If this has all been done here, just tell me and post a link or two, but here it goes.

In response to my suggestion to use a sub with all but giant cabinets flat to 30hz, Bo correctly pointed this out:
Which in my opinion, sound far less musical. They got "thump", but nothing else...
I responded with this:
I mean a really nice, musical sub, like a good Canton or a 2245H large box powered by a first class amp. I have two 2245H cores on hand, so I may get there eventually. The Cantons, like the Vento AS 850 SX, are out of my price range. I totally agree that most subs are better left in the store.
Well look at this :
The VMPS program includes Subwoofers, all passive (i.e. no builtin amplifier), all quite substantial size and weight (the "Dedicated" Sub is the baby at 38kg), all requiring no equalization to pump out bass in the teens and twenties, and all easy to add to any system via the existing main amplifier and our optional Passive Crossovers, or via the biamp route with an outboard Electronic or Passive Crossover and a separate drive amplifier. Typically, the distortion of our Subs is an order of magnitude lower than the competition. We invented the slot-loaded passive radiator in 1979. It remains a feature in all our Subs and Towers, a push-pull, high efficiency means of generating first octave bass with high input sensitivity. Look at the competition, particularly the "powered" subwoofers, and see why we point with pride to our products. The amplifiers in virtually all "powered" woofers are dreadful Class B or (even worse) Class D designs which no self-respecting audiophile would tolerate anywhere else in his system. Indeed, the high power Class D amps in some very expensive subwoofers, which we have examined and tested at length, are the worst measuring, worst performing (unable to reproduce even a good sine wave), worst sounding amplifiers we have encountered in the past 30 years. Cheap, bad amps combined with equalization (which robs the sub of dynamic range), limiters (100dB to 104dB max SPL), and high moving mass (up to two pounds in some subs) make most modern powered subwoofers little more than a joke, suitable only for reproducing sound effects.
From here http://www.vmpsaudio.com/aboutVMPS.htm

Bearing in mind advertisement hyperbole, this still sounds like a pretty accurate assessment of the products usually found in stores. Does anyone have a sub as good as it should be, beside the vintage big B series JBL's? Does the Performance Series, for instance, boast a sub that is HiFi worthy, not just for movies? And does it have high sensitivity like all good speakers should?

I am running an old home built (not in my home) 10 inch sealed box passive sub, and it sounds better to me than anything I have heard in stores, excepting those pricey Cantons. It has a half roll foam surround, very compliant.

Clark