Electrostatic pros and cons.

I recently saw a feature on the program, "how it's made" on electrostatic speakers and it piqued my interest in them. I was wondering the pros and cons of them, their placement, space needs, sound, etc. Any advice would be appreciated.

The main pro I would say is the very low distortion with their air-damped diaphragm. They have a high resolution and high articulation that gives a crystalline, yet fatigue-free sound. The other pro is that as a line source, one can sit very far away with little degradation in sound. Their main problem is the very limited excursion creates with "thwap" effect and they have a limited dynamics. Their dispersion can be considered good and bad. While have keep and even power throughout a room, lateral dispersion can not be so great localizing the sound to the speaker. That can depend on the model. Front wall distance is important. I have heard a set up that caused a mid bass bump because the speakers were too close.  

I would encourage anybody really to hear Soundlabs. They are the best example of electrostatics, imo. Stax SR-009 headphones are also a great experience. 

The strengths of electrostats usually include superb inner detail and articulation, low coloration, very good to superb imaging, and excellent pitch definition in the bass region. They tend to sound startlingly natural.

The weaknesses of electrostats relative to good traditional box speakers usually include more modest SPL capabilities, reduced low-end extension and reduced low-end impact, more difficult load for the amplifier (which translates into higher amplifier cost), requiring a lot of room for proper setup, small sweet spot, and reduced reliability. Also, electrostats tend to be fairly expensive, as building an electrostatic speaker is quite labor-intensive. It means building very large drivers basically from scratch.

There are exceptions to some of the above weaknesses. The big SoundLabs I used to sell had excellent bass extension and a larger sweet spot than most "conventional" speakers; the Beveridges an even larger sweet spot; and some Acoustats and Roger Sanders’ designs are capable of very high SPLs.

Any full-range dipole speaker benefits from being positioned fairly far out into the room. The reason is, if the backwave reflection off the wall behind the speakers arrives too early, it can be detrimental. But if it arrives after a long enough time delay, it is beneficial. Ime 3 feet is borderline; if you can’t position dipole speakers at least 3 feet out from the wall, they are probably not going to work very well in your room. Ime 5 feet is significantly better than 3 feet.


One of my favorite aspects to my King Sound Electrostats is the bass seem to come from within the soundstage between the speakers . Where the instrument is perceived to be coming from .With  box speakers the bass is all around the room . 
The main pro I would say is the very low distortion with their air-damped diaphragm.

Never seen an electrostatic measure well in terms of distortion, if we use the same term used in electronics. ESL's' often _measure_ poorly but sound very good.

The strengths of electrostats usually include superb inner detail and articulation, low coloration, very good to superb imaging, and excellent pitch definition in the bass region. They tend to sound startlingly natural.

Very true. Those large diaphrams can really work acoustic magic. By avoiding floor, ceiling and side to side bounce they can produce some of the same detail as headphones.

Similarly, very wide panel speakers like the Sonus Faber Amati Homage can do much the same.

The smoothest measured in-room frequency response I have ever seen was a SoundLab panel set up in Roger West’s open-floor factory. They ran pink noise through it and I was watching the real-time analyzer display. There was no smoothing and no time gating. The curve was a gently downward-sloping virtually straight line, down maybe 5 dB at 20 kHz relative to 100 Hz, spoiled only by a 2.5 dB up, 2.5 dB down jog at about 500 Hz.

The 500 Hz jog was narrow enough that it might have disappeared almost entirely with 1/3 octave smoothing, which is more representative of what we perceive than is an unsmoothed curve.

I asked Roger why he didn’t use these measurements in his marketing, His reply was, because someone else might get a different curve with their measuring system and accuse him of exaggerating.

When I was a SoundLab dealer, from time to time I'd have other well-respected speakers in the same room.  Usually these other speakers were more efficient than the SoundLabs.  But invariably I'd find myself turning up the other speakers even louder in an effort to hear the details which were clear on the SoundLabs even at their lower sound pressure level. 



Very interesting indeed! :) Always happy to have more information, even if it doesn't agree with what I've seen in the past.



Erik, I’m aware that there have been measurements of electrostats that apparently showed chaotic diaphragm behavior. Such chaotic behavior would be inherently non-coherent and therefore fall off more rapidly with distance than the signal being produced coherently over the entire diaphragm, which approximates a planar source up close, transitioning to approximating a line source or sometimes a point source as the distance increases.

In other words, if this chaotic diaphragm behavior is "noise", I think the "signal to noise ratio" of an electrostatic panel improves with listening distance, because the noise does not propagate as efficiently as the signal does.

