Maybe it's my imagination, but we seem to be living in the golden age of subwoofers. They're getting better, smaller and cheaper! Hsu and SVS come up a lot, but AudioAdvisor.com also offers a ton of inexpensive subs from reputable manufacturers. I don't know their subs, but Energy usually makes a decent product. Their 8" model is $100. A pair of Velodyne SPLR 8" will produce bass about as well as any speaker I've ever encountered (I use 2 in my system with the Velo SMS controller) and now costs $600 per. There are probably 2 dozen choices between those price points.
My first pair of high end speakers was the Kef Corelli (ca. mid 1970s). I tried adding an M&K sub, but never got it to work right. Later I tried that sub with the ProAc Tablette. Again, no luck. Today, the Velodyne/Ohm combo I'm using works brilliantly. Sub integration is damn near perfect. Total cost for the Ohms ($1800) SPLRs ($1200) and SMS-1 ($600) is $3600. I'd be surprised to find a (non-sub) system at any price that can produce significantly better bass in my room. IMHO, the economics of high end loudspeakers are really being transformed by these developments.
Marty
PS The SMS-1 allows seamless integration of subs/mains. I've used analyzers before, but this one integrates PEQ and active x-over in a way that is uniquely effective IME. It's a truly amazing tool.
