I have a vivid memory of playing Doom 2 on a 486 in the 90's, hiding in a building with a cyberdemon circling around the outside, and being able to tell exactly where he was based on sound alone. Needless to say Doom produced no more than 2 channels of audio.

Interestingly Doom's audio code was licensed from a third party. When they open sourced it, they had to rewrite that part; I think Carmack said he backported Quake's code. I wonder if that third-party code was just really good or something.