Speech segregation using event synchronous auditory vocoder

We present a new auditory method to segregate concurrent speech sounds. The system is based on an auditory vocoder developed to resynthesize speech from an auditory Mellin representation using the vocoder STRAIGHT (Kawahara, H. et al., Speech Communication, vol.27, p.187-207, 1999). The quality of the transmitted sound is improved by introducing an event synchronous procedure to estimate glottal pulse times. The auditory representation preserves fine temporal information, unlike conventional window-based processing, which makes it possible to segregate the speech synchronously. The results show that the segregation is good even when the SNR is 0 dB; the extracted target speech was a little distorted but entirely intelligible (like telephone speech), whereas the distracter speech was reduced to a non-speech sound that was not perceptually disturbing. This auditory vocoder has potential for speech enhancement in applications such as hearing aids.