BRUEL & KJAER 4297 User manual

USER MANUAL
www.bksv.com © Brüel & Kjær. All rights reserved.
Sound Intensity Calibrator
Type 4297
BE 1653 – 14
English
ËBE-1653---(Î BE 1653 – 14

BE 1653 – 14
April 2017 www.bksv.com
Sound Intensity Calibrator Type 4297
User Manual

Health and Safety Considerations
This apparatus has been designed and tested in accordance
with IEC/EN 61010 – 1 and ANSI/UL 61010 – 1
Safety
Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use
. This manual contains
information and warnings which must be followed to ensure
safe operation and to retain the apparatus in safe condition.
Safety Symbols and Signal Words Used
The apparatus will be marked with this symbol
when it is important that you refer to the
associated danger or warning statement given in
this manual
The manual uses this symbol when a danger or
warning statement is applicable
Hazardous Voltage/Electricity. Both the apparatus
and manual use this symbol when there is a risk for
shock or electrocution
Hot Surface. This manual will use this symbol when
there is a risk for burning or scolding
Earth (Ground) Terminal. The apparatus will be
marked with this symbol when applicable
Protective Conductor Terminal. The apparatus will
be marked with this symbol when applicable
Alternating Current. The apparatus will be marked
with this symbol when applicable
Danger Signals an imminent hazardous situation, which, if
not avoided, will result in death or serious injury
Warning Signals a possibly hazardous situation, which, if
not avoided, will result in death or serious injury
Caution Signals a hazardous situation, which, if not
avoided, could result in minor or moderate injury
or damage to the apparatus
Notice Signals a situation or practice that requires
attention, but does not directly result in personal
injury if ignored
Risks and Hazards
Explosion Hazards
Danger: The apparatus is not designed to be used
in potentially explosive environments. It should
not be operated in the presence of flammable
liquids or gases
Electrical Hazards
Warning: Any adjustment, maintenance and
repair of the open apparatus under voltage must
be avoided as far as possible and, if unavoidable,
must be carried out only by trained service
Caution: Switch off all power to equipment before
connecting or disconnecting their digital
interface. Failure to do so could damage the
equipment
Mechanical Hazards
Caution: Whenever it is likely that the correct function or
operating safety of the apparatus has been
impaired, it must be made inoperative and be
secured against unintended operation
Waste Handling
Brüel & Kjær complies with the EU’s Waste Electrical
and Electronic Equipment (WEEE) Directive, which issues
the following waste handling instructions:
• Do not dispose of electronic equipment or
batteries as unsorted municipal waste
• It is your responsibility to contribute to a clean
and healthy environment by using the
appropriate local return and collection systems
• Hazardous substances in electronic equipment or
batteries may have detrimental effects on the
environment and human health
• The symbol shown to the left indicates that
separate collection systems must be used for any
discarded equipment or batteries marked with
that symbol
• Waste electrical and electronic equipment or
batteries may be returned to your local
Brüel & Kjær representative or to Brüel & Kjær
Headquarters for disposal

Brüel & Kjær has made every effort to ensure the accuracy of
the information contained in this document. No responsibility
is accepted for any errors or omissions herein. It is the
responsibility of the user to ensure compliance with any legal
or statutory requirements in the country of use. Data may
change, as well as legislation, therefore you are advised to
obtain copies of the most recently issued applicable
regulations, standards and guidelines.
All descriptions, illustrations and any other information relating
to the product are made by way of general description, are
approximate only and for the general guidance and information
of the user. They cannot be construed to imply representation or
warranty as to their accuracy, currency or completeness and are
not intended to form the basis of any contract.
The information in this document does not constitute a
warranty, representation or guarantee concerning the
suitability or performance of the product.
Brüel & Kjær shall not be liable for any loss whether direct,
indirect, incidental or consequential arising from the use of or
reliance upon any of the content of this document, regardless
of whether such content has been accurate or complete.
Brüel & Kjær will not pay any damages whether for loss or
injury, punitive or otherwise, because of use of or reliance upon
any of the content in this document.
Brüel & Kjær and all other trademarks, service marks, trade
names, logos and product names are the property of
Brüel & Kjær or a third-party company. Nothing in this
document may be construed as granting, by implication, or
otherwise any license or right to use any of the trademarks
without a prior written permission of Brüel & Kjær or the owner
of such trademark.
© Brüel & Kjær. All rights reserved.
Brüel & Kjær Sound & Vibration Measurement A/S
DK-2850 Nærum · Denmark
For service and support, contact your nearest Brüel & Kjær
Customer Care support team:
Headquarters: [email protected], [phone]
China (Beijing): [phone]
France: s[email protected], [phone]
Germany: [email protected], [phone]
Italy: [email protected], [phone]
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North & South America: [e-mail],
[phone]
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UK & Ireland: [e-mail], [phone]
Go to www.bksv.com/contact for contact information to our
other global offices.

