Need advice on subwoofer


I've been upgrading my circa 20yr old system since visiting a B&W shop in Beijing (of all places). Discovered that I was not deaf after all. Being British (tho living in US), B&W had some appeal. Also wife factor important in mycase & B&W's look cool. Now have B&W 804s front, B&W 805s rear and 1 804 as center. (Fedex lost one 804 in shipment hence the 'spare' 804). Denon 3805 AVR. Music tastes vary, Blues, Rock & sometimes classical. Also hook up Denon for DVD's, TV etc, but main love is music. Room about 14' x 18' high ceiling. Extending to kitchen/bfast of 14'x15'. Now looking for subwoofer to complete system. Although I like the 'brightness' of the B&W's, maybe a sub may add some balance at the bottom end. Been looking at Axoim EP500, Paradigm Seismic 10 or 12, and Velodyne DD's. Suggestions welcomed! Also, strange request, anyone tried putting an 804 on its side to use as a center?
dnallob10001
Can you put the center 804 speaker behind the TV on something tall as a stand so it is above the TV? Just a thought.

Post a new thread for this question. There are lots of folks that use large "non-center" speakers
thanks for all the advice thus far. REL looks wonderful, but so too are the prices on the SumikoAudio US dealer site. I may have refound my hearing, but the screech of the dollars leaving the wallet (I'm Scottish) might not be totally countered by the bass notes from the REL! I had an 'open box' Velodyne 15" DD from Tweeter last night..I had gone looking for a 12", but they didnt have that & the 15" DD had 200$ off. 15" vs 12" to me is 225 vs 144, so 56% larger. But there was a reason for the open box...it was DOA & missing the handheld. Still, it looked cool and helped establish a "this is what a woofer looks like" rapport with the other half...(this is important) So I'm still looking.

Anyone with a comment on running a Nautilus 804 on its side as a center?
The best place for specs is the REL website.
The REL website is hard for some to find because it is not a .com

Click here to find the REL website ....

.
Another vote for Rel. I'm using a pair of Strata III's
and they are excellent. Rel subwoofers have a highly
adaptable crossover network with provisions for both
high and low level inputs simultaneously. I have mine
set up on low level input with my 5.1 home theater sound
system and on high level with my Magnepan 1.6QR's for
two channel stereo. Rel subwoofers are easy to integrate
with many systems including challenging matches such as
Magnepans.
Your Nautilus speakers are very refined, so you do not want a cheap sub to muddy up the bass. This is one reason I recommended the REL Stsdium or better.

I have a REL Storm III that I used for 2 channel until I got my latest speakers. In the past the Storm always made the room sound better. My new speakers have reached the point where that is no longer the case.
I think the new Revel Sub 30s are awesome. However I think more depends on the subs setup and integration than you suspect. From what I've learned an experienced acoustic tech with serious testing equipment is a necessity if one is going to get the must thump from the buck!
Try out a earthquake MKV-12 or 15. Price is right and you just cant beat it for music mkv-12 is fast but capable of impressive DB even down to 20hz. You can get them for great deals on the net. I ran onto them at CES with the MKV-15, as they were reproducing a 15hz signal wave at 98db.
OK, you're British, so we'll type slow OK. (Just kidding, calm down).
I have two HSU's - one in a bedroom system, and one in my guitar system - they're excellent at their price point, however the EQ set-up in the Velo DD and (my personal fav after trying everything it seemed), the Revel B-15 is something you don't want to be without if you don't have to.
The AerialSW12 is also exquisite, albeit expensive and without the EQ feature.
CHECK OUT THE ACI FORCE , AS GOOD AS A REL FOR LESS MONEY,THIS SUB INTEGRATES WITH ANY SPEAKERS
Get the Velo DD with the accoustic correction.. just like what your 3805 can do but better. This will be the most important thing you can do. Plus you haven't really heard a movie since you haven't had an LFE channel yet... Look out it's about to get cool!

Chris
Take a look at Essex Audio subwoofers. English and VERY musical. Just bought one and couldn't be happier.

http://www.essex-audio.co.uk/
I have both REL and Hsu Research and love them both. The Hsu gives you the option of returning it if you don't like it.