Originally Posted by rbinck
Welcome to the forum.
Actually we hear in more directions than stereo. Just like with two eyes we are able to see in more than two dimensions, with two ears we are able to hear from multiple directions. Are you saying you can't tell when a sound is from behind you as opposed to a sound in front of you?
Being able to hear from multiple directions IS stereo. We have two eyes, so we 'see in stereo' too! Two images give us a sense of depth to help with localizing the position of what we are looking at, just like with sound, two ears allow us to hear in a way in which our brains can localize the position of the sound.
Our ears hear sounds coming from all directions, and get mixed together into two tracks, left and right. So why have more channels other than L & R?