GRAS 40BP-FV 1/4″ Ext. Polarized Pressure Microphone GRAS 40BP-FV 4Hz~70kHz

Introduction

• The 40BP-FV is an IEC 61094 WS3P 1/4″ externally polarized pressure microphone with front venting.
• It is a high-precision condenser microphone made according to IEC 61094-4 requirements. It is a low-sensitivity microphone for sound measurements at high levels and high frequencies. Its low sensitivity makes it ideal for measuring high sound pressure levels of up to 174 dB. Its small size reduces the effects of diffraction and reflections around the microphone resulting in a frequency range extending up to 70 kHz.
• 40BP-FV is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity and pressure frequency response.

Typical applications and use

• 40BP-FV is typically used for sound pressure, high frequency, and high level pressure measurements. It is suitable for general purpose acoustic measurements in couplers and at boundaries.
• The 40BP-FV is a very versatile microphone when connected to the RA0086 Transmitter Adapter for 1/4″ Microphones. The 40BP-FV 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 40BP-FV behaves like a microphone.

Compatibility

• The 40BP-FV requires a standardized 1/2″ or 1/4″ LEMO preamplifier and an input module that supports this technology with a 7-pin LEMO connector.

System verification

• For daily verification and check of your measurement setup, we recommend using a calibrator like GRAS Sound Level Calibrator 42AG
• For proper sensitivity calibration, we recommend using a pistonphone like GRAS Intelligent Pistonphone 42AP