Harmonic alternatives to sine-wave speech

Sine-wave speech (SWS) is a three-tone replica of speech, conventionally created by matching each constituent sinusoid in amplitude and frequency with the corresponding vocal tract resonance (formants). We propose an alternative technique of starting from a high-quality multicomponent sinusoidal representation, then decimating this model to only three components per frame. In contrast to SWS, the resulting signal contains only components that were present in the original signal. Consequently it preserves the harmonic fine structure of voiced speech. Perceptual studies indicate that this signal is judged more natural and intelligible than SWS. Furthermore, its tonal artifacts can mostly be eliminated by the introduction of only a few additional components, which leads to an intriguing speculation about grouping issues.