I think it was Hugo Zucarelli, the inventor of Holophonics, the recording system used for albums by Roger Waters and Pink Floyd, who discovered that the human ear generates a sound of a specific frequency which it uses through interference to discern the spatial location of a sound source. This has always been a mystery as to how, besides knowing if a sound is to our left or right, we can also tell if it comes from behind or in front of us, above or below us, which should be impossible with just two ears on the sides of our head.