Audibility of Spectral Differences in Head-Related Transfer Functions

The spatial resolution at which head-related transfer functions (HRTFs) are available is an important aspect in the implementation of three-dimensional sound. Specifically, synthesis of moving sound requires that HRTFs are sufficiently close so the simulated sound is perceived as moving smoothly. How close they must be, depends directly on how much the characteristics of neighboring HRTFs differ, and most important, when these differences become audible. Differences between HRTFs exist in the interaural delay (ITD) and in the spectral characteristics, i.e. the magnitude spectrum of the HRTFs. The present study investigates the audibility of spectral characteristics. To this purpose, binaural audibility thresholds of differences between minimum-phase representations of HRTFs are measured and evaluated.

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