1 Integrating Speaker-nonspecific Timbre Transformation to an HNM Based Speech Synthesis Scheme

In this paper, a speech signal synthesis scheme based on harmonic-plus-noise model (HNM) is extended to provide the function of speaker-nonspecific timbre transformation. To transform synthetic speech’s timbre, we have developed a formant based frequency mapping method called piece-wise linear frequency mapping (PLFM). Additionally, a commonly adopted method is frequency axis scaling (FAS). Both methods have been integrated into the HNM based signal synthesis scheme, and a real-time speech synthesis system has been implemented according to this scheme. By using the speech files synthesized, perception tests are conducted. The results show that the proposed scheme can indeed transform the source timbre of a female adult into the timbre of a male adult, boy, or girl. In addition, the method PLFM is shown to be better than FAS in obtaining more masculine timbre