Most Voice Conversion (VC) systems exploit source-filter decomposition based on linear prediction (LP) to transform spectral envelopes, incurring as a result various issues related to the oversimplification of the LP voice source model. Whilst residual prediction methods can mitigate this problem, they cannot be used to modify voice source quality. In this paper, a system which employs linear transformations to convert both the spectral envelope and the LF glottal waveform is presented. Its performance is shown to be comparable to that of a state-of-the-art VC implementation in terms of speaker identity conversion but its output has better quality. In addition, it is also capable of transforming the quality of the voice source.
Bibliographic reference. Pozo, Arantza del / Young, Steve (2008): "The linear transformation of LF glottal waveforms for voice conversion", In INTERSPEECH-2008, 1457-1460.