Operating from ICP sensor power, the Model 377A21 prepolarized, ½-in. RI (random incidence) response microphone from PCB Piezotronics provides a linear frequency range of 4 Hz to 20 kHz (2 dB). Most ½-in. RI response microphones are limited to a maximum frequency of 12 kHz and cannot be used in applications where the full audible range is required.
The Model 377A21 is specifically designed for applications that require the measurement of diffuse sounds or the total sound coming from different locations. Such applications include automobile and aerospace cabin testing, environmental tests with sound-level meters, and reverb chamber testing. The 3% distortion factor of the 377A21 microphone, which is the maximum amplitude that a microphone can measure and still be linear, was increased from 146 dB (re 20 µPa) to 155 dB. This increased amplitude, in combination with the low noise floor rating of 20 dBA, makes this microphone a suitable choice for many aerospace, automotive, and military applications.
