Spectral Cue in Median-Plane Localization Based on Multiple Databases

The first pinna notch in head-related transfer function (HRTF) caused by the interaction between incident sound waves and pinna plays an important role in the median-plane localization. Based on five human subjects' HRTF databases, this work investigated the distribution of occurring frequency of the first pinna notch; furthermore, monaural loudness spectra (MLS) of HRTFs were calculated and the perceptual influences of the pinna notch were explored. Results show that (1) the occurring frequency of the first pinna notch for subjects from different populations is between 6.8 kHz and 11.6 kHz, and the standard variance is relatively stable; (2) the occurring frequency of the first pinna notch and its corresponding minimal MLS varies with elevation in a similar manner, suggesting the spectral cue for elevation localization can map from the physical level to the perceptual level; ( 3) the correlation coefficient of amplitudes between the first pinna notch and its corresponding minimal MLS reflects the nonlinearity of human auditory system to some extent.