Consideration on multiple body-conduction transfer functions contributing to speakers’ own voice perception

Speakers perceive their own voices, transmitted through both air-conduction (AC) and body-conduction (BC) pathways. BC voice transmission is divided into at least two different types: induction of sound in the ear canal (EC) due to vibrations of the EC wall (i.e., the outer-ear BC component) and transmission of bone/tissue vibrations to reach the middle/inner ear directly (i.e., the middle/inner-ear BC component). The author’s group has continuously attempted measuring transfer functions of those two pathways and simulating one’s own voice using the transfer functions. However, our previous attempt remained to be discussed regarding (1) methods of transfer function measurement and (2) different trends among articulation. The present study measured the acoustic transfer function between the oral cavity and the EC (which corresponds to the outer-ear BC component) and the vibration transfer function between the larynx and the condyle (which corresponds to the middle/inner-ear BC component) separately to explore amplitude and phase characteristics of the BC voice for multiple articulations. For both the former and latter transfer functions, lower frequency components (e.g., below 500 Hz) were found to be relatively preserved. Moreover, local trends of the transfer functions were found to be strongly dependent on the articulations.