Subjective evaluations for perception of speaker identity through acoustic feature transplantations

Perception of speaker identity is an important characteristic of the human auditory system. This paper describes a subjective test for the investigation of the relevance of four acoustic features in this process: vocal tract, pitch, duration, and energy. PSOLA based methods provide the framework for the transplantations of these acoustic features between two speakers. The test database consists of different combinations of transplantation outputs obtained from a database of 8 speakers. Subjective decisions on speaker similarity indicate that the vocal tract is the most relevant feature for single feature transplantations. Pitch and duration possess similar significance whereas the energy is the least important acoustic feature. Vocal tract + pitch + duration transplantation results in the highest similarity to the target speaker. Vocal tract + pitch, vocal tract + duration + energy and vocal tract + duration transplantations also yield convincing results in transformation of the perceived speaker identity.