BRUEL & KJAER 2245 User manual

Sound Level Meter Type 2245
with Microphone Type 4966
From Hardware Version 1.0
Instruction Manual

Sound Level Meter Types 2245 – Instruction Manual Page 2 of 110
Contents
Table of Contents
Chapter 1 Introduction...........................................................................................5
1.1 About This Manual.....................................................................................5
1.1.1 Conventions Used in this Manual....................................................5
1.2System Overview.......................................................................................5
1.2.1 Hardware and Software on the Sound Level Meter ........................5
1.2.2 Basic PC Software...........................................................................5
1.2.3 Hardware Setup...............................................................................6
1.2.4 Block Diagrams ...............................................................................8
Chapter 2 Short Guide to the Sound Level Meter.................................................9
2.1 Introduction................................................................................................9
2.2 Switch sound level meter On/Off...............................................................9
2.3 Setting up the sound level meter...............................................................9
2.3.1 Measurement settings...................................................................10
2.3.2 Display settings .............................................................................13
2.3.3 System Settings.............................................................................13
2.3.4 Data explorer.................................................................................13
2.3.5 Calibration history..........................................................................14
2.3.6 Status.............................................................................................14
2.4 Calibration................................................................................................15
2.4.1 Calibration Procedure....................................................................15
2.4.2 Calibration Check Procedure.........................................................17
2.5 Measuring with the sound level meter.....................................................19
2.5.1 Start/Pause/Stop of Measurement ................................................19
2.5.2 Overload and Underrange.............................................................20
2.6 Looking at the measurement...................................................................20
2.7 Looking at saved measurements.............................................................21
2.8 Placing the Microphone (Sound Level Meter) .........................................23
2.9 Mounting the Sound Level Meter on a Tripod .........................................23
2.10 Measuring Low-level Sounds...................................................................23
2.11 Measuring at Low Static Pressure...........................................................24
2.12 Mechanical Vibration ...............................................................................25
2.13 Frequency Weightings.............................................................................25
2.14 Measured Quantities................................................................................27
2.14.1 Instantaneous Broadband Measurements ....................................27
2.14.2 Timed Broadband Measurements.................................................29
2.14.3 Spectrum Measurements ..............................................................34
2.14.4 Instantaneous Spectrum Measurements.......................................34
2.14.5 Timed Spectrum Measurements ...................................................34
2.15 Overload and Underrange .......................................................................35
2.15.1 Overload........................................................................................35
2.15.2 Underrange....................................................................................35
Chapter 3 Conformance Testing .........................................................................36
3.1 Introduction..............................................................................................36
3.2 Microphone, Accessories and Sound Fields ...........................................36
3.2.1 For acoustical tests........................................................................36
3.2.2 For electrical tests .........................................................................36
3.3 Calibration during Pattern evaluation and Periodic tests.........................36
3.3.1 Acoustic calibration........................................................................36
3.3.2 Electrical Substitute for Microphones............................................37