For example, if the bias voltage is up a bit high on the SoundLabs (and/or if your humidity drops significantly), you can hear a waterfall-like sound up close to the diaphragm.  This is an incoherent noise, and it does not propagate to the listening position.  You can play music at very low volume, down around that waterfall noise floor when you listen with your ear up near the panel, but move back to the listening position all you hear is the music at very low level; the "waterfall" doesn't make it that far. 


From measurements I've seen int he past, several ESL's I've seen just don't measure well in the frequency or distortion domains.

That may not be true for every ESL though, that's a broad generalization based on what I've seen.

There were still plenty of good reasons to listen to them though. :)



I've seen frequency response measurements published by Toole for a hybrid electrostat that looked horrendous, but I don't think they were well done, nor the ensuing listening test.  Here's why:

SPL will fall off more rapidly with distance from the point-source woofer than from the line-source panel.  So a hybrid electrostat either has to be designed to be a good match for its target room size (NOT the big spin-o-rama room that Harmon uses), OR it has to be carefully adjusted to work well in that particular room. 

In the Harmon test, I believe it was an essentially non-adjustable Martin Logan hybrid electrostat, and the room was many times too large for it.  Also the listeners sat side-by-side and the Martin Logans had as small sweet spot, so that further handicapped it in the listening evaluation.

Not that I'm the world's biggest Martin Logan fan, but imo they were not properly evaluated in that test.


I think we are debating technology and not the sound. I think listeners should try out an ESL / Amp combination and see if the like them for the money.

While you do have to carefully match the woofer's level to the panel, the issues I'm talking about have more to do with ragged frequency responses within the panel itself, especially between the mid to treble range. Something a number of people have tried to correct with room correction software with varying levels of success.

I don't think this should matter as much as personal listening experience however. I'm just trying to be clear about spepcmanship.


"I think we are debating technology and not the sound."

I thought I was responding to critiques of the measured response of some electrostats.

But Audiogon is not a technical forum, so perhaps I should have just said "that’s not how some of them sound to me. Mr. Salami should try them and decide for himself."

If tech talk is off the table, that's all I have to offer. 


Apart from midrange transparency at which they excel, there's an overall coherence to an all electrostatic set up (not using dynamic speakers for woofers), but my experience is no doubt dated. I bought my first pair of original Quad ESLs (a/k/a the '57) in 1973 and ran them in various configurations, with subs, ribbon tweets and unadorned, until about 1990, when I bought a pair of Crosby modified Quad '63s- a better overall speaker with less beamy high frequencies, more apparent bass and the ability to play louder. But, to my ears, those '63s- which had the benefit of the Crosby tweaks from the era- never achieved that see through quality of the original '57, so when I decided to restore a set, I chose to have the '57s refurbished, not the '63s.
Over the years, I've listened to others (also dated)- Dayton Wright, some huge Martin Logan (I think it might have been called a Monolith but could be wrong) driven by Jadis amps at a lovely little boutique on the Il St Louis in Paris, their early, original CLS, and going back further, double KLH 9s with Marantz tube electronics, Janzen tweeter arrays, etc. I did not hear the Soundlabs- I should, nor the Beveridge, from back in the day. I gather that the Sanders are a preferred maker these days. 
I hung in with electrostats until 2006, when i switched to a horn array, one that also depends on dynamic woofers-- the Avantgarde. In some ways, a very similar experience in getting the deeper bass to cohere with an unfettered midrange. I keep the restored Quads as part of a second vintage system that is just "yummy"- perhaps a bit romantic, but oh, those old Quads- maybe I'm just lost in a nostalgic sound. The folks with the Soundlabs and Sanders might tell you that you can have it all without the shortcomings. 
Interestingly, on amps, I long ran mid-power ARC amps- high quality in the day, from a Dual 75a, to a D70 mk ii, to a Classic 60 (which was part of the newer ARC sound at the time- less tubelike). The best the old Quads have sounded, though, is with the measly old pair of Quad II amps running real NOS GEC KT 66s. Within the limits of that speaker, it's the best sound I have obtained on them. 
Electrostats can be addictive, even if other speakers can do some things (bass thwack, high dB) better. FWIW, I didn't confine myself to chamber music, string quartets and small jazz combos. You can hear into the music at lower volume levels. I would guess that with the right current model, large enough panels, you can come pretty close to getting it all. And perhaps, with more modern woofer technology, you can enhance them effectively without the seams-- I now run the '57s unadorned, without any tricks, mods or augmentation. 
They are insensitive to side wall placement, want to be well away from the front wall (the wall behind the speaker) and at least with the Quad, were acutely sensitive to tiny adjustments in angle- no doubt due to the very beamy tweeter panel.  Mine are in a relatively small room. 
Viz: https://thevinylpress.com/a-tribute-to-quad/
Thank you , all, for your input. I am definitely curious about them and just might grab a pair to see for myself.  
Being an owner of ESL speakers for several years, and having used and reviewed others and these in many systems, I disagree with several of the generalities associated with ESL speakers. I do not find ESL inherently superior in terms of cleanness, clarity, definition, etc. In fact, in some respects they are poorer than the finer dynamic or hybrid dynamic speakers. 

