Measurement of sensitivity level pressure corrections for LS2P laboratory standard microphones

The corrections for the influence of atmospheric pressure on the sensitivity levels of laboratory standard microphones vary with frequency. The sensitivity level pressure corrections for Bruel and Kjaer 4180 and G.R.A.S. 40AG laboratory standard microphones were measured. Over the barometric pressure range from 94 kPa to 106 kPa, the sensitivity levels of the model 4180 and model 40AG laboratory standard microphones changed by 0.05 dB at 1 kHz and 0.12 dB at 20 kHz, respectively. Empirical equations for sensitivity level pressure corrections for the above microphones are presented.