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3.4 Wi-Fi and Bluetooth during tests..............................................................37
3.5 Mounting for Acoustical Tests..................................................................37
3.6 Periodic Testing of Acoustical Frequency Responses ............................38
3.7 Mounting for Mechanical Vibrations Tests...............................................38
3.8 Testing 1/1-octave-band and 1/3-octave-band Filters.............................38
3.9 EMC Test Procedures .............................................................................38
3.9.1 Signal Sources for Immunity Test .................................................38
3.9.2 Reference Orientation ...................................................................39
3.9.3 Securing of Cables During EMC Test ...........................................39
3.9.4 Accessories Included in EMC Test................................................40
3.9.5 Normal Mode of Operation During EMC Test ...............................40
Chapter 4 Specifications......................................................................................42
4.1 Specifications...........................................................................................42
4.2 Standards.................................................................................................42
4.3 Reference Environmental Conditions......................................................42
4.4 Reference Conditions for Acoustic Calibration........................................43
4.5 Microphone..............................................................................................43
4.6 Frequency Responses.............................................................................44
4.6.1 Electrical Frequency Responses...................................................44
4.6.2 Typical Low-frequency Responses ...............................................45
4.6.3 Acoustical Frequency Responses.................................................46
4.6.4 Free-field Frequency Responses ..................................................46
4.6.5 Diffuse-field Frequency Responses ..............................................46
4.6.6 Free-field Frequency Responses for Diffuse-field
Calibrated Instruments ..................................................................47
4.7 Directional Responses.............................................................................48
4.8 Self-generated Noise...............................................................................55
4.8.1 Maximum Broadband Self-generated Noise .................................55
4.8.2 Typical Broadband Self-generated Noise......................................55
4.8.3 Typical Self-generated Noise Spectra...........................................55
4.9 Measuring Ranges...................................................................................56
4.9.1 Maximum Sound Level..................................................................56
4.9.2 Total Range...................................................................................56
4.9.3 Primary Indicator Range................................................................57
4.9.4 Indicator Range .............................................................................57
4.9.5 Linearity Range .............................................................................57
4.9.6 Pulse Range..................................................................................58
4.9.7 Linear Operating Range................................................................58
4.9.8 Peak C Range ...............................................................................58
4.10 Detectors..................................................................................................59
4.10.1 Exponential Averaging...................................................................59
4.10.2 Linear Averaging ...........................................................................60
4.10.3 Peak...............................................................................................60
4.11 Spectrum Analysis...................................................................................60
4.11.1 1/1- octave Band Centre Frequencies...........................................60
4.11.2 1/3-octave Band Centre Frequencies............................................61
4.11.3 Linear Operating Range................................................................63
4.11.4 Measurement Range.....................................................................63
4.11.5 Octave Band Time Constants........................................................63
4.12 Influence from the Operating Environment..............................................64
4.12.1 Environmental Stabilisation Time..................................................64
4.12.2 Temperature..................................................................................64
4.12.3 Humidity.........................................................................................64
4.12.4 Vibration.........................................................................................64
4.12.5 Immunity to Power Magnetic Fields ..............................................64
4.12.6 Immunity to Power and Radio-frequency Fields............................65

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4.13 Wireless interface to the Sound Level Meter...........................................65
4.13.1 Bluetooth........................................................................................65
4.13.2 Wi-Fi ..............................................................................................65
4.14 Electrical interface to the Sound Level Meter..........................................65
4.14.1 Output for Headphone and test.....................................................65
4.14.2 Digital Interfaces............................................................................66
4.14.3 Charge /power Interface................................................................66
4.15 Power Supply...........................................................................................66
4.15.1 External AC Main Supply Adapter.................................................66
4.15.2 Battery ...........................................................................................66
4.16 Warm-up Time.........................................................................................67
4.17 Real-time Clock........................................................................................67
4.18 CE-mark and C-Tick mark Compliance...................................................67
Chapter 5 Regulatory ..........................................................................................68
5.1 Regulatory ID’s summary ........................................................................68
5.2 Certified Antennas –do we need this?....................................................68
5.3 FCC and IC/ISED Regulatory..................................................................68
5.3.1 FCC (Federal Communication Commission Interference
Statement).....................................................................................68
5.3.2 IC (Industry Canada Statement)....................................................69
5.4 EU Declarations of Conformity ................................................................69
Appendix A Tables.............................................................................................70
Electrical Frequency Responses .......................................................................70
Free-field Frequency Responses.......................................................................72
Diffuse-field Frequency Responses...................................................................76
Free-field Frequency Responses for Diffuse-field Calibrated Instruments
.................................................................................................................80
Directional Responses .......................................................................................82
Periodic Testing of Acoustical Frequency Responses.....................................100
Appendix B Cross-references to Standards ....................................................103
Introduction ......................................................................................................103
Cross-references to Standards........................................................................103
Irrelevant Topics...............................................................................................110

