The Quad ESL-989 Electrostatic Loudspeaker

The Quad ESL-989 Electrostatic Loudspeaker

Cutting Edge or Simply What is Old is New?

Dan Dzuban

17 September 2002


Maximum Power Output 2N/m2 at 2m on axis 
Sensitivity 1.5u bar per volt referred to 1m (86dB/2.83V RMS) 
Impedance 8 ohm nominal 
Maximum continuous input voltage (RMS) 10V 
(20Hz to 20 kHz) Program peak for undistorted output : 50V 
Directivity index 125Hz – 5.0dB 
500Hz – 6.4dB 
1kHz – 7.2dB 
8kHz – 10.6dB 
Axis band limits -6dB at 30Hz 3rd order
(low level) -6dB >20kHz 
AC Input (double insulated) 110-120V 
Dimensions (H × W × D) 49 × 27 × 11″
Weight 56 lbs. 
Retail: $7999

Distributed in the US by:
IAG America
15 Walpole Park South 
Walpole, MA 02081 
Telephone: 508-850-3950 

Heritage or Baggage?

The Quad ESL-63 (and 57) is one of the most famous loudspeakers ever produced, and seems to draw a generally fond remembrance from about every middle aged person who considers themselves to be an audiophile. So what does this mean to me? Very little. I am not yet middle aged, and I although have heard about Quads and their transparency and imaging, etc., I have heard a lot of talk about a lot of speakers. So any discussion as to whether this model lives up to the great expectations of what a modern Quad should be must be left to someone else to write about. All I know is that I may not yet be middle aged, but I have listened to quite a few speakers in my day, and I can tell you that this one is quite special.

The Quad ESL-988 (not reviewed here) is the direct descendent of the ’63, but with improved component quality, a stiffer frame, and overall modernized construction. According to the consensus of many reviews, the 988 does improve on the original in almost every way. The 989 (reviewed here) is based on the 988, but includes double the bass panels, and a larger spec transformer. The result is supposed to be even greater bass, dynamics and output capability. 

The 989 (and 988) is an electrostatic speaker that is different from other electrostat designs in that it has a system of concentric delay lines within each speaker. As sound is reproduced, it sequentially starts from the center of the array and they radiates outward. This is meant to mimic a point source speaker and is supposed to provide greater imaging capability than other electrostat designs. It is run full-range, so it is crossoverless. It is supposedly offers a relatively easy to drive nominal 8 ohm load, and is recommended to be driven by generally 100 watts or so and lower. The result of all this technology is that Quad claims their speaker possesses among the lowest distortion of any speaker. 

The speaker itself is a plain-Jane black obelisk, with a black cloth wrap and a kind of flimsy black plastic base and top cap. Not nearly as cool looking as your average Martin Logan, for example, with their exposed transparent driver element and metal grid, but new color schemes are available for wrap, base and top cap. It has removable IEC power cords, but unfortunately has cheap-looking plastic speaker binding posts.

Inspiration from Jerry Seinfeld

Writing about the 989 reminded me of the premise of Jerry Seinfeld’s formula for a situation comedy about nothing. How do I describe the sound of a speaker that has very little sound of its own to describe? I’ll take a stab at it, but it is probably easier to describe by what it allows music to do and what its limitations are. And I will try to curb my enthusiasm.

This speaker is water; fresh, clear, clean and continuous; generally characterless, with the exception that the impurities of what it contains define how it is sensed. That is really what is going on here with the 989. What you have is a transducer that is essentially invisible, save for the sonic signature of your content, your source and your amplification. At certain points during the review, I thought I detected something that I could identify as the “sound” of the 989, but each time a substitution in equipment proved that I was listening to the particular component, rather than the speaker. Is this simply another way to say the speaker is revealing? Ruthlessly revealing? I guess the 989 fits the definition of revealing, but in my mind “ruthlessly revealing” implies that it was harsh, clinical or analytical – which it never was (at least with the equipment I paired it with). Furthermore, the 989’s resolving power is balanced throughout the entire spectrum, so unlike other speakers that have been labeled ruthlessly revealing, the 989s resolution does not bring attention to a particular frequency or band thereof.

Audiophile Blabber

In audiophile terms, the 989 is capable of world-class imaging, soundstaging, inner detail, microdynamics, clarity, transparency, and transient impact – dependant, of course, on upstream components. 

