To Sub or not to Sub...?

"One man's meat is another man's poison" Nowhere is it more true than in choice of loudspeakers. What features do you look in a loudspeaker? The perfect loudspeaker doesn't exist, and many of the requirements are incompatible when applied to practical loudspeaker design. If we want one we must sacrifice another.
' 'Tinfoil' is interested in classical music. He didn't mention anything about 'explosions' home theater or for that matter size, shape and associated gear. We do not know these facts. The fact is that amount of bass, that can be fully developed in any listening room depends on the room size. The lowest frequencies that can be produced is governed by the longest room dimension and is given by: f=560:d (divide). Where f is the lowest frequency and d is longest dimension in feet. So 12ft dimension limits the response to 46Hz. It follows than that throwing out other furniture to make room for large speakers or SUB, that goes well below the room's frequency limit does no good at all!
For 'Tinfoil' purchasing best speakers he can afford is best way to start.

I just installed a home theater system consisting Paradigm active 40s with active center and surrounds they each all have their own 325 watt amp. This is supplemented by their Sub 15. This has its own 400 watt amp. The Sub is marvelous during classical listening.

The other thing to remember is what you are buying as you go up a speaker line is better bass performance. The Tweeter in all the B+W Nautilus Speakers is the same. Not everyone can afford a pair of N802 at $8000 List. A pair of N805 and a REL Stratus III Sub is $3300 List, less than a pair of $3500 N804s (maybe the same with stands). If bass performace matters to you, the N805/Stratus combo will kill a pair of N804, and probably give a $5000 pair of N803 a run for the money.
I attend over a dozen classical concerts a year and perform in another half dozen. I cannot reproduce the sound I experience in the Meyerhoff Symphony Hall and Kennedy Center without my REL Storm III sub. Not even close. My opinion is not based on any hypothetical theory about MHz, room resonances, or how the phases of the moon affect sound in Mongolia. It is based 25 years of real life listening. Even if I were to get a pair of mega dollar speakers someday, I will then start saving for a mega dollar sub to make is sound even better.

Sorry guys, my computer got excited I guess.