The 40BH is an IEC 61094 WS3P ?" externally polarized high-pressure microphone with rear-venting.

40BH is a high-precision condenser microphone made according to IEC 61094-4 requirements. Its very low sensitivity and wide frequency response make it ideal for measuring very high sound pressure levels of up to 194 dB. It is extremely robust and reliable and can handle acoustic impulse measurements in frequencies of up to 20 kHz.

40BH is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity and pressure frequency response.

40BH is typically used for sound pressure, very high level measurements, and impulse-sound measurements. It is suitable for general purpose acoustic measurements in couplers and at boundaries.

The 40BH is a very versatile microphone when connected to the RA0086 Transmitter Adapter for ?" Microphones. The 40BH becomes a high-impedance sound source when the RA0086 takes a calibration signal directly from the signal generator and makes the microphone behave like an electrostatic loudspeaker. When used for calibrating an acoustic coupler, this gives a frequency response that is as good as when the 40BH behaves like a microphone.

The 40BH requires a standardized ?" or ?" LEMO preamplifier and an input module that supports this technology with a 7-pin LEMO connector.

For daily verification and check of your measurement setup, we recommend using a calibrator like GRAS Sound Level Calibrator 42AG.