Ok, I need a good sub. I want one in the $400 price range. I have a Sony 5.1 surround that came in one box 3 years ago for $500 and a Sony 51" HDTV. I know this isnt great but it will do for now. I will gradually upgrade. My sub that came with it just isn't good for me. My room is about 21' x 13' Tv on the 21' side. At the other end there is a double door way with doors that can be closed and on one 13' side there is a reg. door that goes to the kitchen. My current sub is on the side with the door to the left of the tv in the corner. I was looking at the SVS PB10-ISD an wondered if I could go wrong with this sub. I know my speakers need upgrading but it's not happening just yet. Would this sub be right for me? I want it for mainly DVD, TV and Xbox 360. Help me out.