The Quad ESL63 and its successors are classics of audio. The design, begun in 1963 and presented to the public as a finished product in 1981, was a sensation from the start and has been a contender for “the world’s best speaker” ever since—or, more precisely, the world’s best speaker in certain ways. The current 2812 model is the best version of the design to date in physical integrity. Its bass performance also seems superior to earlier versions. Sometimes, when family firms are sold and moved, the products go downhill in fit and finish. But this is not the case here. The new model is a work of the highest level of craftsmanship. One is almost tempted to call it a work of art. And it sounds essentially as one expects a Quad to sound. Going on memory alone, it seems to me to have preserved the essential Quad balance, though for some reason, it seems slightly brighter than the 2805, though I did not have a chance to compare the 2812 and 2805 side by side.
Before I go further, I want to point out that Chris Thomas did an online TAS preview (theabsolutesound.com/articles/quad-esl-2812-electrostatic-loudspeaker) which amounts to a thorough review in itself. I strongly recommend reading this as a supplement to what I have to say here, with a different emphasis.
When the ESL63 first came out long ago, HiFi Choice commented: “The sound was something of an acquired taste, [but] if its particular qualities appealed, they could assume such overriding importance that no other model [of speaker] would suffice.” I think it is fair to say this remains the case. There are many serious people in audio, our own Paul Seydor among them, for whom some version of the Quad ESL63 design remains the one and only. They may add subwoofers on occasion, some of them use DSP to fill in the lower mid and upper bass, and so on. But when the chips are down, the times may be a changin’ but their speaker is not.
Since Quad has had very limited distribution in the U.S. for a while, there may be a good many people who are not familiar with its distinctive and in many respects distinctively marvelous sound. For those of you in this situation, I am going to describe the sound ab initio. For people familiar with the design’s sound from earlier iterations, all you really need to know is that the latest version is very similar to former ones but in detail it is the best yet, I think—in particular, it is physically and sonically more solid.
How the Quads Work
The speaker looks like a single-diaphragm electrostatic, without a box, operated as a dipole. But it is not, in fact, a single unit in its operation. A small, inner, disc-shaped part is operated first. Then a ring around that central disc is fed the signal a bit later, the next ring out later still, and so on. (Physically, four panels fit together, each playing various parts in this concentric arrangement.) The idea that such an arrangement could be made to emit a spherical wavefront (to a very good approximation) was developed by Christiaan Huygens in 1678 (that is not a typo—late seventeenth century). It must have been embarrassing to Quad founder Peter Walker when, upon the first appearance of the ESL63, some audio reviewers described his genius in thinking of this wavefront-synthesis idea, which of course he well knew was old and standard physics. But regardless of previous theory, a great deal of ingenuity was required to make the thing a practical reality and the design is one of the signal achievements in audio history.
Nowadays one would run computer simulations. But back when, Walker described himself as working it out on the back of an envelope. The whole matter was not made any easier by the fact that in the analog world, pure time delays do not arise naturally. One has to make rather complicated cascaded passive networks for this. But it was all figured out, and the result was and is an approximation of a “virtual point source” about 30 centimeters behind the speaker (from either side!). The speaker does not, in fact, really sound like a point source when heard at close range. It sounds like a distributed radiator to some extent. But it does have a very consistent radiation pattern, effectively a true dipole up to a fairly high frequency range, above which the pattern is deliberately narrowed. A smoothly varying radiation pattern is a key to low coloration (something which Walker clearly understood long before Floyd Toole publicized this). And low coloration is exactly what Walker got.
A dipole panel of the size here (effectively two feet square) starts to roll off considerably above the deep bass. This roll-off is offset in part by a resonance around 80Hz. It also helps that the speaker is on the floor so part of the backwave is blocked from coming around to the front (in reverse polarity). But deep bass is not the specialty of the Quads even so. Below 50Hz or so, they are on their way out, though the bass down to where they roll off is quite convincing and defined and clean.
As electrostatics tend to be, the Quads are very low in distortion overall. Quad used to advertise proudly that THD (total harmonic distortion) was under 0.1% from 100Hz on up. This amounts to distortion at least 60dB down from signal. The present manufacturer’s “specs” on this are a bit higher, but are quoted at a 100dB level—very high—and the figures are still low. Even in the bass, in the 50 to 100Hz octave, the distortion is under 1%, a figure few box speakers can equal.
