Binaural Hearing
Two ears beat one, localization and noise mastery
Overview
Two ears compute sound direction two ways: interaural time differences, ITDs, microseconds of arrival delay for lows, and interaural level differences, ILDs, head shadow for highs. The resulting localization acuity, 1 to 2 degrees, plus binaural squelch, brainstem noise cancellation, explains why one good ear struggles so much in restaurants. Binaural hearing also separates sources, the basis of the cocktail party effect. Single sided deafness removes all of it, why CROS and implants aim to restore two ear input.
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