Adaptive Frequency Response Calibration Method for Microphone Arrays

Frequency response mismatch among microphones inevitably leads to performance deterioration of signal processing algorithms of microphone arrays, especially for distributed microphone networks. An adaptive frequency response calibration method for microphone arrays based on frequency domain least mean square (FLMS) algorithm is proposed in this paper. Adaptive calibration filters are first introduced to calibrate the frequency response mismatch among microphones, which are concatenated with microphone channels. Then, the frequency response mismatch problem is formulated with a combined spectrum mean square error criterion of pairwise microphone outputs, and an unit-norm constraint is imposed to avoid undesired solutions. Finally, FLMS algorithm is used to design the calibration filter in each microphone channel. This method achieves good frequency response calibration performance even under severe ambient noise and reverberation conditions. Experimental results reveal the validity of the proposed method.