Numerical study of the influence of the torso on the HRTF

Understanding and simplified modeling of how humans generate cues from the scattering of sounds from their bodies holds the key to many applications in spatial audio. Scattering from the torso is thought to provide cues for source localization. A simplified two-sphere model has been proposed to understand the influence of the torso, and experimental studies have been performed. The availability of a validated numerical model can enable further parametric study and improved understanding using this model. Here we provide such a numerical model using the multipole method. Our method is validated by comparison with experimental data and commercial boundary element software. We find that most features of this “snowman” HRTF are reproduced by a simple model that places the “head” in the field of the source and the scattered field from the torso.