A spatial sound processor for headphone and loudspeaker reproduction

Abstract

A spatial sound processor for stereo headphone and loudspeaker reproduction is described that can position sound elements within a three‐dimensional reverberant space surrounding the listener. Spatial motion of sound sources in three dimensions is created by dynamic filtering based on head‐related transfer functions. Additional filters and delay lines capture air absorption and Doppler shifting as the propagation time is manipulated for both direct and indirect sound. The spatiotemporal distribution of early reflections is captured for a given source/listener orientation: The gain, delay, and directional filtering of simulated reflections are responsive to changes in the specified position and orientation of the sound source and the listener's head in the simulated environment. The spatial processor can be used for headphone reproduction using a head‐tracking device, and can also be used in more typical reproduction settings such as living rooms with stereo loudspeakers. In the latter case, additional processing is employed to stabilize the stereo image and produce a spatially diffuse reverberant surround effect over a wide range of listening positions.