Theoretical analysis of musical noise generation for blind speech extraction with generalized MMSE short-time spectral amplitude estimator

In this paper, we discuss the amount of musical noise generation for blind speech extraction using minimum mean-square error short-time spectral amplitude (MMSE-STSA) estimator. To achieve high quality speech enhancement, we have previously proposed blind spatial subtraction array (BSSA). However, BSSA always suffers from artificial distortion, so-called musical noise, owing to nonlinear signal processing. Therefore, we propose the improved BSSA using the MMSE-STSA estimator and its generalized method as the post-processing part of BSSA. Also, we conduct a theoretical analysis for the amount of musical noise generation in the proposed method. From the theoretical analysis and objective evaluation results, we derive the optimal parameter for the proposed method.