Robust low-complexity multichannel equalization for dereverberation

Multichannel equalization of acoustic impulse responses (AIRs) is an important approach for dereverberation. Since AIRs are inevitably estimated with system identification error (SIE), it is necessary to develop equalization designs that are robust to such SIE, in order for dereverberation processing to be beneficial. We present here a novel subband equalizer employing the relaxed multichannel least squares (RMCLS) algorithm in each subband. We show that this new structure brings improved performance in dereverberation as well as a reduction in computational load by up to a factor of more than 90 in our experiments. We then develop a novel controller for the dereverberation processing in subbands that guarantees robustness to even very severe SIEs by backing off dereverberation in any subband with excessively high levels of SIEs.