A METHOD FOR BINAURAL SOUND REPRODUCTION WITH WIDER LISTENING AREA USING TWO LOUDSPEAKERS

Crosstalk cancellation is a technique for binaural sound reproduction using two loudspeakers. Crosstalk cancellation filters are formulated for a binaural sound to be reproduced at the positions of the ears of a listener. The drawback of crosstalk cancellation is the narrowness of the listening area, that is, the quality of the reproduction is sensitive to the movement of the head. A new method that achieves wider listening area is proposed. In this method, filters are formulated for not the binaural sound itself but its interaural complex sound pressure ratio (IACR) to be approximately reproduced at plural listening positions. It is assumed that the listener can perceive a virtual sound source in the nearly identical direction by reproducing the IACR. Compared with trying to reproduce the binaural sound itself, the error amount of the reproduction is small in the case of trying to reproduce the IACR at the listening positions. The sound image the listener perceives is almost unchanged even if about 10 centimeters head movement occurs, so the head positioning is easier than that of crosstalk cancellation. The reproduction demonstrations have held using loudspeakers below a TV display, USB loudspeakers connected to a personal computer, and built-in loudspeakers of a personal computer, a handheld game console, and a tablet computer, for many listeners to enjoy the virtual sound effects of the binaural sounds.