Bass is also non-directional so that's why Dolby Digital can send all of the bass to one sub (and why Bose systems can have the bass module hidden behind a sofa). I think that most music compression techniques (ala mp3s in the empeg) convert the bass to mono because it's hard to detect but will save on bit rate.

Anyway, that's a bit off topic. I didn't really think of the speaker placement that way - it makes sense.

I'm loving this thread, this topic is one of the very first posts I made "way back when" and it looks like it can happen. The other was cross-fading and that looks like it's on the distant horizon too. woohoo!