ESL speakers can reveal a wonderful amount of information, however they do not reveal more information than other types of speakers. It is more so the type of information they reveal which is construed as "more". Dipole and line source speakers produce unique wave forms, and I believe that is mistakenly taken as more information. 

While the scale of ESL is typically superior to most dynamic speakers, the resolution and fine detail of the center/phantom image is not superior. It is splayed, and that is unavoidable due to the nature of the drivers. 

Bass is typically a weakness with large panels. Some manufacturers do better than others in that regard. Declarations of one brand as inherently superior to others are highly subjective, and in my case not supported by actual use. 

I do not agree that they are superior in midrange transparency. I can get equally fine midrange from all sorts of speakers, line source, dynamic, hybrid dynamic. The character of the midrange, as with all frequencies is different with ESL. I am unwilling to give up LF in using an ESL speaker, and then try to compensate by saying the midrange is so great. That is simply not true in my experience. No one should buy an ESL because they think the midrange will be vastly superior. 

I do not agree that they are insensitive to side wall placement; placing material to their side along the wall has an audible impact on the sound, and I recommend people experiment with that. 

ESL can be a fantastic listening experience - or else I wouldn't own one. But, it has inherent weaknesses, and is not wholesale superior to other genres of speakers. Anyone who tells you so is speaking from emotion, not fact. 

I am not interested in debating or arguing my perspective. 
If tech talk is off the table, that's all I have to offer.

@audiokinesis: I think the technical aspect of the ESL is quite important.

The Beveridge lens revolutionized how ESL's sound, especially as it applies to sound dispersement and I'm not sure anyone realizes this but per Roger Modjeski who worked for Beveridge, Harold Beveridge designed these speakers to be placed on the side walls (Duke - recall that RMAF show where the room I was working had the speakers on the side walls - that guy whose name now escapes me worked for Beveridge too and copied the concept using dynamic drivers). The early Janzsen ESLs were also quite unique and the Soundlabs speak for themselves.

Having learned a thing or two from Bev, Roger Modjeski designed his ESLs to have uniform sound dispersement, without curving the panels. In addition, he realized the inherent weakness was in the bass and designed his speakers to be bi-amped with dynamic woofers which he selected to work best at 100 Hz and below. We modified a set of my Acoustat Model 2's using one of his panels (actually a half size version) to go along with the stock panel. I use a 4 box woofer array along with the Beveridge RM-3 crossover to filter the highs and lows at 100 Hz (4th Linkwitz-Riley 24 dB slope with a unique passive EQ added by Roger on the low pass board).

The other major tech improvement we made to the Acoustat's was removing the interfaces. Inherently, Roger felt the step up transformer is the real issue with ESLs. Anyone who hasn't heard an ESL with direct drive amps hasn't really heard what they are capable of. I'm working on taking my ESL 57s in that direction as well. As an aside, and from my perspective I do think the ESL 57 is still the standard by which any ESL is judged (it's what Roger Modjeski used as the model for his ESL), especially when it comes to the mid-range, but I also think people underestimate the bass in that speaker.
Bill, I like your room. Why do you have Avant Garde Duo and not Trio, by the way ? Too big or not much of a difference ?
Coherence is so important.
@inna- uhm, money? at the time I bought the Duo I can’t remember what the Trio sold for, but remember that it needed more woofs to make it right.
I do think the Trio would probably benefit from a decent sized room, especially with those bass horns. I suspect a used pair might be a good deal.
PS: BTW, the room shown in that link is not my main system room, but the front "parlor," a sort of small living room area on the main floor of an old Victorian house. The horns are up in a loft space on the second floor. 

