Well, I must admit ever since I gota clearance/open-box deal on my PSW-350 I've been in HT (and Music) heaven. With one small problem however... My home-theater room is about 13x22 ft and the location of my chair (the 5.1 sweet spot) had a HUGE bass drop due to reflections/standing waves. The sub was about 3.5 feet from the front wall and 1 foot from the left wall beside a couch. The room was pumped with excellent bass in every place except MY CHAIR!
The Solution: I have couch parallel with the left wall. The sub was near the end of the couch nearest the front wall. I decided...hmmm....why not use an extender on my cable and put the sub on the other side of the couch....the one nearer me. BIG DIFFERENCE. Now I hear the bass I dreamed of. My friends are blown away too. The sweetspot is now my chair and all the other seats in the room. My room demands a dead-zone somewhere....now that spot is in a small area directly front of the tv screen (where no one would be sitting anyway!).
Moral of the story...if you have a rectangular room and your sweet spot is lacking in bass...try moving that sub and putting that dead-zone where it doesn't touch any of your seating. :-)