That's an interesting idea. I guess the part that I am missing is if mame does not output data on 6 discrete channels, then re-encoding that will just produce stereo on two of the speakers and the other channels will have no sound, right? I thought for true discrete channels you need information to be encoded to those speakers. By discrete channels I am talking FL, FR, RL, RR, sub, + side or height speakers. I guess this would be a dolby PZII setup.
I think what you're suggesting would just be the same channel across 6 different speakers, possibly a LPF for the bass. But isn't that the same as if I wire the speakers in two sets of 3 and just have left right stereo directly from the computer? Also the sound card I am using has 6 channel output right on the board. Perhaps I should just try it with mame and see what happens. Thanks for the input.