-
ty the SD Card.
Other Error Messages on Display
In case error messages, such as Error 900, Error 901, ..., is
shown on the XL2 display , then follow “Resetting to Factory
Default” in this chapter. These error messages describe a com-
mon status information and are not associated with a dedicat-
ed issue. If such errors occur frequently, then kindly report the
full error message back to NTi Audio for resolution. Thank you.
248
Further Information
Stored Data or Wav-files not available on SD Card
The file system might be corrupted.
• On the PC, right-click on the “NTi Audio XL2” drive, select
“Properties” and click “Check Now” as shown below.
• Thereafter all stored data should be available again.
Date and Time Lost
The XL2 Analyzer has a small internal battery installed. This
powers the real time clock (RTC), and ensures the accurate
display of the date and time on the instrument and in the mea-
surement reports, even if the device has been powered down
for a period of time. This, so called, RTC battery is soldered on
to the internal circuit board. The typical battery lifetime is 8-9
years.
Kindly return the instrument for service. For convenience, this
service may be combined with the recommended annual cali-
bration of the XL2 Sound Level Meter.
249
Further Information
Firmware Update
You will find information about the installed firmware ver-
sion in the systems settings of the instrument. The firm-
ware revision history is listed on the XL2 Support Page
https://my.nti-audio.com.
Updating the firmware on the XL2 is executed by placing the
XL2Vxxx.xx file in the root directory of the XL2. When started,
the XL2 automatically completes the firmware update.
1
1
XL2.htm
This file opens the XL2 instrument status page, for online
• Firmware updates
• Activation of options
Firmware update with XL2 in hand, PC online:
• Start the XL2 and connect it to the PC.
• The XL2 displays the pop-up window USB Mode.
• Select Mass storage. The PC thus recognizes the XL2 as a
mass storage device.
• Double-click the file XL2.htm
1
. The web screen “XL2 In-
strument Status“ opens.
• Select “Look for FW Updates“. The web screen “XL2 Sup-
port Page“ opens.
• Compare the firmware version to the latest version avail-
able.
• If an update is required, download and save the firmware
file XL2Vxxx.xx into the XL2 root directory (the root direc-
tory shows the folders “Projects”, XL2_SYS”, the file
“xl2.htm” and others).
• Remove the USB cable and power up the XL2
.
• Watch the display and wait until the update is finished.
• All settings are back to factory default. Adjust the display and
reporting settings according your requirements.
No PC available
If you have no web access at all, please contact the local NTi
Audio partner.
250
Further Information
Options
The System menu shows the installed options on the XL2.
The following options extend the measurement functions of
the XL2:
Extended Acoustic Pack
NTi Audio #: 600 000 339
The Extended Acoustic Pack offers the following additional fea-
tures for sound level- and acoustic measurements.
• SLMeter/RTA function
- Recording of linear wav-files (24 bit, 48 kHz)
- Percentiles for wide band and spectrum with flexible set-
ting from 0.1% to 99.9%
- Sound Exposure Level L
AE
- 100 ms logging
- RTA logging of Lmin and Lmax
- Event-triggered audio and data recording
- Time weighting: Impulse (LxI, LxIeq with x= A, C, Z)
- True peak level in 1/1 and 1/3 octave resolution
- Clock-impulse maximum level (TaktMax) in accordance
with DIN 45645-1 and DIN 45657
- Impulsiveness detection in accordance with BS4142:2014
and NordTest ACOU 112
• FFT function
- High-resolution Zoom-FFT with selectable frequency
ranges and resolution up to 0.4 Hz in the range of 5 Hz to
20 kHz
- Recording of linear wav-files (24 bit, 48 kHz)
• RT60 function
- Reverberation time in 1/3 octave resolution
• 1/12 octave Spectral Analyzer
(requires Spectral Limits Option)
- Recording of linear wav-files (24 bit, 48 kHz)
Projector PRO Option
NTi Audio #: 600 000 439
The Projector PRO option enables the following two additional
functions to the Projector PRO software:
• “XL View” for large screen dB level display
• “Sound Level Predictor” that indicates the headroom for the
next few minutes during live sound mixing
251
Further Information
Speech Intelligibility STIPA
NTi Audio #: 600 000 338
The XL2 Analyzer measures the speech intelligibility accord-
ing to the latest revision of standard IEC 60268-16:2020
(edition 5) and older editions. It includes ambient noise cor-
rection and automated averaging of measurements. The XL2
displays the measurement results as STI or as CIS results, ac-
companied by the individual levels and modulation indices of
the seven octave bands.
The measurement results are acquired from the dedicated
STIPA test signal source:
• NTi Audio TalkBox, acoustic signal generator
required for audio systems with voice microphones, thus
measuring the complete signal chain
• Minirator MR-PRO, test signal generator
required for audio systems with line inputs
• Other Audio Players
Register the XL2 and download the STIPA test signal at
https://my.nti-audio.com/support/xl2
Remote Measurement Option
NTi Audio #: 600 000 375
The Remote Measurement option allows the real-time acquisi-
tion of XL2 measurement data directly into a computer applica-
tion via USB. The option adds a real-time acquisition facility to
the Sound Insulation Reporter software.
Alternatively you can write your own unique measurement ap-
plications for sound level monitoring or automated measure-
ments, e.g. with MS Excel or LabView. A documented com-
mand set for data retrieval via USB is available. The following
XL2 measurement functions are supported:
• Sound level meter and spectrum analyzer SLMeter/RTA
• Vibration Meter VibMeter
• FFT Analyzer + Tol
• RT60 Reverberation time
• Audio analyzer RMS/THD+N
• High-resolution RTA function 1/12 Oct + Tol
The Remote Measurement Option includes the functionality
available in the Projector PRO option.
252
Further Information
Spectral Limits Option
NTi Audio #: 600 000 376
The Spectral Limits Option extends the XL2 function range in
both, the sound and vibration mode. It adds noise curves, trace
capturing, relative curve display and comprehensive tolerance
handling for the FFT Analysis and high-resolution spectral anal-
ysis up to 1/12th octave. The vibration mode is enabled upon
installing the vibration option.
• FFT and 1/12 octave Analyzer
- Capturing of multiple readings into the internal memory
- Comparing measurement results against captures with
relative or absolute curve display
- Comprehensive tolerance handling with tolerance masks
based on captures for passed/failed measurements
• 1/12 octave Spectral Analyzer
- High-resolution spectral analyzer 1/12 Oct + Tol
- Selectable 1/1, 1/3, 1/6 and 1/12 octave resolution
- Frequency band listening at rear speaker
- Sound Mode: 11.5 Hz to 21.8 kHz
- Vibration mode: 0.73 Hz to 1.36 kHz
• FFT Analyzer
High-resolution Zoom-FFT with selectable frequency ranges
and resolution up to 0.4 Hz in the range of
- Sound mode: 5 Hz to 20 kHz
- Vibration mode: 1 Hz to 20 kHz
• Sound Level Meter
True peak level in 1/1 and 1/3 octave resolution (disabled with
type approved firmware)
• Noise Curves
In accordance with ANSI S12.2-2019, -1995 and ISO 1996
253
Further Information
Type Approval Option
NTi Audio #: 600 000 377
The Type Approval Option upgrades the instrument to the
XL2-TA, the sound level meter dedicated to certified mea-
surements. The XL2-TA with the M2230 microphone forms
a type approved sound level meter offering class 1 per-
formance in accordance with IEC61672, IEC61260 and
ANSI S1.4.
The Type Approval Option includes
• XL2-TA Firmware V4.71 (approved Firmware)
• Sticker XL2-TA
• XL2-TA Manual (available online at www.nti-audio.com/XL2)
How do I get my XL2-TA ready for accreditation?
• Install the Type Approval Option on the XL2 and apply the
XL2-TA sticker on top of the XL2 label on the display.
• Download the dedicated firmware for accreditation to your
XL2 from the XL2 Support Page at https://my.nti-audio.com.
• After the firmware installation, the XL2-TA starts with a pop-
up window “XL2 Type Approved SLM/RTA“. The sound level
meter function SLM/RTA may be accredited now.
The type approved firmware deactivates the X-Curve in the
SLM function and the unit SPL in the RMS/THD+N function.
XL2 Vibration Option
NTi Audio #: 600 000 436
The Vibration Option turns the XL2 Analyzer into a professional
vibration meter with broadband measurements and spectral
analysis in 1/3 or octave resolution. The XL2 Vibration Meter
determines vibration acceleration, velocity and deflection with
standard-compliant weighting filters in the frequency range
from 0.8 Hz to 2.5 kHz. Detailed recording of measurement
data and audio files allow for comprehensive evaluation and
reporting. In addition, the XL2 Vibration Meter comes standard
with an FFT analysis and an oscilloscope function. Selectable
FFT frequency ranges from 1 Hz to 1.69 kHz allow a detailed
examination of the measured vibrations.
The Spectral Limits Option adds functions to the Vibration Me-
ter including a zoom FFT up to 20 kHz and a 1/12 octave band
analysis from 0.73 Hz to 1.36 kHz. Also, it adds the ability to
record reference spectra and set tolerances for pass / fail qual-
ity control measurements. The Remote Measurement Option
allows the real-time acquisition of measurement data directly
into a computer application via the USB interface. A document-
ed command set is available.
The Vibration Option is supported by the XL2 with firmware
V4.11 or higher.
254
Further Information
Cinema Meter Option
NTi Audio #: 600 000 379
The Cinema Meter Option forms the dedicated solution
for efficient calibration and repetitive verification of cinema
loudspeaker systems according to the SMPTE ST 202:2010,
SMPTE RP 200:2012 and ISO 2969:2015 standards. An interac-
tive assistant guides the user through dedicated measurement
procedures.
• Create new cinema
Generates measurement templates according the cinema
size with dedicated X-curve selection.
• Calibrate cinema
Calibration menu for reference data recording of each chan-
nel as well as headroom tests and averaging measurement
results of different microphone positions
• Verify Cinema
Verification menu for periodical cinema measurements and
comparison against the reference data
• Lock into Verify Mode
Locks the XL2 Analyzer in the Verify Cinema mode. After
powering off the instruments starts up directly in the Verify
Mode again. The user may unlock the instrument anytime.
• View verification results
Displays measurement deviations of periodical measure-
ment against reference data.
• Exit
Returns back to other XL2 measurement functions.
The Cinema Meter Option consists of
• Spectral Limits Option
NTi Audio # 600 000 376
• Cinema Assistant Option
NTi Audio # 600 000 378
255
Further Information
XL2 Data Explorer Option
NTi Audio #: 600 000 430
The Data Explorer Option enables the import of logged sound
level data into the Data Explorer software, a PC-based soft-
ware application with a powerful data processor for easy and
fast analysis of noise monitoring data.
Visualize, analyze and control millions of data points with this
tool that is dedicated to acoustic consultants and noise mea-
surement professionals. It provides a convenient way to view
and manage your data and quickly create customized reports.
Features of the XL2 Data Explorer software:
• Data visualization
• Fast zoom and pan
• Audio playback synchronized to graph
• Markers with on-the-fly calculations
• Automated tonal and impulsive marker generation
• Percentile levels Ln and Rating level Lr calculation
• Customized Reporting
Data Explorer 365
NTi Audio #: 600 000 431
Annual subscription service for one XL2 Sound Level Meter.
XL2 Sound Insulation Option
NTi Audio #: 600 000 432
The Sound Insulation Option enables the import of measure-
ment data into the Sound Insulation Reporter software.
Sound Insulation Reporter is a PC-based software application
that provides all the standard reports for Airborne, Impact and
Facade sound insulation measurements. Designed for acous-
tic consultants, this comprehensive tool uses data gathered
by the XL2 Sound Level Meter, and quickly returns graphical
analysis of all measurement positions.
Features of the Sound Insulation Reporter software:
• Airborne, Impact and Facade Sound Insulation
• Visualization of all measurement data
• Customized Reporting
• Standards ASTM E336, ASTM E413, ASTM E1007, ASTM
E989, ASTM E966, ASTM E1332, BB93, DIN 4109, Docu-
ment E, GB/T 19889, ISO 16283, ISO 140, ISO 717, ISO
10140, NEN 5077:2019, SIA 181:2006, SIA 181:2020
Sound Insulation Reporter 365
NTi Audio #: 600 000 433
Annual subscription service for one XL2 Sound Level Meter.
256
Further Information
XL2 Room Acoustics Option
NTi Audio #: 600 000 440
The Room Acoustics Option enables the import of measure-
ment data into the Room Acoustics Reporter software.
The Room Acoustics Reporter is a PC software for automati-
cally generating reverberation time measurement reports and
analyzing the RTA frequency response spectrum. The software
supports acousticians and experts in the visualization and de-
tailed evaluation of measurement data recorded with the XL2
Sound Level Meter.
Features:
• Room acoustic simulation according to Sabine or Eyring
• Import of own sound absorber database and tolerances
• Frequency response spectrum and Noise Curves
Room Acoustics Reporter 365
NTi Audio #: 600 000 441
Annual subscription service for one XL2 Sound Level Meter.
The following standards are supported
• IEC 61260: Octave-band and fractional-octave-band filters
• GB 50371 - Code for sound reinforcement system design
• ANSI/ASA S12.2-2019 - Noice criteria curves NC
• ANSI/ASA S12.2-2019 - Room noice criterion RNC
• DIN 15996:2020 - Grenzkurven GK
• ISO R 1996-1971 - Noise rating curves NR
• ASR A3.7:2021 - Working Place
• DIN 18041: 2016 - Acoustic quality in rooms
• ISO 3382-1:2009 - Reverberation time in performance spaces
• ISO 3382-2:2008 - Reverberation time in ordinary rooms
• ÖNORM B 8115-3:2015 - Room Acoustics
• ASTM C423-17 - Sound Absorption
• ISO 354:2003 - Sound absorption in a reverberation room
257
Further Information
XL2 Sound Power Option
NTi Audio #: 600 000 434
The Sound Power Option enables the import of measurement
data into the Sound Power Reporter software.
Sound Power Reporter is a PC-based software application that
provides all the standard reports for sound power measure-
ments. Designed for industrial professionals, this comprehen-
sive tool uses data gathered by the XL2 Sound Level Meter,
and quickly returns graphical analysis of all measurement posi-
tions.
Features of the Sound Power Reporter software:
• Visualization of all measurement
• Customized Reporting
• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-ASA S12.51,
S12.54, S12.56
Sound Power Reporter 365
NTi Audio #: 600 000 435
Annual subscription service for one XL2 Sound Level Meter.
258
Further Information
Installation of Options
1.
Login
(https://my.nti-audio.com)
Activate option
6.
5.
Mass storage
Open XL2-TA.htm
3.
4.
1.
PC
2.
Power On XL2
259
Further Information
8.
Insert License number
7.
Get Activation Key
1.
10.
Download activation file and copy to XL2 (xx_0xxxx.txt)
9.
260
Further Information
Accessories
Calibration
Certificate
Manufacturer Calibration Certificate
The calibration certificate lists the individ-
ual product data with serial number. The
calibration and adjustment procedures
follow the documentation and traceability
requirements of the EN ISO / IEC 17025
standard. Annual re-calibration of the in-
strument is recommended ensuring ac-
curate measurements.
NTi Audio # 600 000 018
Ever-ready Pouch
The Ever-ready Pouch protects the XL2
during transport and operation. With its
convenient belt-clip, the XL2 can be kept
close-by for those tasks requiring both
hands. The Ever-ready Pouch allows oper-
ation of the XL2 while fitted in the pouch.
NTi Audio #: 600 000 335
Mains Power Adapter
Mains Power Adapter the XL2 Audio and
Acoustic Analyzer with removable plug
types. The Mains Power Adapter suits the
typical power sockets in Australia, China,
Europe, Japan, US and UK.
NTi Audio #: 600 000 333
Spare Li-Po Battery
Rechargeable spare battery for portable
measurements at any time.
NTi Audio #: 600 000 337
ICP Adapter ASD
The ICP Adapter connects to the XL2 and
generates ICP power supply for acceler-
ometers and other custom sensors. The
adapter offers an electronic data sheet,
which stores the sensitivity and individual
serial number of the connected sensor.
NTi Audio #: 600 010 223
ICP is a registered trademark of PCB Piezotronics.
261
Further Information
XLR Adapter ASD
XLR male/female Adapter with electronic
data sheet for automated sensor detec-
tion (ASD) of other sensors. The adapter is
available in two variations: The type ASD-
2 is used for measurement microphones
with isolated housing ground connection
and the type ASD for induction loop and
other sensors.
NTi Audio #:
• XLR Adapter ASD: 600 000 383
• XLR Adapter ASD-2: 600 000 385
System Case
This compact system case provides the
professional transport protection for work
in the field. It offers space for the hand-
held instruments, cables and connectors.
NTi Audio #: 600 000 701
Battery Charger
The Battery Charger efficiently recharges
the spare battery whilst you are using
your XL2 Audio and Acoustic Analyzer.
One spare Li-Po battery is included with
the battery charger.
NTi Audio #: 600 000 332
XL2 Mounting Adapter
This mechanical adapter piece mounts
the XL2 on a microphone stand. Adapters
for 3/8” or 5/8” stands are included.
NTi Audio #: 600 000 372
Ball Head Mount
This flexible universal joint mounts the
XL2 on a 1/4” or 3/8” stand. It provides
the facility to mount the XL2 at any an-
gle.
NTi Audio #: 600 000 387
A 5/8” stand requires additionally the
Mounting Adapter, # 600 000 372.
262
Further Information
I/O
Digital I/O Adapter PCB
The Digital I/O Adapter serves to control
external peripheral devices, such as indi-
cating sound levels that exceed limits on
a big external red-orange-green lamp. It
connects to the digital I/O interface.
NTi Audio #: 600 000 380
XL2 Input Keypad
The XL2 Input Keypad offers four marker
keys to trigger an event recording or cat-
egorize any noise during measurements.
Requires the optional Extended Acoustic
Pack.
NTi Audio #: 600 000 384
ASD Cable
The ASD Cable allows for extended con-
nections of the NTi Audio measurement
microphones. It supports the transfer of
the electronic data sheet from the micro-
phone to the XL2 Analyzer.
NTi Audio #:
• 5 meter (16 foot): 600 000 336
• 10 meter (32 foot): 600 000 364
• 20 meter (64 foot): 600 000 365
The ASD technology for the electronic
data sheet transfer is applicable for a ca-
ble length of up to 20 meters (64 feet).
263
Further Information
1 1
2 2
3 3
Housing Housing
ASD
STARQUAD cable
with low capacitive load
do not connect
Capacity between ASD line to shield total < 2.7nF
ASD Flat Ribbon Cable 1m
Microphone cable for passing closed win-
dows or doors. It supports the transfer of
the electronic data sheet from the micro-
phone to the XL2 Analyzer.
NTi Audio #: 600 000 367
NetBox
The NetBox connects the XL2 Sound
Level Meter to the internet for unat-
tended noise monitoring. It transfers the
measurement data to the fully-managed
NoiseScout Web Portal in real time or
provides a secure internet FTP access to
the instrument. The noise monitor may
be connected via 3G, 4G, 5G, LAN or
Wi-Fi (an external modem is required for
4G/5G).
NTi Audio #:
• NetBox (LAN & Wi-Fi): 600 000 450
• NetBox with 3G-Modem, LAN & Wi-Fi:
600 000 458
• NoiseScout 365
(subscription service for one year)
or Data Credits
- 30 Days: 600 000 490
- 100 Days: 600 000 491
- 366 Days: 600 000 492
- 1096 Days: 600 000 493
264
Further Information
WP30 Weather Protection
Protect your measurement microphones
M2230 and M2340 from rain, wind, dust
and perching birds with this professional
outdoor weather protection kit. Ideal
for precise acquisition of environmental
noise data in outdoor applications.
