Motion-Tracked Binaural Sound for Personal Music Players

Motion-tracked binaural or MTB recording enhances headphone-based spatial sound reproduction by capturing and exploiting localization cues that result from voluntary head motion. For music reproduction, the sound field can be stabilized for any arbitrary head rotation by using sixteen microphones to sample the space around the head, and by employing the signal from a head tracker to interpolate between these channels. MTB's use of headphones makes it particularly suitable for portable music players. However, the technique must be modified to meet the special needs of this application. Methods are described for (a) converting legacy recordings to MTB format, (b) reducing the number of channels from 16 to 2.5, and (c) processing the head-tracker signal to extract head motion from the combination of head and torso motion.