Importance of window shape for phase-only reconstruction of speech

The authors recently conducted a human perception experiment to measure the intelligibility of speech stimuli synthesised either from short-time magnitude spectra or short-time phase spectra. The results of the experiment indicate that even for small window durations (of relevance for automatic speech recognition applications), the phase spectrum can contribute to speech intelligibility as much as the magnitude spectrum if the analysis-modification-synthesis parameters are properly selected. This intelligibility is significantly more than that reported by Liu et al. (1997), who carried out a similar experiment with the same analysis-modification-synthesis framework. The significant improvement in intelligibility over Liu's results may be attributed to the differences in the parameter settings adopted. In this paper, we review our previous experiment and conduct an additional experiment to determine the contribution that each parameter setting provides towards the intelligibility of stimuli reconstructed from short-time phase spectra. The parameter selection that contributes most to the intelligibility of the phase-only stimuli is that of a rectangular analysis window, as opposed to a Hamming window (which is generally used in speech analysis).