3D-continuous-azimuth acquisition of head-related impulse responses using multi-channel adaptive filtering

A new method for fast acquisition of head-related impulse responses (HRIRs) for 3D-continuous-azimuth representation of the auditory sphere is presented. While the continuous HRIR representation in the azimuth direction is important for the rendering of moving sources in binaural sound systems, an HRIR discretization in the elevation is more tolerable. Basically, the paper suggests a multi-channel adaptive system identification technique which is eventually suitable for online calculation of HRIRs. In a first step, several discrete elevations of the sphere are equipped with sound sources and a subject of interest is rotated in the center of the sphere during simultaneous reproduction of multi-channel probe noise. On the basis of the simultaneous binaural recording of all sources, the rotating HRIRs are then extracted gradually by the adaptive system identification. This concept overcomes discrete-azimuth HRIR tables and their traditional need for interpolation. While the quality of HRIRs was formerly expressed in terms of the azimuth-spacing of the HRIR, we now feature quasi-infinite resolution.