Contribution
IIR Modeling of HRTFs in the Spherical Harmonic Domain
* Presenting author
Abstract:
Head-related transfer functions (HRTFs) describe the acoustical transfer functions from a sound source to the human ears in a free field.In this paper, HRTFs are modeled by using parallel combination of IIR filters. This approach is motivated by the fact that transfer functions of a point source evaluated on a rigid sphere are characterized by a set of poles and zeros in the Laplace domain. Given that the shape of the human head is more closely approximated by an ellipsoid than a sphere, it is assumed that the spherical harmonic responses of a HRTF dataset can be modeled by a combination of rigid sphere responses of varying radii. The impulse responses of the individual spherical harmonic components are modeled by poles corresponding to the rigid sphere models that are subject to different delays. The residuals not accounted for by the scattering of a sphere may optionally be modeled by an FIR part, which characterizes other direction-dependent effects such as pinna or shoulder reflections. The proposed approach is applied to a generic HRTF dataset, and the resulting accuracy is evaluated for varying modeling parameters.