Modulation Domain Spectral Subtraction for Speech Enhancement

In this paper we investigate the modulation domain as an alter-native to the acoustic domain for speech enhancement. More specifically, we wish to determine how competitive the mod-ulation domain is for spectral subtraction as compared to the acoustic domain. For this purpose, we extend the traditional analysis-modification-synthesis framework to include modula-tion domain processing. We then compensate the noisy mod-ulation spectrum for additive noise distortion by applying the spectral subtraction algorithm in the modulation domain. Us-ing subjective listening tests and objective speech quality eval-uation we show that the proposed method results in improved speech quality. Furthermore, applying spectral subtraction in the modulation domain does not introduce the musical noise ar-tifacts that are typically present after acoustic domain spectral subtraction. The proposed method also achieves better back-ground noise reduction than the MMSE method. Index Terms: speech enhancement, spectral subtraction, mod-ulation domain, analysis-modification-synthesis (AMS