Comparison of Modal Versus Delay-and-Sum Beamforming in the Context of Data-Based Binaural Synthesis

Several approaches to data-based binaural synthesis have been published that capture a sound field by means of a spherical microphone array. The captured sound field is typically decomposed into plane waves which are then auralized using head-related transfer functions (HRTFs). The decomposition into plane waves is often based on modal beamforming techniques which represent the captured sound field with respect to surface spherical harmonics. An efficient and numerically stable approximation to modal beamforming is the delay-and-sum technique. This paper compares these two beamforming techniques in the context of data-based binaural synthesis. Their frequencyand time-domain properties are investigated, as well as the perceptual properties of the resulting binaural synthesis according to a binaural model.