recomended musical sub for 2 channel audio

I am looking for advice on a sub to add depth to my 2 channel audio system. thinking of rel but have never had a chane to listen too.
room is 13 x 26 set along long wall at one end ( not ideal)
system details
proac 1.5 speakers
mit 750 bi wire speaker cable
marsh msd a400s amp
audio research ls 16 pre
cal audio cl 15 cd
mit 330 shogun low impeedance balanced interconect
mit 330shogun rca
I listen to a little everything but love piano, vocals and jazz
ML Depth. everyone who hears mine says it's the most musical, seamless, unobtrusive sub they've ever heard.
The Rel Storm III and is amazing. It integrates seamlessly, and expands the soundstage 2x. No boominess, ot thump, just deep tones . . .
Or 2 REL Strata IIIs (total $1600-1800 used), as this might improve LF frequency response. I run one in an 17X15 room, and it could use another. The ML is also excellent.
I second the Rel Storm III. I upgraded to the Stentor III recently which simply places the Organ "in your room", but short of flattening your chest with the last pedal note (as only the Stentor III can do) the Storm III is the best I have heard for pure music. I just opens up and spreads out the whole soundstage and adds magic to the mid range as well. I run full range but set the high filter ~ 35Hz or lower. A pair of Spendor S 3/5's or LS 3/5 a's and a Storm III could convince you that someone slipped a pair of pipedreams in your room when you weren't looking.
a pair of velodyne spl 1200r's blend very well with my system. are very tuneable and sound excellent.
Seconding ML, even Grotto is a real audio deal and reasonably priced compared to the rest of your set up. I demoed one with a pair of ProAc 1SC and had settled on the combo before upgraditis hit again. 22Hz is good enough for most of us!!!!
ACI Titan for sure. IMO, it is the most musical of all subs I've heard: Rel, Martin Logan, Klipsch, B&W, Sunfire Jr., Polk. It is also the best looking and most versatile: continuously variable phase and cross-over. And if you don't like it you can send it back for a refund within 30 days. You owe it to yourself to check it out:

And check out this review:

Do it. Get a Titan. I swear you'll love it.
The most musical sub for a reasonable price that I've heard is the one I own - the Nola Thunderbolt. The RELs are very good as well, but I'm happier for less $$ with my TB.

The TB is fast, articulate and musical. Absolutely rave reviews from everyone who's tried one (or two). New one (mkIII) are $1695 new but you can find the mkIIs on A'gon under $1000. A steal at that price.

Check out the reviews at
thanks for everyones advice. I'm going to look at a used storm 3 on saterday for 1095
You said:
"I'm going to look at a used storm 3..."
What did you think?