Best Subwoofer for B&W 805s Speakers


As many might know the B&W 805s speakers lack bass and I am trying to find a subwoofer under $1000 that would integrate well these speakers. I've been doing a lot of research on the web and there are too many choices out there (SVS, HSU, AV123, EPIK...) and I can't seem to decide. This is srictly for a 2 channel stereo system so no HT. My Equipment is all Rotel. Any suggestions? Thanks.
fast_944t
I never knew I needed a crossover, I guess that shows my inexperience. The SVS SB12 plus is one of the first subs I looked at, the word on the street I got was SVS was better for HT than music, the HSU(VTF 2.3 or 3.3) was better for music. How do I know whether I need a crossover with a sub for future reference? I already tried out the Martin Logan Dynamo and it didn't sound too bad. I'd like to thanks everyone for their input.
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Anyone have any feedback on the Robert Acoustics Vigor? They have B-stocks on sale for $549.