@clio09, were the speakers on the side wall ESP’s, and the designer’s name Sean McCaughan? I saw and heard them in the 1990’s at Acoustic Image in Studio City, CA, a great high end shop in SoCal. Never got to hear the Beveridge, though I heard the Dayton Wright’s in 1972 or 3 when David Fletcher (designer of the SOTA table and Sumiko MDC 800 "The Arm") had a little retail shop in Berkeley.

Anyone who has heard the original Quad and doesn’t think it is extremely good at reproducing vocals and other acoustic instruments, well, I don’t know what to say. Uncolored, see-through liquid transparency (low energy storage in the near-massless Mylar, which starts and stops on a dime), natural timbres and textures, the ability to make every thread in a densely-woven tapestry or fabric (every voice in a choir, for instance) clearly audible as a separate entity. Other ESL’s, too. All speaker designs have their own strengths and weaknesses; you have to find one that excels at those characteristics in reproduced music you value most, your priorities.

The downfall of ESL's for me is the fact they are delicate and the repair cost is very high if something goes wrong. I had a pair of Martin-Logan years ago and they were excellent sounding speakers. When one speaker started playing at a lower volume than the other one, I called M-L. They said the panels have a definitive life span (like anything) and had probably reached the end of it. So I had to order new panels, and from M-L they only came in pairs, so I could not just replace the one that played at a lower volume. The panels were shipped to me and they were easy enough to replace but the cost was very high. The panels alone were almost as much as I paid for my Magnepan MG 1.6 at the time. Other companies may sell you just one panel and may have different repair options, but this was the real deterrent to me for ESL's in the future. I buy all my equipment used, but I would never buy a pair of ESL's used because of their delicate nature and the repair cost.
I thought I was responding to critiques of the measured response of some electrostats.

I am not faulting you, @audiokinesis  I just like to be explicit about my own angles. Just because I may feel ESL's are overall not that great measuring doesn't mean you should not like them.

I seem to recall that the Quads measured with the lowest distortion of any speaker available at the time (back in the 1960s-70s).

The Sound Labs seem to be the Sate of the Art in ESLs. The newer ones are fairly efficient- once you translate the numbers to real world, about 90dB by comparison.

Getting the older Quads and the Sound Labs to play bass is a bit of a trick- you have to have an amplifier that can make power into higher impedances. If you do, they play bass very nicely!

ESLs are different from a lot of speakers in that they work best if the amplifier can make constant power into them at any frequency rather than constant voltage. IOW an amplifier that can double power as the impedance is cut in half will be bass shy and too bright on many ESLs.  The reason is that the impedance curve of an ESL is not a map of its efficiency as is common with most box speakers. That has a lot to do with the fact that there is no box and its associated resonance and also because the impedance curve of the speaker is based on a capacitance.

There was that place called Hi-Fi Farm that sold some big electrostatic speakers made in the Netherlands. They were bigger than the biggest SoundLabs, don't know better or not. Retail was about $100k, I saw their demo for I think $40k.
Hybrid speakers like Avant Garde Duo, Rogers, Martin Logan etc. is never a good idea. You don't want hybrids because you will never achieve the proper integration, not that you will fully achieve it with the Trio. I guess, overall best dynamic speakers are still the best speakers. And best tube amps are best amps. What else is new ?

@erik_squires , I use measurements every time I design a speaker, which is fairly often. Sometimes there is a discrepancy between my observations and the measurements, and in those cases I try to find the explanations. I remember my first attempt at designing a speaker using decent measuring equipment, and the closer I got to "flat" the worse it sounded. My measurements were accurate, yet there was more going on than what my measurements were telling me.

Often a particular measurement doesn’t tell enough of the story, but attempting to understand "enough of the story" is inevitably a descent into the technical.

Of course I could be wrong at any point along the way.


You don't want hybrids because you will never achieve the proper integration

I can say that hasn't been my experience.
@bdp24: Yes that was him and those were the speakers. IIRC Sean told me he worked on the Beveridge 4.

In addition to being on the side walls the speakers were positioned equidistant from the front and back walls. You could sit on either side of the room and listen to the speakers.
Cone woofers and electrostatics can work together wonderfully.

The issue is the room, EQ and levels. Fix that and you can have a mind-blowing ESL experience. :)

Also, fixing that is sometimes very hard! :)
Is tricky though. I never solved that equation back in the day with my original Quads, but that was before 1990. I didn’t bother with the Quad 63. (I do like the bass on the original Quad and room positioning can make a difference- what’s there is taut and tone-full). I used to have them on ARcicI stands which really reduced bass but made them ear height-- I know people still like to get them up a bit but one answer is to sit lower. :) The little feet that are stock give them a proximity to the floor that helps the low end. 
With the horns, I found that adding an additional set of woofers, beyond those integrated into the Duo, helped. Adjust position, crossover point, phase and I cheat and use DSP on the external subs. Still took some time to get it right though.

