A comparative study of voice conversion techniques: A review

Speaker identity, the sound of a person's voice, is one of the most important characteristics in human communication. Voice conversion (VC) is an emergent problem in voice and speech processing that deals with the process of modifying a speaker's identity. More particularly, the speech signal spoken by the source speaker is modified to sound a sifit had been pronounced by another speaker, referred to as the target speaker. A variety of VC techniques has been proposed since the first appearance of the voice conversion problem. The choice among those techniques represents a compromise between the similarity of the converted voice to the target voice and the quality of the output speech signal, both rated by the used technique. In this paper, we review a comprehensive state-of-the-art of voice conversion techniques while pointing out their advantages and disadvantages. These techniques will be applied in significant and most versatile areas of speech technology; applications that are far beyond speech synthesis.