the duplex theory of sound localization

The duplex theory of sound localization explains how we determine where a sound is coming from using two cues: the timing and the loudness difference between our ears. When a sound reaches one ear slightly before the other, we can tell the direction based on the tiny delay. Additionally, if the sound is louder in one ear, we perceive it as coming from that side. Our brain combines these two clues—interaural time difference and interaural level difference—to accurately locate sounds in space, especially for high-frequency sounds.