Syllable intelligibility for temporally filtered LPC cepstral trajectories

The intelligibility of syllables whose cepstral trajectories were temporall y filtered was measured. The speech signals were transformed to their LPC c epstral coefficients, and these coefficients were passed through different filters. These filtered trajectories were recombined with the residuals and the speech signal reconstructed. The intelligibility of the reconstructed speech segments was then measured in two perceptual experiments for Japanes e syllables. The effect of various low-pass, high-pass, and bandpass filter ing is reported, and the results summarized using a theoretical approach ba sed on the independence of the contributions in different modulation bands. The overall results suggest that speech intelligibility is not severely im paired as long as the filtered spectral components have a rate of change be tween 1 and 16 Hz. (C) 1999 Acoustical Society of America. [S0001-4966(99)0 1705-1].