Contents
CHAPTER 1
Introduction and Description ................................................................................................... 1
1.1 Introduction .............................................................................................................................. 1
1.2 Description................................................................................................................................ 1
CHAPTER 2
Calibration Procedure with Hand-held Analyzer Type 2270-S Sound Intensity System.............. 9
2.1 Sound Pressure Calibration....................................................................................................... 9
2.2 Phase Calibration and Pressure-Residual Intensity Index Verification ................................... 13
CHAPTER 3
Calibration Procedure with Type 2260-E Investigator™ .......................................................... 15
3.1 Sound Pressure Calibration..................................................................................................... 15
3.2 Phase Calibration and Pressure-Residual Intensity Index Verification ................................... 18
CHAPTER 4
Use of the Calibrator with Other Instruments ........................................................................ 21
4.1 PULSE LabShop........................................................................................................................ 21
4.2 Other Instruments .................................................................................................................. 21
4.3 Using an External Signal.......................................................................................................... 22
CHAPTER 5
Pressure-Residual Intensity Index .......................................................................................... 23
CHAPTER 6
Specifications......................................................................................................................... 27
CHAPTER 7
Service and Repair ................................................................................................................. 29
APPENDIX A
Sensitivity to Sound Pressure at the Equalization Vent........................................................... 31
A.1 Measurement Errors............................................................................................................... 32
A.2 Effect of Ambient Conditions.................................................................................................. 33
INDEX............................................................................................................................................................. 35

1
Chapter 1
Introduction and Description
1.1 Introduction
Sound Intensity Calibrator Type 4297 is used for on-site sound pressure calibration and pressure-
residual intensity index verification.
The most important and unique feature is that there is no need to dismantle the sound intensity
probe. The calibrator is optimized for use with Type 2270-S and Type 2260 E Investigator™ sound
intensity systems for phase enhancement, but it can also be used with sound intensity analysis
systems such as PULSE™.
Type 4297 is a complete sound intensity calibrator in one compact, portable unit with a built-in
sound source. A barometer is not required as the acoustic feedback system automatically adjusts
for variations in atmospheric pressure. Type 4297 fulfils the requirements:
• IEC 61043 –1993; Electroacoustics – Instruments for the measurement of sound intensity –
Measurements with pairs of pressure sensing microphones
• ANSI S1.9 – 1996; Instruments for the Measurement of Sound Intensity
Table 1.1 Comparison of various capabilities in sound intensity calibrators
1.2 Description
1.2.1 General
Sound Intensity Calibrator Type 4297 enables instruments that measure sound intensity to be
accurately calibrated.
Type
Number
Pressure
Level
Intensity
Level
Velocity
Level
P-R Int.
Index
Dismantling
Necessary
Sound Source
Included
Supports ¼″
Microphones
4231+
DP-0888
Yes No No No Yes Yes No
3541-A Yes Yes Yes Yes Yes Yes Yes
4297 Yes No No Yes No Yes No

Sound Intensity Calibrator Type 4297 – User Manual
2
Type 4297 is intended for use with Brüel & Kjær Sound Intensity Probes Type 3599 or 3654 (or
earlier Types 3545, 3548, 3583, 3584 or 3595) with a Sound Intensity Microphone Pair Type 4197
(or earlier Type 4181). The microphones must be used with ¼″preamplifiers, and a 12 mm spacer.
Note that Type 4297 can be used up to 6.3 kHz without a spacer to check the pressure-residual
intensity index.
The Sound Intensity Calibrator can be used for calibration of sound pressure sensitivity. To do
this, the microphones are both positioned in the calibration chamber. There is no need to
dismantle the probe and both microphones are exposed to exactly the same sound pressure
(amplitude and phase).
The broad-band pink noise sound source is provided for measurement of the pressure-residual
intensity index spectrum. This is used to assess the accuracy of sound intensity measurements.
A calibration chart is supplied that states the levels that should be detected during calibration.
✐Please note: The wrist strap has a protection plug attached. This is designed to be placed inside the
calibrator to prevent dust and dirt entering the acoustic chamber when the instrument is
not in use. The rubber gasket can be cleaned with a clean dry cloth. To remove specks of
grease or other sticky substances, use a a cloth slightly dampened with pure alcohol.
Fig.1.1 Sound Intensity Calibrator Type 4297

