Hey guys, I've read up a little bit about hooking two subs up, the benefits (+6 db gain if stacked, +3 db gain if not) and what not. However, there are still a few questions I have that I've seen different people answer differently, so was wondering if I could get a general concensus on them.

The first one is, I've heard how having two subs can eliminate/decrease standing waves where if you move outside the "sweet spot", the preceived sub output fluctuates. Well, with my one PSW505 hooked up, I know I'm getting that a bit in my room. I know because I tried that whole "put the sub in your seating position and crawl around the floor" trick to find the best place to put the sub, and as I moved around the floor, it would go up and down big time. The sad thing is, due to space constraints, I had to put the sub in a location that fluctuated a lot. Anyways, if I buy a second sub and locate it in a different part of the room (again, due to space constaints, it wont be a "perfectly optimized" location but at least it's on the other side of the room) would that help enlarge the sweet spot and make the flucations less apparent? Or could doing that somehow make it worse? Where the two bass waves hit each other and cancel each other out?

My second question is, I've heard some people say that it's best to get the same type of subs for dual subs. Then I've heard other people say they like to buy one large sub, one small sub, and let each handle different frequencies. Which should it be?

Last quick question: Barring aside whatever the answer is to question #2, is it okay to have two subs from different manufactors as dual subs? I mean, I like Polk speakers, but their subs aren't exactly... the most well regarded. The only reason I got it is cuz I could get it REAL cheap. Actually, originally I was interested in replacing the sub with a better one but then I thought about dual subs. Would pairing the 505 with a HSU or SVS mismatch the system audio wise?