0 - 50 dB microphone 40AN

50 - 100 dB100 - 150 dB20+ mV/Pa

GRAS 40AN is a high-precision condenser microphone made according to IEC 61094-4 requirements. The 40AN’s design is based on the similar GRAS 40AF ½” free-field microphone, but optimized for low-frequency measurements. The cut-off frequency is as low as 0.5 Hz and obtained by modifying the equalization. 40AN is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity, pressure, and corrected free-field frequency responses. Typical applications and use The low-frequency property combined with its high sensitivity and robust design make 40AN the obvious choice for infra-sound measurements—a fast growing discipline following the need for monitoring and reducing low-frequency noise from, for example, power and production plants and the increasing number of wind turbines. Compatibility The 40AN requires a standardized ½” or ¼” LEMO preamplifier and an input module that supports this technology with a 7-pin LEMO connector. Note that to benefit from 40AN’s low frequency capabilities, it is important that the microphone preamplifier, analyzer input module, or sound level meter is designed to match 40AN. System verification For daily verification and check of your measurement setup, we recommend using a calibrator like GRAS 42AG Sound Level Calibrator. Calibration When leaving the factory, all GRAS microphones have been calibrated in a controlled laboratory environment using traceable calibration equipment. Depending on the use, measurement environment and internal quality control programs we recommend that the microphone is recalibrated at least once a year.