Best Home Theater sub or subs for a large room

A single JL Audio sub woofer would be where I would start with wiring for additional subs to come in later. The JL audio sub woofers are amazing.

Two I would spend less money on fancy seats and put more money into the components.

I checked out the Bradford Wells site, other than a very nice looking site their theaters are nothing spectacular and quite frankly illustrate a lack of knowledge about what current state of the art products and room tuning is all about.

For starters no one who is building a state of the art theater today will recommend a micro perf screen from anybody! There are much more acoustically transparent screens out there which have 1.5 db reduction of high frequencies, no moire, and no comb filtering effects.

Also an M&K or even a Genelec based Theater is second best to a JBL Synthesis or other Horn based systems.

Many of the seats in their pictures look like high back recliners which are a no no in a real theater.

There is no mention of tactile transducers, power conditioning, real acoustical treatments, proper cabling etc. This is a great deal of looking good.

If you want to really get your monies worth hire a real home theater professional.

If you have the ability, the Infinite Baffle sub systems are the way to go. The is a forum called "Infinitely Baffled" that has tons of info, and I did it in my room, which is a couple feet narrower than yours. I used (4) 15" drivers in 2 manifolds in the floor, the bass is better that any sub I ever owned (Velo, Def Tech, Earthquake, etc.) for movies, and music. I use them all the time. The effect of the floor shaking is the best for movies. Anything else for a dedicated theater is not going to be as good, IMHO.
You will not believe it, and the total system, which included the 4 drivers, 2 pro amps, 1 xover, and the wood for the manifolds was around $1000.
Good Luck !!

I would recommend Velodyne DD18 to shake your nice room. I have been using it since October last year and literally, my neighbor has reported me of shaking his house at night!

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Get a used Velodyne DD-18. My room is huge, it is 22 feet wide 70 feet long with a 22 foot high ceiling. The Velodyne DD-18 brings the room to its knees begging for mercy. Fast accurate and tight bass. A real slam-bam earth shaker.
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Also check out the Vandersteen subs. One is better for 2-channel systems seamlessly blending low bass with the main speakers, the other model is more geared towards home theater. And both are well-built and reasonably priced. Widescreen Review magazine wrote a nice review a few years back.