BRUEL & KJAER 2203 User guide

\ Instructions
, .i and Applications ~
1
Il l
Precision Sound Level Meter
Type 2203
A portable sound level meter made to
the precision standards of IEC 179.
It can also be used with an accelero-
meter input for the measurement of
vibration.
~

PRECISION SOUND LEVEL METER
TYPE 2203
Applicable to instruments from serial
no. 467152
December 1 973

CONTENTS
1. INTRODUCTION ..................... .. .. .......................... ............. 7
1.1. Precision Sound Level Meter Type 2203 ........ .. .. .. .... . 7
1.2. Precision Sound Level Meter Standards .................... 7
2. CONTROLS ..... .. .... .. .................... ......... ................... ........... 9
Meter Scale .. .. ............................................ .. ......... 10
Meter Mechanical Zero Adjustment . .. ... ......... .. ......... 10
Power On Flasher .................................................. 10
Meter Light Switch ................................................. 10
Meter Switch ......................................................... 10
Input Attenuator (black) .. ...... ............ .................... ... 11
Output Attenuator (transparent) ............................... 11
Gain Adjustment .................................................... 11
External Filter In .................................................... 11
External Filter Out ........................... ............ .. .. ...... . 12
AC
Output ............................................................. 12
Tripod Mounting Threads ............... ....... .................. 12
3. OPERATION ....................................................................... 13
3. 1. Battery Replacement and
General Considerations ................................... ........ 13
Battery Replacement .......................................... .... 13
General Considerations ........................................... 13
3.2. Calibration for Sound Measurements ........................ 13
Using the Sound Level Calibrator
or Pistonphone ...................................................... 13
Using
the built-in Reference Voltage ............. .. .. .. .... . 15
Determination of K-factor ........... .................. .. .. ...... . 16
3.3. Sound Measurements .. ... ........................ .. ............. 16

General Considerations ......................... .. ................ 16
Specific
Sound Measurement Procedure ................... 17
3.4. Calibration for Vibration Measurements .................... 18
Using Accelerometer Calibrator 4291 ....................... 18
Using built-in Reference Voltage ... ...... .. . .. .. .. .. .. ...... .. 19
3.5. Vibration Measurements ......................................... 20
General Considerations ............................................ 20
Specific Vibration Measurement Procedure ............... 20
3.6. Calculation of Vibration Amplitude ............................ 21
With 4291 Calibration, Without Integrator ................ 21
With 4291 Calibration, With Integrator .................... 22
With built-in Calibration, Without Integrator .............. 24
With built-in Calibration, With Integrator .................. 24
4. DESCRIPTION ................................................................... 25
4.1. Condenser Microphone ........................................... 25
4.2. Input Stage .................................................... . ...... 26
4.3. Input Attenuator and Input Amplifier ........................ 26
4.4. Reference Oscillator ............................................... 27
4.5. Weighting Networks ............................................... 28
4.6. Output Attenuator and Output Amplifier ................... 28
4. 7. RMS Detector ........................................................ 28
4.8. Power Supply· .......... . ............................................. 29
5. OPERATIONAL CHARACTERISTICS
AND ACCURACY ............................................................... 30
5.1. Directional Characteristics ....................................... 30
5.2 ·. Reflection ..................................................... . ........ 36
5.3. Effect of Background Noise ...................................... 37
5.4. Distortion ............................................... . .............. 37
5.5. Effect of Temperature ............................................. 39
5.6. Effect of Humidity .................................................. 39
5.7 . Inherent Noise Levels ............................................. 39
5.8. Effect of Sound Field .............................................. 41
5.9. Effect
of Vibration ...:..... .. . .. .... .. .............. .. . .. .. .. . .. .. .. 41
5.1
0. Effect of Atmospheric Pressure ................................ 41
5.11. Effect of Electrostatic and
Electromagnetic Fields
.. .. .. .... ....... . .. ...... .. ..... .. . .. .... .. 41
5.12. Weighting Networks ............................................... 48

6. ACCESSORIES AND MEASUREMENTS ............................. 50
6.1. Accessories Included with 2203 .............................. 52
Adaptor JJ 2614 ................................................... 52
Half-inch to one-inch Adaptor DB 0962 .................... 52
Flexible Extension Rod UA 0196 .............................. 52
Half-inch to one-inch Adaptor DB 0375 .................... 52
Random Incidence Corrector UA 0055 ..................... 53
Windscreen UA 0207 ............................................. 53
Plugs JP 0006 ...................................................... 53
6.2. Optional Accessories ......................... .. ................... 53
Octave Filter Set 1 61 3 .. .. .. .. .. .. .. .. .. .... .. ... .. . .. .. .... .. ... 54
Third Octave Filter Set 1616 ................................... 54
Microphones ......................................................... 54
Microphone Adaptor UA 0030 ................................. 56
Nose Cones ........................................................... 56
Extension Cables AO 0033/59 ............................... 56
Artificial Ears 41 52/53 .......................................... 57
Artificial Mastoid 4930 ................. . ......................... 57
Accelerometers ...................................................... 57
Accelerometer Calibrator 4291 ................................ 57
Integrator ZR 0020 ................................................ 58
Adaptor JJ 2615 ................................................... 58
Connection Cable AO 0007 .................................... 58
Carrying Case KE 0055 .......................................... 58
6.3. Complete Measuring Sets ........................................ 60
Sound and Vibration Sets Type 3501 and 3509 ........ 60
Audiometer Calibration Set Types 3502 and 3510 .... 60
7. USE WITH OTHER INSTRUMENTS ..................................... 61
7.1. Systems Considerations
.. .... .. ........ .. .. .. ... .. ... .. .... .... .. 61
7.2. Level Recorders ..................................................... 61
7.3. Noise Dose Meter .................................................. 62
7 .4. Tape and Digital Recording ...................................... 62
7.5. Analysis ........ ... ..................................................... 63
7.6. Loudness Evaluation ............................................... 63
8. SPECIFICATIONS ............................................................... 64
8.1. Frequency Response ............................................... 64
0

