Proc. of the Western Pacific Acoustics Conference (WESPAC), Seoul, 2006 (Invited Paper)
Temporally enhanced speech is more intelligible in reverberant environments
T. Arai and N. Hodoshima
Abstract: Reverberation causes degradation in speech comprehension, especially for elderly people, the hearing-impaired and non-native listeners. In order to prevent intelligibility degradation, we developed several pre-processing techniques, where signals are processed before being radiated through the loudspeakers of a public address system. The two main techniques are modulation filtering and steady-state suppression, both of which enhance the temporal dynamics of speech. Previously we had found that the important frequencies of temporal dynamics for speech perception, the modulation frequencies, lie between 1-16 Hz (Arai et al., 1999). Therefore, we configured the modulation filtering to emphasize these modulation frequencies (Kusumoto et al., 2005). In this paper, we mainly discussed steady-state suppression (Arai et al., 2001, 2002), which suppresses steady-state portions of speech to reduce overlap-masking and improve speech intelligibility for young, elderly, and non-native listeners in reverberant environments (Hodoshima et al., 2006a; Miyauchi et al., 2005; Hodoshima et al., 2006b). Especially, we discussed how the “pre-processing” technique, such as the steady-state suppression, is effective with recent results including speech-rate slowing with the steady-state suppression exceeding a simple speech-rate slowing approach (Arai et al., 2005).
Keywords: Speech enhancement, Reverberation, Speech Intelligibility, Steady-State Suppression