Numerical study on the low frequency sensitivity variation of the microphone in laser-pistonphone based primary calibrations

Abstract

The low frequency sensitivity of microphone is crucial for monitoring large-scale natural and artificial activities, but is acoustically controlled by the disturbing pressure leakage and heat conduction effects in its back-chamber. This issue has been partly studied by theoretical and experimental means, and is further studied here through numerical simulations on the laser-pistonphone based primary calibration of the microphone. Firstly, the frequency response of the calibrating sound-field, affected by the disturbing pressure leakage and heat conduction effects, is studied. Independent and coupling correction values for two effects are obtained based on the proposed model comparison method. Then, joint simulations on the primary calibration process are proposed for both the vent located in the calibrating sound-field and out. Simulation results verified previous studies, and more details about the parameter adjustment of both the pistonphone and microphone affecting the diaphragm deformation and sensitivity output of the microphone are elaborated here.