Voice conversion based on piecewise linear conversion rules of formant frequency and spectrum tilt

The paper proposes a new algorithm to convert the speech of one speaker so that it sounds like that of another. To modify formant frequencies and spectral tilt, the algorithm provides piecewise linear conversion rules which make it possible to control spectrum parameters in detail. Because the rules are statistically generated using training data, reliability of the conversion rules are guaranteed, and the rules are automatically generated for any pair of speakers. According to the conversion rules, formant frequencies and spectral tilt are modified by a formant modification algorithm based on the minimization of spectral distortion. Evaluation by listening tests shows that the proposed algorithm makes it possible to convert speaker individuality while maintaining high quality