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Chapter 1
Introduction
1.1 About This Manual
This Instruction Manual for Sound Level Meter Type 2245 has been created to fulfil the
documentation requirements of the national and international standards that the sound
level meter conform to. These standards are listed in section 4.2.
For other microphone configurations, supplements to this manual will be provided.
Other documentation and sales material will also contain specifications for the sound
level meter. In the event of any unintended inconsistency between these and those in
this instruction manual, the instruction manual takes precedence.
Appendix B of this manual provides cross-references between specific paragraphs in
the standards that require topics to be documented and the corresponding sections in
this manual that conform to them.
PC Software and smart device software contains online help including user help for the
sound level meter.
1.1.1 Conventions Used in this Manual
The term “sound level meter” is an abbreviation for "Sound Level Meter Type 2245"
throughout this manual.
Icons, Buttons and pages on the Screen
Indicated by bold typeface (for example, MEASUREMENT SETTINGS page).
Parameter Values, Text and Variables
Parameter values, instructions, descriptions appearing on the screen and variables are
indicated by italics (for example, Free-field ).
Menu, Parameters and Screen Navigation
Indicated by bold typeface (for example, Measurement settings > Input > Sound
field).
1.2 System Overview
1.2.1 Hardware and Software on the Sound Level Meter
The About screen lists the hardware and software versions currently installed. See
section 2.3.3.
1.2.2 Basic PC Software
Noise Partner for PC can be used for transferring measurement data from the sound
level meter to a standard PC for post-processing and reporting.
Noise Partner for smart devices can be used for controlling the sound level meter and
for transferring data from the sound level meter to the smart device for display and
post processing.
Noise Partner can be downloaded from Brüel & Kjær’s web site. For instructions on this
software, see the software’s online help.

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1.2.3 Hardware Setup
This section provides an overview of the hardware components used with the sound
level meter.
A hardware overview is provided in Fig. 1.1, optional accessories are designated on the
diagram.
The components needed for conformance testing Sound Level Meter Type 2245 are
listed in Table 1.1.
Fig. 1.1 Hardware overview

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Table 1.1 Hardware components needed for conformance testing of Sound
Level Meter Type 2245
Quantity*
Brüel & Kjær
Type/Part Number
Description
1
Type 4966
Prepolarized Free-field ½" Condenser Microphone
1
WA-0302-B
Electrical Substitute for Microphone Type 4966, 15 pF
1
UA-0245
10–32 UNF to BNC Adapter
1
UA-1650
90mm Windscreen with auto detect insert, for Sound
Level Meter Type 2245
1
UA-1651
Tripod Extension for Hand-held Analyzers
ZG-0484
Power supply with integrated USB-C cable, for Sound
Level Meter Type 2245
1
AO-0821-D-010
USB Shielded I/O Cable, Type A-to-C, USB 2.0, 1.0m, for
Sound Level Meter Type 2245
1
AO-0846
USB-C to 3.5mm (Mini) Jack Adapter for analog
Headphone, for Sound Level Meter Type 2245
1
HT-0015
Earphones, unscreened cable
1
Type 4231
Sound Calibrator
1
Type 4226
Multifunction Acoustic Calibrator

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1.2.4 Block Diagrams
The Block Diagram for Sound Level Meter Type 2245 is shown in Fig. 1.2.
Fig. 1.2 Block Diagram for Type 2245
Amplifier
Amplifier
USB-C
Interface
Output
External
Power
Input
Main
Processor
A/D
Converter
D/A
Converter
Power
Supply
Battery
Keyboard
Light
ring
Display
BLE
Interface
WiFi
Interface
GPS
Data

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Chapter 2
Short Guide to the Sound Level Meter
2.1 Introduction
This chapter contains a brief guide to the use of the sound level meter.
The user interface of the sound level meter is classic:
A screen for displaying settings, results and status
A keyboard for navigating on the screen, changing settings and controlling the
measurement
A light ring to indicate which colour-coded to reflect the status of the
instrument.
2.2 Switch sound level meter On/Off
Switch on the sound level meter by pressing the Power/Menu/Select button for
a few seconds. The instrument will start in the last used measurement display.
Pressing and holding down the button for at least 4 s will switch off the sound level
meter.
2.3 Setting up the sound level meter
Note: Not all settings might be available on your sound level meter –only settings
being part of the licensed features are available.
Press the Power/Menu/Select button to enter the menus.
The menus are hierarchically ordered, you
navigate in them using up/down buttons and
between them using the left/right arrow
buttons.

