A new approach to capturing and reproducing either live or recorded three-dimensional sound is described. Called MTB for "Motion-Tracked Binaural," the method employs several microphones, a head tracker, and special signal-processing procedures to combine the signals picked up by the microphones. MTB achieves a high degree of realism by effectively placing the listener's ears in the space where the sounds are occurring, moving the virtual ears in synchrony with the listener's head motions. MTB also provides a universal format for recording spatial sound.