Pinna reflections form comb filters encoding sound direction in three dimensions

Evidence

These pinnae reflections will be delayed, by a very small but significant amount, and so will form comb filter interference effects on the sound the ear receives. The delay that a sound wave experiences will be a function of its direction of arrival, in all three dimensions, and we can use these cues to help resolve the ambiguities in direction that are not resolved by the main directional hearing mechanism. The delays are very small and so these effects occur at high audio frequencies, typically above 5 kHz. — David Howard, Jamie Angus, coustics and Psychoacoustics, 728

Categorization

• DEFINE: Comb filter interference from pinna reflections is the standard explanation of HRTF-based directional cues.