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2.3.1 Measurement settings
The acoustical frequency response and calibration depends on the sound field, the
microphone, the microphone accessories used and the electrical frequency response.
To improve the quality of the measurement and help the user to measure correctly the
sound level meter compensates for the sound field, the microphone and the
microphone accessories used by automatically changing the electrical frequency
response and calibration.
This means that it is very important that parameters in Measurement settings and its
sub menus are correct.
Use Measurement settings > Inputto select:
Microphone to use (if more than one has
been specified in System settings > Advanced
settings > Microphones)
Sound field. Select a correction matching
the sound field of your measurements, that is,
you can make correct measurements in a
diffuse-field using a Type 4966 free-field
microphone, by selecting Diffuse-field
correction. Even Free-field correction of a free-
field microphone will enhance the overall
frequency response of the system. Generally,
ISO requires free-field conditions and ANSI
requires diffuse-field conditions. Check your
local standards for the setting you require. No
correction is made for an unknown
microphone.
Windscreen detect. Enabled/Disabled
automatic detection of windscreen UA-1650
when mounted on the microphone
preamplifier.
Windscreen type. Select type of
windscreen, when Windscreen Detect is
Disabled.

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Use Measurement settings > Measurement control to setup how to control your
measurement:
Logging mode: Select Enabled to log
measurement data at every Logging interval.
Measurement time: Select Preset for the
measurement to run for Preset time –or Free
to run until you stop it.
Back-erase mode: Select Enabled to back-
erase all data for the last Back-erase time,
when continuing a paused measurement. Only
available for Logging mode is Disabled
Use Measurement settings > Broadband parameters to select the frequency
weightings to use and the broadband parameters to measure:
The use of keyboard in this display.
See details on measured broadband parameters in sections 2.13 Frequency Weightings
and 2.14 Measured Quantities.

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Use Measurement settings > Spectrum parameters to select Bandwidth (1/1-
octave or 1/3-octave ), Frequency Weighting to use and the spectrum
parameters to measure.
The use of keyboard in this display.
See details on measured broadband parameters in sections 2.13 Frequency Weightings
and 2.14 Measured Quantities.
Use Measurement settings > Statistical parameters to select the Basis parameter
for the statistics ( LAeq, LAF or LAS ) and up to five percentiles.
See details on statistics in section 2.14.2.
Use Measurement settings > Audio recording to select whether you want to record
the audio in Listen quality (mp3-files) or not.

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2.3.2 Display settings
Use Display settings > Screen brightness and > Light ring brightness to adjust the
brightness of the screen and light ring on the instrument.
Use Display settings > Colour scheme to select either Light or Dark scheme.
Use the rest of the Display settings to specify how to display your measurement data.
There is a view for each of the five possible displays to specify which parameters to
display, the max and min levels of the graphs and whether to enable the view for display
or not. Here we only show the Spectrum view.
2.3.3 System Settings
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Godkendelsesmæssigt skal der være noget om Network og Voltage output ????
Use System settings > Regional settings > Language to select your preferred user
interface language.
Use System settings > Advanced settings > About to see the Serial number,
hardware versions and software versions currently installed.
2.3.4 Data explorer
See section 2.7

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2.3.5 Calibration history
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2.3.6 Status
Use Status to see the Battery and Disk status:
The small icon in the bottom left corner
of the display gives a brief overview of
the battery status. This icon is on all
displays.

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2.4 Calibration
Calibration is an adjustment of your sound level meter to measure and display correct
values. The sensitivity of the microphone as well as the response of the electronic
circuitry can vary slightly over time or could be affected by environmental conditions
such as temperature and humidity. While you are unlikely to ever experience a large
drift or change in sensitivity with the sound level meter, it is nevertheless good practice
to perform regular checks of the calibration, normally before and after each set of
measurements.
It is strongly recommended that Brüel & Kjær Sound Calibrator Type 4231 is used.
2.4.1 Calibration Procedure
The sound level meter requires a stable signal of either 94 dB or 114 dB. Use Sound
Calibrator Type 4231. It provides a stable sound pressure at 1 kHz and has minimal
susceptibility to environmental factors. The calibration procedure is semi-automatic:
you just need to select calibration mode and mount and switch on the calibrator, then
the sound level meter will calculate the sensitivity.
To perform acoustic calibration:
1. Stand away from loud sound sources that may interfere with the calibrator’s
signal.
2. Switch on the sound level meter.
3. Press the POWER/MENU/SELECT button and the arrow buttons to
navigate to System settings > Advanced settings and set Service mode to
Enabled .