Features
• Class 1 compliant with IEC 61672 and
ANSI S1.4 for vertical and horizontal
sound incidence
• Protection from rain and dust (IP54),
wind and perching birds
• Built from corrosion-free materials
• Removable top section for easy micro-
phone calibration
• Standard 3/8” tripod mount
• Weight: 270 g (9.5 oz.)
• Optional Pole Mount Adapter
• Optional sturdy outdoor carrying case
available
NTi Audio #:
• 600 040 060 (WP30-90)
• 600 040 090 (WP30-150)
4G/LTE Gateway
The 4G/LTE Gateway is a small, light-
weight, and energy-efficient industrial
gateway equipped with mission-critical
LTE capabilities, Gigabit Ethernet inter-
face, digital Inputs/Outputs, and micro-
USB port.
This 4G/LTE Gateway has been specially
selected for use with the XL2 Sound Lev-
el Meter. It connects XL2+NetBox to the
internet for remote monitoring of noise
levels.
NTi Audio #:
• 600 076 011
4G/LTE Gateway for NetBox
(worldwide excluding Americas, China,
Japan)
• 600 076 012
4G/LTE Router for NetBox
(worldwide)
265
Further Information
WP61 Weather Protection for M4261
Protect your M4261 microphone from
rain, wind, dust and perching birds with
this professional outdoor weather protec-
tion kit.
Features
• Class 2 compliant with IEC 61672 and
ANSI S1.4 for vertical and horizontal
sound incidence
• Protection from rain and dust (IP54),
wind and perching birds
• Built from corrosion-free materials
• Removable top section for easy micro-
phone calibration
• Standard 3/8” tripod mount
• Weight: 270 g (9.5 oz.)
• Optional Pole Mount Adapter
• Optional sturdy outdoor carrying case
available
NTi Audio # 600 040 080
Pole Mount Adapter
The outdoor measurement microphone
may be installed on a pole using this
adapter. The microphone is connected to
the sound level meter by the ASD cable,
which runs through the pole and the
adapter to the microphone. The adapter
is available in two different sizes.
NTi Audio #:
• 600 040 067
Pole Mount Adapter PM 1”
supports pole diameter 25 - 33 mm
(1-1.3”)
• 600 040 068
Pole Mount Adapter PM 1 1/4”
supports pole diameter 32 - 44 mm
(1.25-1.75”)
266
Further Information
Limit Light
The XL2 Audio and Acoustic Analyzer in
combination with this Limit Light offers
a turnkey solution for live sound monitor-
ing. The sound level limits are set in the
XL2. The Limit Light provides a pre-warn-
ing with an orange light and indicates that
levels have been exceeded with a red
light.
NTi Audio #: 600 000 600
Stack Light
The XL2 Audio and Acoustic Analyzer in
combination with this Stack Light pro-
vides a turnkey solution for noise level
monitoring or passed / failed measure-
ments where a prominent visual indica-
tion is required. The Stack Light connects
directly to the XL2 Analyzer and shows
the actual measurement result with three
different colors; green, orange and red.
NTi Audio #: 600 000 610
Class 1 Sound Calibrator
The battery-operated Class 1 Sound
Calibrator is classified for the calibration
of class 1 measurement microphones,
sound level meters and other acoustic
measurement equipment. This precision
microphone calibrator delivers 94 or 114
dB at a frequency of 1 kHz.
NTi Audio #: 600 000 388
The optional 1/4” adapter ADP-1/4-P is
required to fit 1/4” measurement micro-
phones.
NTi Audio #: 600 000 391
Class 2 Sound Calibrator
The battery-operated Class 2 Sound
Calibrator is classified for the calibration
of class 2 measurement microphones,
sound level meters and other acoustic
measurement equipment. This micro-
phone calibrator delivers 114 dB at a fre-
quency of 1 kHz.
NTi Audio #: 600 000 394
267
Further Information
Weatherproof Enclosure for
Noise Monitoring Terminal
The weatherproof enclosure is the tai-
lored fixed installation solution for unat-
tended noise monitoring. The enclosure is
IP66 rated, highly secure and constructed
of strong, hard-wearing reinforced fiber-
glass.
NTi Audio #: 600 000 480
Shroud MXA01
The Shroud reduces the acoustic reflec-
tions from the XL2 housing back to the
microphone capsule for precision class
1 measurements. It supports the XL2 in
combination with the 1/2” measurement
microphones M2230, M2340, M2211 and
M2215. The Shroud is included within the
Type Approval Option.
NTi Audio #: 600 040 110
Basic Outdoor Case
The Basic Outdoor Case is a simple and ef-
ficient solution for outdoor noise monitor-
ing. Powered either by an external mains
supply or a small, high-capacity battery
pack, the case is more than adequate for
a number of days of monitoring. The ro-
bust and lightweight design protects the
XL2 and accessories from a wide range
of inclement weather conditions.
NTi Audio #:
• IP43 rating: 600 000 471
• IP63 rating: 600 000 473
Heavy-duty Outdoor Case
The heavy-duty outdoor case is a profes-
sional solution for short- and medium-
term unattended noise monitoring. The
case provides comprehensive protection
against dust, water and impacts. Internal
dimensions provide ample space for bat-
tery packs to power the XL2 Sound Level
Meter.
NTi Audio #:
• IP43 rating: 600 000 476
• IP65 rating: 600 000 477
268
Further Information
GPS Receiver (customized)
The specially adapted GNSS receiver
comes with a built-in active antenna in
a white housing. It connects to the XL2
Sound Level Meter and the NetBox. Typi-
cal applications are to synchronize the
start time of one or multiple XL2s pre-
cisely with the GPS signal (+/- 0.7 ms) or
presenting the precise instrument posi-
tion in NoiseScout Gateway mode for un-
attended noise and vibration monitoring.
The GNSS receiver supports Galileo, GPS
and other systems.
NTi Audio #: 600 000 357
Data Explorer Software
Data Explorer is a PC-based software ap-
plication with a powerful data processor
for easy and fast analysis of sound level
measurement data. The data import re-
quires that the Data Explorer Option be
installed on the XL2. Download the soft-
ware at https://my.nti-audio.com.
Sound Insulation Reporter Software
Sound Insulation Reporter is a PC-based
software application that provides all the
standard reports for Airborne and Impact
sound insulation measurements. The
Sound Insulation Option enables the im-
port of measurement data into the Sound
Insulation Reporter software. Download
the software at https://my.nti-audio.com.
Room Acoustics Reporter Software
The Room Acoustics Reporter is a PC soft-
ware for automatically generating rever-
beration time measurement reports and
analyzing the RTA frequency response
spectrum. The Room Acoustics Option
enables the import of measurement data
into the Room Acoustics Reporter soft-
ware. Download the software at https://
my.nti-audio.com.
269
Further Information
Sound Power Reporter Software
Sound Power Reporter is a PC-based
software application that provides all the
standard reports for sound power mea-
surements. The Sound Power Option
enables the import of measurement data
into the Sound Power Reporter software.
Download the software at https://my.nti-
audio.com.
89.4 dBA
85.3 dBLeq
XL2 Projector PRO Software
The Projector PRO software displays the
XL2 screen in real-time on your PC when
connected by USB. The Projector PRO op-
tion enables the “XL View” and “Sound
Level Predictor” for live sound monitor-
ing. Free download from the XL2 Support
Page at https://my.nti-audio.com.
1/2” Windscreen 90 mm
for M2230, M2340, M2211 and M2215
measurement microphone
NTi Audio #: 600 040 109
WP30-90/WP61
Windscreen Replacement
The replacement package contains two
spare windscreens for outdoor measure-
ment microphones. The outdoor wind-
screen is recommended to be replaced
annually.
NTi Audio #: 600 040 061
WP30-150 Windscreen Replacement
The replacement package contains two
spare windscreens for outdoor measure-
ment microphones. The outdoor wind-
screen is recommended to be replaced
annually.
NTi Audio #: 600 040 095
8 GB SD Card (default)
1x included with XL2
NTi Audio #: 600 000 374
270
Further Information
SD Card 32 GB
Every 32 GB SD Card is individually test-
ed.
The XL2 requires an SD card that can con-
tinuously and simultaneously store many
data streams. Unfortunately, many cards
available on the market are known to in-
terrupt the read/write process for periods
of more than 10 seconds. This leads to
data loss in the XL2. These interruptions
can occur regardless of the speed rating
of the card. Even cards of the same type
and from the same vendor behave differ-
ently depending on the production date.
Therefore, to ensure the integrity of the
XL2 data recording, NTi Audio verifies ev-
ery single card over a period of several
days before the card is sent to our cus-
tomer. Requires XL2 Firmware V4.10 or
higher.
Requires XL2 Firmware V4.10 or higher.
NTi Audio #: 600 000 386
Lightweight Tripod
Retractable, lightweight tripod with 1/4”
ball head and 3/8” mounting thread. The
flexible ball head mounts the XL2 Ana-
lyzer at any angle. The tripod is suitable
for all measurement microphones, out-
door measurement microphones and the
TalkBox.
NTi Audio #: 600 000 397
Minirator MR-PRO
The MR-PRO is an extremely powerful
analog audio generator designed for the
professional engineer. It generates the
following analog audio signals:
• Sine Waveforms, freely selectable fre-
quencies and levels up to +18 dBu
• Sweep Signals, any frequency interval
up to 1/12 octave
• White Noise, Pink Noise
• Polarity Test Signal
• Delay Test Signal
• Uploaded wav-files (*.wav)
NTi Audio #: 600 000 310
271
Further Information
NTi Audio TalkBox
The NTi Audio TalkBox greatly simplifies
the acoustic feed of the STIPA intelligibil-
ity test source signal into closed sound
reinforcement systems. It presents the
standardized voice-like acoustic signal
emission simulating a human talker in ac-
cordance with IEC 60268-16, combined
with a certified speech intelligibility signal
at standardized levels.
NTi Audio #: 600 000 085
Tracer Battery Adapter Cable
The Tracer Battery Adapter Cable con-
nects the Tracer battery pack to a NetBox
or an XL2 Analyzer. It ensures that the
connected instruments start up properly
if the battery has been completely dis-
charged.
NTi Audio #: 600 000 478
Warranty Conditions
International warranty
NTi Audio guarantees the function of its products and the in-
dividual components for a period of one year from the date
of sale. During this period, defective products will either be
repaired free of charge or replaced.
Limitations
These guarantee provisions do not cover damage caused by ac-
cidents, transportation, incorrect use, carelessness, non-origi-
nal accessories, the loss of parts, operation with non-specified
input voltages, adapter types or incorrectly inserted batteries.
NTi Audio accepts no responsibility for subsequent damage of
any kind. The warranty will be voided by carrying out repairs
or services by third parties who are not part of an approved
NTi Audio Service Centre.
Statutory Rights
Consumers may have legal (statutory) rights under applicable
national laws relating to the sale of consumer products. This
warranty does not affect your statutory rights. You may assert
any legal rights you have at your sole discretion.
272
Further Information
Service and Repairs
If your product is not functioning correctly or is damaged,
please contact the local NTi Audio partner for assistance. If
the product needs to be returned for service, kindly follow the
service guidelines at www.nti-audio.com/service.
Damage through shocks and moisture
• The protective shock jacket shields the instru-
ment against reasonable impacts that could
occur in normal use.
• Do not intentionally subject the instrument to
extreme stress!
• Please do not drop the instrument!
• Damage caused by dropping or impact is not
covered by warranty.
• Do not use the instrument in damp environ-
ments! The instrument can be permanently
damaged if exposed to moisture.
Calibration Certificate
Your NTi Audio instrument has been tested during manufacture
and conforms to the specifications listed in “Technical Data”.
The XL2 combination with the appropriate measurement mi-
crophone forms a precise class 1 or class 2 sound level meter
in accordance with the standards and configurations listed in
“Technical Data”.
You may order a manufacturer calibration certificate of your
new instrument at the local NTi Audio partner either with or
any time after the purchase of the instrument. The certificate
lists the individual instrument data with serial number recorded
prior to the shipment.
NTi Audio recommends annual calibration of the products start-
ing one year after the purchase. The calibration provides docu-
mented and traceable measurement accuracy and confirms
that your NTi Audio product meets or exceeds the published
specifications. The calibration and adjustment procedures fol-
low the documentation and traceability requirements of the
EN ISO / IEC 17025 standard.
For calibrations kindly follow the service guidelines at
www.nti-audio.com/service.
273
Further Information
Sample Calibration Certificate
The following instrument has been tested and calibrated to the manufacturer specifications.
The calibration is traceable in accordance with ISO/IEC 17025 covering all instrument functions.
• Device Type: XL2 Audio and Acoustic Analyzer
• Serial Number: A2A-11667-E0
• Date of Calibration:
• Certificate Number:
• Results: PASSED
(for detailed report see next page)
Tested by: M. Frick
Signature:
Stamp:
Manufacturer Calibration Certificate
25 July 2016
42576-A2A-11667-E0
NTi Audio AG • Im alten Riet 102 • 9494 Schaan • Liechtenstein • Europe • Tel: +423 239 6060
www.nti-audio.com • HR-Nr: 2.012.557 • MwStNr: 54306 • Bank: VP Bank, Vaduz, Acc No: 322.235.015
1/2
Sample
Calibration of: XL2 Audio and Acoustic Analyzer
Serial Number: A2A-11667-E0
Date:
• Measurement Data on Receipt: in tolerance
• Detailed Calibration Test Results:
reference before actual unit
RMS Level @ 1kHz, XLR Input 0.1 0.100 0.100 V ≤0.1% ±0.5% ±0.10%
1 0.999 1.000 V ≤0.1% ±0.5% ±0.09%
10 9.987 9.989 V -0.1% ±0.5% ±0.09%
Flatness, XLR Input
1
20 Hz 1 0.997 0.996 V -0.4% ±1.1% ±0.09%
20 kHz 1 1.004 1.004 V 0.4% ±1.1% ±0.09%
Frequency 1000 1000.00 999.99 Hz ≤0.003% ±0.003% ±0.01%
Residual Noise XLR < 2 uV < 2 uV <2 uV ±0.50%
THD+N @ 0 dBu, 1 kHz, XLR Input -98.5 -98.9 dB typ. -100 dB ±0.50%
• Test Conditions: Temperature: 28.2 °C
Relative Humidity: 51.7 %
• Calibration Equipment Used:
- Agilent Multimeter, Typ 34401A, Serial No. MY 5300 4607
Last calibration: 17.08.2016, Next calibration: 17.08.2017
Calibrated by ELCAL to the national standards maintained
at Swiss Federal Office of Metrology. SCS 002
- FX100 Audio Analyzer, Serial No. 10408
Last Calibration: 04.05.2016, Next Calibration: 04.05.2017
Manufacturer calibration based on Agilent 34410, Serial No. MY47014254,
Last Calibration: 03.06.2016, Next Calibration: 03.06.2017
which is calibrated by ELCAL to national standards maintained
at Swiss Federal Office of Metrology. SCS 002
1
The specified tolerance +/-0.1 dB @ 1V = +/- 1.1%
2
The reported expanded uncertainty is based on a standard uncertainty multiplied by a coverage factor k=2, providing a
level of confidence of approximately 95%. The uncertainty evaluation has been carried out in accordance with the
regulations of the GUM.
25 July 2016
actual
error
XL2
tolerance
calibration
uncertainty
2
NTi Audio AG • Im alten Riet 102 • 9494 Schaan • Liechtenstein • Europe • Tel: +423 239 6060
www.nti-audio.com • HR-Nr: 2.012.557 • MwStNr: 54306 • Bank: VP Bank, Vaduz, Acc No: 322.235.015
2/2
Sample
274
Further Information
Declaration of Conformity
CE / FCC Compliance Statement
We, the manufacturer NTi Audio AG, Im alten Riet 102, 9494
Schaan, Liechtenstein, do hereby declare that the XL2 Ana-
lyzer, the measurement microphones M2230, M2340, M2211,
M2215, M2914, M4261, the preamplifiers MA220, MA230
and accessories, comply with the following standards or other
standard documents:
• EMC: 2014/30/EU
• Harmonized standards: EN 61326-1
• Explosive atmospheres (ATEX): 2014/34/EU
• Directive 2011/65/EC on the restriction of the use of certain
hazardous substances in electrical and electronic equipment
(RoHS).
• Directive 2012/19/EU on waste electrical and electronic
equipment (WEEE).
This declaration will become invalid if modifications to the
instrument are carried out without the written approval of
NTi Audio.
Date: 07. July 2023
Position: CEO
Information for Disposal and Recycling
Dispose of the instrument in accordance with
the legal environmental regulations in the
country.
Regulations for the EU and other European countries
with corresponding laws
The instrument must not be disposed of in the household gar-
bage. At the end of its service life, bring the instrument to a
collecting point for electrical recycling in accordance with the
local legal regulations.
Other countries outside the EU
Contact the respective authorities for the valid environmental
regulations in the country.
275
Further Information
276
Specifications
23. Technical Data XL2
All specifications are according to the IEC61672 standard.
Other standards are listed the corresponding specifications.
Sound Level Meter
Certified
Product Con-
figurations
Class 1
• XL2 with TA-Option, M2230 Microphone and
Shroud MXA01 form an integrating sound level
meter with type approval in accordance with
class 1 requirements of IEC 61672 and ANSI S1.4
Product Con-
figurations
Class 1
The XL2 is identical to the certified configuration,
just using the latest firmware.
• XL2 with M2230 or M2340 microphone
Class 1 in accordance with IEC 61672 and
ANSI S1.4
• XL2 with M2211 or M2215 microphone
Class 1 frequency response in accordance with
IEC 61672 and ANSI S1.4
These specifications apply for operation with the
microphone attached using the Shroud MXA01 or
the microphone detached using the ASD cable. This
prevents possible acoustic reflections from the XL2
housing and ensures a high measurement accuracy
in accordance with the standards IEC 61672 and
ANSI S1.4.
Product Con-
figurations
Class 2
• XL2 with M4261 microphone
Class 2 in accordance with IEC 61672 and
ANSI S1.4
Conforms
with Stan-
dards
• IEC 61672:2013, IEC 61672:2003,
IEC 61260:2014, IEC 61260:2003,
IEC 60651, IEC 60804, IEC 61183
• SMPTE ST 202:2010, ISO 2969:2015
• China: GB/T 3785:2010, GB/T 3241, GB 3096-2008,
GB 50526, GB-T 4959
• Germany:
» DIN 15905-5, DIN 45657:2014, DIN 45657:2005,
DIN 45645-2
» DIN 45645-1
(optional with Extended Acoustic Pack)
• Japan: JIS C1509-1:2005, JIS C 1513 class 1,
JIS C 1514 class 0
• Switzerland: V-NISSG
• UK: BS 4142:2014, BS 5969, BS 6698
• US: ANSI S1.4:2014, ANSI S1.43, ANSI S1.11:2014,
ANSI/ASA S12.60
• International IEC standards are adopted as European
standards and the letters IEC are replaced by EN.
XL2 conforms to these EN standards.
• WELL Buildings, LEED Green Building
• FGI Facility Guidelines Institute
Weighting • Frequency weighting: A, C, Z (simultaneous)
• Time weighting: (simultaneous)
» Fast, Slow
» Impulse (optional with Extended Acoustic Pack)
Level Details • Measurement bandwidth (-3dB): 4.4 Hz - 23.0 kHz
• Level resolution: 0.1 dB
• Internal noise: 1.3 µV A-Weighted
277
Specifications
Audio
Recording
• Default
» Recording of compressed wav-files
(ADPCM - 4 bit, 24 kHz)
» a new wav-file starts every 12 hours
(max. wav-file size 512 MB)
» Bandwidth: 2.0 Hz - 10.2 kHz
• Optional: Extended Acoustic Pack
» Recording of linear wav-files (24 bit, 48 kHz)
» a new wav-file starts every 1 hours
(max. wav-file size 512 MB)
» Bandwidth: 2.0 Hz - 23.6 kHz
• Optional: NoiseScout - Managed Mode
» Recording of compressed wav-files
(4 bit, 12 kHz)
» Bandwidth: 2.0 Hz - 5.1 kHz
» requires activated “NoiseScout 365” or
“Data Day Credits”
• Audio files include meta data (scaling, time, ...) in
Broadcast Wave Format BWF according to EBU
TECH 3285
Measure-
ment
Ranges with
different
microphones
• XL2+M2230: 17 dB(A) - 137 dB
• XL2+M2340: 18 dB(A) - 138 dB
• XL2+M2215: 25 dB(A) - 153 dB
• XL2+M2211: 21 dB(A) - 144 dB
• XL2+M4261: 27 dB(A) - 146 dB
@ typical microphone sensitivity
Linear Mea-
surement
Range acc.