CHAPTER 1
Introduction and Description 3
What the Calibration Procedure Includes
Calibration of an intensity-measuring instrument includes:
• sound pressure calibration of the individual microphone channels
• measurement of the pressure-residual intensity index spectrum of the sound intensity
measurement system
Pressure-Residual Intensity Index Measurement
Fig.1.2 shows an arrangement for measuring the pressure-residual intensity index. The probe is
placed in the Type 4297. The sound source produces the same sound pressure level at each
microphone, so both microphones are exposed to the same sound pressure and same phase, and
therefore any intensity detected is residual intensity. The microphone channels are calibrated
against this known sound pressure level (nominal value 94 dB).
Fig.1.4
shows how small differences in the phase responses of the microphones and input
channels result in the detection of ‘residual intensity’. Residual intensity is a parameter that
should be taken into account when interpreting measured intensity data. The pressure residual
intensity spectrum is not fixed; it is ‘tied to’, and rises and falls with, the measured sound pressure
level.
It can be shown that, for a given measurement system and frequency, the difference between
measured sound pressure level and detected residual intensity level will be a constant. This
constant difference is called the pressure-residual intensity index.
The pressure-residual intensity index spectrum can be measured with the arrangement shown in
Fig.1.2 by subtracting the detected intensity spectrum from the sound pressure spectrum. An
example is shown in Fig.1.4.

Sound Intensity Calibrator Type 4297 – User Manual
4
Fig.1.2 Type 4297 Sound Intensity Calibrator with a sound intensity probe in place. This configuration is used for both
sound pressure calibration and pressure-residual intensity index measurement
Fig.1.3 Simplified block diagram of an intensity measuring instrument. The signals from two pressure microphones,
p1 and p2, are used to determine the pressure midpoint of the probe axis, p, and the particle velocity along
the probe axis, v Multiplying p and v gives the intensity reading I
Residual Intensity Level
If a pressure-residual intensity index spectrum is to be used to assess the accuracy of sound
intensity measurements, then the mean sound pressure spectrum in the field must also be
measured. The residual intensity level is then quickly established by subtracting the pressure-
residual intensity index spectrum from the measured mean sound pressure spectrum.
The residual intensity level is then compared to the measured sound intensity level. It can be
shown that, for a certain frequency, the residual intensity level must be at least 7 dB lower to
ensure a measurement error of less than 1 dB when measuring intensity level. Refer to IEC 61043
for details.
p1
p2
Preamp. ADC Phase
correction
Ch. 1
Ch. 2 Diff. Int.
Sum
+
+
+
∑1/3-oct.
filters
v
p
I
-
980277/2e
ADC Phase
correction 1/3-oct.
filters XAveraging
∑
Preamp.

CHAPTER 1
Introduction and Description 5
Microphones and Vent Sensitivity
Type 4297 has been designed to work with Microphone Pair Types 4197 and 4181, which have an
extremely low sensitivity to sound pressure at the equalisation vents due to their patented
acoustical filters. When microphones are inserted into the calibrator, their diaphragms are
exposed to the sound pressure in the calibrator, but their pressure-equalization vents are not.
Type 4297 cannot be used to measure the pressure-residual intensity index with pairs of
conventional microphones as they have vent sensitivities several orders of magnitude higher
than that of Types 4197 and 4181.
Fig.1.4 Typical intensity and sound pressure levels measured with 12 mm spacer using the arrangement shown in
Fig.1.2. The pressure-residual intensity index spectrum is characteristic of the sound intensity measurement
system and is obtained by subtracting the intensity spectrum from the pressure spectrum
90
80
70
60
50
40
30
20
10
0
10 100 1000
Frequency (Hz)
10000
SPL in Coupler
Intensity Level in Coupler
Pressure-Residual Intensity Index
010006/1

Sound Intensity Calibrator Type 4297 – User Manual
6
Fig.1.5 Typical intensity and sound pressure levels measured without spacer
1.2.2 Calibration Chart
A calibration chart is supplied with each instrument in the lid of the protective case. This confirms
that the specification of the calibrator is within the stated limits. The following information is
provided:
• Product serial number
•Soundpressurelevel
•Frequency
• Reference conditions
• Pink noise sound pressure level
The date of issue of the calibration chart and the signature of the test engineer who performed
the tests are shown. An example of a calibration chart is shown in Fig. 1.6.
90
80
70
60
50
40
30
20
10
0
10 100 1000
Frequency (Hz)
10000
SPL in Coupler
Intensity Level in Coupler
Pressure-Residual Intensity Index
010246