I compared the 989 to my Magnepan SMGc, which really isn’t a fair comparison due to the price differential. My concern is not for fairness but rather just to highlight the differences. Magnepans in my experience have a wonderful ability to make nearly any recording come alive with immediacy and ambiance. Furthermore, they do this with a variety of equipment and in a wide variety of room placements. The Quad only does this when the content, equipment and room placement allow it. I at first wondered which speaker is objectively better: a speaker that sounds great in almost any situation, or a speaker that truly delivers exactly what is on a recording. My conclusion is that it depends. If you have a limited budget, or really can’t control your room’s set up or acoustics, you may find that the powers that be at Magnepan are geniuses for creating a speaker that will give you so much performance with so little fuss. The 989s on the other hand, are high maintenance. They sounded pretty unimpressive until I could find the exact correct placement in my listening room. Similarly, the sound I got out of them was also unimpressive with less ambitious gear – not that it sounded bad, but your $8K could have been put to better use with more evenly priced components. But unlike the Magnepans, get the 989s with the right gear, and play them within their limits and you are getting a strong taste of cost no object sound – and once you have gotten that taste, there is no going back.

The Quads were much more difficult to set up than the Magnepans, which generally sounded pretty good as long as they were reasonably evenly spread apart from each other and from room boundaries. The Quads required lots of fiddling, and often changed character depending on toe-in, distance apart, and distance from boundaries. I ended up settling on a very wide spread that was almost sidewall to sidewall, with some pretty extreme toe-in – the focus being slightly in front of the listening position. This is in stark comparison to my Maggies, which had never really been toed-in more than an inch or so. I found I could listen to the Quads in the nearfield as well as at a more standard distance. Moving further away resulted in a bit more laid back perspective, whereas listening nearfield resulted in the feeling that you could walk right in between the performers. It was sometimes nice to move further back if the close-mic’ed nature of a recording became too up front. But nearfield was my listening position of choice because it seemed to have the least room reflection/interaction and resulted in superior clarity. The ability to listen nearfield was the result of the Quad’s lack of crossover, which normally dictates a certain distance from the speakers so that the soundwaves from the drivers will integrate. 

The Maggies were similarly forgiving in the size of the sweet spot they generated. You could easily share the sweet spot with a friend. The Quads were much more stingy. I could only move my head an inch or two to the left or right without skewing the soundstage drastically to that direction. This phenomenon was most prevalent listening nearfield, but even farfield the sweetspot never got large enough for two people.

Although the Magnepans and Quads are roughly the same sensitivity, they did not sound the same dynamically. The Quads were much more dynamic in terms of massive macrodynamic crescendo capability, but they also had much greater microdyamic capability. The audiophile term “microdynamics” never really meant much to me, but the ability of the Quads to portray every tiniest bit of dynamic inflection in a vocal or instrument made it a clear communicator of the emotion the musician was trying to express, and this proved to be very addictive.

Both speakers produced that huge soundstage that planars are noted for, but each produced a different soundstage. The Maggies gave me a reasonably detailed, sweeping, all-encompassing soundstage that transported me to the venue of the recording. With the Quads, I realized that the Maggies really did not give me nearly the detail I thought they did. The Quads unraveled minute spatial, tonal and textural musical details. I initially did not think that they produced the Maggies’ sense of a broad sweeping stage, but I soon realized that it depended on the components. When I switched from the Quad 909 amplifier to the Bel Canto Evo 200.4, I not only got the Magnepan’s expansiveness, but I also got the ability of focus on details that previously simply did not otherwise exist. You have heard the usual audiophile babble about “walk through” or “holographic” soundstaging, but I have to tell you that the damn things consistently took my breath away with their ability to recreate the reality of the recording right before my eyes. The 989s gave me a strange sensation – not only did I get that sweeping soundstage, but the clarity and detail of the images was headphone like. This is something I have never before heard, and something I will not forget.

Any Limitations?

I have heard many speakers that play louder, and with less strain. The 989 played loud enough for my tastes, but I generally am not into what I would consider dance-club levels for my critical listening. What I heard was that the speaker started to congest dynamically and just plain sounded strained. I could see that in the scope of tradeoffs, this may be a deal breaker for some people. Don’t get me wrong-I fed the 989 with some serious rock and beat laden electronica at levels that well… prevented my concentration, and I tended to flinch before the 989s did. Similarly, my room is midsized-being about 20 × 15′ with 10′ ceilings. Larger rooms may require a speaker with greater output capability.

I have heard speakers that do deeper, louder, more dynamic bass, but I have never heard bass of the 989’s quality. Within its bandwidth, it is blazingly tight and quick with plenty of impact. It is supposed able to reach a flat 30 Hz, but I think that is a bit generous. Upper 30s would seem more realistic, in my room at least. So what you do get, you get done correctly. I tried to add subwoofers to the mix, but with mixed results (stay tuned). That rock and electronica I told you about sounded as I have never heard it before. Zero overhang and enough detail to match the precision of its midrange and treble. I have heard Moby’s Play [BMG] on many systems, and I know it’s beats can sound muddied. With optimum set up and ancillaries, there was no muddiness or bloat, but I did miss when the bottom octave or so should have kicked in.

