I have the EP500 and find it to be a truly exceptional sub. Before I purchased it though I had purchased a 10" sub driver to build my own sub. I finally got around to completing the project. All the parts came from Parts Express. My room size is 20' x 13' by 7'8" with two semi-open areas giving me about 2200 cubic feet of space including the open areas. The Ep500 filled the sapce without any trouble at all. Since I already had the parts for the second sub I went ahead and built it and placed it behind my couch along the back wall. After some tweaking now the bass response is fuller and even less directional than before. Especially when seted on the couch. Even though you couldn't really tell where the EP500 was located by itself, you could determine that it was situated towards the front of the room. Now with the second sub the bass comes at you from all directions more evenly and sounds more even. Not to mention having the second sub behind the couch adds to the vibrations of loud explosions that you can feel. Since I have a 7.1 system and all the other sounds come from all the other directions in the room, having the bass do the same thing adds to the movie wathcing experience. Plus, this second sub, which can really put out some serious bass on it's own, only cost me a little over $400.00. So in my opinion having a second sub of relatively decent quality is worth having.
