Despite them being two small holes, there's actually quite a bit of acoustics that goes into your ear. Consider the vibration of your skull as well as the reflections of sound waves down the ear canal. Ever considered how we're able to aurally perceive that something is behind us rather than in front of us, given the two sources can be an equal distance to the ears? Plus, as the article notes, we can also figure out if the sound is above us.
Biting the hand that feeds IT