The Finnish company Gradient made OB/Dipole subwoofers for both the QUAD 57’s and 63’s. Though the subs used dual dynamic cone woofers, they being employed in OB/Dipole fashion allowed them to blend better with the QUAD’s (because of the inherent advantages of OB’s, and the dipole characteristics shared between speaker and sub) than any sealed, ported, or infinite baffle sub.

Ad a reminder (I have spoken of them here before), Rythmik Audio and GR Research designers Brian Ding and Danny Richie have collaborated on a joint product, their OB/Dipole Servo-Feedback Subwoofer. A very unique sub (or even woofer---it can be used up to 300Hz), THE sub for QUAD’s, and any other dipole speaker, whether ESL, magnetic-planar, or ribbon. Or even dynamic---Siegfried Linkwitz used OB/Dipole subs in his loudspeaker kits, very similar to the Rythmik/GR (and almost as good ;-) . Whart, you should really look into the Rythmik/GR for use with your QUADS, and even your horns!

Electrostatics are very fast and transparent. Can any woofer match ?
This is all BS, you need big panels and right amp, no hybridization please.
Bill, time to replace your horns/not horns with something like JM Labs Grand Utopia.
Electrostatics are very fast and transparent. Can any woofer match?

Yes but my experience is with a bi-amp set up and woofer array. I think the Sander’s Sound speakers are a great example of a hybrid speaker. The Martin Logan speakers I have heard, not so much.
"Mr Salami" classic response!! That induced a nice laugh here!
Kudos to Duke (and his speakers)

@bdp24 - I don't want to mess with woofers on the Quads at this point. (There's a Rythmik 12" with a paper cone in that room for the theatre system-it's where we watch movies-altogether separate system). 
I have a pair of 15" Rythmiks running with the Avantgardes, and they are pretty dialed in. I'm good. ":)
There is a guy on one of the forums with a fantastic speaker/sub combo: Martin Logan ESL panels, passed off to a pair of Magneplanar Tympani T-IVa bass panels (which make a great sub for ESL's), and finally to an Eminent Technology TRW-17 Rotary Woofer for the bottom octave (20-40Hz) and below. Yes, below. He's one of the few people in the world who can hear the sound of the cathedral or concert hall Classical and Opera recordings are often made in reproduced in his listening room. Total price for the above is far less than that of the big Wilson and other dynamic "super-speakers".
Indeed. Big Sounlabs with big Atma-Sphere or VTL amps would be great. No woofers/subwoofers needed. If that's your kind of sound.
Bill, yeah they are about $250k.
I've heard and now dream about the Sanders speakers. Quick, dynamic, clean, transparent, life-like, moved me like no other. Downside was requiring bi-amping, 2 sets of speaker cables and 2 extra XLR cables, can add up $$$$$ quickly. Will one day own them.
Wow! All this talk of measurements and tech issues, and little or no
acknowledgment of another critical component - YOUR ROOM!
Yes - you can sit nearfield 8 feet from a pair of "Studio"-quality
Monitors and detect minutia. The minute we enlarge the listening
area, the more it becomes a factor in the sounds we perceive. Surfaces
add to the variables.  And while we focus on analysis of our equipment, little qualification is attempted on room dynamics (good reason - they're all different!).
 Bottom line? Just trust your ears. Try stuff and pick what sounds best
to you.... in YOUR environment. (Buy the way - our audio perception 
- what we each hear - is a non-constant, too!)
Had to throw this in.
@broockies:  Thanks for posting the relevant information about ROOMS.  As I keep posting on this forum, whatever you think you like may sound different in YOUR ROOM.  Take it home and listen and then buy.

Next, Levinson loved electrostatics in the '70s and made the HQD system, which we made some stands for:


This was dual quads, a Decca Ribbon between them, and one or two Hartely 24" subwoofers.  It was driven, unfortunately, by a bunch of his stuff at the time, which was built like a tank but sounded pretty bad.

Next to a pair of Magnepan speakers, it was shrill, beamy, and took some effort to tone down the woofer(s).  It sounded nice, but electrostatics (back then, anyway) had a bunch of issues.  RTR had a line of them that we carried, and Bob Fulton used their biggest pair in his FMI "J" Modular system:


A lot of work and time went into both of these designs--notice that they are all 6' tall--I wonder where they got that idea?  It could not have been from Magnepan, of course...but I digress.

