TS - you amp - can it process DTs / DD or just plain old analog Pro-Logic? If it's old technology pro-logic, use the 3-stereo function ... coz it's twaeked for front 3 speaker system + sub, without rear speakers. But if you're ok with no surround in Pro-logic, it won't sound too bad as long as you have decent sounding subs.

And I believe a soundbar needs a squarish room to get the soundwaves to be reflected properly in order to get decent surround sound. If you ahve too big a space that can't bounce sound, you won't feel surround...

just my 2-sen