Subwoofer match for Harbeth 30.1

I'm considering adding a single sub to my system, now running the Harbeth 30.1 monitors. Considering the usual suspects - REL or JL Audio. In my room, the 30.1 have a great midbass, but would benefit from some support below 50hz.

Has anyone had particularly good results matching a sub with the 30.1?

Thanks 'Goners,
-Bob R
Bob, I have often heard that Harbeths don't have very low bass, My brother wouldn't part with his JBL Century 100's because of this. I would go with a REL Britiania series B1 or B2 you can find them used and the upgraded SPKON cord from will make any REEL sound much more solid. Or go with a New JL Sub. I will say that I have great success with matching a REL to my super fast Dynaudio Contour 3.0's. I really like the older B series REL subs over the new shiny black stuff.
Google the reviews and the specs on the Vandersteen 2WQ subwoofer and its hi-end crossovers as a match for 2 channel audio systems.

It has three downward firing drivers.

Note: NOT the V2W model for home theatre which has the LFE output from an AV preamp/ processor.

Highly recommended .... The dealer suggested it for a demo for 2 channel that bested all comers that day.
The new E Sub line from JL audio; There are several good reviews out that are easy to find. I think you would be hard-pressed to find better performance or better value. I love also that they are made in America.
take that, REL
The new E Sub line from JL audio; There are several good reviews out that are easy to find. I think you would be hard-pressed to find better performance or better value. I love also that they are made in America.
take that, REL
Thanks all-
Looks like everybody is thinking along the same lines. I'll check into the Vandersteen 2WQ as well.

Let me know if anyone has any specific RELs that would match up best. I've been looking at the older B Series, but think that maybe a sealed design (as opposed to ported) would match the quickness and resolution of the Harbeth 30.1 a bit better.
If you are open to used, I believe that the definitive match is the
REL Strata III . I have seen them in the $8-$900 range. I have one which I use with compact 7s and feel it is a fantastic match. It isa sealed 10 inch downward firing design. If you look at the old reviews, I think you will be impressed. In its day it was hands-down the most musical sub woofer. The Vandersteen is clearly also a good choice.One drawback however is that it is designed to match with a speaker that goes down to 40 Hz. There will be a slight mismatch with the 30.1.
I use a REL Strata III with my 30.1's. It is a good match. If you go with a REL forget about the stock neutrik cable and upgrade it.
Bob, I had the B1 with Harbeth HL-3s some years ago. It was great, and I think you would be fine with this sub and speaker combination. That said, unless it is important for you to match wood grain finishes, I would not count out the newer RELs or the JLs, for that matter. I currently have the JL E-112 paired with KEF LS50s, and depending on the music you listen to, the JLs have a nice 'clean' (accurate) bass response that pairs well. I would also recommend the older REL ST series. While I liked the Britannia B1, it did not seem to load the room like the ST series did (I had a storm some years before). But either way, I think you'll be well served by either brand. The RELs are musical, as everyone says. The JLs do put out more low bass, as the measurements suggest. Also, as another data point, I have had 3 RELs and never had any technical problems with them. They are well made and the amplifiers seem to work forever.
Bob, you might try a REL T5. I use this sub with my SF GH's, as the sub can keep pace with these speakers. Perfect blend down to about 35Hz. If you have a small to medium size room, I think the T5 would be a very good match up with the Harbeth 30.1's.
Thanks! Great suggestions all. Keep them coming...
Hi Bob, I've had very good results pairing JL Audio's F110 sub with my Focal Diablo monitors. I started with one F110 and recently added a second and am running them as a stereo pair. They have seamlessly integrated with the Diablos and provide fast, tight, tuneful bass. The addition of the second has smoothed the bass response, widened and deepened the soundstage and overall conveys a more believable sense of realism. I also use a Sound Anchors stand for the sub (I have a second ordered for the new sub) and have found it helpful in decoupling the sub from the floor, resulting in tighter, more articulate bass. I also have found JL's setup instructions to be easy to follow and their built-in Automated Room Optimization functionality to be very effective. Overall, setup and optimization was quite easy. I don't have experience with Harbeth or other subs so can't offer any comparative info. From my experience, I'd say that your addition of a good sub (or two) will prove quite beneficial. Good luck.