Best Subwoofer for Quad 2805 under $5k

Looking for musical subwoofer for 2 channel listening (Not home theatre!) that has the speed and finesse to keep up with Quad 2805s. Heard the Wilson Benesch Torus is an amazing combination, but don't want to spend $13k.
Thinking about the REL Gibralter G2 (carbon fiber driver) or the JL Audio Fathom f112. Has anybody tried these subs with the Quads? Any other thoughts?
check out the review of the VANDERSTEEN V2Q here in AGON
one of the fastest and most musical subs out there at any price

Review: Vandersteen 2Wq Subwoofer
Might want to take a look at the manepan bass unit:
Experiencing great results using 2 REL B2 subs with Quad 2905's. After much experimentation seamless intergration was found in my room by placement only about 3 feet behind the inside edge of the Quads and toed inward.

Room resonances were controled with cast concrete blocks under the Rel's (aprox 25 kilos) and about 5" thick. Cones are placed under the front feet resulting in a backward tilt.

A pair of REL B2 or B3 here on can be had well under your budget and 2 subs are better than one in my subjective opinion.

I havn't had any experience with the subs in your enquiry and don't doubt their application, but I've found subs are like real estate ,location , location, location .

Keep us posted on what you end up with and the results, very interesting.

I have used a pair of REL 505s and later the G1s with great success with the Quad 2905s. Superb subs, easy to blend as the G1s have a remote.
My recommendation would be a pair of Anthony Gallo TR1D subs. They are small and unobtrusive sealed cylindrical encloseure with a 10" woofer and a 200 watt amp. They are simple to integrate and do not produce ponderous bass. I use them with ESP speakers driven full range and the subs connected speaker line input and utilize the sub crossover. The ESP's are sealed and the bass they produce is tight and quick but not that deep. The TR1D's match perfectly adding the deep bass without bloat.
I never could get my REL B3 or the six previous subs to perform to expectation. The Gallo's do what I want and for only 1200.00 for the pair.
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Ime when it comes to low bass, the elephant in the room is the room. No matter how flat the subwoofer starts out, the room will superimpose its effects. We can change the room-imposed peak-and-dip pattern by moving the sub and/or moving our listening position, but we cannot make it go away. It is impossible to find a location for a single sub that provides approximately flat response in the sweet spot, much less elsewhere in the room.

Distributed multiple subs offers an elegant solution, each sub being in a different location and therefore generating a different peak-and-dip pattern, but the sum of several such dissimilar patterns will be vastly smoother than any one alone. Instead of a few big peaks and dips that are quite audible, we end up with more, smaller, closer-spaced peaks and dips, and the subjective improvement is even greater than we might expect because (at low frequencies) the ear/brain system will average out peaks and dips that are within about 1/3 octave of each other.

While it's possible to equalize a single sub to be flat at the microphone location, its response will be far from flat at other locations within the room. A distributed multisub system significantly reduces the spatial variation in response, such that the difference from one location to another is greatly reduced. If further EQ is needed, it is likely addressing gentle global problems, rather than acute local ones.

As a general rule of thumb, two subs have about half as much variation in in-room response as a single sub, and four subs have about half as much in-room response variation as two subs (assuming they're spread around somewhat). Smooth bass = fast bass, because it is the excess energy in peaks that makes a subwoofer sound slow (the ear/brain system having poor time-domain resolution at low frequencies, it is the frequency response that dominates our perception). Also, smooth bass = powerful bass, because we're likely to set the average level of the subwoofer lower than it should be if the response has distracting peaks that stick out like sore thumbs.

Dipoles have smoother in-room upper bass than monopoles do, so the discrepancy between two dipole mains and a single monopole sub is greater than what we get with conventional main speakers. If you read accounts of people who have tried subs with dipole speakers, it seems like most people who try a single sub eventually give up because they can hear the discrepancy. Most people who try two subs keep them, because they don't hear much discrepancy. Three or four subs would be better still, and they can be small subs.