IEC61672 /
ANSI S1.4
• XL2+M2230: 24 dB(A) - 137 dB, 27 dB(C) - 137 dB
• XL2+M2340: 25 dB(A) - 138 dB, 28 dB(C) - 138 dB
• XL2+M2215: 33 dB(A) - 153 dB
• XL2+M2211: 29 dB(A) - 144 dB
• XL2+M4261: 33 dB(A) - 146 dB
@ typical microphone sensitivity
Stabilization
Time
< 10 seconds
Integration
Time
• Minimum: 1 second
• Maximum: 100 hours minus 1 second
Display
Measure-
ment
Ranges
Three level ranges depending on the microphone
sensitivity with manual setting. For example:
• M2230, M2340 @ sensitivity = 42 mV/Pa
» LOW, lower level range: 0 - 100 dBSPL
» MID, mid-level range: 20 - 120 dBSPL
» HIGH, upper level range: 40 - 140 dBSPL
• M2215 @ sensitivity = 8 mV/Pa
» LOW, lower level range: 20 - 120 dBSPL
» MID, mid-level range: 40 - 140 dBSPL
» HIGH, upper level range: 60 - 160 dBSPL
• M2211 @ sensitivity = 20 mV/Pa
» LOW, lower level range: 10 - 110 dBSPL
» MID, mid-level range: 30 - 130 dBSPL
» HIGH, upper level range: 50 - 150 dBSPL
• M4261 @ sensitivity = 16 mV/Pa
» LOW, lower level range: 10 - 110 dBSPL
» MID, mid-level range: 30 - 130 dBSPL
» HIGH, upper level range: 50 - 150 dBSPL
278
Specifications
Residual
noise in [dB]
@ S =
42 mV/Pa
of XL2
without
measure-
ment
microphone
• Frequency weighting A
Level range L
eq
L
peak
LOW 4 17
MID 18 31
HIGH 43 55
• Frequency weighting C
Level range L
eq
L
peak
LOW 3 16
MID 17 30
HIGH 41 55
• Frequency weighting Z
Level range L
eq
L
peak
LOW 7 20
MID 21 34
HIGH 46 58
Measure-
ments
• SPL actual, Lmin, Lmax, Lpeak, Leq, Lp
• Gliding LAeq and LCeq with selectable time win-
dow from one second to one hour
(=running Lxeq or sliding Lxeq with x= A or C)
• All measurement results simultaneously available
• Correction value measurement wizard based on
LAeq, LCeq and LCpeak
• Noise exposure level LEX with post-processing
• Logging all data or subsets in selectable intervals
• Recording of voice notes
• Monitoring of sound levels that exceed limits
• Digital I/O interface for external peripherals control
Real-Time
Analyzer
RTA
• Conforms with class 1 of IEC 61260:2014 and
ANSI S1.11-2014
• 1/1 octave band display: 8 Hz - 16 kHz
sub ranges 8 Hz - 4 kHz or 31.5 Hz - 16 kHz
• 1/3 octave band display: 6.3 Hz - 20 kHz
sub ranges 6.3 Hz - 8 kHz or 20 Hz - 20 kHz
• Level resolution: 0.1 dB
• Measurement Units: Volt, dBu, dBV and dBSPL
• Band pass filters (base 10) conform with class 1 of
IEC 61260:2014 and ANSI S1.11-2014
» 1/1 octave spectrum: > 16 Hz band
» 1/3 octave spectrum: > 16 Hz band
• Broadband A/Z levels simultaneously
• Frequency weighting: X-Curve @ 500 seats in ac-
cordance with SMPTE ST 202:2010 and
ISO 2969:2015 (not available for XL2-TA)
• Capturing of a single reading into the internal
memory for comparative measurements
• Leq logging
279
Specifications
Remote
Measure-
ment
(optional)
• Querying measurement data online via the USB
interface of the following functions:
» Sound level meter and spectrum analyzer
SLMeter/RTA
» FFT analyzer
» RT60 reverberation time
» Audio analyzer RMS/THD+N
» High-resolution spectral analyzer 1/12 Oct + Tol
• Typical response time: 10 ms
@ querying the frequency spectrum in SLMeter
Functions of
Extended
Acoustic
Pack
(optional)
• SLMeter/RTA function
» Recording of linear wav-files (24 bit, 48 kHz)
a new wav-file starts every 1 hour (max. wav-file
size 512 MB)
» Percentiles for wide band, 1/1 and 1/3 octave
spectrum
- Flexible setting from 0.1% to 99.9%
- Sampling: every 1.3 ms
- Wide band: in 0.1 dB wide classes, based on
sampling Lxy (x= A, C or Z, y= F, S or EQ
1”
)
- 1/1 and 1/3 octave spectrum: in 1.0 dB wide
classes, based on Lxy (x= A, C or Z, y= F or S)
- Dynamic range: 140 dB
» Sound Exposure Level LAE
» 100ms logging
» RTA logging of Lmin and Lmax
» Event-triggered audio and data recording
» Time weighting: Impulse
(LxI, LxIeq with x= A, C, Z)
» True peak level in 1/1 and 1/3 octave resolution
» Clock-Impulse Maximum Level (TaktMax) in ac-
cordance with DIN 45645-1 and DIN 45657
» Impulsiveness detection in accordance with
BS4142:2014 and NordTest ACOU 112
• FFT function
» High-resolution Zoom-FFT with selectable fre-
quency ranges and resolution up to 0.4 Hz in the
range of 5 Hz to 20 kHz
» Recording of linear wav-files (24 bit, 48 kHz)
• RT60 function
» Reverberation time in 1/3 octave resolution
• 1/12 octave Spectral Analyzer
(requires Spectral Limits Option)
» Recording of linear wav-files (24 bit, 48 kHz)
280
Specifications
Functions of
Spectral
Limits
Option
(optional)
• SLMeter/RTA function
» True peak level in 1/1 and 1/3 octave resolution
• FFT function
» High-resolution Zoom-FFT with selectable fre-
quency ranges and resolution up to 0.4 Hz
» Sound mode: 5 Hz to 20 kHz
» Vibration mode: 1 Hz to 20 kHz
• 1/12 octave function
» High-resolution RTA function “1/12 Oct + Tol”
» Selectable 1/1, 1/3, 1/6 and 1/12 octave spectral
resolution
» Frequency band listening at rear speaker
» Sound Mode: 11.5 Hz to 21.8 kHz
» Vibration mode: 0.73 Hz to 1.36 kHz
• FFT and 1/12 octave function
» Capturing of multiple readings into the internal
memory
» Comparing measurement results against cap-
tures with relative or absolute curve display
» Comprehensive tolerance handling with toler-
ance masks based on captures for passed/failed
measurements
» Export and import of tolerance and capture files
• Noise Curves
» Noise Rating NR according to ISO/R 1996-1971
» Noise Criteria NC
in accordance with ANSI S12.2-2019 and -1995
» Room Noise Criteria RNC
in accordance with ANSI S12.2-2019
» Room Criteria RC
in accordance with ANSI S12.2-1995
» Preferred Noise Criteria
in accordance with ASA 1971
Reporting and Analysis Software
Data
Explorer
(optional)
• Enables the import of measurement data into the
Data Explorer software
• Powerful data processor for easy and fast analysis
of sound level measurement data on PC
Sound
Insulation
Reporter
(optional)
• Enables the import of RTA and reverberation time
measurement data in 1/3 octave band resolution
into the XL2 Sound Insulation Reporter software
• Software provides all tools for fast data analysis
and standardized reporting of airborne, impact and
facade sound insulation measurements on PC
• Standards ASTM E336, ASTM E413, ASTM E1007,
ASTM E989, ASTM E966, ASTM E1332, BB93,
DIN 4109, Document E, GB/T 19889, ISO 16283,
ISO 140, ISO 717, ISO 10140, NEN 5077:2019, SIA
181:2006, SIA 181:2020
Room
Acoustics
Reporter
(optional)
• Frequency response spectrum and Noise Curves
• Room acoustic simulation according to Sabine or
Eyring
• Import of own sound absorber database and toler-
ances
• Standards GB 50371, IEC 61260, ANSI/ASA S12.2-
2019, DIN 15996:2020, ISO R 1996-1971, ASR
A3.7:2021, DIN 18041:2016, ISO 3382-1:2009,
ISO 3382-2:2008, ÖNORM B 8115-3:2015, ASTM
C423-17, ISO 354:2003
281
Specifications
Sound
Power
Reporter
(optional)
• Enables the import of RTA and reverberation time
measurement data in 1/1 and 1/3 octave band res-
olution into the Sound Power Reporter software
• Software provides all the standard reports for
sound power measurements
• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-
ASA S12.51, S12.54, S12.56
Acoustic Analyzer
FFT Analysis • Real-time FFT with actual level, L
eq
, L
min
, L
max
• Level resolution: 0.1 dB
• Frequency Band Ranges: 7 Hz - 215 Hz,
58 Hz - 1.72 kHz, 484 Hz - 20.5 kHz with 143 fre-
quency bins shown on display
• Measurement Units: Volt, dBu, dBV and dBSPL
• Optional with Extended Acoustic Pack or Spectral
Limits: High-resolution Zoom-FFT with selectable
frequency ranges and resolution up to 0.4 Hz in
the range of 5 Hz to 20 kHz
• Optional with Spectral Limits:
Capture and tolerance function with multiple read-
ings for comparative measurements and passed/
failed analysis
Reverbera-
tion
Time RT60
• Conforms with ISO 3382 and ASTM E2235
• 1/1 octave bands results from 63 Hz - 8 kHz,
based on T20 and T30
• Optional with Extended Acoustic Pack:
1/3 octave bands results from 50 Hz - 10 kHz
based on T20 and T30
• Range: 10 ms - 30 seconds
• Minimum reverberation time (typical)
» < 100 Hz: 0.3 second
» 100 - 200 Hz: 0.2 second
» > 200 Hz: 0.1 second
• Measurement based Schroeder-method
• Test signal: Impulse source or interrupted pink
noise generated by the MR-PRO, MR2 or the in-
cluded NTi Audio Test CD / USB Flash Drive
282
Specifications
Polarity • Checks polarity of speakers and line signals
• Positive/Negative detection of wideband and
individual 1/1 octave bands through internal micro-
phone or XLR/RCA connector
• Test signal: NTi Audio polarity test signal gener-
ated by the MR-PRO, MR2 or the included NTi
Audio Test CD / USB Flash Drive
Delay Time • Propagation delay between electrical reference
signal and acoustic signal using the internal micro-
phone
• Range: 0 ms - 1 second (0 m - 344 m)
• Resolution: 0.1 ms
• Test signal: NTi Audio delay test signal generated
by the MR-PRO, MR2 or the included NTi Audio
Test CD / USB Flash Drive
Noise
Curves
• Noise Rating NR according to ISO/R 1996-1971
• Noise Criteria NC
in accordance with ANSI S12.2-2019 and -1995
• Room Noise Criteria RNC
in accordance with ANSI S12.2-2019
• Room Criteria RC
in accordance with ANSI S12.2-1995
• Preferred Noise Criteria
in accordance with ASA 1971
• Application range of measurement microphones:
» M2230: down to NC15
» M2340: down to NC15
» M2211: down to NC20
» M4261: down to NC25
1/12 Octave
Analysis
(optional)
• Actual level, L
min
, L
max,
L
eq
,
Leq1”, Leq4”
• Selectable 1/1, 1/3, 1/6 and 1/12 octave spectral
resolution
• Measurement Units: Volt, dBu, dBV and dBSPL
• Band pass filters (base 10)
• Capturing of multiple readings into the internal
memory
• Comparing measurement results against captures
with relative or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captures for
passed/failed measurements
Cinema
Meter
(optional)
• Measurements in 1/3 octave resolution in accor-
dance with SMPTE ST 202:2010 and SMPTE RP
200:2012
• An interactive assistant guides the user through
dedicated measurement procedures.
• Consists of
» Spectral Limits Option
NTi Audio # 600 000 376
» Cinema Assistant Option
NTi Audio # 600 000 378
283
Specifications
STIPA
Speech
Intelligibility
(optional)
• Measurement in accordance with the standards
» IEC 60268-16 (edition 2, 3, 4 or 5)
» AS 1670.4
» BS 5839-8
» CEN/TS 54-32:2015
» DIN EN 50849:2017
» ISO 7240-16
» ISO 7240-19:2007
» DIN VDE 0833-4
» VDE V 0833-4-32:2016
» VDE 0828-1:2017-11
» NFPA 72
» UFC 4-021-01
• Direct measurement method (IEC 60268-16)
• Frequency range: 125 Hz - 8 kHz in octave band
• Modulation frequencies 0.63 Hz - 12.5 Hz in third-
octave resolution
• Single value STI and CIS test result
• Ambient noise correction
• Automated averaging of measurements
• Modulation indices and individual band level re-
sults with error indicator
• Test signal: NTi Audio STIPA signal generated by
the MR-PRO, NTi Audio TalkBox or other audio
players (download wav-file at https://my.nti-audio.
com/support/xl2)
Audio Analyzer
Conforms
with Stan-
dards
• IEC 61672, IEC 60651, IEC 60804
• DIN EN 60065, VDE 0860, IEC 468-4
Level RMS • True RMS detection in V, dBu, dBV, dBSPL
(dBSPL not available for XL2-TA)
• Power measurement in Watt W or dBm
with flexible load setting from 1.0 to 9999 Ohm
• Range XLR/RCA input: 2 µV - 25 V (-112 dBu to
+30 dBu)
• Accuracy: ± 0.5 % @ 1 kHz,
• Flatness: ± 0.1 dB @ 12 Hz to 21.3 kHz
• Bandwidth (-3 dB): 5 Hz to 23.6 kHz
• Resolution: 3 digits (dB scale),5 digits (linear scale)
or 6 digits (x1 scale)
Real-Time
Analyzer
RTA
Following measurement functions offer audio spec-
trum in Volt, dBu and dBV
• Sound Level Meter
• FFT
• 1/12 Octave (optional with Spectral Limits)
Frequency • Range: 9 Hz to 21.3 kHz
• Resolution: 6 digits
• Accuracy: < ± 0.003%
THD+N
(Total Har-
monic
Distortion +
Noise)
• Range: -100 dB to 0 dB (0.001% to 100%)
• Minimum level: > -90 dBu
• Fundamental frequency range: 10 Hz to 21.3 kHz
• Measurement bandwidth: 2 Hz to 23.6 kHz
• Resolution: 3 digits (dB scale) or 4 digits (linear
scale)
• Residual THD+N @ XLR/RCA input: < 2 µV
Scope Auto ranging, auto scaling
284
Specifications
Filter • Frequency weighting: A, C, Z
• Highpass 100Hz, 400 Hz, 19 kHz,
• Bandpass 22.4 Hz - 22.4 kHz in accordance with
IEC468-4
Remote
Measure-
ment
(optional)
Querying measurement data online via the USB
interface of the following functions:
• Sound level meter and spectrum analyzer
SLMeter/RTA
• FFT analyzer
• RT60 reverberation time
• Audio analyzer RMS/THD+N
• High-resolution spectral analyzer 1/12 Oct + Tol
Calibration
Free-field
Correction
• NTi Audio Class 1 Sound Calibrator
» M2230: -0.1 dB
» M2340: -0.1 dB
» M2211: -0.1 dB
» M2215: -0.1 dB
• NTi Audio Class 1 Sound Calibrator with
1/4” Calibration Adapter, type ADP 1/4-P
» M4260: +0.1 dB
» M4261: +0.2 dB
Wind Screen
Correction
• 50 mm Wind Screen: +0,12 dB
• 90 mm Wind Screen: +0,19 dB
• WP30/WP61 Wind Screen 90 mm: +0,19 dB
Calibration • Recommended calibration interval: one year
• Microphone calibration with external calibrator
supported
• Optional calibration certificate for new instru-
ments available
Vibration Meter
Channels • 1 (Single-channel)
Parameters • Real time measurement in
» Acceleration: m/s2, g, in/s2, dB
» Velocity: m/s, in/s, dB
» Displacement: m, in, dB
» Peak particle velocity PPV: mm/s, in/s
» Levels: RMS, Peak, Peak-Peak
VibMeter • Broadband level
» Frequency range:
0.8 Hz - 2.5 kHz
• Spectral
» 1/1 octave band display: 1 Hz - 2.0 kHz
sub ranges 1 Hz - 500 Hz or 4 Hz - 2 kHz
» 1/3 octave band display: 0.8 Hz - 2.5 kHz
sub ranges 0.8 Hz - 1.0 kHz, 2.5 Hz - 2.5 kHz
» Broadband level measured with
bandwidth (- 3dB): 0.7 Hz – 23.6 kHz
• Display according to DIN 45669-1:2010
» Unweighted velocity v(t)
» Maximum absolute velocity ¦v¦max
» Averaging duration T
m
» Measurement duration T
M
Filter • Flat (no filter)
Bandwidth (- 3dB): 0.7 Hz – 23.6 kHz
• 10 - 1000 Hz according to ISO 2954 with decay
rate = 18 dB / octave
• 1 - 80 Hz, 1 - 315 Hz acc. to DIN 45669-1:2010
with decay rate = 12 dB / octave
285
Specifications
Audio
Recording in
VibMeter
• Default
» Recording of compressed wav-files
(ADPCM - 4 bit, 24 kHz)
» a new wav-file starts every 12 hours
(max. wav-file size 512 MB)
» Bandwidth: 2.0 Hz - 10.2 kHz
• Optional: Extended Acoustic Pack
» Recording of linear wav-files (24 bit, 48 kHz)
» a new wav-file starts every 1 hours
(max. wav-file size 512 MB)
» Bandwidth: 2.0 Hz - 23.6 kHz
FFT Analysis
• Frequency range:
1 Hz - 1.69 kHz
• Optional with Extended Acoustic Pack or Spec-
tral Limits: High-resolution Zoom-FFT with se-
lectable frequency ranges and resolution up to
0.4 Hz in the range of 1 Hz to 20 kHz
1/12 Octave
Analysis
(optional)
• Actual level, L
min
, L
max,
L
eq
,
Leq1”, Leq4”
• Selectable 1/1, 1/3, 1/6 and 1/12 octave spec-
tral resolution
• Measurement Units
» Acceleration: m/s2, g, in/s2, dB
» Velocity: m/s, in/s, dB
» Displacement: m, in, dB
• Band pass filters (base 10)
• Frequency range:
0.73 Hz - 1.36 kHz
Maximum Input
Level
• 353 m/s2, 36 g @ 20 mV/(m/s2)
with ICP Adapter ASD
Residual Noise
(typical) with
ICP Adapter
ASD
• 17 µV @ 0.7 Hz ... 23.0 kHz
• 14 µV @ 1 Hz ... 315 Hz
• 14 µV @ 1 Hz ... 80 Hz
Reference-
measurement
range
• Mid
286
Specifications
Input / Output Interfaces
Audio Inputs • XLR balanced
» Input impedance = 200 kOhm
» Phantom power: +48 VDC switchable with maxi-
mum 10 mA supply current in accordance with
IEC 61938
» Automated sensor detection for NTi Audio’s ASD
measurement microphones and pre-amplifiers
• RCA unbalanced with input impedance >30 kOhm
• Built-in condenser microphone for polarity testing,
delay measurements and voice note recording
Audio
Outputs
• Built-in speaker
• Headphone connector
» 3.5 mm Minijack
» mono monitor wired to both channels of stereo
jack
» Linear output signal over a measurement range
of 57 dB in SLMeter measurement function
» Maximum output level: 0.33 Vrms / 0.47 Vp
USB Inter-
face
USB mini connector for data transfer to PC, XL2
Projector PRO and/or charging of Li-Po battery
Digital I/O Connection interface to accessories
• XL2 Input Keypad
• Limit Light
• Stack Light
• Digital I/O Adapter PCB
TOSLink 24 bit linear PCM audio signal output
(prepared for later firmware extension)
Memory SD Card included (8 GByte), removable, storing
measurement data in ASCII format, screen shots,
voice notes and wav-files
Data logging every second offers following noise
monitoring periods:
• Logging default noise levels: > 2 years
• Additional logging of 1/3 octave data: > 6 month
• Additional
» compressed audio recording: > 1 week
» linear audio recording: > 15 hours
Optional 32 GB SD Cards are available for longer
monitoring requirements; requires XL2 Firmware
V4.10 or higher.
