Effect of Loudspeaker Position on the Robustness of Acoustic Crosstalk Cancellation

Acoustic crosstalk cancellation is a signal processing technique whereby two (or possibly more) loudspeakers are used to deliver desired signals exactly at the listener's ears. Such a system is useful for 3D audio applications, and removes the requirement for the listener to wear headphones. However, crosstalkk cancelers are notoriously non-robust to slight movements in head position. Recently, a system consisting of two closely-spaced loudspeakers (referred to as the "stereo-dipole") has been proposed to improve the robustness of the crosstalk canceler, although no rigorous analysis of its performance has been presented. In this paper, we perform a mathematical analysis of why placing loudspeakers closer together improves robustness, and present a method for determining the best loudspeaker position to use in a given situation.