An optimal control point method for cross talk cancellation

Spatial audio is critical for improving immersive experience in various virtual and augmented reality applications. Cross-talk cancellation (CTC) is required to deliver binaural audio through loudspeakers to people’s two ears discretely. Various CTC methods have been widely studied in literature, among which the optimal source distribution (OSD) is a popular one. By analyzing the singular values of the plat matrix, the OSD method chooses the loudspeaker positions that lead to an optimally conditioned system. Theoretically, an infinite number of continuously distributed sound sources are required in the OSD method, but in practical implementations, several pairs of discrete loudspeakers are used, with each pair controlling sound in a frequency band. Instead of changing the sound source positions in the OSD method, this paper proposes an alternative optimal control point distribution (OCPD) approach using a single pair of loudspeakers at fixed locations, where the control point can move freely. Theoretical analysis shows that although the control points are away from the evaluation points (two ears), the performance of the CTC system can be dramatically improved as long as the control points are properly chosen. Numerical simulations demonstrate that the proposed OCPD approach can achieve similar performance to the OSD method with only two loudspeakers.