Something I deal with a lot in games is putting sounds into a 3D space and attempting to make that sound realistic.
To make a sound truely sound as if its behind, above you, round a corner etc surround sound systems and mixing using API middleware such as FMOD or WWISE is pretty much the best we have on offer. Any of you that play COD for example will probably know that investing in 5.1 surround sound headphones puts you at a distinct advantage in Death Match.
This is an article I came across a while ago I thought might be interesting. A rocket scientist in his spare time has come up with a way to enhance the stereo field making it more 3D using only an algorhythm to remove the cross talk between the left and right speakers.
Many games companies are eager to get their hands on this but it also has musical application and can already improve the spacial elements within existing material, let alone what someone can do mixing specifically with it in place.
It got me to thinking I wonder how many have mixed to their music 5.1 or even concidered it? I know I have only done it when working to film and then it was mostly FX and foley that got moved about in the mix in the main the music remained stereo.
Anyway check out the aritcle…
http://www.ifc.com/news/2011/05/rocket-scientist-makes-breakth.php
http://blog.dubspot.com/surround-sound-systems-for-live-performance-zemi17-interview/
Recent surround sound installation