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Subwoofer with ESL 63

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Posted on March 15, 2017 at 15:42:13
howie.stone
Audiophile

Posts: 1
Location: United Kingdom
Joined: March 15, 2017
Hi everyone

I'm thinking of buying a MJ Acoustics Reference 100 or a B&W PV1D to complement some Quad ESL 63s. Anyone had any experience with this sort of thing?

http://www.mjacoustics.co.uk/MJ_Acoustics/Product_html/Ref_100.htm

http://www.bowers-wilkins.co.uk/Speakers/Home_Audio/Subwoofers/PV-Series/PV1D.html



I don't have room for a large subwoofer.

 

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RE: Subwoofer with ESL 63, posted on March 15, 2017 at 15:53:46
airheadair
Audiophile

Posts: 232
Location: California
Joined: October 18, 2010
Not everyone thinks you need a subwoofer with Quads. It probably depends on your amplifier as well as your taste and your room. However there is also a school of though that says that adding a subwoofer to nearly any system can improve midrange clarity as well as add some solidity and clarity to the bass.

I personally have Stax F83 loudspeakers, which can put out some reasonable bass but have a resonance that can detract from the "tunefulness" of the bass. Furthermore because of the speaker's strange impedance curve, it is hard for my OTL amps to drive them properly in the bass region. I supplemented them with a pair of Roger Modjeski's subwoofers (designed for his own ESL's), along with a separate crossover and amplifier. These are small speakers that are quite fast and integrate well with ESL's, and they are not too expensive. I am quite happy with them.

In any case, I highly recommend getting two small subwoofers rather than one large one.

 

RE: Subwoofer with ESL 63, posted on March 16, 2017 at 05:33:36
louie3
Audiophile

Posts: 536
Location: Signal Mountain, TN
Joined: January 14, 2006
After experimenting with every type of sub known to man, I had a pair of H-Frame dipole woofers built using two 12 inch woofers each. These are driven by a pair of Quad QMP mono amps. Crossover is either a modified Dahlquist LP 1, running the Quad 63s above 55 hertz, or a Krell crossover running only the subs and the Quads full range.

In my room, in my system, this is the best integration I have heard.

 

RE: Subwoofer with ESL 63, posted on March 16, 2017 at 05:44:13
louie3
Audiophile

Posts: 536
Location: Signal Mountain, TN
Joined: January 14, 2006
In my system, and probably in yours too, the subs really only add "air" and hall impact.

I listen mainly to classical music and my sub system makes the music more lifelike.

Yes, my ESL 63s do have decent bass down to around 40hz in my room, but they do not "load" the room with the air and spatial impact that a full orchestra playing...say Shostakovich' first.

I would love to hear Roger's subs, I don't doubt they work very well with electrostats, he's a really smart guy.

My H-frames work well, sound really good, but boy are they big and ugly.

 

RE: Subwoofer with ESL 63, posted on March 16, 2017 at 06:24:08
PerStromgren
Audiophile

Posts: 10
Location: Karlstad
Joined: January 28, 2015

I have used the Gradient SW-63 dipole subs together with my ESL-63's for a number of years with very good results.

I have recently replaced this system with a pair of Quad 2912, which I think can do fine without the sub system. I did, however, do some experimenting with the common type of active-12"-in-a-vented-box subwoofers, but did not get it to work as good as the dipole variety.

Neither system can do electronic dance music with any grace.

 

RE: Subwoofer with ESL 63, posted on March 16, 2017 at 15:00:01
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
For anyone interested in dipole subs such as the Gradient, there is one now available that is really special. It is an open baffle/dipole subwoofer that was developed in collaboration between Danny Richie of GR Research and Brian Ding of Rythmik Audio. It features two 12" woofers mounted in an open baffle H-frame, powered by the Rythmik Audio Servo-Feedback amplifier system. Those components are offered as a kit, with the plans for the H-frame posted on the GR Research website. Danny has a woodworker in Canada CNC-machining the frame out of 1-1/2" thick MDF! You can paint or veneer the MDF (or have it done for you), then install the components in the frame. The resulting performance is exactly the kind of bass that dipole speaker owners (ESL, Magnetic-Planar, Ribbon) desire---no boom, no bloat, just lean, clean, low bass. Read all about it on the GR research website, and look for the kit on the Rythmik Audio site.

 

RE: Subwoofer with ESL 63, posted on March 17, 2017 at 12:16:29
josh358
Industry Professional

Posts: 9491
Joined: February 9, 2010
Contributor
  Since:
February 3, 2012
I think that's the way I'd go. You just can't integrate a monopole sub with a dipole speaker, the sub will be less clean and there will be a glitch where the radiation patterns change -- the sound will be adding in front at the crossover point, but cancelling in back, so without EQ you get a 3 dB dip, and a radiation pattern that changes from dipolar to cardioid to monopolar.

If you want a slightly smaller baffle you might consider transplanting your drivers to a V-frame like on the LX-521's . . .