Power
Supply
• Rechargeable Li-Po battery included
» Type 3.7 V / 2260 mAh
» Typical battery lifetime > 4 hours
» Range: 3.3 - 4.5 VDC
» Volume energy density = 339 Wh/l
• Dry cell batteries type AA, 4 x 1.5 V
» Typical battery lifetime > 4 hours
» Range: 3.7 - 6.0 VDC
• Linear external power supply 9 VDC
» Range: 7.5 - 20.0 VDC @ minimum 6 Watt
» Charges Li-Po battery during operation
» Connector C5.5 x 2.1 x 12 mm
• USB-Power Supply
» for short-term operation < 1 day
» charging power is equal or less than power con-
sumption
287
Specifications
Power
Supply
• External battery pack
» 22 Ah battery pack: 4 days
» 44 Ah battery pack: 8 days
General
Clock • Default
» Real-time clock with lithium backup battery
» Typical life backup battery: 8 years
» Return instrument for battery replacement
» Drift < 1.7 seconds per 24 hours
• Special XL2 edition, NTi Audio # 600 000 356
» VCXTO clock
» Drift < 0.04 seconds per 24 hours
Mechanics • Tripod or microphone stand mount 1/4”
• Wire stand mounted on rear side
• Display: 160 x 160 pixels grey scale with LED back
light
• Dimensions (L x W x H)
» 180 mm x 90 mm x 45 mm
» 7.1” x 3.5” x 1.8”
• Weight: 480 g (1 lb) including built-in Li-Po battery
Temperature -10 °C to +50 °C (14° to 122°F)
Humidity 5% to 90% RH, non-condensing
Static air
pressure
65 kPa to 108 kPa
Susceptibil-
ity to radio
frequencies
Classification Group X
Electromag-
netic Com-
patibility
CE compliant:
EN 61326-1 Class B, EN 55011 class B
EN 61000-4-2 to -6 & -11
Protection
Rating
IP51
ATEX • For applications in explosive atmospheres within
zone 2 in accordance with IEC 60079
• Directive 2014/34/EU
288
Specifications
24. Technical Data Microphones
M2230 M2340
(with self-test)
M2211 M2215
(high levels)
M4261 M2914
Low-Noise
Classification with XL2 according
to IEC 61672, ANSI S1.4
Class 1
certified
Class 1
certified
Frequency Response
Class 1
Class 2 Frequency Re-
sponse Class 1
Consisting of PreAmplfier
MA220 +
MC230 or
MC230A
Capsule
PreAmplfier
MA230 +
MC230A
Capsule
PreAmplfier
MA220 +
Capsule 7052
PreAmplfier
MA220 +
Capsule 7056
M4261 micro-
phone with
permanently
installed
capsule
Microphone Type Omnidirectional, pre-polarized condenser,
free field microphone
Capsule / Transducer 1/2” detachable, 60UNS2 thread,
type WS2F, IEC 61094-4
1/4” permanent-
ly installed
1/2” detachable,
60UNS2 thread,
type WS2F,
IEC 61094-4
PreAmplifier Type MA220 MA230 MA220 - MA214
System Self-test (CIC) - with XL2 -
Flatness tolerance bands
typical
±1 dB @ 5 Hz - 20 Hz
±1 dB @ >20 Hz - 4 kHz
±1.5 dB @ >4 kHz - 10 kHz
±2 dB @ >10 kHz - 16 kHz
±3 dB @ >16 kHz - 20 kHz
+1/-4.5 dB @ 5
Hz - 20 Hz
±1.5 dB @ >20
Hz - 4 kHz
±3 dB @ >4 kHz
- 10 kHz
±4.5 dB @ >10
kHz - 16 kHz
±5 dB @ >16
kHz - 20 kHz
±2 dB @ 10 Hz –
16 kHz
±3 dB @ 5 Hz –
20 kH
289
Specifications
M2230 M2340
(with self-test)
M2211 M2215
(high levels)
M4261 M2914
Low-Noise
Actual Frequency Response
freely available as Excel-data, register product at https://my.nti-audio.com and
contact [email protected]
Frequency Range 5 Hz - 20 kHz
Residual Noise Floor typical 16 dB(A) 17dB(A) 21 dB(A) 25 dB(A) 27 dB(A) 6.5 dB(A)
Maximum SPL
@ THD 3%, 1 kHz, S_typical
137 dBSPL 138 dBSPL 144 dBSPL 153 dBSPL 142 dBSPL Peak 103 dB /
RMS 100 dB
Sensitivity typical @ 1 kHz -27.5 dBV/Pa
±2 dB
(42 mV/Pa)
-34 dBV/Pa
±3 dB
(20 mV/Pa)
-42 dBV/Pa
±3 dB
(8 mV/Pa)
-36 dBV/Pa
±4 dB
(16 mV/Pa)
320 mV/Pa
Temperature Coefficient < -0.01 dB / °C < ±0.015 dB / °C < ±0.02 dB / °C < ±0.01 dB / °C
Temperature Range -10°C to +50°C
(14°F to 122°F)
0°C to +40°C
(32°F to 104°F)
–20°C to +60°C
(–4°F to 140°F)
Pressure Coefficient -0.005 dB / kPa -0.02 dB / kPa -0.04 dB / kPa –0.00001 dB/Pa
Influence of Humidity
(non-condensing)
< ±0.05 dB < ±0.4 dB < 90% R.H.,
non-condensing
Humidity 5% to 90% RH, non-condensing
Long-term Stability > 250 years / dB -
Power Supply 48 VDC phantom power ICP
Current Consumption typical 2.3 mA 0.8 mA 2.3 mA 1.7 mA 4 – 20 mA
Electronic Data Sheet NTi Audio ASD in accordance with IEEE P1451.4 V1.0, Class 2, Template 27
Output Impedance 100 Ohm balanced < 100 Ω
Connector Balanced 3-pole XLR BNC
Diameter Dimensions 20.5 mm (0.8”) 12.7 mm (0.5”),
protection grid
13.2 mm (0.52”)
290
Specifications
M2230 M2340
(with self-test)
M2211 M2215
(high levels)
M4261 M2914
Low-Noise
Length Dimensions 154 mm (6.1”) 150 mm (5.9”) 135 mm (5.3”)
Weight 100 g (3.53 oz) 83 g (2.93 oz) 250 g (8.8 oz)
Environmental Protection IP51
Windscreen Diameter 50 mm (2”) 90 mm (3.5”) 33 mm (1.3”) 33 mm (1.3”) 33 mm (1.3”) 50 mm (2”)
Scope of Supply Windscreen, Microphone Holder with Adapter 5/8“ - 3/8“, Manual
NTi Audio # 600 040 050 600 040 230 600 040 022 600 040 045 600 040 070 600 040 240
Outdoor Measurement Microphones
M2230-WP
(M2230+WP30)
M2340-WP
(M2340+WP30)
M4261-WP
(M4261+WP61)
Classification with XL2 accord-
ing to IEC 61672, ANSI S1.4
Class 1
certified
Class 1
certified
Class 2
System Self-test (CIC) - with XL2 or XL3 -
Windscreen Diameter 90 mm (3.5”)
Diameter Dimensions 36 mm (1.4”) 36 mm (1.4”) 36 mm (1.4”)
Length Dimensions 378 mm (14.9”) 378 mm (14.9”) 378 mm (14.9”)
Weight 430 g, 15.17 oz 430 g, 15.17 oz 413 g, 14.57 oz
Environmental Protection IP54 in vertical position IP54 in vertical position IP54 in vertical position
Mounting Standard 3/8” tripod mount included
Optional Pole Mount Adapter • Pole Mount Adapter PM 1” for pole diameter 25 - 33 mm (1-1.3”) NTi Audio # 600 040 067
• Pole Mount Adapter PM 1 1/4” for pole diameter 32 - 44 mm (1.25-1.75”) NTi Audio # 600 040 068
NTi Audio # 600 040 050 + 600 040 060 600 040 230 + 600 040 060 600 040 070 + 600 040 080
291
Specifications
Typical Frequency Response of Measurement Microphones
(free field conditions @ reference direction 0°)
log frequency [Hz]
-8
-6
-4
-2
0
2
4
6
8
1 10 100 1000 10000 100000
Sensitivity relative [dB]
5 10 20 100 1000 10000 20000
8
6
4
2
0
-2
-4
-6
-8
Tolerance
Class 1, IEC61672-1
M2230, M2340,
M2211, M2215
M4261
Tolerance
Class 2, IEC61672-1
292
Specifications
Linear Measurement Range
acc. IEC61672 / ANSI S1.4
(typ. microphone sensitivity)
XL2 + M2230: 24 dB(A) - 137 dB XL2 + M2340: 25 dB(A) - 138 dB
XL2 + M2211: 29 dB(A) - 144 dB XL2 + M4261: 33 dB(A) - 146 dB
293
Specifications
Free Field - Pressure Correction Factors
If a measurement microphone is held in a free-field environ-
ment, then the measurement microphone acts at high fre-
quencies like a reflector. The sound pressure increases in
front of the microphone capsule membrane. M2230, M2340,
M2211 and M2215 are free-field equalized measurement mi-
crophones, they compensate for the increased pressure inter-
nally. The calibration of the measurement microphones M2230
and M2340 with the B&K 4226 requires the accessory Adapter
Ring MXR01, NTi Audio # 600 040 105. Please note, never
touch the diaphragm of the measurement microphone capsule.
The calibrator no longer offers free-field conditions. Therefore,
the free-field equalization of the microphone must be compen-
sated. This needs to be considered prior the calibration. The
correction value needs to be added to the pressure response
of the microphone.
Example:
• During the calibration, the XL2 measures the sound level in
the calibrator. If the B&K 4226 calibrator is used and it is set
to 16 kHz, then the XL2+M2230 reads just 86.7 dBA.
• The free-field sound level is calculated by summing the XL2
measurement value and the correction value (86.7 dB +
7.3 dB = 94.0 dB).
The following corrections apply with the B&K 4226 calibrator.
Nominal
Frequency
[Hz]
M2230,
M2340
with
MXR01
Adapter
[dB]
M2211
[dB]
M2215
[dB]
Measurement
Uncertainty U
[dB]
31.5
63
125
-0.3
0.0
-0.2
-0.2
0.0
-0.1
0.0
0.0
-0.1
0.3
0.3
0.3
250
500
1000
-0.2
-0.2
0.0
-0.1
-0.1
0.0
-0.1
-0.1
0.0
0.3
0.3
0.3
2000
4000
8000
0.1
0.7
2.7
0.1
0.7
4.5
0.0
0.4
4.7
0.3
0.3
0.4
12500
16000
7. 2
7. 3
5.8
7. 9
6.1
7. 9
0.7
0.8
Correction values for other calibrators for M2230 and M2340.
Type
Correction
Value
Calibration
Frequency
Calibration
Level
NTi Audio CAL200 -0.1 1 kHz 114 dB
B&K 4231 -0.2 1 kHz 114 dB
Norsonic Nor-1251 -0.2 1 kHz 114 dB
294
Specifications
Actuator Correction
The following free-field 0° incidence corrections apply for
calibration using a protection grid actuator (e.g. B&K UA033,
GRAS RA0014). Please note, never touch the diaphragm
of the measurement microphone capsule. The maximum
DC bias for the actuator calibration is 200 VDC.
M2211, M2215
Nominal
Frequency
[Hz]
M2211
[dB]
M2215
[dB]
31.5
63
125
0.0
0.0
0.0
0.0
0.0
0.0
250
500
1000
0.0
0.1
0.1
0.0
0.0
0.0
2000
4000
8000
0.6
1. 7
4.2
0.2
1. 2
3.9
12500
16000
7. 3
9.2
6.7
9.0
M2230, M2340
The calibration requires the accessory Actuator Grid, NTi Audio
# 600 040 112. The Actuator Grid comes with an insulation ring
dedicated for this measurement method.
Nominal
Frequency [Hz]
M2230, M2340
[dB]
<400 0.0
400
500
630
-0.2
0.0
-0.2
800
1000
1250
0.0
0.0
-0.1
1600
2000
2500
0.2
0.2
0.3
3150
4000
5000
0.8
1. 0
1. 6
6300
8000
10000
2.4
3.6
4.8
12500
16000
20000
6.5
9.3
11. 7
295
Specifications
Diffuse-field Sensitivity Level Correction
A diffuse sound field is characterized by the sound arriving at
the receiver from all directions with more or less equal prob-
ability. The M2230, M2340, M2211, M2215 and M4261 are
free-field equalized measurement microphones. The default
frequency response refers to a 0° sound incidence. The diffuse-
field sensitivity level correction is calculated by averaging the
directional characteristics in accordance with IEC 61183. The
corrections for diffuse-field conditions are documented in the
following table and may be activated directly on the XL2; see
Spectral Corrections. The directional response of the M2230 is
described in the appendix.
Example:
• The sound pressure level in a diffuse sound field shall be
determined. The display of the XL2 with the M2230 reads
80.0 dBA for the 20 kHz third-octave band.
• The diffuse sound level is now calculated from the sum
of the XL2 measurement value and the correction value
(80.0 dB + 5.9 dB = 85.9 dB).
The diffuse-field sensitivity level correction is
not necessary using a diffuse field equalized
measurement microphone.
Nominal
Frequency
[Hz]
1/2” Microphone
M2230, M2340,
M2211, M2215
[dB]
1/4” Microphone
M4261
[dB]
<63
63
80
0.0
0.0
0.0
0.0
0.0
0.0
100
125
160
0.0
0.0
0.0
0.0
0.0
0.0
200
250
315
0.0
0.0
0.0
0.0
0.0
0.0
400
500
630
0.0
0.0
0.0
0.0
0.0
0.0
800
1000
1250
0.0
0.0
0.1
0.0
0.0
0.1
1600
2000
2500
0.2
0.2
0.4
0.1
0.1
0.2
3150
4000
5000
0.6
0.8
1. 3
0.3
0.3
0.5
6300
8000
10000
1. 8
2.5
3.4
0.8
1. 1
1. 6
12500
16000
20000
4.4
5.3
5.9
2.2
2.8
3.4
296
Specifications
Free-field and Diffuse-Field Sensitivity for M2230 and M2340
sensitivity relative [dB]
-8
-7
-6
-5
-4
-3
-2
-1
0
1
10 100 1000 10000 100000
diffuse
field
1
0
-1
-2
-3
-4
-5
-6
-7
-8
log frequency [Hz]
10 20 100 1000 10000 20000
idealized
free-field
297
Specifications
The outdoor measurement microphone fulfills the require-
ments of IEC 61672 and ANSI S1.4 for vertical sound incidence.
For compliance with horizontal sound incidence a spectral cor-
rection is employed in the associated XL2 Sound Level Meter.
Select Calibrate Menu: Show Spec Correction in the Sys-
tem Settings. This will enable the spectral correction field in
the Calibration menu.
Spectral Correction for horizontal Sound Incidents using the Outdoor Microphone
Spectral Correction for horizontal sound incidents:
Nominal
Frequency
[Hz]
WP30
Weather Protection
[dB]
WP61
Weather Protection
[dB]
1/3 Octave 1/1 Octave 1/3 Octave 1/1 Octave
<800 0.0 0.0 0.0 0.0
800
1000
1250
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
1600
2000
2500
0.2
0.3
0.7
0.4
0.2
0.3
0.8
0.4
3150
4000
5000
1. 3
2.0
2.7
2.0
1. 4
2.1
2.5
2.0
6300
8000
10000
2.9
3.3
3.9
3.4
2.3
2.4
2.8
2.5
12500
16000
20000
4.6
6.4
6.8
5.9
3.0
3.1
3.1
3.0
298
Specifications
25. Technical Data PreAmplifier
MA220 PreAmplifier MA230 PreAmplifier
with self-test (CIC)
Microphone PreAmplifier Compatible with 1/2” microphone capsules type WS2F in accordance with IEC61094-4
Frequency Range (-3dB) 4 Hz - 100 kHz 1.3 Hz - 50 kHz
Residual Noise Floor typical
1.9 mV(A) at C_in 15 pF ≙ 5.6 dBA @ 42 mV/Pa 2.4 mV(A) at C_in 15 pF ≙ 9.1 dBA @ 42 mV/Pa
Frequency Response Flatness ±0.2 dB ±0.1 dB, 10 Hz - 20 kHz
Phase Linearity < 1° @ 20 Hz - 20 kHz
Maximum Output Voltage
@ THD 3%, 1 kHz
21 Vpp ≙ 7,4 Vrms ≙ 138,9 dBSPL @ 42 mV/Pa 22 Vpp ≙ 7,8 Vrms ≙ 139,3 dBSPL @ 42 mV/Pa
Electronic Data Sheet Containing user calibration data; default factory sensitivity = 4.9 V/Pa
Read/write by XL2 Audio and Acoustic Analyzer
NTi Audio ASD in accordance with IEEE P1451.4 V1.0, Class 2, Template 27
Impedance Input: 20 GOhm // 0.26 pF, Output: 100 Ohm balanced
Power Supply 48 VDC phantom power, 2.3 mA typical 48 VDC phantom power, 0.8 mA typical
Attenuation < 0.17 dB (Rphantom 2x 6.8 kOhm) < 0.07 dB (Rphantom 2x 6.8 kOhm)
Connector Balanced 3-pole XLR
Thread for Capsule 60 UNS2
Weight 90 g, 3.17 oz
Dimensions Length 142.5 mm (5.6”), diameter 20.5 mm (0.8”)
Temperature Range -10°C to +50°C (14°F to 122°F)
Humidity 5% to 90% RH, non-condensing
NTi Audio # 600 040 040 600 040 200
The product specifications may vary based on the mounted microphone capsule type.
299
Specifications
Appendix
Appendix 1: Standard - Optional Features
Standard Features Optional
Sound Level Meter
Frequency Weighting
-
Sound Level Meter
Time weighting
• Extended Acoustic Pack:
Impulse
Sound Exposure Level
Percentile Sound Pressure Levels for wide band, 1/1 and
1/3 octave spectrum with flexible setting from 0.1% to
99.9%.