I spent several years trying to design a super subwoofer that was "fast enough" to keep up with Quads and Maggies while offering good extension and impact. I tried sealed, transmission line, dipole, isobaric, aperiodic, and more. Then a conversation with Earl Geddes changed everything, and I'm now an advocate of distributed multiple subs, in particular for use with dipole mains. I'm using his ideas with his permission.

Imo, ime, ymmv, etc.

Ken Kreisel
An under-appreciated sub is the Martin Logan Depth i (and I assume the Descent would be aswesome as well, though I have not heard one). I have used either a single or a pair of the Depth i in my systems for years. They are very configurable, very musical, and fast, and I never had an issue paring them with any speakers that graced my system, including Eggleston Andras, Klipsch LaScallas, Zu Essence, etc. They also server dual duty for HT.

I'd be lost without at least one!
There are a lot of great subs out there. I use Rythmiks (they pair wonderfully with little Maggie panels), but SVS, HSU, and several others are also well regarded. I'd only offer a couple of general thoughts you might want to consider.

Think of "tight" rather than "fast" bass. IMO, You'll get to the same end and save yourself some headaches of mis-communication along the way. Tighter bass may or may not be better for your system/taste, but at least it makes sense conceptually.

Integration of subs can be executed in several different ways and may affect your choice of subwoofer. If you use room correction software, you may end up happy with a single, high quality subwoofer. If you use a more traditional, non-EQ approach, I'd think hard about Duke's multi-sub, distributed bass advice.

Good Luck

Depending on room size, I would recommend a REL T5. Very fast sub which works great with my SF GH's and I'm sure will work great with Quads.
I have had the Rel T5 with my Quad 2805's and the Rel T5 is surprisingly very good with the Quads. Very fast and satisfyingly deep on a lot of music. However, I upgraded to the Rel R328. The R328 is in a different league with a 10" active and 12" passive. Very Fast,very musical and articulate deep bass. I am very happy with the R328 with my Quads 2805. Well under the 5k. The Rel G1 or G2 would be worth an audition. You can't go wrong with the Rel Subs.
I have Quad 988s with Electrostatic Solutions' maximum current upgrades and the Mye Stands filled with lead shot which provide a great deal of firm bracing for the Quad's driving panels. With the upgrades and the stands, my 988s have better LF performance than when stock, but they still roll off fast below 40CPS and rapidly lose LF impact. I submit that this is the reason that Quads are thought to be "polite" and are not known to good with pop and rock. I recently got an REL S-5 and now have it partially broken in and fully dialed in. The S-5 is not distinguishable and calls NO attention to itself, irrespective of how much very LF information is fed to it. The 988 sound has not been compromised by the addition of the REL. The REL is dialed in at about 40 CPS (the control that does this does not allow precise measurements other than the start point at 7PM on the dial of 30CPS and the end point at 5PM on the dial of 125 CPS. I have set the frequency cap at 9PM which means that its output is severely curtailed above 40 CPS.) The S-5 is fed full range by the output of my amps, as are the Quads. Frequencies above 40 CPS are severely curtailed by a filter circuit in the REL that has no impact on the full range Quads. When the REL receives information that is 40CPS and below, the impact, the power and the high definition of the LF information seems to be coming from the Quads - down to 20 CPS. Now, my studded up 988s are quite good with pop and rock and are no longer "polite" in the negative sense. All sources of music now have a strong and tight LF platform, which with Quads is transformative. This what REL calls a sub bass speaker is highly recommended for use with modern Quads.

REL is the best sub period! Any model will do in your system, especially, the "T" series. Even the older models are simply outstanding. Keep me posted & Happy Listening!
The Finnish company Gradient made a dipole sub for the Quad 63 in the late 70's, I believe it was. it was a pair of 12" woofers in an open baffle H-Frame, the woofers facing in opposite directions and wired in opposite polarity. At least theoretically this is a design well suited to use with a dipole speaker.

