The 40BD is an IEC 61094 WS3P ¼″ prepolarized pressure microphone with rear-venting. It is a high-precision condenser microphone made according to IEC 61094-4 requirements. Its low sensitivity makes it ideal for sound measurements at 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 that extends up to 70 kHz. NOTE: Optimized for use without protection grid—remove grid before measuring.

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

NOTE: At low frequencies, protection grids are acoustically transparent; however, around 20 kHz and above, protection grids can act as resonators and influence the frequency response. So for higher frequency measurements, ¼ ″ and ⅛ ″ microphones have been optimized for use without the protection grid. Please remove the protection grid when measuring.