DUAL SUBS IN THE $10,000-$15,000 RANGE


I just sold my pair of JL F212's after hearing the Gotham(big mistake!). I'm about to drop $15G's for a pair of used(store demo's) Gotham's that have being upgraded from v1 to v2. Now since I'm about to spend big mula on bass, why not consider others awesome subs that may even be better than the Gotham's(if possible). I want my subs to do both music(primary) & bombastic movies(secondary) with LOW distortion. Please comments on the list below or add others I am missing. I listing them in my preference. Thank you!

JL Audio Gotham 213 for $15,000 pair(used with warranty)

Funk Audio 21.0 $10,136 pair new(20% discount for the month of December)

Revel Rhythm 2 pair used

DIY with multiple TCsounds LMS ULTRA 5400 18"'s






ptheo
Those are all great choices. Another is the Rythmik F25 at $3k (plus shipping) for a pair, $6 for a quad, $9k for a sextet, $12k for an octet, and $15k for ten (a dectet? ;-). Rythmik's 10% discount for a purchase of multiples will pay for the shipping. The F25 features two aluminum-coned 15" woofers controlled by designer Brian Ding's patented Direct Servo Feedback circuitry, each driver powered by it's own 400w amp. That is less power than that found in some other subs, but the Rythmik driver is unusually sensitive/efficient, not needing as much power to produce a given SPL as the woofers used in those subs. The TC Sounds LMS Ultra 5400, for instance, is extremely insensitive, needing far more power than other woofers to reach full output. The Rythmik F25 is a very sophisticated, high-performance subwoofer, and an absolute bargain.
If you are dropping that much, you should consider consulting a sound engineer.  You may get more bang for your buck by running different size subs to cover the frequency range better (12, 15 & 18 inch)?  If this is mainly theater, putting transducers/bass shakers under every seat might get the effect you want.
Personally, I love the story from about 10 years ago where a guy in Italy (I think) built 24 inch subs into the foundation of his house.  Imagine horn loaded subs under your floor built of poured concrete...
Another option to consider at your price level. Something different.   
Eminent technology rotary TRW-17 subwoofer

http://www.rotarywoofer.com/

http://www.soundandvision.com/content/eminent-technology-trw-17-rotary-subwoofer#Lpu6qStoHOLVAQpm.97

regarding the DIY with multiple TCsounds LMS ULTRA 5400 18"'s

Do you have a carpenter/speaker builder who will build the cabinets?
I am looking at a couple of subs as well for one of my rooms and am currently exploring the DIY route with a local custom speaker builder. I could bring him the parts; he builds the cabinet and I or he does the assembly.   
One of the cons I can see with this type of approach, if things change down the road  - resale.
I too am looking for a pair of subs to add fill-in for my Horning Aristotles, since I have open room corners. I was pointed towards M.J. Acoustics.

ct0517---Oh yeah, the ET Rotary sub. I don't remember it's price, but what a sub---flat to 0hz! Bruce Thigpen has one of the most creative minds in the history of Hi-Fi.

For an enclosure in which to install an 18" woofer, go to the DIY Soundgroup website, where you can buy a well designed MDF flat pack for $115 plus shipping. I believe Parts Express sells the same flat pack for a bit more.