Subwoofer reccomendations for B&W 805S?

I use REL S series subs. How much bass and at what level you want determines the size of sub as much as room size. Your room is large enough for quite large subs but since your main speakers will play at a reasonable but not overpowering level [I have older 805s] there is no need for very high output ones. Two are better than one but one good one will work very well. Hsu is also good, there are several others that work well. I have found that the flexibility of the RELs is very helpful and any will work in your room. Avoid their T series. Cross them over very low and you will be surprised at the improvement in sound quality.

I agree with Stanwal, check out an REL sub. I could never get a sub to integrate with my speakers until I bought an REL Storm III, which I've used with many speakers and it always sounds great; which means it really doesn't draw attention to itself, it makes the speakers themselves sound better.

Thanks for the suggestions. Another question I have is right now I'm actually in a 13 x 14 1/2 room. I have them set up on the long wall (6ft away) and sit 6 feet back. When I move to the new 17x15 room I will be setting them up on the short wall (15ft) and will have the speakers about a 1/2 foot more off the wall, and will be sitting about a 1/2 feet more back (setting them up using the cardas method) Am I going to lose much volume going into the new larger room? I like to listen pretty loud at times. (85-90db) I hope my 805s will be good enough for the room. Right now they sound great in the 13 x 14 1/2ft room.

Also I am running them at 200wpc.