Sound Level Meter
Correction
-
300
Appendix
Standard Features Optional
Sound Level Meter
Parameter
• Extended Acoustic Pack:
Clock-Impulse Maximum Level (Taktmaximalpegel) in ac-
cordance with DIN 45645-1:
Calculated levels in accordance with DIN 45645-1:
Impulsiveness in accordance with BS4142:2014 and
NordTest ACOU 112
Sound Level Meter
RTA Spectrum Analyzer
supported • Extended Acoustic Pack or Spectral Limits Option:
True peak level
301
Appendix
Standard Features Optional
Sound Level Meter
Audio Recording
• Recording of wav-files
(ADPCM compression)
• Voice note recording
• Extended Acoustic Pack:
Recording of wav-files (24 bit, 48 kHz)
Sound Level Meter
Triggered Event Recording
-
• Extended Acoustic Pack:
Sound Level Meter
Logging
supported • 100 ms logging
• RTA logging of Lmin and Lmax
FFT Analysis
Measurement Range
• Extended Acoustic Pack or Spectral Limits Option:
with zoom function
FFT + Tol
Capture and Tolerance
- • Spectral Limits:
Capture and Tolerance functionality
RT60 Octave band resolution • Extended Acoustic Pack:
1/3 octave band results
1/12 Oct + Tol - • Spectral Limits:
1/12 Oct + Tol
Capture and Tolerance functionality
302
Appendix
Standard Features Optional
Noise Curves - • Spectral Limits Option
STIPA - • STIPA Option with STIPA functionality
Cinema Meter - • Cinema Meter Option
Querying measurement
data online via the USB
interface
- Remote Measurement Option supporting
• Sound level meter and spectrum analyzer SLMeter/RTA
• FFT analyzer
• RT60 reverberation time
• Audio analyzer RMS/THD+N
• High-resolution spectral analyzer 1/12 Oct + Tol
303
Appendix
Appendix 2: Factory Default Profiles
You may start up the XL2 with individual preset application pro-
files.
The profile Full mode is the default configuration with all avail-
able measurement functions enabled.
304
Appendix
DIN15905-5 / DIN15905-5 & Audio
(Sound Level Monitoring in accordance with DIN15905-5)
The following limits apply at all areas accessible by the visitors
during the measurement period of 30 minutes:
• Maximum averaged level = 99 dB
The XL2 displays this maximum level with the measure-
ment result L
Aeq+k1
.
• Maximum peak level L
Cpeak
= 135 dB
These levels are shown in the numeric result page:
L
Aeq5”
+k1 Time-averaged sound pressure level L
Aeq
with correction value k1 and a moving time
window of 5 seconds.
L
Aeq
+k1 Time-averaged sound pressure level L
Aeq
with correction value k1.
L
Cpeak
+k2 C-weighted peak level L
Cpeak
with correc-
tion value k2.
The following sound levels are displayed in the real-time ana-
lyzer page:
L
ZFhold3
For tracing of feedback frequencies. The
peak hold time is set to 3 seconds.
L
ZFlive
Actual real-time spectra.
305
Appendix
How to Measure
• Select the page K
SET
with the rotary wheel
.
• Measure the correction values k1 and k2 as described in the
chapter Sound Level Meter: Correction Value K
SET.
• Press the start button
.
• The icon LOG flashes during the ongoing measurement. In
the case where the profile #DIN15905-5 & Audio has been
selected the icon AUD flashes, indicating the additional au-
dio wav-file logging.
• During the measurement you can monitor the actual sound
level L
Aeq5”
+k1 in order to remain below the permitted lim-
its; alternatively you may monitor the spectrum analyzer for
tracing possible feedback frequencies.
• Press stop
to finish the measurement.
In accordance with DIN15905-5, all sound lev-
els are measured, displayed and logged to the
SD Card automatically. The settings are locked,
which ensures that the correct parameters are
measured.
The profile #DIN15905-5 & Audio includes the
recording of Compressed+AGC wav-files.
Limits
This profile is configured with the following limits, which trigger
the lights on the limit button and external Digital I/O Adapter.
This facilitates a quick response to sound levels that exceed
these limits.
Measurement Results
You may import the log files into a report generator soft-
ware based on MS Excel, providing automatically-completed
live event reports with noise level charts. The report genera-
tor software is a free download on the support website at
https://my.nti-audio.com for all registered XL2 customers.
306
Appendix
V-NISSG 100dB / V-NISSG 100dB&Audio
(Sound Level Monitoring in accordance with V-NISSG)
The following limits apply at all areas accessible by the visitors
during the moving measurement period window of 60 minutes
during the live event:
• Maximum averaged level
The XL2 displays this maximum level with the measurement
result L
Aeq60‘+k1
.
Type of
live event
Max. level Requirements
3 100 dB
- Sound level recording
- Results to store for 30 days
- Level warning to visitors
- Hearing protection distributed
- Chill out zone < 85 dB(A)
2 96 dB
- Sound level monitoring
- Level warning to visitors
- Hearing protection distributed
1 93 dB
- Sound level monitoring
• Maximum peak level L
AFmax
= 125 dB
These levels are shown in the numeric result page:
L
Aeq5”
+k1 Time-averaged sound pressure level L
Aeq
with correction value k1 and a moving time
window of 5 seconds.
L
Aeq60’
+k1 Time-averaged sound pressure level L
Aeq
with correction value k1 and a moving time
window of 60 minutes.
L
AFmax
+k1 Maximum sound pressure level L
AFmax
with correction value k1.
307
Appendix
The following sound levels are displayed in the real-time ana-
lyzer page:
L
ZFhold3
For tracing of feedback frequencies. The
peak hold time is set to 3 seconds.
L
ZFlive
Actual real-time spectra.
How to Measure
• Select the page K
SET
with the rotary wheel
.
• Measure the correction value k1 as described in the chapter
Sound Level Meter: Correction Value K
SET. (k2 is not required
for V-NISSG)
• Press the start button
.
• The icon LOG flashes during the ongoing measurement. In
the case where the profile #V-NISSG 100dB&Audio has
been selected the icon AUD flashes, indicating the additional
audio wav-file logging.
• During the measurement you can monitor the actual sound
level L
Aeq5”
+k1 in order to remain below the permitted lim-
its; alternatively you may monitor the spectrum analyzer for
tracing possible feedback frequencies.
• Press stop
to finish the measurement.
In accordance with V-NISSG, all sound levels
are measured, displayed and logged to SD Card
automatically. The settings are locked, which
ensures that the correct parameters are mea-
sured.
The profile #V-NISSG 100dB&Audio includes
the recording of Compressed+AGC wav-files.
308
Appendix
Limits
This profile is configured with the following limits, which trig-
ger the lights on the limit button and external Digital I/O Adapt-
er. This facilitates a quick response to sound levels that exceed
these limits.
Measurement Results
You may import the log files into a report generator soft-
ware based on MS Excel, providing automatically-completed
live event reports with noise level charts. The report genera-
tor software is a free download on the support website at
https://my.nti-audio.com for all registered XL2 customers.
Appendix 3: Description Sound Levels
A-Frequency Weighting Filter in accordance with
IEC 61672
Applicable for most common sound pressure level
measurements, compensating for human hearing
perception at lower sound pressure levels.
C-Frequency Weighting Filter in accordance with
IEC 61672
Applicable for very high sound pressure levels,
compensating for human hearing perception at
high sound pressure levels; typically used for mea-
surement of peak values, e.g. L
Cpeak
Capture
This selection offers the reference curve, which has
been previously stored with Capture in the spec-
trum analyzer of the SLMeter function.
Application example:
• Comparing the performance of the left and right
speakers in a live event sound setup.
309
Appendix
Sound Exposure Level
The sound exposure level L
AE
characterizes the
total energy content of a signal and corresponds
to the LAeq normalized to one second. The sound
exposure level is measured for example to compare
noise events with different time durations. The L
AE
reports the amount of noise from an event such as
an individual aircraft fly-over. An earlier used level
name is SEL.
L
AE
= L
Aeq
+ 10 x log (time in seconds)
Time-Average Sound Level or
Equivalent Continuous Sound Level in accor-
dance with IEC 61672
Octave-band Time-Average Sound Level or
Equivalent Continuous Sound Level in accor-
dance with IEC 61672
with selectable 63 Hz or 125 Hz octave-band level
for low frequency noise monitoring; in case of a
selected 1/3 octave resolution in the RTA window,
these levels are calculated by summing the corre-
sponding one-third-octave levels.
Moving Time-Average Sound Level or
Moving Equivalent Continuous Sound Level
With selectable time window from one second
up to one hour, four individual levels can be con-
figured. The moving time-average sound level is a
Leq based on a moving time window. This level is
also called “running Leq,T”, “gliding Leq,T” or “slid-
ing Leq,T”.
The measurement result is updated every second
for the first 60 seconds. Afterwards the update rate
is every five seconds. This is an example:
10h 00min 00sec Start of XL2 measurement
10h 00min 05sec Leq5” = Leq of the 5 seconds
10h 00min 06sec Leq5” = Leq of the time win-
dow from 10h 00min 01sec to
10h 00min 06sec
10h 00min 07sec Leq5” = Leq of the time win-
dow from 10h 00min 02sec to
10h 00min 07sec
310
Appendix
Application example:
• Display the moving Leq over 5 seconds in accor-
dance with DIN15905
• Measure the moving Leq over 60 minutes in ac-
cordance with V-NISSG
Fast Time Weighting
Time constant t = 125 ms; the time weighting is
an exponential function of time, which defines
how changes of the instantaneous sound pressure
level are averaged for useful sound pressure level
results. The measurement results are shown accu-
rately for sound sources with a minimum length of
0.5 seconds. The decay rate is 34.7 dB/s. Fast time
weighting is typically used for common sound level
measurements.
Holding Maximum Level
For tracing of feedback frequencies in the RTA page.
The hold time can be set to 3, 5 or 10 seconds.
Impulse Time Weighting
Time constant attack t = 35 ms; time constant de-
cay t = 1500 ms; the time weighting is an exponen-
tial function of time, which defines how changes
of the instantaneous sound pressure level are av-
eraged for useful sound pressure level results. The
measurement results are shown accurately for
sound sources with a minimum length of 0.1 sec-
onds. Impulse time weighting is used for impulsive
sound sources.
Impulse Penalty ImpPenalty
Impulsive penalty in accordance with BS4142:2014
and NordTest ACOU 112. The LAF is sampled with
a time interval of 12 ms. The penalty is calculated
as follows:
Penalty KI= 1.8 * (Prominence P - 5) for P > 5
P=3*lg(onset rate[dB/s]) + 2*lg(level difference[dB])
The Prominence P is designed to give a maximum
around 15; concluding the maximum impulse pen-
alty is 18 dB.
311
Appendix
Correction Value k1
The correction value k1 is based on an LAeq mea-
surement. It is measured or manually set in the
page K
SET of the sound level meter function.
Correction Value k2
The correction value k2 is based on either LCeq or
LCpeak measurement. It is measured or manually
set in the page K
SET of the sound level meter func-
tion.
Parameter live
Actual current sound pressure level.
Parameter max
Maximum sound level of the measurement cycle.
Parameter min
Minimum sound level of the measurement cycle.
Correction Value off
No correction value, default setting.
Peak Level
Application example:
Measure L
Cpeak
in accordance with DIN15905
The RTA spectrum analyzer measures the true peak
level with the optional Extended Acoustic Pack. The
peak hold time can be set to 0, 1 or 5 seconds.
Percentile Sound Level - Level Statistics
The statistical distribution of sound pressure levels
is commonly used for environmental noise analy-
sis, such as road traffic or community noise assess-
ments. For example, L
AFxx%
is the noise level
exceeded during xx% of the measurement period;
e.g., LAF90% is the noise level exceeded during
90% of the measurement period.
Please see the specifications at chapter Technical
Data XL2: Functions of Extended Acoustic Pack
(optional) in this manual.
Previous Level
Applicable for timer mode Repeat or Repeat Syn-
chronized; displays the selected sound pressure
level of the last measurement cycle.
312
Appendix
Slow Time Weighting
Time constant t = 1 second; the time-weighting is
an exponential function of time, which defines how
changes of the instantaneous sound pressure level
are averaged for useful sound level results. The de-
cay rate is 4.3 dB/s.
Parameter T3
Clock-Impulse Maximum Level (Taktmaximalpegel)
L
AFT3
in accordance with DIN 45645-1; maximum
sound pressure level measured with frequency
weighting A and time weighting F within a time in-
terval of 3 seconds.
Parameter T3eq
Time-average Clock-Impulse Maximum Level
(Taktmaximalpegel) L
AFT3eq
in accordance with
DIN 45645-1 and DIN 45657.
Parameter T5
Clock-Impulse Maximum Level (Taktmaximalpegel)
L
AFT5
in accordance with DIN 45645-1; maximum
sound pressure level measured with frequency
weighting A and time weighting F within a time in-
terval of 5 seconds.
Parameter T5eq
Time-average Clock-Impulse Maximum Level
(Taktmaximalpegel) L
AFT5eq
in accordance with
DIN 45645-1 and DIN 45657.
Inverted X-Curve
In the film and recording industry an X curve is also
known as a wide-range curve, e.g., used for cinema
installations conforming to SMPTE ST 202:2010 or
ISO 2969:2015 @ 500 seats.
Z-frequency weighting in accordance with
IEC 61672 (= flat frequency response, no filter)
Overall sound pressure level, all sound signal com-
ponents are included; required for special applica-
tions.
Sound Pressure Level Lp
Lp is a commonly used abbreviation for sound pres-
sure level (p for pressure); for example, Lw is used
for Sound Power Level
313
Appendix
Appendix 4: Common Sound Levels
Display Application Setting
L
AE
Sound Exposure Level
The sound exposure level L
AE
characterizes the total energy
content of a signal and corresponds to the LAeq normalized to
one second. The sound exposure level is measured for example
to compare noise events with different time durations. The L
AE
reports the amount of noise from an event such as an individual
aircraft fly-over. An earlier used level name is SEL.
L
AE
= L
Aeq
+ 10 x log (time in seconds)
->
L
Aeq
Time-Average Sound Pressure Level or
Equivalent Continuous Sound Pressure Level
Averaged sound level over time with A frequency weighting.
->
->
L
Aeq
_dt Level LAeq_dt “delta t” in report
Level of the preset logging interval in the LOG-menu; e.g. Log-
ging interval = 1 second, then LAeq_dt is the time averaged level
of the past 1 second.
314
Appendix
L
Aeq
+k1 Time-Average Sound Pressure Level with Correction Value
The actual measurement position often differs to the loudest posi-
tion of the live event. Thus, the correction value k1 is the correc-
tion value of L
Aeq
between the loudest position and the actual
measurement position, measured using pink noise. The correc-
tion value k1 is measured or manually set in the page K
SET of the
sound level meter function.
->
->
L
Aeqxx
Moving Time-Average Sound Pressure Level
Measurement of the moving sound level over time Leq with A-
weighting frequency and F-weighting time responses; the param-
eter xx is user-defined from one second up to one hour. This level
is also called “running Leq,T”, “gliding Leq,T” or “sliding Leq,T”.
Four individual levels can be configured, e.g.
• 5 seconds for live sound monitoring
• 10 minutes (in accordance with the French standard)
• 15 minutes (in accordance with the British standard)
• 60 minutes (in accordance with V-NISSG)
->
->
->
L
Aeq20-200
Time-Average Sound Pressure Level 20 - 200 Hz
Summed time-averaged sound pressure level over time with
A frequency weighting of the third-octave frequency bands
20 - 200 Hz.
->
315
Appendix
L
Aeq60’
+k1 Moving Time-Average Sound Pressure Level with
Correction Value k1
The actual measurement position often differs to the loudest po-
sition of the live event. Thus, the correction value k1 is the cor-
rection value of L
Aeq60’M
between the loudest position and the
actual measurement position, measured using pink noise. The
correction value k1 is measured or manually set in the page K
SET
of the sound level meter function.
Application: Measurements in accordance with V-NISSG
->
->
->
L
AF
Actual Sound Pressure Level
Sound pressure level with A frequency weighting and F time
weighting, compensating for human hearing perception at lower
sound pressure levels; applicable at levels lower than 100 dB.
->
->
->
L
AFmax
Maximum Sound Pressure Level
Measures the maximum environmental noise level during the
measurement period.
->
->
L
AFmax
_dt Maximum Sound Pressure Level “delta t” in report
Maximum level of the preset logging interval in the LOG-menu,
e.g. 1 second.
L
AFmin
Minimum Sound Pressure Level
Measures the minimum environmental noise level during the
measurement period.
->
->
316
Appendix
L
AFmin
_dt Minimum Sound Pressure Level “delta t” in report
Minimum level of the preset logging interval in the LOG-menu,
e.g. 1 second.
L
AFxx%
Percentile Sound Pressure Level
The statistical distribution of sound pressure levels is commonly
used for environmental noise analysis, such as road traffic or com-
munity noise assessments. For example L
AFxx%
is the noise
level exceeded during xx% of the measurement period; e.g.,
L
AF90%
is the noise level exceeded during 90% of the measure-
ment period.
Please see the specifications at chapter Technical Data XL2: Func-
tions of Extended Acoustic Pack (optional) in this manual.
90
80
70
60
Time [seconds]
Sound Level [dB] vs Time
LAF10% = 88.8dB
LAF50%= 76.4dB
LAF90%= 66.6dB
LAeq= 84.2dB
->
->
317
Appendix
L
Ceq
Time-Average Sound Pressure Level or
Equivalent Continuous Sound Pressure Level
Averaged sound level over time with C frequency weighting.
->
->
L
CPK
Peak Sound Level
Peak sound level with C frequency weighting. Measures the peak
level. High peak levels can damage the human hearing.
->
->
L
CPKmax
Maximum Peak Sound Level
Maximum peak sound level with C frequency weighting. Mea-
sures the peak level. High peak levels can damage the human
hearing.
->
->
->
L
CPK
_dt Maximum Peak Sound Level „delta t” in report
Maximum peak sound level with C frequency weighting of the
preset logging interval in the LOG-menu, e.g. 1 second.
L
CPK
+k2 Peak Sound Level with Correction Value
The actual measurement position often differs to the loudest posi-
tion of the live event. Thus, the correction value k2 is the correc-
tion value of L
CPK
between the loudest position and the actual
measurement position, measured using pink noise. The correc-
tion value k2 is measured or manually set in the page K
SET of the
sound level meter function.
->
->
318
Appendix
L
EX
Noise Exposure Level LEX
The Noise at Work Directive 2003/10/EC lays down minimum re-
quirements for the protection of workers from risks to their health
and safety arising or likely to arise from exposure to noise and in
particular the risk to hearing.
• Steady noise L
EX,8h
=
L
Aeq
: (applies to L
AS,
deviation < 5 dB
)
L
Aeq
measured over a short time equals L
EX,8h;
the following
formula applies for a measurement period < 8 hours:
L
EX,8h
= L
Aeq
+ 10 x log ( T / 8 hours )
• Steady noise with stepped level variations:
Measure L
Aeq
at the different levels and enter the data with
the corresponding exposure time in the NTi Audio noise expo-
sure level post-processing form; the L
EX,8h
will be calculated
and displayed.
• Varying noise levels:
L
EX,8h
=
L
Aeq
measured for 8 hours
The exposure limit values and respective actions are:
L
EX, 8h
L
Cpeak
Action
Lower limit value 80 dB(A) 135 dB The employer shall make individual hearing protectors available
to workers
Upper limit value 85 dB(A) 137 dB Hearing protectors shall be used
Exposure limit 87 dB(A) 140 dB The attenuation characteristics of the hearing protectors worn
must adequately reduce the levels below this limit
->
->
319
Appendix
Appendix 5: Vibration Meter Functions
Acceleration a
in units m/s2, g, in/s2, dB
L
a
[dB] = 20*log (a / 10
-6
)
Velocity v
in units m/s, in/s and dB;
Velocity is calculated based on the acceleration a
and the frequency f: v = a / (2 * π * f)
L
v
[dB] = 20*log (v / 10
-9
)
Displacement
in units m, in, dB;
Displacement is calculated based on the accelera-
tion a and the frequency f: d = a / (2 * π * f)
2
L
d
[dB] = 20*log (d / 10
-12
)
RMS level
Measurement result is based on RMS
Peak level
Measurement result is based on peak level
• Peak level a(Pk) = √2 * a
• Peak level v(Pk) = √2 * v
• Peak level d(Pk) = √2 * d
Peak-peak Level
Measurement result is based on peak-peak level
• Peak-peak level a(PP) = a(Pk) * 2
• Peak-peak level v(PP) = v(Pk) * 2
• Peak-peak level d(PP) = d(Pk) * 2
Moving Time-Average Level or
Moving Equivalent Continuous Level
with selectable time window 1, 2, 4 or 8 seconds.
