The Wide-Band Calibration of Capacitor Microphones
D.L.H. Gibbings, A V Gibson · Metrologia · 1984
The sensitivities of a group of 1-inch capacitor microphones over the audio-frequency spectrum from 39.8 Hz to 19.95 kHz have been obtained as a composite of closed-coupler response from 39.8 Hz to 1 kHz and free-field response from 316.2 Hz to 19.95 kHz. The region of overlap is low enough in frequency for it to be possible to draw convincing curves through the two sets of points which depart insignificantly from the coupler values up to 316.2 Hz and by less than 0.1 dB from the free-field values. The electrostatic actuator offers a more rapid means of routine calibration and the differences between the composite and electrostatic actuator responses have been studied. They have been found to be consistent to 0.1 dB over almost the whole range.