I have heard speakers that make a wider variety of music and components sound more pleasing. As I mentioned earlier, the Magnepan is a good example. At certain points, I heard a bit of a lower treble edge. I still cannot say if this is an inherent Quad trait because this edge disappeared with the Bel Canto Evo 200.4, as well as with a few other upper-end amps that I auditioned. The 989 is known to interact with the negative feedback circuitry found typically in solid state amps. This interaction will supposedly result in harshness. So does this tendency qualify the Quad as having an edge? With many amps, the answer will be yes. Yet, the Bel Canto does not sound overtly smooth or rolled off to me, so is it the Quad or the Bel Canto that gets the credit for the otherwise flat treble? Arguably it is more common for amplification to have a flat response, so under this reasoning the Quad must be reasonably flat as well.

Some Important Caveats

If I understand it correctly, the 989 does not like high-current amplification, and will in fact trip its internal protection circuitry when it reaches its current limits. Conventional wisdom is that you should not try to pump more than 150 watts through the 989s so that you don’t pump too much current through them. What this means is that the usual bass-master solid-state amps may not be a good match. I tripped the current protection circuitry only twice, and once I was actually trying to find the limit. However, what I have found is that the speaker seems to bottom out when the electrostatic element begins to flap so much that it contacts its metal grid (i.e., stators). But somehow, high power amps seem to have greater control over the element. For example, when I tripped the circuit, I was using the Quad 909 amp, which is 140 watts per channel. Furthermore, I disagree that the Quads are compatible with low power amps. I tried Sharp’s 50 watt per channel SM-SX1 digital amplifier, but despite my high hopes, it never quite had enough power for the Quads to really open up.

Interestingly, I hooked up the Bel Canto Evo 200.4 in differential bridged mode. This seemed to defy physics, and changed the 989 to a beast even greater than before. When bridged, the Evo produces nearly 400 watts per channel, and it simultaneously pushes from the positive terminal, while pulling from the negative terminal. This saw-like push pull nature supposedly drastically increases the efficiency of the amp because the demands on the power supply are somehow reduced. I am speculating, but I think a similar phenomena is occurring at the electrostat level: the 989 should not be able to handle 400 watts, yet somehow it was – without flinching. It seemed to benefit from the increased dynamics, bass control, sense of effortlessness and overall loudness associated with 400 watts per channel, but as I said – without flinching or tripping any protection circuitry. And at the same time the Quad communicated the Evo’s inherent sweetness, vivid harmonics and dimensional texturing. Make no mistake – this is a kind of miracle; conceptually similar to taking an 800 watt Krell and feeding a pair of minimonitors, thereby imbuing the minimonitors with superhuman strength while keeping those virtues associated with minimonitors, and without causing them to spontaneously combust under the high wattage.

What the 989 does for music

Telling you what the 989 does for music gives you a much better idea of what this speaker is capable of than any litany of audiophile traits. No speaker that I am aware of reproduces vocals with more purity or realism. For those who truly love music, the Quad’s ability to transcend that metaphysical boundary between the listener and the performance is what really will seal the deal. You just simply cannot get more intimate with Sade without marrying her.

You have the choice of basking in the realistic naturalness of the whole presentation, or focusing on the instrument of your choice within that presentation.

As for individual instruments, horns are amazing – especially anything with a reed. Stringed instruments are also amazing. Massed or single violins indicate not only the amount of rosin in their bows, but the emotional intensity within a single bow stroke. Plucked strings have a startling impact that exposes their respective construction material, and a delicate decay that reveals the hollowness of the body of the instrument. You will be reminded that a piano is in fact an instrument with hammered strings, while you will also feel the scope of its hollowness. The piano in Sade’s “Haunt Me” from Stronger than Pride[EK44210] is a great example of this.

Any acoustic rock is amazing, so anyone with an appreciation for drums will be in heaven. Whether it be the impact of a kick drum or the rattling of a tom, the strike to the skin of the drum is comprised of so many more textures and sounds than simply just being a single beat to keep a rhythm. Over and over, drums that had previously merely functioned for the purpose of rhythm now existed as a sound in itself, to be enjoyed as a whole, but examined for each elemental texture. Some of my drummer friends have told me this before, but now I hear it. It takes some heroic coherency, dynamic composure and clarity throughout the entire spectrum to pull this off. Along this vein, the Grunge era, with its signature snare drums, will become more interesting to listen to than ever. I never knew how propulsive, yet ambient, Pearl Jam’s Ten [Epic ZK47857] could be. An even better example is Alice in Chains’ Jar of Flies EP [Columbia CK57628]. This album is a subdued, mainly acoustic set by a band that could otherwise rock with the best of ’em. It is recorded with growling deep bass, lots of popping snare drums, plenty of miscellaneous stringed instruments and cavernous ambiance and depth – as well as a spookiness to vocalist Layne Staley’s singing that seemed to foreshadow his untimely death. The 989 sailed through it all, which would otherwise have taken the respective strengths of several different speakers to accomplish.


