High end sub for big room. Suggestions?

2 18 inch Bag End subs with elf stereo processor and I defy any other set-up to top the preformance with either HT or stereo.

There is no substitute for displacement. The REL may be the right choice because it integrates so well and is musical, but you will not be happy with HT unless you have 2 in your room... or you listen at low levels (U571 was not meant to be listened to at low levels ...) . I am a BIG advocate of stereo subs. Much improved imaging. Further, with 2 subs, MUCH easier to integrate into the room and get it right. I have a dedicated 30x16 room with 15' cathedral ceilings. One sub does not really cut it in term of impact at references levels for HT. Get the REL, get two of them.

Depending on how you are going to use it and how much you want to spend. If for movies get a 18 in sub the bag end is modest in price and a good peformer. The Velodine 18 is good but is twice the price.

You asked about a HIGH END sub - not just the big bang.
Go for the REVEL SUB 15 (with REVEL LE-1 crossover/bass amp).
The latter can drive two SUB 15s at 1000W output. They really can shake your house AND they are HIGH END! Good luck!

Krell makes probably the best subwoofer ever. But that is to be expected!

Entec is the way to go.

I also have a pair of the Entec subs mentioned above. Use them with Wilson WATTs. They are certainly better than the Puppies.

However, for movies and really deep loud bass I wanted even more. I've chosen the Stryke HE15, which by all accounts is up there with the big Krell and Wilson units.

Here is link to more information:

http://www.digitaltheater.com/cfb/index.cfm?fuseaction=thread&CFB=1&TID=97226&StartRow=26

You may find the price pleasantly surprising.

I use some Entec L2f woofers with Rockport Syzygy speakers in a room not much smaller than yours, 16' x 24' x 8.5', but I would sure use two of them just outside the Hales....The presentation becomes about 20% larger than running the Rockports full range (they fall off the map in the mid thirties).....The Entecs will image in the bass as I can turn off the main amps and listen to bass image all over the place here.....They also have a 1hz notch filter wherein you can notch out the room modes, the nasty ones in the 70s and 80s.....Demian Martin hasn't built these in years, but I can put you in contact with him if you like as he might be able to find a pair for you.....

I have transcendance speakers also. I talked with the vp of Hales at lenth about witch sub would be best and He urgered me yo buy a Rel . I did and am very happy I bought the Stadium II 2500.00 retail now the III is 3000.00 . They are the best integrating subs that I have ever heard , go to there web site. Check reviews at audio review. The Stentor is the next step up . Don't be skeptical about the power either My sub is only 100 watts My room is 18w x 32l with 12' cielings and it fills it just great.
John