Pinna frequency-shaping cues, not level cues, drive sound localization at typical angular thresholds

Evidence

This study investigated whether the frequency-shaping differences caused by changes in pinna-cue filtering across different incidence angles were discriminable by test subjects. However, the subjects did not only have the frequency shaping to listen for, but consequently also a level cue. To quantify whether the level cue was large enough for the test subjects to take advantage of it, the rms-levels were calculated for the three different cue sets. Unfortunately, the specific hearing loss of a specific test subject, and the frequency range one includes in the analysis, very much affects the rms difference between different incidence angles, making it difficult to make conclusions. However, at large angular differences it was clearly observed that the level cue becomes prominent, whereas the level cue decreased with decreasing incidence angle. At average MAAs (< 35° for HI) level-cue magnitudes (< approximately 1 dB) were found to be smaller than the level just-noticeable-differences for HI test subjects reported to be 1–2 dB (Moore 2003 ). This indicates that most subjects likely used the frequency-shaping cue rather than the level cue. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3130

Categorization

• XREF: Connects to the broader Pinna-related localization literature and to the reader’s interest in psychoacoustic mechanisms underlying spatial hearing.