Modeling of non-individualized head-related transfer functions for nearby sources

Abstract

The minimum realization method was used to model the non-individualized head-related transfer functions (HRTFs) of B&K HATS (Head And Torso Simulator) type 4128C measured with a special acoustic point-source positioned at various distances within 1 m from the head center for 3D sound implementation in hand-held devices such as MP3 players and cellular phones. The interaural time delays (ITDs) at various source distances on the horizontal plane were estimated using both the Woodworth/Schlosberg and Röser ray-tracing formulas assuming the head could be modeled as a simple circle or an ellipse. Results show that the proposed modeling technique is more systematic and accurate than the conventional pole-zero modeling technique such as Shanks’ method and modeling the head as a circle provides better approximations for measured ITDs than an ellipse. It is also shown that the Röser’s formula provides better ITD estimations for nearby sources.