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4. Use right arrow button to enter Calibration and insert the Calibrator serial
no. (use up/down arrow buttons to change the number)
5. Use right arrow button to enter Calibrate:
6. Fit Sound Calibrator Type 4231 carefully onto the microphone of the sound
level meter. To avoid handling vibrations that disturb the calibration, rest the
assembly in a roughly horizontal position on a table or other flat surface.
Ensure that the calibrator fits snugly on the microphone.
7. Switch on the calibrator. Wait a few seconds for the level to stabilize.
8. Press the button to start the calibration
9. Detection signal appears on the screen as feedback. When the signal has
been detected and verified for a while, then the sensitivity is calculated and
displayed on the screen together with deviations from last calibration and
from initial calibration:

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10. Press the button to accept the calibration and remove the calibrator. It will
automatically switch off after a few seconds.
If no calibration signal is detected, you will be informed about an unstable calibration
signal and asked to mount the calibrator, switch it on and press Retry to restart the
calibration.
If the calibration deviates more than ± 1.5 dB (± 1.1 dB in Spain) from the initial
calibration, then the calibration is stopped without changing the calibration of the
sound level meter.
You can verify the calibrations made by navigating from the main menu: Calibration
history > Calibrations >
2.4.2 Calibration Check Procedure
It is good practice to perform regular checks of the calibration, normally before and
after each set of measurements. This can easily be done without changing the
calibration. The sound level meter keeps a history of all the checks.
Use Sound Calibrator Type 4231. It provides a stable sound pressure at 1 kHz and has
minimal susceptibility to environmental factors.
Kræver Automatic check enabled
To perform an acoustic check of the calibration:
1. Stand away from loud sound sources that may interfere with the calibrator’s
signal.
2. Switch on the sound level meter.
3. Be sure that the instrument doesn’t measure or is paused but is stopped and
reset (press ) –and is on a measurement screen (not in settings).
4. Fit Sound Calibrator Type 4231 carefully onto the microphone of the sound
level meter. To avoid handling vibrations that disturb the calibration, rest the
assembly in a roughly horizontal position on a table or other flat surface.
Ensure that the calibrator fits snugly on the microphone.
5. Switch on the calibrator. Wait a few seconds for the level to stabilize.

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6. The sound level meter will detect the signal and pop up the message:
7. Press the button to start the calibration check
8. Detection signal appears on the screen as feedback. When the signal has
been detected and verified for a while, then the sensitivity is calculated and
displayed on the screen together with deviations from last calibration and
from initial calibration:
9. Press the button to terminate the calibration check and remove the
calibrator. It will automatically switch off after a few seconds.
You can verify the calibration checks made by navigating from the main menu:
Calibration history > Checks >

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Note: You can disable the automatic calibration check in System settings > Advanced settings
> Calibration:
2.5 Measuring with the sound level meter
Before a measurement is started and after it is stopped, the sound level meter displays
an instantaneous broadband measurement. Which one can be selected with the
left/right arrows.
This measurement cannot be saved but it is useful to survey where to measure.
To make a measurement over a time period that can be saved follow the procedure in
the next section.
For more information on instantaneous and timed measurements, see section 2.14.
2.5.1 Start/Pause/Stop of Measurement
The upper part of the measurement display shows the measurement status:
Stopped mode, shows current time and number for next measurement
Press to start a measurement, the measurement status turns green and the
elapsed time is displayed to the right.
Press again to pause the measurement, shown as yellow status. You can
continue the measurement by pressing the button again.
Press to stop and automatically save the measurement (as #5)

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Press again to reset the measurement and display, ready for a new
measurement.
2.5.2 Overload and Underrange
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2.6 Looking at the measurement
There is a number of measurement displays (SLM, List, Spectrum, Profile and About
data), you navigate between them using the up/down arrow buttons :
Note: Use right and left buttons in the measurement displays to toggle the (main)
parameter in the display without going into the Display settings. Press and hold the
buttons down to move the cursor (Spectrum and Profile only).
Press and hold the up button down to zoom the y-axis on the spectrum and the
profile.
The About data display shows the precondition for the measurement.