Circumaural transducer arrays for binaural synthesis

Abstract

Binaural cues such as the interaural time and level differences are the primary cues for estimation of the lateral position of a sound source, but are not sufficient to determine elevation or the exact position on the "cone of confusion". Spectral content of the head-related transfer function (HRTF) provides cues that permit this discrimination, notably high frequency peaks and notches created by diffraction effects within the pinnae. For high quality binaural synthesis, HRTFs need to be individualized, matching the morphology of the listener. Typical means for this are to measure or calculate the HRTF of the listener, but these lengthy and costly methods are not feasible for general public applications. This paper presents a novel approach for HRTF individualization, separating the head and torso effect from that of the pinnae. The head/torso component is numerically modeled while the pinnae component is created using a multiple transducer array placed around each pinna. The philosophy of this method consists in trying to excite the correct localization cues provided by the diffraction of the reconstructed wave front on the listener's own pinnae. Simulations of HRTF reconstruction with various array sizes and preliminary auditory localization tests are presented.

Current Use and Future Perspectives of Spatial Audio Technologies in Electronic Travel Aids

“…Greff and Katz [159] extended the above solutions to a multiple transducer array placed around each ear (8 speakers per ear) recreating the pinna-related component of the HRTF. Simulations and subjective evaluations showed that it is possible to excite the correct localization cues provided by the diffraction of the reconstructed wave front on the listener's own pinnae, using transducer driving filters related to a simple spherical head model.…”