One-inch Microphone Type 4145 ............................ 64
Half-inch Microphone Type 41 33 ............................. 64
Amplifiers ......... . ............... . ................................... 65
8.2. Dynamic Range .......... ..... ...................... . ................ 65
One-inch Microphone ............................................. 65
Half-inch Microphone .......... .... ............................... 65
8.3 . Input .................................................................... 66
8.4. Output .................................................................. 66
8.5. External Filters ...................................................... 66
8.6. Meter Indication ..................................................... 66
8.7. Inherent Noise ....................................................... 67
8.8 . Polarization Voltage ................................................ 67
8.9. Calibration ........................... ... ...... ........................ 67
Sound Measurements ............................................. 67
Vibration Measurements .. ........ .. .............. ............... 67
Internal . ....... .. ................. . ..................................... 67
8.1 0. Directional Characteristics ...................................... . 67
8.11. Effect of Humidity .................................................. 68
8.1 2. Effect of Vibration .................................................. 68
8.13. Effect of Sound Field .............................................. 68
8.14. Effect of Static Pressure .......................................... 68
8.15. Effect of Electrostatic Field ...................................... 68
8.1 6. Operating Temperature ........ ...................... ............. 68
8.1 7. Batteries ................ . .............................................. 68
8.18. Dimensions ........................................................... 69
8.1 9. Weight .... .............................................................. 69
8.20. Accessories Supplied .............................................. 69

1. INTRODUCTION
1.1. PRECISION SOUND LEVEL METER TYPE 2203
The Bruel and Kjmr Precision Sound Level Meter Type 2203 is a com-
pact, portable instrument for precision sound and vibration measure-
ment. The 2203 meets the standards of IEC 179/1973 for Precision
Sound Level Meters.
Built into the 2203 are the A, B, and C weighting networks. Provision
is also
made for external filters such as the 1 613 (Octave) and 161 6
(Third Octave)
filters permitting truly portable analysis.
The 2203 is capable of sound measurements over a wide frequency
and dynamic range with the Condenser Microphone (4145) provided
with it. It accurately measures the RMS values of signals with crest fac-
tors up to 5. Slow and Fast meter dampings are provided according to
IEC 179. It can also be used for vibration measurements when fitted
with a suitable accelerometer.
Sound Level Meters Type 2203 from serial number 467152 are of a
new construction featuring generally improved gain stability with tem-
perature variation, lower output impedances, and a new expanded list of
accessories.
The
2203 is available with a wide range of accessories making it a
versatile, portable instrument.
1.2. PRECISION SOUND LEVEL METER STANDARDS
The IEC (International Electrotechnical Commission) has set various
standards
for sound level meters. IEC Publication 1 23 gives the require-
ments for general purpose Sound Level Meters which are made more
stringent in Publication 179 for Precision Sound Level Meters. The B &K
2203 meets or exceeds all requirements of IEC 1 79, the main points of
which are given below:
7

8
Free-field sound pressure level measurement accuracy of± 1 dB.
Essentially omnidirectional microphone characteristics (see
Section 5.1 ). Square law type measurement indication.
Tolerances on meter scale calibration and range shift error are
specified.
A "Fast" meter dynamic characteristic: Response to a 200 millisec-
ond pulse must be within -2 and 0 dB of the indication for a con-
tinuous signal of same frequency and amplitude. Damping such that
overswing on a suddenly applied steady signal is between + 0,1 and
+ 1,1 dB.
An alternative "Slow" meter characteristic (optional): Response to a
500 millisecond pulse must be within -5 and -3 dB of the indica-
tion for a continuous signal of same frequency and amplitude.
Damping such that overswing on a suddenly applied steady signal is
between + 0,1 and + 1,6 dB compared to final steady indication
(which must be within 0,1 dB of level indicated with "Fast" charac-
teristic).
Specifications are also given for frequency range capabilities, and
maximum permissible sensitivity to external and environmental in-
fluences.
The IEC publication specifically states that the Precision Sound
Level Meter is designed to give objective measurements which un-
der certain conditions approximate the subjective impression of
soL.nd. The 2203 meets all applicable IEC criteria and can be used
for "1.' 1e measurement of most continuous sounds.
Full d: scussion of sound and vibration measurement techniques is
given in two Bruel & Kjcer books; "Acoustic Noise Measurements"
and "Mechanical Vibration and Shock Measurements" which are
available on request.