Abstract: Spatialization of soundfields is accomplished by filtering audio signals using filters having unvarying frequency response characteristics and amplifying signals using amplifier gains adapted in response to signals representing sound source location and/or listener position. The filters are derived using a singular value decomposition process which finds the best set of component impulse responses to approximate a given target set of impulse responses corresponding to head related transfer functions. Efficient implementations for rendering reflection effects, air absorption losses and other ambient effects, and for spatializing multiple sound sources and/or generating multiple output signals are disclosed.

Abstract: A method and apparatus is capable of accurately deriving acoustic transfer functions such as head-related transfer functions (HRTF) at low cost. Various aspects of the invention include constraining the reflection geometry of a measurement system to facilitate removal of reflection effects, establishing ambient noise level and ambient reverberation time to calibrate test signals, generating soundfields using Golay code test signals, invalidating measurements by detecting test subject movement and short-duration ambient sounds, deriving distance and/or interaural time difference (ITD) using minimum-phase forms of impulse responses, and deriving equalized HRTF suitable for use in acoustic displays without knowing output or input transducer acoustical properties. Spatial resampling of derived HRTF and spectral shaping of test signals are discussed.