Synthesis of vibrato singing

Vibrato is an important factor in the production of good quality singing of western classical songs. Vibrato is characterized by a temporal modulation of the singing pitch, as well as of the spectral structure. We are trying to synthesize singing using the large database, selection synthesis scheme. Simple waveform concatenation-modification synthesis can produce unnatural sounding vibrato sounds. A method to synthesize more natural vibrato sounds is described. This method works by ensuring that the phase of the vibrato in the original (source database) unit, used for synthesis, is consistent with the vibrato phase of the synthesized (target) vibrato sound. By doing so, the required modification of the original unit's prosody can be minimized, and the production of the characteristic vibrato spectral modulations can be improved.