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Subs with electrostatics; is this a tricky one?

Mike Reed

pfm Member
Wouldn't mind a bit more bottom end on my Quads but have feeling that there's no guaranteed way of integrating a sub-woofer, powered or otherwise. Anybody had any experience in this?
 
Unfortunately, it's notoriously difficult to match a sub to the Quad's. Part of this is because of the relative speed of the electrostatic membrane, but matching the dipole radiation pattern to the monopole radiation of most subs is as much (if not more) of an issue. Of course dipole subs do exist, but I haven't been very impressed with the ones I have heard.
 
My father in law used to use an Rel stadium with his Martin Logan CLS speakers. Worked very well. I'm not sure whether this would work with Quads though.
Del
 
I have had decent results with a LF system designed by a friend of mine in combination with a pair for ESL57QAs. The key to success is excellent transient response. This is not really related to speed - at LF the transducers don't have to move particularly fast but they MUST stop when the music stops otherwise you will get Martin Logan syndrome.

One benefit you will not get from taking the bass away from the Quads, unlike "ordinary" speakers, is an increase in loudness capability. This is because they will still flash over at the same voltage level at higher frequencies.

Given that my friend's LF system is not commercially available I would tend to look for something servo controlled e.g.

http://www.rythmikaudio.com/products.html

Anything with a hole in it is a non starter. Sealed box subs might just be OK. I would also recommend 2, it's the only way to get the phase to align properly with the main speakers IMHO.

Subjectively (with the 57QAs) we noted a modest improvement in clarity, tighter and deeper bass plus a larger, deeper and better defined stereo image. The Quads on their own have a slightly tubby bass with not much extension - sort of LS3/5A-like.
Using this bass system with conventional 2-way speakers results in a massive improvement. With the Quads the improvement is rather less.
 
I use a REL Q50 with my stand mounted 57's, set up as per REL instructions (in corner) the sub gives a well integrated lowerend to the 57's as well as benefits up into the midrange.
The sub stops and starts tunefully with no hint of overhang and very little feeling of a "sub sound"
The floor of my listening room is carpeted concrete. I use the sub without the spikes fitted.
I have heard the sub on a suspended floor with 57's, set up half way along the wall, in a larger room than mine, with the driver facing towards the wall, the integration of the sound was pretty much the same.
Hope this is of some help.

Errol.
 
Some interesting and positive replies; thanks. Not sure whether passive sub(s) powered by another amp or active sub(s) is the way to go, but I note the caveat of ported ones.

Have never entertained subs before in 45 years of (big speaker) hifi, and therefore know bugger-all about them. REL does seem to be a name I've come across for decades, though, so maybe I should research in that direction.
 
The old Celestion sl6000 dipole Subwoofer worked very well with my CLS'2 - its about the only Subwoofer that I've heard that works with ESL's

John
 
The old Celestion sl6000 dipole Subwoofer worked very well with my CLS'2 - its about the only Subwoofer that I've heard that works with ESL's

John

Beat me to it!Was just going to recommend SL6000 then reached end of thread!
No boxes.... At all....
 
Wouldn't mind a bit more bottom end on my Quads but have feeling that there's no guaranteed way of integrating a sub-woofer, powered or otherwise. Anybody had any experience in this?

I have 2805s with an Acoustic Energy Aegis sub. I've spent a lot of time getting speaker positions and room acoustics right, but the result seems pretty good to me and to those who have heard it. In an ideal world (i.e. if I had the money) I'd buy two Velodyne subs.

- Richard.
 
One benefit you will not get from taking the bass away from the Quads, unlike "ordinary" speakers, is an increase in loudness capability. This is because they will still flash over at the same voltage level at higher frequencies.
.

Still worth trying however, since low bass can easily push the input transformers into saturation, so while absolute spl potential might not be higher it should be cleaner at high levels.
 
Still worth trying however, since low bass can easily push the input transformers into saturation, so while absolute spl potential might not be higher it should be cleaner at high levels.

Agreed, the Quads weakest link is there transformers - there transformers THD rapidly raises from 150Hz and below, even at very low power levels (under 1W).
 
Wasn't the transformer in the ESL essentially the same as the output transformer from the Quad II turned around?

I think that an H-Frame dipole would make a good subwoofer for quads. There are plenty of plans for those on the speaker DIY sites.
 
Still worth trying however, since low bass can easily push the input transformers into saturation, so while absolute spl potential might not be higher it should be cleaner at high levels.

I'm not so sure about this one.... if low bass is filtered out and fed to the subwoofer then that's a whole lot of the volts not going to the bass panels in the first place... plus there will be less excursion meaning that the distance an arc would have to travel to ionise in the first place would not be reduced on each half cycle....
 
After moving into the new room I started getting quite reasonable results with
the XTZ 99W12DSP and ESL-63.

At which time the sub promptly self-destructed (something in the supply, it
only blows fuses now) . XTZ are quite unreasonably unhelpful, and shipping these
40 kg around Europa is also not quite reasonable.
 
Wasn't the transformer in the ESL essentially the same as the output transformer from the Quad II turned around?

...

Is that correct? Interesting (I always fancied providing a dedicated HV supply to each panel).

I would add that getting either 57s or 63s up off the floor improves bass clarity IMO, with 57s getting better when they are tilted vertical, and 63s back a bit. All in my experience.

Richard
 
I had the 6000 dipole system with my 63s. Rather large! And quite complex what with the extra amps and the crossover. Still, it worked nicely if just a touch 'dry.' It's true that dipole bass sounds different to that from 'normal' boxes, and to my ears more natural.
Recently, I used a standard REL sub with a pair of 57s, and it sounded pretty good. However, people seem to vary a great deal in what is 'acceptable' with integrating bass. So, as always, it is a case of try it and see what you think, with your system in your room . Personally, I wouldn't be without a good sub, but a lot of my friends don't like it at all. We all seem to differ so much in what is acceptable in hi fi. Which is why these forums exist!
 
Yes that looks v interesting. I completely agree with this para

"Music, unlike sound effects, requires that harmonics and fundamentals from the subwoofer and the mains maintain close timing relationships in acoustic space for realism. Harmonics by definition must arrive at the ear at the same time as the fundamental to sound real." on this page/
http://www.tbisound.com/dsp_sound.asp

Not sure how they achieve it with some sort of mixture of port and transmission line loading though.

As an aside - I really liked the way the new Kudos Titans do bass (+ the rest!) and they are ported isobariks.
 
My Quads Unlimited restored ESL57 are supplemented by 2 REL Storm subs - no problems with integration... Speakers run fullrange of course as recommended by REL. The bass of restored Quads is very very good - fast,detailed,controlled and goes to 40hz in my room. Interestingly restorer recommends using of very big amps with them to kill distortions - up to 300w! They have protection circuit built-in so you cannot destroy them with power. 12" high stands and rear side felt elimination helps with bass as well-less boom and more detail and image depth.
 


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