BRUEL & KJAER 4184-A, Technical Documentation Manual, Page: 11 / 52

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Chapter 3
Conformance Testing
3.1 Introduction
This chapter contains the information needed to conduct conformance testing according to the specified
standards.
3.2 Mounting for Acoustical Tests
For acoustical tests, it is important that the test rig for mounting the microphone to be tested is designed to
minimise the influence of reflections to a level that is comparatively smaller than the test parameter’s
maximum Expanded Uncertainties of Measurement. This has to be demonstrated with a good, known
laboratory microphone.
For Acoustical tests, Weatherproof Microphone Unit Type 4184-A should be mounted on a standard 1.5

water pipe, see section 2.2. The pipe must be of sufficient length, so as to avoid influence of reflections
from the mounting of the pipe in the test rig. The microphone must be connected to the analyzer with
Microphone Cable AO-0697-D-100.
3.3 Periodic Testing of Acoustical Frequency Responses
Acoustical signal test of frequency response can be made with plane progressive waves in an anechoic
facility. However, this is normally very time-consuming and difficult to do with sufficient accuracy. For
the purpose of periodic testing, it is recommended that you use the Brüel & Kjær Multifunction Acoustic
Calibrator Type 4226 for acoustic frequency response tests.
For instructions on how to mount the calibrator on the microphone, see appendix D.2.
The Multifunction Acoustic Calibrator must be set to its Calibration and Pressure sound field modes. The
calibrator must be calibrated. Further details can be found in the Multifunction Acoustic Calibrator
Instruction Manual (BE 1041).
Adjustment data, which must be applied to the sound levels displayed in response to the sound pressure
produced by Multifunction Acoustic Calibrator Type 4226 in order to obtain the equivalent sound levels
that would be displayed in response to plane progressive sinusoidal sound waves incident from the
reference direction, are given in Table A.49.
3.4 Mounting for Mechanical Vibrations Tests
Only Weatherproof Microphone Unit Type 4184-A contributes significantly to the sensitivity to mechanical
vibrations and the microphone cannot be mounted directly onto the analyzer. Therefore, only the
microphone needs to be tested.
Tripod Adaptor UA-1707 can be used for mounting the microphone on the shaker. Alternatively, the inner
M53 × 1.25 thread of the mounting ring of the microphone or pole adaptor DB-3068 can be used.