Crosstalk Cancellation System Using a Head Tracker Based on Interaural Time Differences

To accurately reproduce binaural signals through loudspeakers, proper crosstalk cancelation filters have to be added to the reproduction chain. When the crosstalk cancellation filters are time invariant, head rotations cause the perceived position of virtual sound sources to shift towards the loudspeakers’ region. Further, errors in the interaural time difference (ITD) of the reproduced virtual sound sources are more critical than errors in the interaural level differences (ILD). This suggests that to relax the location of the listener with respect to the loudspeakers and to reproduce the virtual sound sources correctly, we need to have a good knowledge of the location of the listener or the acoustical impulse responses (AIRs) between the loudspeakers and the ears of the listener. Given that the loudspeaker signals are highly correlated, doing an on-line estimation of these AIRs remains a challenging task. This paper explores the use of microphones placed close to the ears of the listener to estimate the head orientation based on ITDs. By estimating the difference between the ITD of the signals arriving at the microphones and the ITD of the desired binaural signal, the orientation angle is estimated and the crosstalk cancellation filters are updated. A model describing the relation between the ITD error and the orientation angle is presented. Two ITD estimation methods are compared and results of a preliminary evaluation of the proposed system are discussed.