For comparison, most dynamic-driver speakers are happy to get under 45dB down across the board, though some few get down consistently to close to Quad levels. The Infinity Primus 363s are 50dB or more down (above the deep bass), for example. And the Cerwin Vega CLS 215s have bass distortion under 1%, even at high levels.
The Wonderful Part of the Sound
Let us listen first to the Irish harp on “Come Ye Back” [Joanna Mell, harp, Donegal]. The clarity and purity of the sound, the complete coherence of the speakers, the absence of any sense of material drivers, and the image floating in the air between the speakers are the sorts of things that makes one think that audio really can be as beautiful as live music. This reminded me of the end of the Lovejoy episode “No Strings,” where one of the characters remarks, after the ancient Celtic harp is played, “Music for the angels indeed.”
Or listen to one of the Water Lily Acoustics recordings of Ali Akbar Khan. The purity and coherence and perfection of imaging give one the feeling that this is as close as one is going to get to hearing the great man play live, and of being immersed in the original performance space as well, provided one sits in the right spot and near to the speakers.
These are the kinds of music where the Quads excel and where few other speakers are even close. In purity and delicacy and coherence there is hardly anything else like them.
Now it is worth pausing a moment to talk a bit further about the immersion effect, the sense of being in the recording venue. If one sits close to the speakers and rather low (the acoustic center of the speaker is only about two feet off the floor), then the dipole pattern all but eliminates first sidewall reflections, the sound off the floor is integrated with the direct arrival, and the reflection off the back wall is a long time in coming if you have adequate space behind. (Damping the wall behind is also very desirable, for maximum purity and focus.) In effect, one is not hearing much of anything except the recorded venue for a long time. The effect is quite remarkable. Remarkable things can also be done with using the sound off the walls on purpose (as with the Carver ALS speakers I reviewed recently), but there is something special as well in hearing primarily direct arrival at least for a considerable time interval.
One can become addicted to this. When I owned an earlier version of the ESL63 design (the “USA Monitor” Quads), I used to spend a lot of time with the lights out sitting on the floor listening into other voices, other rooms, and the music in them. Harry Pearson, who heard this system when he came for a visit, said it sounded like gigantic headphones—but he had to admit that on the right recordings, there was a quite overwhelming effect of being transported elsewhere. I really liked this effect then, and I still do.
None of this is to suggest that the Quads do not sound good at greater distances. It is just that they have this amazing immersiveness at close range. Most speakers lack the necessary coherence as one gets close. With the Quads, one can listen in something much more like the “nearfield” than usual with no sense of anything but perfect coherence. It is a unique and entrancing experience. One does notice, however, that the synthesized point source idea does not quite work out in practice. The sound at close range does not seem to come from a single point, but coherent it is.
The Other Part of the Wood
So far, we have talked about what in olden days HiFi Choice called the qualities that could assume such overriding importance that no other speaker would do. And that can happen (I used the Quads as my main speakers for many years). But there is another part of the story.
Let us start directly with music again. A little less than two minutes from the end of the powerful march that is the third movement of the Tchaikovsky “Pathétique” Symphony No. 6, just after a rising sequence in the strings, the violins stop playing and there is a bass drum and timpani roll accompanying a powerful brass passage. In real life, the drums are soul stirring. (They are marked ff and fff. This is letter DD in the usual edition). This sounds in description like the kind of thing that electrostatics do not do well, and the reader is probably prepared for remarks about electrostatic limitations. But as it happens, this passage was quite convincing. And it was loud enough, too, for a room of moderate size. All right, so it was not Cerwin Vega territory (the CV CLS-215s—now there are speakers for Tchaikovsky). Still, it was exciting—and loud enough unless you have a very large listening room and want to fill it, rather than sit fairly close to the speakers.
Admittedly, the Quads are embarrassed if one asks them for something like the Gnomus from Mussorgsky’s Pictures at an Exhibition arranged for organ and played by Jean Guillou on Dorian (an amazing bass passage). For this sort of thing, one needs subwoofers. But ordinary orchestral or rock music, which both mostly end around 40Hz, will be all right both for bass and for volume (within reason).
