@faxanadu - Stereo goes far beyond that. You're not thinking from audio design perspective. Stereo promotes 2 separate channels of sound. Mono is only 1 channel of sound being transmitted to all the speakers. Let's use a live band as an example: If the band's music was in mono, all the instruments would come out of the available speakers. If it is in stereo, you can route the bass to come out of the left speaker and the guitar out of the right speaker, pan the drums (mike'd up of course) so that it's dithered between both channels to give a "centered" feel, along with the vocals. A grungy guitar and bass out of the same speaker used to distort each other's sound, which was why audio recordings switched from being mono to stereo many many years ago. Technology has gotten better since the old days, but how mono and stereo work haven't changed. Feeling a little silly now for telling me to "do my research"? Mono
@SHMUP - Yeah, as said above, MONO will transmit its 1 channel to every available output if you let it. The same sound signal will come out of every speaker. However, if you watch a movie that has surround sound, you will not hear any sound displacement.
@Rol - It's debatable. DD5 allows for a whole separate use of the subwoofer that DPL2 fails at. You'll get a lot more "theater experience" sound out of that subwoofer (explosions, etc) than DPL2 can do. From an audio programming/design side, its easier to use a program like DirectSound (part of Direct X tools) to drop an audio file into a channel and have it always played out of the assigned speaker. DPL2 takes a bit more work.