BRUEL & KJAER 4184-A, Technical Documentation Manual, Page: 14 / 52

Weatherproof Microphone Unit Type 4184-A – Supplement to Instruction Manual BE 1712 8
4.6.2 Typical Low-frequency Responses
The typical Low-frequency Responses for Z-frequency weighting are given in Fig.4.2. The Electrical
Responses are for the rear (Input) socket. The Acoustical Responses include Weatherproof Microphone
Unit Type 4184-A (which again includes Microphone Preamplifier ZE-0773).
Fig.4.2 Typical low-frequency responses
The Low-frequency Responses depends on the state of the Extended Low Frequency parameter on the
Setup display, under Input .
The Low-frequency Responses are not influenced by the microphone accessories described in
section .1.2.4.
The Low-frequency Responses for introduction of the electrical signal through the recommended means to
substitute the microphone with an electrical input facility (see section 3.5) differs from the electrical
responses because it also includes Microphone Preamplifier ZE-0773.
4.6.5 Free-field Frequency Responses
The free-field frequency responses for plane progressive sinusoidal sound waves incident from the
reference direction with Z-frequency weighting are provided in Fig.4.6a and Fig.4.6b, Table A.4a and
Table A.4b. The tables also provides the ‘Expanded Uncertainties of Measurement’ required by
IEC 61672–1, see the start of section 4.6
in the Instruction Manual .
Fig.4.3 Weatherproof Microphone Unit Type 4184-A is not specified without windscreen
Fig.4.4 Weatherproof Microphone Unit Type 4184-A cannot be mounted directly on the analyzer
Fig.4.5 Weatherproof Microphone Unit Type 4184-A cannot be mounted directly on the analyzer
-4
-2
0
2
4
dB
1 10 100 Hz
Electrical Response, Extended Low Frequency 'On'
Electrical Response, Extended Low Frequency 'Off'
Acoustical Response with Type 4184-A, Extended Low Frequency 'On'
Acoustical Response with Type 4184-A, Extended Low Frequency 'Off'
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