But the reproduction of full-range music does present a problem, even though it is not in the bass where you were perhaps expecting it. It is, rather, in overall tonal balance. The Quads are midrange oriented: There tends to be a definite hole between 150 and 500Hz or so. The Quads are not so much bass deficient—as far down as it goes they are quite good in the bass, as noted—but they are deficient in lower-midrange energy. And the upper mids and lower treble sound projected comparatively.
The roll-off further up emphasizes this even more. The speaker sounds a lot like upper midrange only, to exaggerate quite a bit but just to give you the idea. Stories have circulated over the years that Peter Walker pushed the 2–3kHz region on purpose because he thought that sounded better and reduced the lower mids to avoid any possibility of “boom.” If so, I must say I disagree—the speakers sound better if you take this projection further away and fill in the lower mids—quite a bit better, actually, to my ears. But it’s worth noting that Walker has not been involved in design work for many decades, and obviously had no hand in the 2812.
This overall slightly peculiar balance is a serious matter for large-scale music and, once you start to notice it, for other music as well. The orchestra sounds somehow miniaturized, with diminished fullness in the brass and weakness in the cello and viola sections, and even the lower part of the violins is affected. (The bottom note of the violin is just under 200Hz.) The orchestra sounds a bit as if the instruments were toys. Perhaps this seems like the famous cartoon from the old days with the frantic audiophile and the caption, “Crisis: the second oboe is too weak.” But this is actually a real problem for orchestral or other large-scale music, and indeed for music in general. You might like it but it is wrong. In spite of the impressive bass, impressive for a relatively small full-range electrostatic anyway, the effect is miniaturization and a balance that is just not correct.
I am well aware that this type of balance is admired, perhaps even preferred, by some people—witness the ongoing popularity of the LS3/5a, which is like this to an extreme (and does not even have bass, which the Quads do have). But still, it is a problem if you want to hear music as it is (or even as it is recorded).
There is also a roll-off in room sound in the top octave or so, though this is arguably not all that unnatural in musical terms since concert hall sound is similarly rolled-off. But it sets off the 2kHz emphasis even more, by contrast, and of course affects micro-detail directly. On the harp recording mentioned, you will surely notice that the micro-structure of the sound, the little twanginess and texture that the harp has in reality, is considerably reduced compared to a speaker with a flat and non-beaming top end. Better too little top than too much—too little being at least more or less consistent with live acoustic music. But one does miss some texture with the Quads.
The Quads sound smooth and in one sense uncolored—the sense of the absence of box colorations and resonances (except in the bass). But they are not really flat in-room. They are quite smooth as speakers go but not really neutral. (This is obvious on pink noise where one can hear both the lower midrange hole and 2kHz whooshing away at you, and to a lesser extent 4–5kHz.)
Also, one needs to damp the wall behind the speakers a lot to get the best results. Dipole operation in the lower frequencies is a good way to interact with a room, but in the higher frequencies it definitely is not, from my viewpoint anyway. One really does not want the top end (what there is of it) to bounce hard off a back wall. Damping behind is really needed for satisfactory results. A lot of damping. If you do that right, however, you will be rewarded with a really extraordinary purity of sound. You have to do some work but the rewards are great.
The Quads also have a certain subtle glaze to the sound when there is a hard attack, though the present version does this much less than the original ELS63. This effect is subtle, especially if the speakers are eq’d to be balanced correctly. But on piano attacks there is a hint of glare. The speakers are never really convincing on piano music in the upper registers for this reason. The phase linearity ought to help to make piano attacks right, but somehow this does not happen. Where this comes from is hard to say. Low-level chaotic motion of the diaphragm has been suggested (the “waterfall” looks pretty junky in the lower treble), though real evidence is missing. Listen for this in any case. Many people do not seem to notice. Some people find it annoying.
In any case, if you are a fan of large music in any sense, something needs to be done about the much less subtle attenuation of the lower mids. Adding subwoofers is a good idea for bass extension and dynamics, but it will not address the lower midrange “energy hole,” which is too far up to be subwoofered away.
Enter DSP correction. The Quads are real naturals for this: The speakers can be made well balanced for large-scale music in this way, while retaining their purity, coherence, and low distortion. The result is an exceptional speaker. Some might want to add a super-tweeter for wider dispersion of the top end, and, as noted, subwoofers for the deep bass are good. But the Quads corrected to fill in the energy hole and reduce the mids above a bit are something special without supplementation at either end. This is not to say that they do not have wonderful virtues without the correction, but with the balance straightened out they enter a rarified realm of excellence. (I should add that I believe virtually any loudspeaker can be improved with DSP correction.)