Clock-Impulse Maximum Level
(Taktmaximalpegel)
Maximum velocity during a periodic 30 seconds
interval with time weighting F in accordance with
DIN 4150-2.
Peak Particle Velocity PPV
Ground or blast vibration amplitude is often mea-
sured as particle velocity or the speed at which a
particle vibrates. This is quantified as peak particle
velocity PPV in the units [mm/s] or [in/s]. PPV
equals the level type vel Pk on the XL2.
320
Appendix
Details IEC 61672 & IEC 61260
The XL2-TA Analyzer, with the M2230 measurement micro-
phone, fully complies with the standards IEC 61672:2013,
IEC 61672:2003, IEC 61260:2014 and IEC 61260:2003 as an
integrating class 1 Sound Level Meter with A, C, Z frequency
weighting and fast/slow time weighting. The impulse time
weighting is optionally available with the Extended Acoustic
Package.
The type approval applies to the sound level meter in accor-
dance with IEC 61672 and the Octave/Third-Octave measure-
ment in accordance with IEC 61260. Attention should be given
to the following recommendations on the environment and the
configuration.
Environment
Persons and objects that are located in the sound field during
the measurement have an absorbing, reflecting or shielding
impact on the sound field and may therefore compromise the
measurement result. Consequently, such objects should be re-
moved from the sound field where appropriate. The measure-
ment microphone should be mounted on a tripod. The operator
should remain as far away as possible behind the microphone
during the measurement.
Configuration “Microphone Detached”
• XL2-TA Sound Level Meter
- Hardware version: D2, E0, E1
- Firmware version 4.71
• M2230 Measurement Microphone, consisting of
- Microphone Preamplifier MA220
- Microphone Capsule MC230 or MC230A
• M2340 Measurement Microphone, consisting of
- Microphone Preamplifier MA230
- Microphone Capsule MC230A
• ASD Cable, 5 meter or 10 meter or 20 meter
• Class 1 Sound Calibrator CAL200
• Optional
- Optional: Extended Acoustic Pack
- NTi Audio Mains Power Adapter Exel Line
- NTi Audio Microphone Clamp MH01
- NTi Audio Windscreen, 50 mm
- NTi Audio Windscreen, 90 mm
- XL2 Input Keypad
With the microphone connected by the ASD Cable, the ana-
lyzer can be held in your hand during the measurement. This
offers the convenience of watching the measurement values
as they occur.
321
Appendix
Configuration “Microphone Attached”
• XL2-TA Sound Level Meter
- Hardware version: D2, E0, E1
- Firmware version 4.71
- Shroud MXA01
• M2230 Measurement Microphone, consisting of
- Microphone Preamplifier MA220
- Microphone Capsule MC230 or MC230A
• M2340 Measurement Microphone, consisting of
- Microphone Preamplifier MA230
- Microphone Capsule MC230A
• Class 1 Sound Calibrator CAL200
• Optional
- Optional: Extended Acoustic Pack
- NTi Audio Mains Power Adapter Exel Line
- NTi Audio Windscreen, 50 mm
- NTi Audio Windscreen, 90 mm
- XL2 Input Keypad
There are no correction values required for
these configurations.
Configuration “Outdoor Microphone Detached”
• XL2-TA Sound Level Meter
- Hardware version: D2, E0, E1
- Firmware version 4.71
• M2230 Measurement Microphone, consisting of
- Microphone Preamplifier MA220
- Microphone Capsule MC230 or MC230A
• M2340 Measurement Microphone, consisting of
- Microphone Preamplifier MA230
- Microphone Capsule MC230A
• Weather Protection WP30 with bird spike BS01
• ASD Cable, 5 meter or 10 meter or 20 meter
• Class 1 Sound Calibrator CAL200
• Optional
- Optional: Extended Acoustic Pack
- NTi Audio Mains Power Adapter Exel Line
- XL2 Input Keypad
- Dehumidifier for Weather Protection WP30
• There are no correction values required for
the configuration “Outdoor Microphone De-
tached” at vertical noise incidents.
• Activate the corresponding correction in the
Calibration menu for “Outdoor Microphone
Detached” at horizontal noise incidents.
322
Appendix
General Information
Reference Sound Pressure Level
The reference sound pressure level is 114 dBSPL relative to
20 mPa.
Reference Level Range
The reference level range is MID, 20 - 120 dBSPL
Reference Orientation
The microphone reference point is located in the middle of the
microphone membrane. The 0° reference orientation and the
orientation of the membrane’s surface normal is identical.
Verified Frequency Range
20 Hz to 20 kHz
Greatest Peak-To-Peak Voltage at the Electric Input
(Refer IEC61672-1 paragraphs 5.1.16, 9.3.i)
The highest sound pressure level at the M2230 microphone
with a sensitivity of S = 42 mV/Pa is 143.5 dB.
Initial Time Interval after Power On (IEC61672-1, 5.1.18)
The XL2-TA Sound Level Meter and M2230 microphone meet
the given specifications for the electro-acoustical response af-
ter an initial time interval of no more than one minute following
switching on the power. This assumes that the devices have
been allowed to reach equilibrium with the prevailing ambient
environment before switching on the power.
Insertion of Electrical Signals
(Refer IEC61672-1 paragraphs 5.1.15, 9.3g)
The capsule replacement NTI-K65-15 can be used to insert
electrical signals to the preamplifier MA220. The device pro-
vides at one side a contact that corresponds to the center con-
tact of the replaced microphone capsule, at the other side a
BNC-plug for the electrical signals. The impedance at the out-
put of the device is 15 pF with a maximum deviation of ±1pF.
The electrical noise floor is measured by shorting the con-
tacts of the BNC plug. Before the NTI-K65-15 can be mount-
ed to the preamplifier MA220, the microphone capsule must
first be detached. The nominal sensitivity S of the capsule is
S = 42 mV/Pa. Measurements with the NTI-K65-15 therefore
require that the sensitivity in the calibration menu is manually
adjusted to S = 42 mV/Pa.
The maximum electrical input voltage is 36 Vpp. The attenu-
ation between the device and the XLR input of the XL2-TA is
0.78 dB at a reference frequency of 1 kHz. A 1 kHz signal with
459 mVrms level is required at the input of the device, to sub-
stitute the signal of a microphone capsule with the sensitivity
42 mV/Pa at a reference level of 114 dBSPL.
323
Appendix
Output (Refer IEC61672-1 paragraphs 5.16.1, 9.2.5p)
The instrument provides no electrical analog or digital outputs
for measurements.
Typical Time Interval Needed to Stabilize after Changes in
Environmental Conditions (IEC61672-1, 6.1.2, 9.3l)
Recommended time interval for stabilizing the sound level me-
ter after changes in environmental conditions, prior to perform-
ing any measurements:
Change in the environmental condition Time Interval
Temperature ±5 °C 15 minutes
Temperature ±20 °C 30 minutes
Air pressure ±5 kPa 15 seconds
Humidity ±30% 15 minutes
The time intervals apply, for instance, after moving from a cold
into a warm room, and assume that combinations of air tem-
perature and relative humidity do not yield a dew point greater
than +39 °C or less than –15 °C.
No Limit on Operational Environment
(Refer IEC61672-1 paragraphs 6.3.2, 9.2.7a)
There are no restrictions in place for parts or components,
which would limit the operational environment.
Exposure to Electrostatic Discharges
(Refer IEC61672-1 paragraphs 6.5.2, 9.2.7b)
Heavy electrostatic discharges directly to the instrument’s
connector or keyboard may interrupt the operation. The XL2-TA
either switches off or freezes at the last valid measurement
value. In such a case re-start the instrument. If the data logging
had been active prior the interrupt, the log file may contain a
gap. However, the acquired results can be identified correct-
ly as each one is saved together with its own individual time
stamp.
Exposure to AC Power and Radio Frequency Fields
(Refer IEC61672-1 paragraphs 6.6.1, 9.2.7c)
The sound level meter complies with the requirements of the
standards IEC61672-1:2013 and IEC61260-1:2014 regarding
immunity against high frequency fields or mains power fields
from 50 to 60 Hz.
324
Appendix
Impact of Electromagnetic Fields
If the device is exposed to electromagnetic fields of 10 V/m,
the measurement of sound levels below 74 dB is not speci-
fied. If the electromagnetic fields exceed 10 V/m, the exposed
instrument is not specified in any level range.
Susceptibility to AC Power and Radio Frequency Fields
(Refer IEC61672-1 paragraphs 6.6.3, 9.3o)
The device has the greatest susceptibility to AC power fre-
quency fields, if the direction of the magnetic field is the same
as the orientation of the microphone axis.
The device has the greatest susceptibility to radio frequency
fields in the lowest measurement range, if the surface normal
of the display and the direction of the incoming radio frequency
field are parallel to each other and the power supply is con-
nected. In this case, the sound level meter should be operated
without a power supply. The configuration with the greatest
radio-frequency emissions levels is provided by connecting the
mains power adapter to the sound level meter.
Measuring Low-Level Sound Fields
(Refer IEC61672-1 paragraphs 5.6.5, 9.2.5d)
If the sound level is very low, the measurement result is af-
fected by the noise floor of the sound level meter. The speci-
fied configuration complies with class 1 within the given linear
measuring range.
Influence of the ASD Cable
(Refer IEC61672-1 paragraphs 7.1, 9.2.6b)
The ASD Cable serves as connection cable between the
XL2-TA sound level meter and the microphone in the detached
configuration. There are no correction values required for this
configuration.
Influence of Mechanical Vibrations
Mechanical vibrations with 1 m/s
2
acceleration perpendicular
to the membrane of the microphone, will raise the lower limit
of the linear operating range to 71 dB (A-weighted) for the fre-
quencies 31,5 Hz, 63 Hz, 126 Hz, 250 Hz, 500 Hz, 630 Hz,
800 Hz and 1000 Hz. Mechanical vibrations with 1 m/s
2
accel-
eration parallel to the membrane of the microphone, will raise
the lower limit of the linear operating range to 68 dB (A-weight-
ed) for the frequencies 31,5 Hz, 63 Hz, 126 Hz, 250 Hz, 500 Hz,
630 Hz, 800 Hz and 1000 Hz.
Modes of Operation and Accessories
The greatest susceptibility to radio frequency fields is indepen-
det of operation mode or connected accessories.
Volume of Measurement Microphone M2230
• Equivalent Diaphragm Volume = 50 mm3
• Volume between grid and membran/housing = 92.5 mm3
• Calibrator Load Volume = 142.5 mm3
325
Appendix
Class 1 Sound Calibrator
(Refer IEC61672-1 paragraphs 5.2.1, 5.2.7, 9.3d)
If an obligatory calibration is required for the sound level meter,
in accordance with the type approval, then the Class 1 Sound
Calibrator CAL200 should be used.
Technical Details
• Type: Larson Davis CAL200
• Level correction: -0.1 dB
• Calibration frequency: 1 kHz (= reference frequency)
• Calibration level: 114 dB (= reference sound pressure level)
Details for Calibration
The calibration has to be executed according to the instructions
given in chapter “Calibration”. Ensure that the calibrator is set
to 114 dB.
Add the free-field correction values to the reference sound
pressure level, and enter the result into the XL2-TA under “Cali-
bration Level“.
Accessory
Input Keypad
The Input Keypad has no effect on measured sound pressure
levels of the instrument.
326
Appendix
Level Linearity
(Refer IEC61672-1 paragraphs 5.5.3, 5.5.9, 9.2.2e, 9.3e, 9.3f).
All values refer to Sref = 42 mV/Pa*. The starting levels for the
level linearity tests are listed in the following tables:
Level range: Low
[dB]
Frequency
L
A
t
* L
C
t
* L
Z
t
*
L
AeqT
* L
AE
*
(t
int
= 10s)
L
Cpeak
*
31,5
Hz
from 24
to 68
starting 54
from 27
to 105
starting 94
from 30
to 108
starting 94
from 24
to 68
starting 54
from 34
to 78
starting 54
1 kHz
from 24
to 108
starting 94
from 27
to 108
starting 94
from 30
to 108
starting 94
from 24
to 108
starting 94
from 34
to 118
starting 104
from 41
to 111
4 kHz
from 24
to 109
starting 94
from 27
to 107
starting 94
from 30
to 108
starting 94
from 24
to 109
starting 94
from 34
to 119
starting 104
8 kHz
from 24
to 107
starting 94
from 27
to 105
starting 94
from 30
to 108
starting 94
from 24
to 107
starting 94
from 34
to 117
starting 104
12,5
kHz
from 24
to 104
starting 94
from 27
to 102
starting 94
from 30
to 108
starting 94
from 24
to 104
starting 94
from 34
to 114
starting 104
Level range: Mid
[dB]
Frequency
L
A
t
* L
C
t
* L
Z
t
*
L
AeqT
* L
AE
*
(t
int
= 10s)
L
Cpeak
*
31,5
Hz
from 31
to 86
starting 54
from 32
to 123
starting 114
from 35
to 126
starting 114
from 31
to 86
starting 54
from 41
to 96
starting 54
1 kHz
from 31
to 126
starting 114
from 32
to 126
starting 114
from 35
to 126
starting 114
from 31
to 126
starting 114
from 41
to 136
starting 124
from 38
to 129
4 kHz
from 31
to 127
starting 114
from 32
to 126
starting 114
from 35
to 126
starting 114
from 31
to 127
starting 114
from 41
to 137
starting 124
8 kHz
from 31
to 126
starting 114
from 32
to 123
starting 114
from 35
to 126
starting 114
from 31
to 126
starting 114
from 41
to 135
starting 124
12,5
kHz
from 31
to 122
starting 114
from 32
to 120
starting 114
from 35
to 126
starting 114
from 31
to 122
starting 114
from 41
to 132
starting 124
* If the sensitivity Sx deviates from the given data, a correction value of 20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB
327
Appendix
Level range: High
[dB]
Frequency
L
A
t
* L
C
t
* L
Z
t
*
L
AeqT
* L
AE
*
(t
int
= 10s)
L
Cpeak
*
31,5
Hz
from 53
to 98
starting 94
from 51
to 137
starting 114
from 56
to 137
starting 114
from 53
to 98
starting 94
from 63
to 108
starting 94
1 kHz
from 53
to 137
starting 114
from 51
to 137
starting 114
from 56
to 137
starting 114
from 53
to 137
starting 114
from 63
to 147
starting 124
from 65
to 140
4 kHz
from 53
to 138
starting 114
from 51
to 137
starting 114
from 56
to 137
starting 114
from 53
to 138
starting 114
from 63
to 148
starting 124
8 kHz
from 53
to 136
starting 114
from 51
to 137
starting 114
from 56
to 137
starting 114
from 53
to 136
starting 114
from 63
to 146
starting 124
12,5
kHz
from 53
to 133
starting 114
from 51
to 131
starting 114
from 56
to 137
starting 114
from 53
to 133
starting 114
from 63
to 143
starting 124
Sound pressure levels, which continiously exceed the specified
linear measurement range and overload the microphone pream-
plifier, may cause in extreme cases a displayed level below the
actual sound pressure level.
328
Appendix
Level Linearity of Octaveband-Spectrum
in accordance with IEC 61260.
All values refer to Sref = 42 mV/Pa*.
Nominal
Frequency
Hz
Level Range
LOW MID HIGH
20 45-108 dB 20-126 dB 32-137 dB
31.5 25-108 dB 20-126 dB 32-137 dB
63 23-108 dB 20-126 dB 32-137 dB
125 14-108 dB 17-126 dB 33-137 dB
250 13-108 dB 15-126 dB 34-137 dB
500 13-108 dB 15-126 dB 36-137 dB
1000 15-108 dB 16-126 dB 39-137 dB
2000 17-108 dB 18-126 dB 41-137 dB
4000 19-108 dB 20-126 dB 44-137 dB
8000 19-108 dB 23-126 dB 47-137 dB
16000 18-108 dB 28-126 dB 51-137 dB
The sampling rate of the filters is 48 kHz.
* If the sensitivity Sx deviates from the given data, a correction value of
20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB
329
Appendix
Level Linearity of Third-Octaveband-Spectrum
in accordance with IEC 61260.
All values refer to Sref = 42 mV/Pa*.
Nominal
Frequency
Hz
Level Range
LOW MID HIGH
12.5
16
20
48-108 dB
46-108 dB
43-108 dB
17-126 dB
17-126 dB
17-126 dB
29-137 dB
29-137 dB
29-137 dB
25
31.5
40
41-108 dB
37-108 dB
28-108 dB
16-126 dB
15-126 dB
14-126 dB
29-137 dB
29-137 dB
29-137 dB
50
63
80
23-108 dB
19-108 dB
11-108 dB
13-126 dB
12-126 dB
11-126 dB
29-137 dB
29-137 dB
29-137 dB
100
125
160
9-108 dB
8-108 dB
8-108 dB
11-126 dB
10-126 dB
10-126 dB
29-137 dB
29-137 dB
29-137 dB
200
250
315
8-108 dB
7-108 dB
8-108 dB
10-126 dB
10-126 dB
10-126 dB
29-137 dB
29-137 dB
30-137 dB
400
500
630
8-108 dB
8-108 dB
9-108 dB
11-126 dB
11-126 dB
11-126 dB
30-137 dB
31-137 dB
31-137 dB
800
1000
1250
9-108 dB
10-108 dB
11-108 dB
11-126 dB
11-126 dB
12-126 dB
32-137 dB
34-137 dB
35-137 dB
Nominal
Frequency
Hz
Level Range
LOW MID HIGH
1600
2000
2500
11-108 dB
13-108 dB
13-108 dB
12-126 dB
13-126 dB
14-126 dB
35-137 dB
36-137 dB
37-137 dB
3150
4000
5000
14-108 dB
14-108 dB
15-108 dB
14-126 dB
15-126 dB
16-126 dB
38-137 dB
39-137 dB
40-137 dB
6300
8000
10000
15-108 dB
15-108 dB
15-108 dB
17-126 dB
18-126 dB
19-126 dB
41-137 dB
42-137 dB
43-137 dB
12500
16000
20000
14-108 dB
13-108 dB
13-108 dB
21-126 dB
23-126 dB
26-126 dB
44-137 dB
48-137 dB
50-137 dB
The sampling rate of the filters is 48 kHz.
* If the sensitivity Sx deviates from the given data, a correction value of
20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB
330
Appendix
Self-generated Noise with Microphone
(Refer IEC61672-1 paragraphs 5.6.1 to 5.6.4, 9.2.5o)
Self-generated noise with electrical input device @ S = 42 mV/Pa
Frequency-
weighting
Level range [dB]
low mid high
Z 22 23 46
A 11 19 43
C 14 18 42
Self-generated noise with M2230 microphone @ S = 42 mV/Pa
Frequency-
weighting
Level range [dB]
low mid high
Z
23 25 46
A
17 21 43
C
20 22 42
The averaging time is 30 seconds for all measurements.
331
Appendix
332
Appendix
Frequency Response Corrections
(Refer IEC61672-1 paragraphs 5.2.4, 5.2.5, 5.2.6 und 9.2.4d)
The below listed wind screen corrections may be selected in the XL2 Sound Level Meter.
The listed uncertainty applies for all here listed measurements and corrections. Its calculated for a level of confidence of 95% with
a coverage factor k=2. It represents the maximum permitted expanded uncertainty in accordance with IEC 62585.
