I only have 2 channel tests :/
Though I can get all speakers to work through other programs (Firefox, VLC, Foobar, etc).
My assumption is that the issue lies within Media Center somehow
EDIT: Actually I think the program may just be cloning the side channels but outputting louder on the given sides. If that doesn't make sense let me explain... I have multiple 5.1 test files (sound and video). One is a voice that speaks through each speaker one after the other, but I noticed the voice speaks in the left LOUDER, but also in the right. The rear speakers have the same thing, but the center works fine and no other speakers make noise during this time.
My official Dolby surround test is a video that plays different ambient-like sounds through each speaker one at a time, then all at once. I hear the tracks the same way as with the other test. In both tests the subwoofer is silent.
In movies it's very hard to really tell if this effect is still occurring. I threw in V for Vendetta as I had it the closest to me and watched the scene in the beginning with the explosions and while it sounded good, I'm not sure if the problem was present or not. Could it be I have to configure windows in something other way for this to work properly? If so, any ideas on how?
EDIT 2: Tried the same tests through VLC - the sound test only played through the front speakers, but the video test played through all but the sub. Oddly enough my sub will work through Firefox still