People, serious people, have noticed this potential. Tam Henderson of Reference Recordings, who has access to pretty much anything, is using subwoofered Quads corrected with Lyndorf Audio’s RoomPerfect with great satisfaction. He calls it his “last system.” And engineer Tony Knight, who has taken on the problem of literal acoustical replication of signal in a room in a profoundly dedicated way, is using subwoofered and DSP-corrected Quads 989s. He is currently using Uli Bruggemann’s Acourate correction system. His recordings of recordings demonstrations at RMAF have created something of a sensation—and no wonder. Even after several generations of recordings of recordings of recordings, the resemblance to the original is striking. (Each channel is recorded with a microphone at the listening position and then the individual channels combined into a stereo recording. This sounds surprisingly like the original recording played, showing how well the system is reproducing acoustically its electrical input.)
I mention this not to emphasize the need of the Quads for DSP correction—after all, many speakers need it at least as badly—but to emphasize how well it works for Quads. Billie Jean King once described a high-bounced tennis ball as “aching to be slugged” with a powerful overhead. In a similar fashion, the Quads, with their all but incomparably low distortion and coherence, are aching to be corrected because the promise of perfection is so strong. And a DSP-corrected Quad setup comes about as close to perfect on its own terms—that is, its radiation pattern choice—as one is likely to get.
A Pause for Explanation
A little more detail about the radiation pattern is justified, I think. We are all used to looking at frequency response graphs and saying, ah yes, there is the little bulge that does this, that, or the other. But with the Quads there is something in addition. This has to do not with “on-axis” response but with power response, the total radiation into the room. Box speakers are omni in the bass and then shift over as frequency rises to forward radiation primarily and even higher up become somewhat “beamy” in the treble.
But the Quads are not like this. They are dipoles all the way down and up into the higher frequencies, too. The radiation pattern does not change until around 5kHz, above which it narrows. So in effect there is a lot less power in the room from say, 300Hz on down than with a box speaker—the box will have become omni, the dipole Quads remaining dipole.
Now this matter is not standardized. One could make an argument that speakers ought not to change pattern with rising frequency. But there is no way around the fact that the difference in directivity will make a difference in sound. Even corrected to be measured flat at the listening position, the Quads sound superb. But they sound different from box speakers because the energy in the room is different. Better or worse…your call. But different for sure.
Almost everyone likes a crisp conclusion. But the Quad ESL63 and its variants have been from the start a speaker family that has gone its own way. They have low distortion, among the lowest; they have almost unparalleled coherence and unity of voice; they have an exceptionally uniform radiation pattern and a very low level of resonant coloration. They are also phase-linear, which I did not mention in much detail earlier, but which is known to have subtle but definitely audible positive effects, on transients in particular (try some woodblocks). In these categories they have always been in the very top echelon and they still are. “Alone at the top” is a phrase that one is tempted to use, though it would be a slight exaggeration since others are in the same realm, though not many. No amount of money will buy a speaker that does definitively better the things that the Quads do well.
But at the same time, nowadays one can find box speakers at much lower prices that will go deeper, play louder, and be flatter in room, and which handle certain types of hard transients better. The Quads are thus something of a paradox, even more than when they first appeared (when fewer box speakers did really well).
The Quad exists in a realm of theoretical design that makes most speakers seem a bit catch-as-catch-can. And anyone who is seriously interested in speaker design needs to listen carefully to this speaker and think hard about what it does and how it does it, just to understand what is possible in certain directions.
Speaker choice is a personal matter, and perhaps especially so with the Quads because of their distinctive sound and balance. But no one’s experience of audio is complete without a careful audition of this great classic of audio design.
SPECS & PRICING
Type: Floorstanding electrostatic panel loudspeaker, 3-degree fixed tilt
Frequency response: 37Hz to 21kHz -6dB
Distortion (100dB at 1m): Above 1kHz 0.15%, above 100Hz 0.5%, above 50Hz 1.0%
Max. power: 200 watts
Impedance: 8 ohms nominal
Dimensions: 25″ x 42″ x 15″
Weight: 77 lbs.
MOFI DISTRIBUTION (U.S. DISTRIBUTOR)
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