Nominal
Frequency
Actual
Frequency
0° Free-field
Frequency
Response
0° Free-field
Correction
Housing Reflection
and Microphone
Diffraction
Correction
Impact of
50 mm
Wind
Screen
0° Free-field
Correction with
50 mm
Wind Screen
Impact of
90 mm
Wind
Screen
0° Free-field
Correction with
90 mm
Wind Screen
Measure-
ment
Uncertainty
Hz Hz dB dB dB dB dB dB dB dB
63 63.10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
125 125.89 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
250 251.19 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
315 316.23 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
400 398.11 0.0 0.0 0.0 0.0 0.0 0.1 -0.1 0.20
500 501.19 0.0 0.0 0.0 0.0 0.0 0.1 -0.1 0.20
630 630.96 0.0 0.0 0.0 0.0 0.0 0.1 -0.1 0.20
800 794.33 0.0 0.0 0.0 0.0 0.0 0.2 -0.2 0.20
1000 1000.00 0.0 0.0 0.0 0.0 0.0 0.2 -0.2 0.20
1060 1059.25 0.0 0.0 0.0 0.0 0.0 0.2 -0.2 0.20
1120 1122.02 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
118 0 1188.50 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
1250 1258.93 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
333
Appendix
Nominal
Frequency
Actual
Frequency
0° Free-field
Frequency
Response
0° Free-field
Correction
Housing Reflection
and Microphone
Diffraction
Correction
Impact of
50 mm
Wind
Screen
0° Free-field
Correction with
50 mm
Wind Screen
Impact of
90 mm
Wind
Screen
0° Free-field
Correction with
90 mm
Wind Screen
Measure-
ment
Uncertainty
1320 1333.52 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
1400 1412.54 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
1500 1496.24 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1600 1584.89 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1700 1678.80 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1800 1778.28 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1900 1883.65 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2000 1995.26 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2120 2113.49 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2240 2238.72 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2360 2371.37 0.0 0.0 0.0 0.3 -0.3 0.3 -0.3 0.20
2500 2511.89 0.0 0.0 0.0 0.3 -0.3 0.2 -0.2 0.20
2650 2660.73 0.0 0.0 0.0 0.3 -0.3 0.1 -0.1 0.20
2800 2818.38 0.0 0.0 0.0 0.3 -0.3 0.1 -0.1 0.20
3000 2985.38 0.0 0.0 0.0 0.4 -0.4 0.0 0.0 0.20
3150 3162.28 0.0 0.0 0.0 0.4 -0.4 -0.1 0.1 0.20
3350 3349.65 0.0 0.0 0.0 0.4 -0.4 -0.2 0.2 0.20
3550 3548.13 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.20
3750 3758.37 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.20
4000 3981.07 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.20
4250 4216.97 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30
334
Appendix
Nominal
Frequency
Actual
Frequency
0° Free-field
Frequency
Response
0° Free-field
Correction
Housing Reflection
and Microphone
Diffraction
Correction
Impact of
50 mm
Wind
Screen
0° Free-field
Correction with
50 mm
Wind Screen
Impact of
90 mm
Wind
Screen
0° Free-field
Correction with
90 mm
Wind Screen
Measure-
ment
Uncertainty
4500 4466.84 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30
4750 4731.51 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30
5000 5011.87 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30
5300 5308.84 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.30
5600 5623.41 0.0 0.0 0.0 0.5 -0.5 -0.3 0.3 0.30
6000 5956.62 0.0 0.0 0.0 0.4 -0.4 -0.4 0.4 0.30
6300 6309.57 0.0 0.0 0.0 0.3 -0.3 -0.4 0.4 0.30
6700 6683.44 0.0 0.0 0.0 0.3 -0.3 -0.4 0.4 0.30
7100 7079.46 0.0 0.0 0.0 0.2 -0.2 -0.3 0.3 0.30
7500 7498.94 0.0 0.0 0.0 0.1 -0.1 -0.3 0.3 0.30
8000 7943.28 0.0 0.0 0.0 0.1 -0.1 -0.3 0.3 0.30
8500 8413.95 0.0 0.0 0.0 0.1 -0.1 -0.4 0.4 0.45
9000 8912.51 0.0 0.0 0.0 0.1 -0.1 -0.5 0.5 0.45
9500 9440.61 0.0 0.0 0.0 0.1 -0.1 -0.6 0.6 0.45
10000 10000.00 0.0 0.0 0.0 0.1 -0.1 -0.5 0.5 0.45
10600 10592.54 0.0 0.0 0.0 0.1 -0.1 -0.6 0.6 0.45
1120 0 11220.18 0.0 0.0 0.0 0.1 -0.1 -0.7 0.7 0.45
118 0 0 11885.02 0.0 0.0 0.0 0.0 0.0 -0.8 0.8 0.45
12500 12589.25 0.0 0.0 0.0 -0.2 0.2 -0.8 0.8 0.45
13200 13335.21 0.0 0.0 0.0 -0.3 0.3 -0.9 0.9 0.45
14000 14125.38 0.0 0.0 0.0 -0.5 0.5 -0.9 0.9 0.45
335
Appendix
Nominal
Frequency
Actual
Frequency
0° Free-field
Frequency
Response
0° Free-field
Correction
Housing Reflection
and Microphone
Diffraction
Correction
Impact of
50 mm
Wind
Screen
0° Free-field
Correction with
50 mm
Wind Screen
Impact of
90 mm
Wind
Screen
0° Free-field
Correction with
90 mm
Wind Screen
Measure-
ment
Uncertainty
15000 14962.36 0.0 0.0 0.0 -0.6 0.6 -1.1 1.1 0.45
16000 15848.93 0.0 0.0 0.0 -0.6 0.6 -1.1 1.1 0.45
17000 16788.04 0.0 0.0 0.0 -0.6 0.6 -1.2 1.2 0.45
18000 17782.79 0.0 0.0 0.0 -0.6 0.6 -1.5 1. 5 0.45
19000 18836.49 0.0 0.0 0.0 -0.7 0.7 -1.7 1.7 0.45
20000 19952.62 0.0 0.0 0.0 -0.9 0.9 -1.5 1.5 0.45
336
Appendix
Frequency Weighting
Nominal
Frequency
Hz
Frequency Weighting
dB
A C Z
10 –70.4 –14.3 0.0
12.5
16
20
–63.4
–56.7
–50.5
–11.2
–8.5
–6.2
0.0
0.0
0.0
25
31.5
40
–44.7
–39.4
–34.6
–4.4
–3.0
–2.0
0.0
0.0
0.0
50
63
80
–30.2
–26.2
–22.5
–1.3
–0.8
–0.5
0.0
0.0
0.0
100
125
160
–19.1
–16.1
–13.4
–0.3
–0.2
–0.1
0.0
0.0
0.0
200
250
315
–10.9
–8.6
–6.6
0.0
0.0
0.0
0.0
0.0
0.0
400
500
630
–4.8
–3.2
–1.9
0.0
0.0
0.0
0.0
0.0
0.0
800
1000
1250
–0.8
0
+0.6
0.0
0
0.0
0.0
0
0.0
1600
2000
2500
+1.0
+1.2
+1.3
–0.1
–0.2
–0.3
0.0
0.0
0.0
Nominal
Frequency
Hz
Frequency Weighting
dB
A C Z
3150
4000
5000
+1.2
+1.0
+0.5
–0.5
–0.8
–1.3
0.0
0.0
0.0
6300
8000
10000
–0.1
–1.1
–2.5
–2.0
–3.0
–4.4
0.0
0.0
0.0
12500
16000
20000
–4.3
–6.6
–9.3
–6.2
–8.5
–11.2
0.0
0.0
0.0
337
Appendix
Directional Response (dB)
Based on the sound-incidence angle. (Refer IEC61672-1 paragraphs 5.3.1, 5.3.2 and 9.2.2b).
The impact on the directional response of the Windscreen 50 mm, Windscreen 90 mm and the Weather Protection WP30 is cal-
culated by adding the frequency response correction at 0° to the below table.
Nomi-
nal Fre-
quency
[Hz]
Actual
Frequen-
cy [Hz]
Angle in Degrees
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
250 251.19 -0.00 0.00 0.00 -0.00 0.00 -0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
315 316.23 -0.00 0.01 0.01 -0.00 0.02 -0.01 0.01 0.01 0.01 0.01 -0.01 0.01 -0.01 0.00 0.01 -0.01 0.00 0.01
400 398.11 0.00 0.01 0.01 -0.00 0.02 -0.02 -0.01 0.00 0.00 0.00 -0.01 0.01 -0.02 -0.01 0.00 -0.02 0.00 0.00
500 501.19 -0.00 -0.02 -0.02 -0.01 -0.00 -0.02 -0.02 -0.01 -0.03 -0.04 -0.04 -0.04 -0.05 -0.05 -0.02 -0.04 -0.04 -0.04
630 630.96 -0.00 -0.09 -0.11 -0.06 -0.04 0.00 0.01 -0.05 -0.05 -0.06 -0.11 -0.11 -0.13 -0.08 -0.07 -0.10 -0.11 -0.13
800 794.33 -0.00 -0.00 -0.01 -0.02 0.00 -0.00 0.02 0.00 0.00 0.00 -0.03 0.00 -0.01 0.01 0.02 -0.01 -0.03 -0.04
1000 1000.00 -0.00 0.03 0.00 -0.02 0.03 -0.02 0.00 -0.01 0.00 -0.01 -0.01 0.03 0.00 -0.01 0.04 0.01 0.02 0.03
1060 1059.25 -0.00 0.03 0.01 -0.02 0.02 -0.03 -0.01 -0.03 -0.03 -0.03 -0.04 0.00 -0.02 -0.02 0.02 -0.01 0.00 0.02
1120 1122.02 -0.00 0.02 0.01 -0.02 0.00 -0.04 -0.02 -0.05 -0.06 -0.06 -0.06 -0.05 -0.06 -0.05 -0.01 -0.03 -0.02 -0.01
118 0 1188.50 0.00 0.01 0.01 -0.03 -0.02 -0.05 -0.04 -0.08 -0.09 -0.08 -0.10 -0.10 -0.12 -0.11 -0.07 -0.07 -0.06 -0.06
1250 1258.93 0.00 -0.01 -0.02 -0.06 -0.05 -0.09 -0.07 -0.14 -0.14 -0.15 -0.16 -0.17 -0.21 -0.20 -0.16 -0.16 -0.13 -0.14
1320 1333.52 -0.00 -0.02 -0.05 -0.09 -0.07 -0.12 -0.10 -0.18 -0.17 -0.21 -0.23 -0.24 -0.29 -0.27 -0.26 -0.26 -0.24 -0.22
1400 1412.54 0.00 -0.01 -0.04 -0.07 -0.04 -0.09 -0.07 -0.13 -0.12 -0.18 -0.21 -0.24 -0.29 -0.27 -0.29 -0.28 -0.31 -0.26
1500 1496.24 -0.00 0.02 0.00 -0.01 0.00 -0.03 -0.02 -0.06 -0.06 -0.11 -0.14 -0.18 -0.23 -0.26 -0.27 -0.27 -0.32 -0.27
1600 1584.89 -0.00 0.03 0.02 0.00 0.02 -0.00 0.01 -0.01 -0.02 -0.06 -0.09 -0.12 -0.17 -0.23 -0.26 -0.28 -0.30 -0.29
1700 1678.80 -0.00 0.02 0.01 0.00 0.04 0.01 0.05 0.04 0.05 0.03 0.00 -0.03 -0.07 -0.12 -0.17 -0.26 -0.25 -0.26
1800 1778.28 -0.00 0.02 0.00 0.01 0.04 0.02 0.04 0.04 0.06 0.07 0.09 0.06 0.00 -0.05 -0.06 -0.18 -0.22 -0.22
1900 1883.65 -0.00 0.00 -0.02 -0.01 0.01 0.01 0.04 0.03 0.05 0.05 0.09 0.13 0.08 0.02 0.00 -0.08 -0.17 -0.23
2000 1995.26 -0.00 0.01 -0.02 -0.03 -0.03 -0.05 -0.05 -0.08 -0.04
0.00 -0.02 0.06 0.04 0.07 0.0
1 -0.08 -0.12 -0.25
2120 2113.49 -0.00 0.02 -0.01 -0.05 -0.05 -0.10 -0.13 -0.18 -0.22 -0.18 -0.19 -0.10 -0.14 -0.06 -0.01 -0.17 -0.19 -0.27
2240 2238.72 0.00 0.02 -0.01 -0.06 -0.08 -0.16 -0.21 -0.25 -0.31 -0.36 -0.44 -0.37 -0.34 -0.32 -0.26 -0.26 -0.33 -0.39
2360 2371.37 -0.00 0.02 0.00 -0.03 -0.03 -0.10 -0.13 -0.22 -0.30 -0.39 -0.46 -0.51 -0.56 -0.47 -0.42 -0.40 -0.33 -0.47
2500 2511.89 -0.00 0.01 -0.00 -0.03 -0.03 -0.08 -0.08 -0.11 -0.16 -0.29 -0.44 -0.48 -0.58 -0.64 -0.52 -0.50 -0.45 -0.41
2650 2660.73 0.00 0.00 -0.01 -0.05 -0.02 -0.03 -0.01 -0.01 -0.06 -0.09 -0.21 -0.34 -0.49 -0.55 -0.62 -0.54 -0.48 -0.42
2800 2818.38 0.00 0.01 -0.01 -0.03 -0.03 -0.09 -0.10 -0.08 -0.07 -0.09 -0.16 -0.18 -0.36 -0.51 -0.58 -0.70 -0.57 -0.55
338
Appendix
Nomi-
nal Fre-
quency
[Hz]
Actual
Frequen-
cy [Hz]
Angle in Degrees
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
3000 2985.38 -0.00 0.00 -0.03 -0.09 -0.12 -0.19 -0.20 -0.25 -0.31 -0.31 -0.30 -0.34 -0.43 -0.52 -0.70 -0.79 -0.84 -0.73
3150 3162.28 -0.00 0.01 -0.00 -0.06 -0.06 -0.13 -0.18 -0.30 -0.36 -0.42 -0.49 -0.47 -0.51 -0.62 -0.70 -0.92 -0.95 -0.97
3350 3349.65 -0.00 0.01 0.01 0.00 -0.01 -0.06 -0.09 -0.15 -0.23 -0.37 -0.46 -0.46 -0.55 -0.55 -0.67 -0.82 -1.05 -1.01
3550 3548.13 -0.00 0.02 0.02 0.01 0.00 -0.03 0.01 0.00 -0.07 -0.18 -0.29 -0.40 -0.47 -0.50 -0.48 -0.65 -0.84 -1.08
3750 3758.37 -0.00 0.01 -0.01 -0.07 -0.08 -0.12 -0.09 -0.09 -0.10 -0.11 -0.22 -0.35 -0.49 -0.62 -0.54 -0.60 -0.78 -0.98
4000 3981.07 -0.00 0.01 -0.02 -0.10 -0.16 -0.24 -0.30 -0.36 -0.39 -0.35 -0.38 -0.41 -0.62 -0.76 -0.86 -0.83 -0.87 -1.11
4250 4216.97 -0.00 -0.00 -0.02 -0.07 -0.09 -0.18 -0.25 -0.40 -0.50 -0.54 -0.60 -0.52 -0.64 -0.77 -0.93 -1.10 -1.01 -1.01
4500 4466.84 -0.00 0.02 -0.01 -0.03 -0.02 -0.06 -0.07 -0.18 -0.27 -0.42 -0.57 -0.58 -0.56 -0.66 -0.77 -1.00 -1.12 -1.05
4750 4731.51 -0.00 0.01 -0.02 -0.08 -0.10 -0.17 -0.14 -0.18 -0.19 -0.32 -0.47 -0.66 -0.70 -0.71 -0.73 -0.94 -1.16 -1.18
5000 5011.87 -0.00 0.00 -0.05 -0.14 -0.20 -0.35 -0.44 -0.54 -0.53 -0.60 -0.63 -0.82 -1.01 -1.12 -1.09 -1.15 -1.41 -1.62
5300 5308.84 0.00 0.02 -0.01 -0.07 -0.10 -0.26 -0.39 -0.58 -0.71 -0.85 -0.87 -0.90 -1.07 -1.30 -1.40 -1.36 -1.43 -1.76
5600 5623.41 -0.00 0.02 -0.01 -0.04 -0.04 -0.10 -0.15 -0.29 -0.45 -0.71 -0.88 -0.94 -1.01 -1.16 -1.39 -1.51 -1.44 -1.54
6000 5956.62 -0.00 0.00 -0.03 -0.12 -0.17 -0.24 -0.27 -0.32 -0.38 -0.57 -0.80 -1.03 -1.20 -1.26 -1.41 -1.71 -1.77 -1.69
6300 6309.57 0.00 0.00 -0.05 -0.13 -0.20 -0.36 -0.45 -0.52 -0.59 -0.67 -0.82 -1.11 -1.40 -1.52 -1.56 -1.83 -2.15 -2.05
6700 6683.44 -0.00 0.01 -0.03 -0.09 -0.14 -0.30 -0.46 -0.67 -0.84 -0.88 -0.94 -1.05 -1.41 -1.78 -1.85 -1.87 -2.17 -2.47
7100 7079.46 -0.00 0.00 -0.05 -0.12 -0.15 -0.22 -0.25 -0.37 -0.56 -0.90 -1.12 -1.09 -1.17 -1.52 -1.96 -2.03 -2.00 -2.38
7500 7498.94 -0.00 0.00 -0.09 -0.21 -0.33 -0.58 -0.71 -0.82 -0.84 -0.96 -1.31 -1.66 -1.82 -1.81 -2.11 -2.57 -2.58 -2.68
8000 7943.28 -0.00 0.00 -0.03 -0.09 -0.15 -0.30 -0.50 -0.77 -1.08 -1.26 -1.30 -1.46 -1.91 -2.16 -2.21 -2.55 -2.90 -3.00
8500 8413.95 0.00 -0.01 -0.08 -0.18 -0.25 -0.37 -0.44 -0.54 -0.71
-1.11 -1
.52 -1.63 -1.75 -2.09 -2.41 -2.56 -2.89 -3.30
9000 8912.51 0.00 -0.00 -0.08 -0.20 -0.32 -0.61 -0.82 -1.10 -1.22 -1.31 -1.56 -2.04 -2.42 -2.47 -2.78 -3.18 -3.29 -3.76
9500 9440.61 -0.00 -0.01 -0.12 -0.23 -0.26 -0.41 -0.46 -0.68 -0.98 -1.38 -1.66 -1.71 -2.12 -2.67 -2.78 -3.08 -3.45 -3.66
10000 10000.00 -0.00 0.01 -0.01 -0.08 -0.16 -0.49 -0.80 -1.13 -1.32 -1.44 -1.72 -2.25 -2.57 -2.74 -3.30 -3.49 -3.95 -4.12
10600 10592.50 -0.00 -0.02 -0.18 -0.44 -0.68 -0.93 -0.95 -1.09 -1.43 -1.89 -2.22 -2.35 -2.88 -3.31 -3.50 -4.13 -4.36 -4.64
1120 0 11220.20 0.00 -0.02 -0.08 -0.13 -0.05 -0.15 -0.48 -1.00 -1.21 -1.38 -1.78 -2.32 -2.55 -3.01 -3.50 -3.73 -4.36 -4.54