 

RE: Subwoofer with ESL 63, posted on March 17, 2017 at 15:34:50
louie3
Audiophile

Posts: 536
Location: Signal Mountain, TN
Joined: January 14, 2006
Thanks. It is easier to just close my eyes and feel the music.

 

RE: Subwoofer with ESL 63, posted on March 17, 2017 at 15:39:37
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
Yup Josh, Linkwitz uses a "W" style open baffle frame, which is what I used before the guy in Canada started making his H frame. They're both good, each having advantages and disadvantages over each other. The H has better structural bracing, the W having a large expanse of unsupported panel on each side, leading to resonance. But the W does purportedly provide some reduction in harmonic distortion due to the opposing force relationship between the two drivers, created by them being mounted on baffles 90 degrees to each other.

But both posses dipole characteristics, with nulls to either side, loading the room in one less direction (side wall to side wall), resulting in less room boom. Being dipoles, their SPL drop-off rate with increasing distance also matches the dipole speakers they are mated with, keeping the balance between the two the same regardless of listening distance.

 

RE: Subwoofer with ESL 63, posted on March 18, 2017 at 05:37:45
fredtr
Audiophile

Posts: 535
Location: Phoenix
Joined: January 4, 2005
I also use Gradients. I like them, but I don't have much to compare them to. The only other sub I tried was a Velodyne, many years ago.

 

RE: Subwoofer with ESL 63, posted on March 18, 2017 at 05:57:09
josh358
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Contributor
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Heh, yes.

 

RE: Subwoofer with ESL 63, posted on March 18, 2017 at 06:04:52
josh358
Industry Professional

Posts: 9491
Joined: February 9, 2010
Contributor
  Since:
February 3, 2012
Interesting, hadn't considered the effect of the unsupported panels on the side.

Also, not only will a dipole woofer trigger fewer room modes, the ratio of direct/reflected sound will be the same as with the line source.

However, the SPL drop-off will still be inverse square since they're point sources, and won't match the 1/R falloff of a line source. Depending on crossover frequency you don't need too many woofers to create a line source, if they're spread out. Two per wavelength, taking into account floor reflections. And if you sit the same distance from the rear wall as the woofers are from the front, the first rear wall bass reflection will be cancelled -- I tried that back when I had 1-D's and it really did work.

 

RE: Subwoofer with ESL 63, posted on March 18, 2017 at 23:42:28
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
Thanks for the clarification and additional info Josh. I forgot to mention that Danny Richie recommends the side panels of a W-frame made from the plans he provides on his site be doubled---an extra 3/4" layer of MDF be added to each side---to stiffen those side panels and prevent audible resonance. Either that or put in a brace connecting the two panels together, running across the open cavity of the "W". Of course, there is nothing preventing one from doing both!---Eric.

 

RE: Subwoofer with ESL 63, posted on March 19, 2017 at 08:11:56
josh358
Industry Professional

Posts: 9491
Joined: February 9, 2010
Contributor
  Since:
February 3, 2012
You're very welcome!

 

Distortion reduction in H-frame ..., posted on March 20, 2017 at 15:24:37
Posts: 903
Location: Orange Co., Ca
Joined: September 19, 2001
... should be same as with a W-frame by physically and electrically reversing one driver. Both drivers move in the same direction but any asymmetry in the summed output is reduced (this reduces even-order distortions but doesn't help with odd-order).

13DoW

 

RE: Distortion reduction in H-frame ..., posted on March 20, 2017 at 22:47:40
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
Right Duke, that I heard of first. But then someone (Linkwitz?) claimed an additional related benefit resulting from the 90 degree differential between the two drivers in a W-frame in particular. Anybody know more about this?

 

RE: Distortion reduction in H-frame ..., posted on March 21, 2017 at 16:27:02
Posts: 903
Location: Orange Co., Ca
Joined: September 19, 2001
I did read his Phoenix dipole woofer design papers but that was some time ago. I wonder if the advantage is that with the two woofers opposite each other and moving in the same direction that cancels vibration in the frame
(as well as reversing one woofer to cancel cone movement asymmetry)?
In an H-frame that would not be the case as the frame will be rocking in opposition to the drivers.

Regards
13DoW

 

RE: Distortion reduction in H-frame ..., posted on March 21, 2017 at 17:14:18
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
In a W-frame, the two woofers are always mounted in opposite directions (typically with the woofer on the bottom baffle facing forward, the one on the top baffle facing the rear of the frame, it's backside being visible listener). In an H-frame, the two woofers can be mounted facing in opposite directions (one forward, one rearward), but they don't HAVE to be. Danny Richie recommends doing so to balance the weight/mass of the woofers in the frame, the magnets being far heavier than the front end of the driver. When so mounted, the two woofers are wired in opposite polarity, of course. Ric Schultz of EVS uses the Rythmik amp and GR Research 12" woofers in his version of the OB/Dipole sub with the two drivers mounted on a flat baffle, both facing forward. He feels by doing so the woofers are in exact time alignment, the sub sounding better as a result. Richie argues that the wavelengths are so long at bass frequencies, that time alignment of woofers in an OB sub is not critical. But as to force-cancellation and harmonic distortion reduction, I'm not sure about the difference between the H-frame (with opposing drivers) and W-frame.