There is a sub design currently available just like the Gradient, but using servo-feedback on the woofers. The plate amp with servo circuitry is made by a company in Austin, Texas named Rythmik (Martykl mentioned his sealed Rythmiks above), and the 12" woofers are a collaboration between Rythmik's Brian Ding and well know speaker designer Danny Richie of GR Research. The sub is offered as a DIY kit only, the user needing to make (or have made) the H-frames into which the two (or three) woofers are installed. Anyone wanting dipole subs to mate with dipole speakers should definitely check out the GR Research website for more info.
The JL subs will work well, but you might want to consider the latest BalancedForce subs from Martin Logan. They are designed to integrate well with their electrostatic speakers and retail at $2,995 (210) or $3,995 (212). With their optional Perfect Bass Kit (PBK) you can optimize your setup using the provided mike and software with your PC.
for music, rel g1
The problem is not the subs but the room. Hence use multiple small subs and dsp room eq like the DSPeaker 8033.
Having used a variety of subwoofers (many named above) with Quads ranging from the 57's to the ESL-63 to my current 2805's, nothing comes close to the Celestion 6000 subs. They are true dipoles and extremely fast. They go low enough for me, especially with the 2805's. I have always positioned them next to my Quads (on the inside/side) rather than putting my Quads on top which really doesn't work well with the larger Quads. Not sure how available they are and they're really heavy and so shipping costs would be high, although worth it!
The REL equals Musicality. The JL Audio equals Punch. That's it in a nutshell.

Matt M

The unique GR Research/Rythmik Servo-Feedback OB/Dipole Sub continues to be ignored by all but the hippest audiophiles. It is absolutely, and by a country mile, the best subwoofer in the world for use with any and all dipole loudspeakers.

The reasons for it’s superiority are many, in terms of both it’s inherent design and how it loads the room, which is the same as dipole speakers. Read all about it on GR Research’s AudioCircle Forum. $1500 for a pair of the sub kits, plus another $500 for the H-frames the kit is installed in. Easy to assemble (not much harder than Ikea furniture), finish (paint or veneer) to taste.

You are dead right. The clarity of the 2805’s is in no small part due to their dipole character. Dipoles excite far fewer room modes, so bass is smoother, tighter, and ’faster’. So combining an ordinary subwoofer with a dipole like the Quads shows up the difference in a painful way. It is not that the sub is any worse than with other speakers, but the stats are so much cleaner.
When I decided a few years to add a subwoofer to my 2805s I did not know what I know now. After a lot of reading and a bit of listening (pretty pointless in the case of subs because you are effectively listenng to the room) I bought a B&W PV1d. It was universally praised as just about the best match for stats, and its looks matched our modern decor.
The result was disappointing, with woolly booming bass that clearly sounded different from the stats. The problem was reduced by lowering the crossover frequency, and by restricting the volume, but to a level where you might wonder why you had a sub at all. So when I read about room modes and the Antimode room eq system I bought an Antimode 8033 (cinema). This largely solved the problem: bass is tight, ’fast’, and without any booming. Since then I have read more, and concluded that multiple subs would improve the sound even more, and allow for equalization over a much wider area. A second PV1d is on the shopping list.
Knowing what I know now two dipole subs would have been an obvious choice (I did investigate that at the time, having heard about them). Unfortunately I do not live in the US, and there is not really anything suitable on the European market. Shipping a GR Research/Rythmik kit would be expensive, and I do not really trust myself building them. Also, the subs would still be pretty large compared to the PV1d. So not for me. Having heard the improvement from the Antimode room eq, I am pretty sure a second sub will cure my remaining issues. More power is also good, having recently experienced the benefits from more amplifier power (moving from a 2x45 watt Quad 303 to a 2x140 watt Quad 606-2). An extra 400 watts is not to be sniffed at.
So, from my experience, and if you can house them comfortably, I would indeed get those GR/Rhythmik dipole subs, but with the Antimode 8033. If you want something small, you could do worse than the PV1d (but in a pair, and with room eq.). The crossover setting I arrived at was 33 Hz with 4th order slope and zero degree phase.