Interaural time and level differences (ITD and ILD) for the Neumann KU100 dummy head, rotated from right to left in a quiet anechoic chamber. Positive differences reflect positive azimuths. Negative differences reflect negative azimuths.
● 400 Hz: ITD varies in an orderly manner across all azimuths. ILDs at peripheral azimuths are small regardless of azimuth (~3 dB).
● 600 Hz: Signal phase must be ‘unwrapped’ (modulo 2π) for ITD to vary in an orderly manner with azimuth. ITD is therefore spatially ambiguous for pure-tones and azimuths beyond ± ~45°. ILDs at peripheral azimuths are larger than at 400 Hz (~5 dB).
● 800 Hz: ITD is spatially ambiguous beyond ± ~25°. ILDs at peripheral azimuths are larger than at 600 Hz (~8 dB).
● 50 Hz - 6,000 Hz: Positive and negative ITDs and ILDs are shown, respectively, by red and blue colors. Spatially ambiguous ITDs are indicated by regions where red colors (positive ITDs) are to the left of blue colors (negative ITDs). ILDs increase above ~500 Hz and are pronounced above ~1,500 Hz.
Interaural differences were computed from Fourier transformations of head-related impulses responses (HRIR) made available by the Institute of Communication Systems, University of Applied Sciences.