This paper describes a new manipulation method of voice quality which is based on the STRAIGHT analysis-synthesis system. This method manipulates voice quality by changing the vocal tract area function calculated from the PARCOR coefficients. The PARCOR coefficients used in the proposed method is obtained from the auto-correlation function of the STRAIGHT spectrum. We have implemented a simple speech morphing system based on the proposed method. As a result, the morphed spectrum by the proposed method has natural spectral transition such as in human voice even if the formant frequencies of input two speech signals are very different, although the morphed spectrum by the conventional linear interpolation method has unnatural spectral transition.
Bibliographic reference. Uchimura, Yoshinori / Banno, Hideki / Itakura, Fumitada / Kawahara, Hideki (2008): "Study on manipulation method of voice quality based on the vocal tract area function", In INTERSPEECH-2008, 1084-1087.