118 0 0 11885.00 -0.00 0.02 0.01 -0.05 -0.28 -0.82 -1.17 -1.21 -1.45 -2.04 -2.28 -2.65 -3.25 -3.53 -4.03 -4.56 -5.04 -5.54
12500 12589.30 -0.00 -0.03 -0.23 -0.54 -0.87 -1.05 -0.98 -1.31 -1.90 -2.08 -2.56 -3.15 -3.36 -3.98 -4.44 -4.86 -5.42 -5.75
13200 13335.20 0.00 -0.02 -0.13 -0.24 -0.27 -0.44 -0.77 -1.35 -1.48 -1.92 -2.49 -2.74 -3.46 -3.76 -4.40 -4.85 -5.54 -5.99
14000 14125.40 -0.00 0.00 -0.08 -0.20 -0.42 -0.85 -1.20 -1.47 -1.81 -2.35 -2.64 -3.39 -3.63 -4.44 -4.84 -5.51 -6.06 -6.53
15000 14962.40 -0.00 -0.01 -0.11 -0.29 -0.54 -0.92 -1.15 -1.59 -2.04 -2.32 -3.03 -3.42 -4.20 -4.53 -5.20 -5.80 -6.52 -6.78
16000 15848.90 0.00 -0.03 -0.13 -0.37 -0.71 -1.08 -1.25 -1.79 -2.16 -2.70 -3.27 -3.73 -4.49 -5.07 -5.65 -6.31 -7.11 -7.72
17000 16788.00 0.00 0.00 -0.14 -0.36 -0.63 -0.97 -1.30 -1.94 -2.24 -2.92 -3.39 -4.12 -4.75 -5.44 -6.07 -6.66 -7.59 -8.07
18000 17782.80 0.00 -0.05 -0.25 -0.48 -0.71 -1.06 -1.54 -2.14 -2.40 -3.27 -3.67 -4.52 -5.26 -5.88 -6.58 -7.38 -8.19 -8.93
19000 18836.50 -0.00 -0.03 -0.25 -0.54 -0.75 -1.13 -1.71 -2.25 -2.67 -3.51 -4.10 -4.84 -5.69 -6.48 -7.12 -7.94 -8.95 -9.48
20000 19952.60 -0.00 -0.04 -0.25 -0.55 -0.85 -1.28 -1.80 -2.42 -2.97 -3.70 -4.54 -5.21 -6.21 -7.04 -7.80 -8.59 -9.59 -10.28
339
Appendix
Nomi-
nal Fre-
quency
[Hz]
Actual
Frequen-
cy [Hz]
Angle in Degrees
90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180
250 251.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
315 316.23 0.01 0.01 -0.01 0.00 0.01 -0.01 0.00 0.00 0.01 0.00 0.01 0.02 0.00 -0.02 0.00 0.00 -0.01 -0.03 -0.03
400 398.11 0.00 -0.01 -0.03 -0.02 0.00 -0.04 -0.01 -0.02 0.00 -0.01 0.01 0.03 0.00 -0.01 0.02 0.02 0.01 0.00 -0.01
500 501.19 -0.06 -0.05 -0.09 -0.08 -0.04 -0.09 -0.05 -0.07 -0.03 -0.05 -0.03 0.00 -0.03 -0.04 0.00 -0.01 -0.01 -0.01 -0.04
630 630.96 -0.13 -0.06 -0.17 -0.10 -0.08 -0.17 -0.14 -0.12 -0.08 -0.09 -0.05 -0.08 -0.10 -0.11 -0.09 -0.12 -0.13 -0.09 -0.22
800 794.33 -0.04 -0.04 -0.08 -0.08 -0.09 -0.09 -0.07 -0.09 -0.05 -0.05 -0.03 -0.04 -0.07 -0.06 -0.05 -0.03 -0.03 0.00 -0.06
1000 1000.00 0.03 -0.02 -0.06 -0.09 -0.06 -0.09 -0.06 -0.10 -0.09 -0.10 -0.07 -0.04 -0.04 -0.06 -0.01 0.00 0.02 0.04 0.00
1060 1059.25 0.03 0.00 -0.06 -0.09 -0.07 -0.10 -0.08 -0.12 -0.10 -0.12 -0.09 -0.06 -0.07 -0.10 -0.05 -0.06 -0.04 -0.02 -0.08
1120 1122.02 0.01 0.01 -0.06 -0.09 -0.10 -0.12 -0.10 -0.14 -0.12 -0.14 -0.11 -0.08 -0.09 -0.11 -0.06 -0.06 -0.04 -0.03 -0.06
118 0 1188.50 -0.05 -0.02 -0.07 -0.11 -0.13 -0.15 -0.13 -0.17 -0.15 -0.17 -0.15 -0.11 -0.12 -0.13 -0.07 -0.06 -0.03 -0.02 -0.01
1250 1258.93 -0.14 -0.11 -0.14 -0.15 -0.19 -0.23 -0.20 -0.23 -0.21 -0.24 -0.23 -0.20 -0.21 -0.22 -0.19 -0.18 -0.13 -0.13 -0.11
1320 1333.52 -0.20 -0.21 -0.23 -0.20 -0.23 -0.31 -0.28 -0.31 -0.28 -0.32 -0.30 -0.28 -0.29 -0.29 -0.29 -0.27 -0.22 -0.22 -0.22
1400 1412.54 -0.21 -0.24 -0.27 -0.23 -0.23 -0.31 -0.29 -0.33 -0.30 -0.36 -0.32 -0.29 -0.28 -0.27 -0.26 -0.21 -0.15 -0.13 -0.16
1500 1496.24 -0.22 -0.22 -0.25 -0.23 -0.22 -0.27 -0.28 -0.33 -0.30 -0.35 -0.32 -0.27 -0.28 -0.29 -0.28 -0.23 -0.18 -0.15 -0.19
1600 1584.89 -0.26 -0.23 -0.23 -0.23 -0.23 -0.24 -0.27 -0.32 -0.29 -0.34 -0.31 -0.24 -0.26 -0.27 -0.25 -0.21 -0.18 -0.16 -0.19
1700 1678.80 -0.27 -0.22 -0.18 -0.20 -0.19 -0.19 -0.21 -0.27 -0.25 -0.31 -0.28 -0.22 -0.21 -0.22 -0.18 -0.11 -0.06 -0.03 -0.06
1800 1778.28 -0.23 -0.22 -0.16 -0.15 -0.16 -0.15 -0.15 -0.23 -0.21 -0.26 -0.26 -0.21 -0.17 -0.21 -0.21 -0.18 -0.11 -0.07 -0.09
1900 1883.65 -0.19 -0.22 -0.20 -0.12 -0.12 -0.15 -0.10 -0.19 -0.18 -0.21 -0.24
-0.19 -0.1
1 -0.12 -0.09 -0.04 0.05 0.07 0.10
2000 1995.26 -0.25 -0.23 -0.29 -0.17 -0.12 -0.23 -0.13 -0.18 -0.24 -0.21 -0.29 -0.24 -0.18 -0.19 -0.20 -0.18 -0.09 -0.04 0.01
2120 2113.49 -0.42 -0.38 -0.40 -0.37 -0.23 -0.33 -0.26 -0.25 -0.39 -0.35 -0.38 -0.36 -0.29 -0.26 -0.25 -0.18 -0.11 -0.04 -0.06
2240 2238.72 -0.48 -0.63 -0.54 -0.60 -0.48 -0.45 -0.47 -0.43 -0.53 -0.55 -0.55 -0.59 -0.48 -0.50 -0.52 -0.49 -0.42 -0.29 -0.33
2360 2371.37 -0.51 -0.65 -0.73 -0.67 -0.68 -0.53 -0.55 -0.56 -0.56 -0.67 -0.64 -0.67 -0.60 -0.55 -0.52 -0.50 -0.39 -0.29 -0.31
2500 2511.89 -0.55 -0.58 -0.77 -0.73 -0.74 -0.64 -0.57 -0.63 -0.59 -0.72 -0.69 -0.72 -0.65 -0.59 -0.58 -0.59 -0.50 -0.41 -0.42
2650 2660.73 -0.43 -0.55 -0.65 -0.76 -0.67 -0.65 -0.53 -0.59 -0.55 -0.72 -0.66 -0.71 -0.65 -0.60 -0.56 -0.56 -0.45 -0.29 -0.27
2800 2818.38 -0.46 -0.55 -0.65 -0.75 -0.71 -0.72 -0.55 -0.61 -0.59 -0.72 -0.72 -0.76 -0.74 -0.60 -0.53 -0.54 -0.43 -0.31 -0.32
3000 2985.38 -0.71 -0.70 -0.83 -0.90 -0.97 -0.88 -0.75 -0.72 -0.76 -0.81 -0.96 -0.92 -1.00 -0.83 -0.76 -0.82 -0.75 -0.60 -0.60
3150 3162.28 -0.84 -0.85 -0.88 -1.10 -1.15 -1.10 -1.01 -0.79 -0.88 -0.85 -1.12 -1.02 -1.20 -1.06 -0.95 -1.02 -0.93 -0.75 -0.69
3350 3349.65 -1.00 -0.80 -0.90 -1.05 -1.16 -1.29 -1.03 -0.91 -0.87 -0.87 -1.07 -1.04 -1.20 -1.11 -0.95 -0.99 -0.91 -0.71 -0.65
3550 3548.13 -0.97 -0.92 -0.78 -0.80 -1.12 -1.20 -1.09 -0.99 -0.78 -0.84 -0.91 -0.99 -1.10 -1.07 -0.81 -0.84 -0.81 -0.62 -0.57
3750 3758.37 -1.25 -1.10 -0.88 -0.94 -0.98 -1.24 -1.31 -1.10 -0.86 -0.93 -0.92 -1.11 -1.13 -1.16 -0.87 -0.85 -0.86 -0.68 -0.66
4000 3981.07 -1.33 -1.47 -1.39 -1.06 -1.10 -1.49 -1.52 -1.35 -1.19 -1.14 -1.11 -1.38 -1.33 -1.43 -1.12 -1.03 -1.09 -0.93 -0.90
4250 4216.97 -1.42 -1.71 -1.57 -1.34 -1.34 -1.48 -1.61 -1.69 -1.47 -1.25 -1.29 -1.49 -1.45 -1.60 -1.29 -1.18 -1.23 -1.07 -1.02
4500 4466.84 -1.09 -1.47 -1.81 -1.62 -1.20 -1.25 -1.63 -1.82 -1.47 -1.20 -1.31 -1.39 -1.45 -1.60 -1.35 -1.14 -1.19 -1.00 -0.94
4750 4731.51 -1.19 -1.42 -1.77 -1.77 -1.45 -1.43 -1.66 -1.76 -1.56 -1.43 -1.41 -1.30 -1.62 -1.66 -1.50 -1.19 -1.23 -1.03 -0.92
340
Appendix
Nomi-
nal Fre-
quency
[Hz]
Actual
Frequen-
cy [Hz]
Angle in Degrees
90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180
5000 5011.87 -1.54 -1.54 -1.97 -2.36 -2.08 -1.67 -1.68 -2.07 -2.18 -1.95 -1.68 -1.64 -2.04 -2.00 -1.93 -1.63 -1.64 -1.37 -1.24
5300 5308.84 -1.97 -1.84 -1.95 -2.45 -2.54 -2.13 -1.97 -2.36 -2.54 -2.17 -1.83 -1.93 -2.27 -2.18 -2.22 -1.86 -1.93 -1.71 -1.57
5600 5623.41 -1.90 -1.97 -1.84 -2.19 -2.63 -2.35 -1.91 -2.14 -2.42 -2.20 -1.96 -2.06 -2.26 -2.20 -2.25 -1.83 -1.86 -1.63 -1.50
6000 5956.62 -1.98 -2.40 -2.27 -2.24 -2.80 -2.94 -2.34 -2.24 -2.58 -2.60 -2.33 -2.27 -2.25 -2.50 -2.48 -2.11 -2.03 -1.76 -1.57
6300 6309.57 -1.97 -2.41 -2.66 -2.33 -2.52 -3.10 -2.82 -2.54 -2.81 -2.94 -2.57 -2.33 -2.46 -2.86 -2.80 -2.41 -2.36 -2.16 -1.95
6700 6683.44 -2.28 -2.33 -2.93 -3.03 -2.93 -3.43 -3.27 -2.75 -2.94 -3.25 -2.84 -2.45 -2.69 -3.26 -3.09 -2.84 -2.68 -2.44 -2.21
7100 7079.46 -2.70 -2.53 -2.80 -3.16 -2.90 -3.24 -3.69 -3.21 -3.11 -3.53 -3.16 -2.69 -2.90 -3.27 -3.15 -2.90 -2.66 -2.49 -2.22
7500 7498.94 -3.25 -3.15 -3.03 -3.66 -3.59 -3.61 -4.21 -3.73 -3.25 -3.83 -3.91 -3.34 -3.41 -3.62 -3.67 -3.40 -3.14 -3.03 -2.78
8000 7943.28 -3.29 -3.52 -3.42 -3.57 -4.16 -3.83 -4.18 -4.54 -3.75 -3.90 -4.18 -3.68 -3.61 -3.79 -4.03 -3.74 -3.41 -3.38 -3.11
8500 8413.95 -3.34 -3.64 -3.82 -3.66 -4.19 -4.16 -4.40 -4.77 -4.11 -4.11 -4.63 -4.00 -3.65 -3.89 -4.28 -4.03 -3.57 -3.59 -3.25
9000 8912.51 -4.04 -4.17 -4.41 -4.47 -4.43 -5.18 -4.56 -5.53 -5.13 -4.45 -5.00 -4.78 -4.29 -4.50 -4.97 -4.73 -4.11 -4.21 -3.86
9500 9440.61 -4.08 -4.32 -4.57 -4.55 -4.70 -5.00 -5.17 -5.01 -5.59 -4.88 -5.00 -4.98 -4.43 -4.61 -5.29 -5.01 -4.21 -4.25 -3.94
10000 10000.00 -4.41 -4.95 -5.13 -5.26 -5.09 -5.64 -5.74 -5.67 -6.17 -5.59 -5.62 -5.57 -4.81 -5.16 -5.96 -5.78 -4.92 -4.99 -4.66
10600 10592.50 -4.84 -5.66 -5.73 -5.89 -5.99 -5.85 -6.61 -6.17 -6.86 -6.35 -6.05 -6.69 -5.69 -5.79 -6.38 -6.32 -5.56 -5.62 -5.33
1120 0 11220.20 -5.08 -5.29 -5.96 -5.82 -6.22 -5.98 -6.40 -6.63 -6.54 -6.77 -6.08 -6.38 -6.07 -5.74 -6.19 -6.46 -5.65 -5.71 -5.42
118 0 0 11885.00 -5.81 -6.22 -6.60 -6.69 -6.84 -7.06 -7.08 -7.77 -7.39 -7.95 -6.88 -7.35 -6.86 -6.32 -6.89 -7.28 -6.63 -6.49 -6.22
12500 12589.30 -6.24 -6.68 -7.02 -7.57 -7.29 -7.66 -7.45 -8.08 -7.93 -8.49 -8.13 -7.96 -7.81 -6.96 -7.43 -8.07 -7.42 -7.11 -6.92
13200 13335.20 -6.47 -6.80 -7.26 -7.56 -7.63 -8.13 -8.10 -8.29 -8.45 -8.48 -8.34
-7.99 -8.30 -7
.15 -7.48 -8.50 -7.89 -7.43 -7.36
14000 14125.40 -7.09 -7.62 -7.91 -8.27 -8.65 -8.89 -9.22 -8.90 -9.58 -9.60 -9.77 -8.84 -9.40 -7.94 -8.18 -9.45 -8.78 -8.17 -8.20
15000 14962.40 -7.77 -8.15 -8.31 -8.80 -9.13 -9.52 -9.70 -9.36 -9.89 -9.60 -9.91 -8.94 -9.53 -8.95 -8.85 -10.27 -9.43 -8.58 -8.69
16000 15848.90 -8.14 -8.57 -9.46 -9.82 -9.82 -10.40 -10.67 -10.30 -10.88 -11.05 -11.53 -10.63 -10.30 -9.99 -9.98 -11.23 -10.39 -9.57 -9.70
17000 16788.00 -9.03 -9.53 -9.85 -10.29 -10.41 -11.12 -11.48 -11.22 -11.33 -11.86 -11.73 -11.51 -11.22 -10.86 -10.22 -11.69 -11.46 -10.42 -10.51
18000 17782.80 -9.76 -10.24 -10.80 -10.99 -11.37 -11.93 -12.53 -12.49 -12.07 -12.86 -12.64 -12.84 -11.76 -11.89 -10.91 -12.08 -12.48 -11.15 -11.39
19000 18836.50 -10.50 -11.05 -11.74 -12.45 -12.44 -12.86 -13.22 -13.33 -12.90 -13.90 -13.76 -13.71 -13.09 -13.30 -12.01 -12.61 -13.63 -12.05 -12.01
20000 19952.60 -11.34 -11.75 -12.63 -13.00 -13.60 -13.92 -14.22 -14.21 -14.52 -14.27 -15.01 -14.99 -13.71 -14.36 -12.72 -13.38 -15.20 -13.07 -12.92
The maximum measurement uncertainty of the data is with 95 % probability (k=2).
• 250 Hz to 1 kHz 0.3 dB
• 1 kHz to 4 kHz 0.5 dB
• 4 kHz to 8 kHz 1.0 dB
• 8 kHz to 12.5 kHz 1.5 dB
341
Appendix
342
Appendix
Information for Calibration
Type Description
• Integrating sound level meter type NTi Audio XL2-TA
Standards
The XL2-TA Sound Level Meter has been certified in accor-
dance with the class 1 requirements of
• ISO 61672-1 (2014 und 2003)
• ISO 61672-2 (2014 und 2003)
• ISO 61260 (2014 und 2003)
• DIN 45657 (2014)
• Welmec 7.2 «Software Guide» (2011)
Approval Identification
The XL2-TA Sound Level Meter requires the approved firm-
ware as follows:
• Germany: V4.71
• France: V4.21
• Austria: V4.21
• Switzerland: V4.11
Hints for Performing the Electrical Measurements
Electrical input facility
(Refer IEC61672-1 paragraphs 5.1.15, 9.3.g)
The capsule replacement NTI-K65-15 is used to insert electri-
cal signals to the preamplifier MA220. The device provides at
one side a contact that corresponds to the center contact of
the replaced microphone capsule, at the other side a BNC-
plug for the electrical signals. The impedance at the output
of the device is 15 pF with a maximum deviation of ±1 pF.
The electrical noise floor is measured by shorting the con-
tacts of the BNC plug. Before the NTI-K65-15 can be mount-
ed to the preamplifier MA220, the microphone capsule must
first be detached. The nominal sensitivity S of the capsule is
S = 42 mV/Pa. Measurements with the NTI-K65-15 therefore
require that the sensitivity in the calibration menu is manually
adjusted to S = 42 mV/Pa. The linear operating ranges accord-
ing to IEC 61672 have been verified during the type approval
procedure.
Certified Calibrator
The following sound level calibrators are certified with the
XL2-TA with a 114 dB, 1 kHz reference signal.
• Larson Davis CAL200
• B&K 4231
• Norsonic Nor-1251, Nor-1256
• Microtech Gefell 4010
343
Appendix
Compulsory Calibrated Applications
The following acoustic measurements have been verified by
German PTB during the type approval process:
Instantaneous sound pressure levels:
• LAF
A-weighted sound pressure level with time weighting FAST
• LAS
A-weighted sound pressure level with time weighting SLOW
• LCF
C-weighted sound pressure level with time weighting FAST
• LCS
C-weighted sound pressure level with time weighting SLOW
• LZF
unweighted sound pressure level with time weighting FAST
• LZS
unweighted sound pressure level with time weighting SLOW
• LAI
A-weighted sound pressure level with time weighting
IMPULSE
Time averaged sound pressure levels:
• LCpeak
Peak value of the C-weighted sound level
• LAeq
A-weighted average level
• LAE
A-weighted sound exposure level
• LAFT3eq
A-weighted clock-impulse maximum level with time weight-
ing FAST for a clock-impulse duration of 3 seconds
• LAFT5eq
A-weighted clock-impulse maximum level with time weight-
ing FAST for a clock-impulse duration of 5 seconds
08.23