The point is that two of the best in the day tried the electrostatics in systems that let them be featured.  Neither sounded all that good, even for the time.  Electrostatic speakers failed QUICKLY under mid-powered amps--a Phase Linear 700 would launch them to the moon, I suppose-- and they tend to be both shirll and beamy. 

If a new inventor has conquered these issues, I suggest you try them out in YOUR ROOM next to a pair of Magnepans of equal quality.  Then, buy the one YOU like.


Full range electrostatics are totally phase aligned, but not full range, because the upper frequencies are rolled off.  Of course, if you have a good jazz or classical FM station nearby, they work great, because FM signals are chopped from 15000 cps up.  Lots of power is neede for bass.  If you get an amp with a 2 ohm rating for power, it will easily drive 'stats. 
If you get an amp with a 2 ohm rating for power, it will easily drive 'stats.
That is a very broad and somewhat incorrect statement - depending on the ESL we are talking about (and I am talking about ESL, not ribbon or planar magnetic which are different animals and for which some people lump together with ESLs).

I'll agree on the full range comment - to an extent, but depending on the amplifier you may not need large amounts of power in the bass. Solid state amps, perhaps, some OTL designs, no. There are some other factors here that would determine the right amp as well that are being overlooked.
The RTR ESL tweeters used in the Fulton Model J discussed above by @richopp were the same tweeters ESS used in their TranStatic I and Infinity in their 2000A. Great tweeters, the 6-tweeter array-in-a-box Fulton used was marketed by RTR itself as the ESR-6. If you ever see a pair, snap 'em up! The J's midrange was covered by the Fulton Model 80, a real nice (transparent, uncolored) little 2-way. 
I have no names to drop or unique experiences from history, but do have a pair of Martin Logan Source (entry level) speakers running on a Denon AVR, and they are "magical" in the sweet spot (in my room and to my ears). No measurements required, the sound is beautiful.
I’ve heard Soundlabs with massive Boulder amps as well as Ayon Triton amps, Kingsound (least favorite), and Martin Logan Neolith with an all McIntosh components and a dual firing balanced subwoofer in different rooms at different times. The Soundlabs were impressive but the Martin Logans were the best over a number of listening sessions. They have a large sweet spot and great micro detail and also had the widest dynamic range with the subs integrated well into the system. It was a tough decision to go with ESL or Magnetic Planer Speakers, I made the decision based on my sound preferences and the true ribbon tweeter in the Magnepan 20.1. Both types of planer speakers are amazing in my opinion and just like all speakers have their specific challenges with set up and room placement/interaction. That being said, I had my 20.1s in an 800sq/ft studio and they sounded great. Not as good as my current space which is much bigger but really good nonetheless. Planers act as line sources and I think they get a bad rap for needing a ton of space or power to operate corrrectly. If you get an amp that will double down in power from 8/4 ohms and can find one that gives stats to 2 ohms you have plenty of power to hear what they can do unless you listen at ear splitting volumes.

Try them out and have some fun!
Ive had several ML's over the years, the key to getting the most sound is room placement out from the walls and having a high bias current amplifier.   Its amazing how same speaker can sound on the same amplifier just by playing with the bias.  No matter what they will never be "loud".   They can be pretty awesome if set up right.

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My first and most long lasting love in speakers was the Quad ESL 63s. I had and they made a lot of beautiful music for more than 20 years. Not a perfect speaker, but did everything right with the music I listened to - contemporary pop, jazz, Celtic, folk and chamber.
Finally, because of a change in the size of my living space, I had to give them up for a smaller pr. of dynamic speakers.

Now back in a bit larger space, am quite happy with my little Maggie 1.7 ribbons and may consider moving up to a larger pair Maggies or possibly something in the smaller Sound Labs, Sanders, Kings, or a nicely re-furbished pr. of Apogee, Duetta Sigs. ( still love the Quads, but their move to China and a host of quality and service problems has spoiled me against them) Regardless of which, am never going back to the box.

I agree with erik_squires, regarding room integration being the key factor, when using subs with stats and ribbons. There is nothing quick or fast about 20, 30, or even 40HZ and anything below 60HZ, in about any home sized room, is non directional. My suggestion is - don’t ask or expect your sub/subs to do the job of your mains for mid base and keep them set to operate at or below 60HZ and do your diligence in room set up.......Jim