 

My bad, I confused the W-frame with the Linkwitz Phoenix sub, posted on March 22, 2017 at 14:11:30
Posts: 903
Location: Orange Co., Ca
Joined: September 19, 2001
So, I have no idea how putting drivers at 90 degrees affects distortion.

13DoW

 

RE: Distortion reduction in H-frame ..., posted on March 23, 2017 at 09:24:18
Davey
Audiophile

Posts: 841
Joined: September 26, 2013
I think some folks are getting confused on the frame designations here.
And there are variations on each (basic) configuration as well.

The "W"-frame was initially a label applied to the full force-cancelling configuration of the Linkwitz Phoenix dipole woofer. However, later (hybrid) configurations actually look more like a "W".
It can get a bit confusing.

The even-order distortion reduction comes primarily from having the cones always moving in opposite directions relative to their magnet assemblies. You can do that with any of the double-woofer configurations.

Dave.

 

RE: Distortion reduction in H-frame ..., posted on March 23, 2017 at 16:13:04
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
The W I was referring to is that found in the Linkwitz LX521 loudspeaker---the two woofer baffles being at 90 degrees/right angle to each other (and 45 degrees to the floor), with the bottom woofer facing the listener, the top woofer's rear magnet facing him (or her). It seems to me it could just as easily be called an M frame! In an H frame the baffles are in the same plane, perpendicular to the floor. The woofers in the H frame can be mounted facing in opposite directions (as Danny Richie does), or both facing the same direction, thereby losing the opposing force cancellation and even-order harmonic distortion reduction provided by opposite-direction mounting.

Davey, does the mounting of the woofers in the 521 (90 degrees apart, rather than 180) and same-direction mounting of woofers in an H frame not create opposing force cancellation and harmonic distortion reduction?

 

RE: Distortion reduction in H-frame ..., posted on March 24, 2017 at 11:42:57
Davey
Audiophile

Posts: 841
Joined: September 26, 2013
No, it doesn't create optimum force cancellation because the cones are not moving in 180 degree opposite directions.
However, one cone is always moving inward towards the basket while the other is always moving outward away from the basket. So, there is even-order distortion cancellation associated with that.

But, some could probably make the case even-order distortion reduction is not beneficial......subjectively.
Many, terrific sounding speakers are asymmetrical in their construction and operation. You need only look at most of the Magnepan lineup of speakers. :)

Dave.

 

RE: Distortion reduction in H-frame ..., posted on March 24, 2017 at 19:23:49
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
Thanks for the clarification, Dave. Isn't it also true that harmonic distortion is less perceivable at bass frequencies than at higher ones? On the question of force cancellation, I imagine the H frame and the mounting of two woofers on opposing baffles and wired in opposite polarities (Seaton Submersive, for instances) in a sealed sub provide about the same degree of opposing force cancellation and harmonic distortion reduction, all else being equal.

 

RE: Distortion reduction in H-frame ..., posted on March 25, 2017 at 08:29:56
Davey
Audiophile

Posts: 841
Joined: September 26, 2013
The Seaton Submersive is a sealed-box design with opposing woofers wired with opposite polarity??
What's the point of that????? To shake the woofer box all over the floor and not generate any bass??? :)

Dave.

 

RE: Distortion reduction in H-frame ..., posted on March 26, 2017 at 14:30:37
Satie
Audiophile

Posts: 4222
Joined: July 6, 2002
It is just a bipolar sub. Not a self cancelling construct.

 

RE: Distortion reduction in H-frame ..., posted on March 26, 2017 at 16:02:18
Davey
Audiophile

Posts: 841
Joined: September 26, 2013
A bipolar sub with two drivers at opposite ends IS a force-cancelling construction.

Do you understand the concepts involved with these types of double-woofer schemes???

Dave.

 

RE: Distortion reduction in H-frame ..., posted on March 26, 2017 at 19:16:27
BDP24
Audiophile

Posts: 158
Location: Vancouver, Washington
Joined: September 12, 2013
Now I get it---the two woofers in the Submersive are wired in same polarity, which I think I use to know! Demonstrations of the sub have included a coin being set on edge on the top of the enclosure, the coin remaining motionless, proof of the benefit of apposing woofers. It was THAT that was the point of my query---is a reduction in harmonic distortion one benefit of Seatons design. I don't think Seaton makes that claim, instead focusing on the design resulting in less enclosure resonance.

 

RE: Distortion reduction in H-frame ..., posted on March 27, 2017 at 15:17:57
Satie
Audiophile

Posts: 4222
Joined: July 6, 2002
Yes, force cancellation on the geometrical on axis vibration transferred by the structure, not cancelling the acoustic output, which is what I presumed you were referring to..

 

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