CHAPTER 1
Introduction and Description 7
Fig.1.6
Type 4297 Calibration
Chart
1.2.3 Use of Power Supply
An external DC power supply can be used. It is not necessary to remove the internal batteries.
The power supply is connected using the 5.5 mm diameter socket at the rear of the unit marked
12 V as shown in Fig.1.7. A smoothed and regulated supply of 10 – 14 V with 100 mV maximum
ripple is required. Ensure that the correct polarity is used – positive to the 2 mm centre pin.
The following Brüel & Kjær power supplies are recommended:
• ZG 0386 EU Power Supply
• ZG 0387 UK Power Supply
• ZG 0388 US Power Supply
Fig.1.7
Rear view of
Type 4297. The
external power supply
input socket marked
12 V is shown on the
left. The external
generator signal is
applied to the LEMO
socket shown on the
right
Battery Replacement
Two type LR6 1.5 V alkaline batteries (part number QB-0013) are used to power the unit. The
batteries must be replaced if neither of the two small red LED indictors fail to light when the start
button is pressed. If the instrument is activated, there is an automatic ‘power-off’ function if the
battery level falls below that needed for correct operation of the calibrator.

Sound Intensity Calibrator Type 4297 – User Manual
8
To replace the batteries, open the unit (see Chapter 2) and pull up the black plastic button. Lift the
hinged flap to expose the battery compartment. Make sure that the new batteries are inserted
with the correct polarity. Close the flap and press the black button to fasten the hinged flap in
place. See Fig.1.8.
Fig.1.8
Type 4297 with the
battery compartment
access cover in the
open position

9
Chapter 2
Calibration Procedure with Hand-held Analyzer
Type 2270-S Sound Intensity System
2.1 Sound Pressure Calibration
2.1.1 General
To open the unit, lift the black handle into the vertical position and turn it anticlockwise through
90°, as shown in Fig.2.1.
Fig.2.1
To open the unit, lift
the handle and turn it
90° anticlockwise
Place the calibrator on a clean, flat surface. Lift the upper half to a near vertical position and
remove the protection plug, shown in Fig.2.2.
✐Please note: The black plastic protection plug is designed to be fitted inside the calibrator to prevent
dust and dirt entering the acoustic chamber when the instrument is not in use.

Sound Intensity Calibrator Type 4297 – User Manual
10
Fig.2.2
With the unit open,
you can now remove
the protection plug
Fig.2.3
Insert the Sound
Intensity Probe into the
holder
As shown in Fig.2.3, place the Type 3545, 3548, 3583, 3584, 3595, 3599 or 3654 sound intensity
probe into the holder. This comprises the intensity probe sound source, which is surrounded by
a two-part black rubber gasket. This gasket ‘contains’ the calibration signal within a controlled
and defined area.

CHAPTER 2
Calibration Procedure with Hand-held Analyzer Type 2270-S Sound Intensity System 11
With the sound intensity probe correctly positioned, close the unit completely by reversing the
procedure described above, as shown in Fig.2.4. The unit should close without any excessive
pressure being required. This indicates that the sound intensity probe is correctly fitted in the
compartment.
Fig.2.4
Type 4297 with a sound
intensity probe in
position
2.1.2 Calibration
You are now ready to start the sound pressure calibration of your Type 2270-S installed with
Sound Intensity Software BZ-7233.
✐Please note: Do not disturb your work surface/equipment during calibration as this will falsely affect
readings.
1) With the sound intensity probe connected to your Type 2270-S, switch on the Hand-held
Analyzer and select
Sound Intensity .
2) Ensure that the analyzer is properly set up for calibration with the calibrator to be used.
a) Tap and select Setup.
b) Expand
Input by tapping it and ensure that the Input line reads Top Socket and that the
Spacer line reads 12 mm .
c) Tap and select Transducers.
If the transducers are not in the system, instructions on entering a new microphone
pair can be found in the documentation that came with your Type 2270-S.
3) Tap and select Calibration from the list of options. The Calibration screen will appear
(Fig.2.5).

Sound Intensity Calibrator Type 4297 – User Manual
12
Fig.2.5
Calibration screen
4) On the Details tab:
a) Tap Calibrator, select
4297 .
b) Tap Calibration level and enter
94 dB .
5) On the
Level tab:
a) Tap Ambient Temperature and enter the current temperature.
b) Tap Ambient Pressure and enter the current barometric pressure.
6) Press the Start button on the Type 4297 control panel (see Fig.2.6). The sine wave (251.2 Hz)
LED indicator should light. If it does not, the batteries need to be replaced, as described in
Chapter 1.
Fig.2.6
Type 4297 control
panel showing the
start, sine wave/
broadband noise
selector buttons and
LED indicators