So is this speaker perfect? You should expect a lot from an $8000 speaker, so I guess I would have to say no. It doesn’t have ultimate dynamics, loudness or deep bass capability. In addition, it is finicky about set up and about what gear you can expect to associate it with. But then again, I have listened to several $100K systems and, after listening to these speakers, and in the right set up with the right equipment, you’ll be surprised at how close this speaker comes to the best at any price – especially when paired with the bridged Bel Canto Evo 200.4. In fact, I would go as far as to say that this speaker reproduces music like few others ever have. 

If you are a middle-aged audiophile, does any of this sound familiar? Perhaps with the ESL-989, Quad has truly succeeded in updating and improving upon a classic… or perhaps it is simply another generation of audiophiles getting to know what Quad magic really is.


With all this talk about Quads and Magnepans, this is an appropriate time to talk about an important element of my playback chain: the equipment rack. I had been using a variety of different supports for my equipment over the years, but nothing audiophile approved or especially heavy duty. In other words I really had not paid much attention to my equipment’s support other than to address spikes, tiptoes, pods, etc. 

Most recently I used a rather large pine cabinet to house my equipment. The determining factor that finally prompted me to upgrade to an audiophile-type rack was that the cabinet, without a doubt, detracted from the sonic performance of my dipole speakers. Think of it in terms of stealth technology; the larger the reflective surface for the sound to bounce off, the greater the influence your cabinet will have on your room acoustics. My cabinet was a huge flashing blip on the radar; positioned between the speakers, it reflected so much of my Magnepan’s back energy that it was impossible to get a clear image. Worse yet, the critical midrange was ruined by this reflection. Instead, I needed a rack that was comprised of some sort of post and shelf structure. 

I researched various racks and settled on a model from Vantage Point, the Euro. I got both a three shelf and a four shelf in the premium oak finish, but I have seen the matte black finish version for about $200. The Vantage Point Euro had MDF shelves rather than the pine I had before, had sand-fillable posts and spiked feet. I am confident that all these features combined to clean up the sound of my system a bit, but I am unable to pinpoint any specific examples. However, the simple post design of the rack had an immediate dramatic effect on the midrange and soundstaging performance. The rack simply did not reflect any of the Magnepan’s dipolar back wave into the listening room; it was… stealthy. I did not do a before-and-after with the Quads, but I can only imagine how much more incredible the difference would have been considering how finicky the Quads are in terms of room placement.

The bottom line is that, before you drop any heavy cash on equipment, you should at least drop the 200 or so bucks on a quality equipment rack. So take my advice – if you have any type of dipolar speaker, a post-based rack like the Vantage Point is an absolute must. And take this more important advice; I converted my pine cabinet into a wardrobe and gave it to my wife, so the cost of the rack became a non-issue. How often can you say that about an equipment upgrade?

Vantage Point is distributed by:
Sonic Integrity Group
P. O. Box 3266
Santa Fe Springs, CA 906

Mea Culpa

I am familiar with what a bridged circuit encompasses and all the technical jargon that goes with it. However, as a reader pointed out, I mistakenly interpreted Bel Canto’s implementation of their bridged circuit to be something it is not. There is in fact only but one bridged circuit-and that is what is found in all bridgeable amps, including the eVo. With such bridging comes a theoretical quadrupling of wattage, doubling of distortion and increased current demands-which results in the reduced ability to supply current into lower impedance loads. However, there are different variations of this same bridged circuit that a designer can implement that will allow a bridged amplifier to increase its wattage delivery, while decreasing distortion, and still drive low impedance loads. Such variations are often more costly to implement, but seem to provide successful results; companies such as Bryston and Krell use such designs to produce high powered amplifiers that have no trouble with the most difficult to drive speakers. But they still rely on the same known concepts of bridging to accomplish this. 

Bel Canto’s eVo design is not revolutionary in that it, too, is based on the basic concepts of bridged amplification. However, their Tripath technology and inverted-phase amplifier board design (power supply) allow them to bridge their amps while decreasing distortion and allowing a decent amount of current delivery into low impedance loads-albeit with just a slightly different means of accomplishing it. But when all is said and done, it is still a bridged circuit.

My apologies for not getting it right the first time around.

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