  In this paper, we introduce a novel approach for effectively reducing
nonlinear distortion in single back-plate condenser microphones, i.e., most
MEMS microphones, studio recording condenser microphones, and laboratory
measurement microphones. This simple post-processing technique can be easily
integrated on an external hardware such as an analog circuit, microcontroller,
audio codec, DSP unit, or within the ASIC chip in a case of MEMS microphones.
It significantly reduces microphone distortion across its frequency and dynamic
range. It relies on a single parameter, which can be derived from either the
microphone's physical parameters or a straightforward measurement presented in
this paper. An optimal estimate of this parameter achieves the best distortion
reduction, whereas overestimating it never increases distortion beyond the
original level. The technique was tested on a MEMS microphone. Our findings
indicate that for harmonic excitation the proposed technique reduces the second
harmonic by approximately 40 dB, leading to a significant reduction in the
Total Harmonic Distortion (THD). The efficiency of the distortion reduction
technique for more complex signals is demonstrated through two-tone and
multitone experiments, where second-order intermodulation products are reduced
by at least 20 dB.
