Specifications 4231

STANDARDS SATISFIED:
IEC 942 (1988), Sound Calibrators, Class 1
ANSI S1.40–1984 (R 1997), Specifications for
Acoustic Calibrators
NOMINAL SOUND PRESSURE LEVEL:
94.0 dB ±0.2 dB or 114.0 dB ±0.2 dB re 20 mPa
at reference conditions
FREQUENCY: 1kHz ±0.1%
SPECIFIED MICROPHONE TYPES:
(Conforms to IEC 942 Class 1)
Brüel &Kjær (and similar types) 1² and 1/2², 1/4²,
1/8² with adaptors
EQUIVALENT FREE-FIELD LEVEL:
(0° incidence, re Nominal Sound Pressure Level)
–0.15 dB for 1/2² Brüel & Kjær Microphones. See
the 4231 User Manual for other microphones
EQUIVALENT RANDOM INCIDENCE LEVEL:
(re Nominal Sound Pressure Level)
+0.0 dB for 1², 1/2², 1/4² and 1/8² Brüel &Kjær
Microphones.
NOMINAL EFFECTIVE COUPLER VOLUME:
>200 cm3 at reference conditions
TOTAL HARMONIC DISTORTION (THD): <1%
LEVEL STABILITY:
Stabilization Time: 5 s
Short-term: Better than 0.02 dB (as specified in
IEC 942)
1 Year: Better than 0.05 dB
REFERENCE CONDITIONS:
Ambient Temperature: 20°C (68°F)
Ambient Pressure: 1013 hPa
Ambient Humidity: 65%RH
Load: Microphone Type 4134 (effective load volume:
0.25cm3)