A Numerical Study Into Perceptually-Weighted Spectral Differences Between Differently-Spaced Hrtfs

Spatial audio rendering techniques often make assumptions about head-related transfer functions to simplify the reproduction process, however, state-of-the-art techniques require critical consideration of the transfer function accuracy. This paper uses boundary-element method HRTFs to investigate the perceptual spectral differences (PSD) that arise with distance and angle discrepancies. PSD between HRTFs at various radial distances is calculated, and between HRTFs in head- and ear-centred systems as function of radial distance. The distance at which the average and maximum PSD falls below the threshold of perception is determined. HRTF average variation reaches perceptual limits by 2-3m, however, perceivable PSD values occur up to and beyond 10m, indicating care must be taken when approximating either the distance or angular location of HRTFs.