Phase estimation in speech enhancement — Unimportant, important, or impossible?

In recent years, research in the field of single channel speech enhancement has focused on the enhancement of spectral amplitudes while the noisy spectral phase was left unchanged. In this paper we review the motivation for neglecting phase estimation in the past, and why recent publications imply that the estimation of the clean speech phase may be beneficial after all. Further, we present an algorithm for blindly estimating the clean speech spectral phase from the noisy observation and show that the application of this phase estimate improves the predicted speech quality.