G.R.A.S. 40DD 1/8" Prepolarized Pressure Microphone Date 10-06-2013. Page 1 of 4 G.R.A.S. 40DD 1/8" Prepolarized Pressure Microphone Sensitivity: 0.7 mV/Pa Freq resp: 6.5 Hz to 80 kHz Dynamic range: 40 dBA to 178 dB The 40DD is an IEC 61094 1/8" prepolarized pressure microphone with rear-venting. It is a high-precision Type 1 condenser microphone made according to IEC 61094-4 requirements. Its tiny size allows it to be used for measuring very high frequency sounds without disturbing the sound field. It can measure sound pressure levels up to 174 dB in the range of 6 Hz to 140 kHz. Introduction The 40DD is an IEC 61094 1/8" prepolarized pressure microphone with rear-venting. Read about the externally polarized equivalent.[40DP] It is a high-precision Type 1 condenser microphone made according to IEC 61094-4 requirements. Its tiny size allows it to be used for measuring very high frequency sounds without disturbing the sound field. It can measure sound pressure levels up to 174 dB in the range of 6 Hz to 140 kHz. 40DD is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity and pressure frequency response.

G.R.A.S. 40DD 1/8" Prepolarized Pressure Microphone Date 10-06-2013. Page 2 of 4 Typical applications and use The 40DD has a low sensitivity making it perfect for sound measurements at high frequencies and very high level pressure, as well as impulse noises. The 40DD is included in the 67SB Blast Probe Microphone because of its wide-frequency response. Compatibility The 40DD must be used with an adapter for mounting a 1/8" microphone onto a 1/4" preamplifier. For more information, see System Setup. System verification For daily verification and check of your measurement setup, we recommend using...

G.R.A.S. 40DD 1/8" Prepolarized Pressure Microphone Date 10-06-2013. Page 3 of 4 Depending on the use, measurement environment, and internal quality control programs, we recommend recalibrating the microphone at least once a year. Learn more about G.R.A.S.' calibration services. Specification Open-circuit sensitivity @ 250 Hz (±2 dB) Resonance frequency Dynamic range lower limit (microphone thermal noise) Dynamic range upper limit Dynamic lower limit with G.R.A.S. preamplifier Dynamic range upper limit with G.R.A.S. CCP preamplifier Microphone cartridge capacity, typical Microphone cartridge...

G.R.A.S. 40DD 1/8" Prepolarized Pressure Microphone Date 10-06-2013. Page 4 of 4 Tradition Since the establishment in 1994, G.R.A.S. have been 100% dedicated to developing and manufacturing high-quality measurement microphones and related acoustic equipment. Founded by the Danish acoustics pioneer Gunnar Rasmussen who for more than 60 years has contributed to the world of sound and vibration with his unique ideas and designs. From the first reproducible 1” condenser measurement microphone that enabled quality measurements and instrumentation for acoustic calibration, Mr. Rasmussen’s ingenuity...