IET Labs 1986 Omnical, User And Service Manual

Page: 11 / 105

3
1986
Condensed Operation
Table A
MICROPHONE CORRECTIONS*
1·kHz 2-kHz 4-kHz
Microphone GR Adaptor Correction Correction Correction
Mfr.& Type Used (dB) (dB) (dB)
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Random-Incidence-Response
Microphones:
GR 1961-9610 or -9601
none 0.0 0.1 1.2
(1 in. electret)
GR 1962-9610 or -9601
1987-7061 0.0 0.1 1.0
( 1/2 in. electret)
GR 1971 (1 in. ceramic)
none 0.0 0.1 1.2
GR 1983 Sound-Level Meter 1987-7061 0.0 0.2 1.1
(1/2 in. ceramic)
GR 1954 Noise Dosimeter
1987-7076 & 0.0 0.1 0.5
(3/8 in. ceramic) 1987-7095
Shure Bros. Model 98108 1987-7066 0.0 --- ---
(1-1/8 in. ceramic)
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Perpendicular-Incidenc
e
Response Microphones:
GR 1961-9611 or -9602
none 0.3 1.0 3.5
(1 in. electret)
GR 1962-9611 or -9602
1987-7061 0.1 0.4 1.8
(1/2 in. electret)
B & K 4131/45 (1 in. condenser)
5855-6920 0.3 1.2 3.5
(O-ring)
B & K 4133/65 (1/2 in. condenser)
1987-2050 0.0 0.3 1.0
B & K 4135 (1/4 in. condenser) 1987-2060 0.0 0.0 -0.2
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Pressure-Response Microphones (GRID ON)
Western Electric 640AA, none 0.0 -0.2 -0.5
B & K 4160 (1 in. condenser)
Tokyo Riko MR103
none 0.0 -0.2 - 0.5
(1 in. condenser)
B & K 4132** (1 in. condenser)
5855-6920 0.0 0.2 0.6
(O-ring)
B & K 4134 (1 /2 in. condenser)
1987-2050 0.0 0.0 0.2
B & K 4136 (1/4 in. condenser) 1987-2060 0.0 0.0 -0.4
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* Measurement Conditions: Atmospheric Pressure, 760 mm (30 in.) of Hg., Temperature, +20°C (68°F).
** Additional microphone-volume corrections required at lower frequencies; refer to Table 2-13.