Altered pinna: exploring shape change of pinna for perception and illusion of sound direction change

Abstract

This study demonstrates that by opening and closing the human pinna, we can change the direction of sound perceived by humans. Each ear was independently transformed into a 100% open, 50% open, and 100% closed state, and all 9 combinations of these ear transformations were tested to evaluate the perceived direction of the sound output from 7 speakers placed 180 degrees around the subject. We demonstrate that by deforming the pinna, we could change the perception of the direction of sound, or make it illusory. We also found that except for 1 out of 7 speakers (or directions of sound), closing 100% of the ear on the side of the speaker where the sound is coming from and 50% of the ear on the other side of the speaker tends produce the most alteration to the perceived direction of sound.