As to how we appreciate music, I’m a big fan of the so called Gestalt theory. Sort of. The theory says, in general terms, that the brain/mind automatically organizes sonic elements into patterns and configurations (Gestalt) to make sense of the environment, and before entering particularistic evaluations. So, rather than taking individual music samples, tracks or records, one by one individually, we first approach music through a more general perception, a pattern, and only after pay attention to individual features of the music in question. As long as it’s Indie music, that is, it sounds, feels and tastes like Indie music, it’s fine, and it matters less what particular kind of Indie music it is. And the same for rock, jazz, classic etc. etc.
Can the Gestalt theory be applied to Hi-Fi? Why not. One such pattern could bring together systems that are built around one-way, crossoverless loudspeakers equipped with a high-quality widebandwidth driver (or two-way concentric a la Tannoy, Altec 604 etc). Friends of such systems care less, which widebandwidth driver (PHY-HP, Voxativ, EM Speakers, Lowther, Feastrix etc.) is actually used as long as the system provides that special intimacy of the listening experience often associated with widebandwidth driver based systems. The same is true, I guess, of systems assembled around multi-way horn speakers, preferably 5- or 6-way in the Japanese/French style, driven by a low-power (tube) amplifiers. Here it’s the holistic pattern of ultimate sonic realism and concreteness of the sound that comes first as the pattern, the illusion of sound coming, not from a recording, but musicians present in the listening room. Mutual differences are secondary.
Now, the third pattern I have in mind has to do with sonic accuracy, general lack of coloration (room or other), details, coherence and purity, the standard attributes of Hi-Fi, as you well know. I could list a number of loudspeakers that more or less fulfill the conditions, but before those I would choose in this case headphones (eg. a small, easily controlled dynamic driver close to the ear) to obtain the above sonic virtues. Headphones do, however, suffer from the fact that the listening experience feels somewhat unnatural. Some people are more allergic to it than others, and some don’t care. Without dipping a spoon into this mess, just want to ask this: if a believable illusion of a musician(s) being present in the listening room, is the aim, would it be better to have the speaker, medium, and ear in different locations, rather than stuck together? The problem with headphone listening is analogous to what is found in the visual arts regarding photorealism: the more realistic the image/sound is, the better it serves as the most glaring reminder that it is not what it represents.
THE WORLD’S LARGEST HEADPHONES
So, finally, we arrive at today’s topic: the legendary QUAD ESL63. If one wants those sonic strengths of headphones, not from headphones but from a pair of loudspeakers, what would be the most obvious option? I’m sure I’m not the only one to whom a loudspeaker especially springs to mind before others: QUAD ESL63, an electrostatic speakers from 1983 – “the world’s largest headphones” as it is sometimes described.
I don’t know who first used the epithet, but the parallel is so obvious that it has later been put into the mouth of several commentators. If you ask the Swedes, the comparison was invented by Svalander Audio’s Josef Svalander; in Denmark Troels Gravesen has described the ESL63 as gigantic quality headphones, and in the Anglo-Saxon world the epithet has been repeated by several authors.
Is the Quad ESL63 worth its reputation? To find out, I had my ESL63s restored with the expertise and experience of Verde Audio’s Mika Rintala (thanks Mika!). And yes, after critical listening, I have to admit the Quad ESL63 is not only a very competent speaker as a speaker, but also a very, very headphone-like sound producer.
As is well known, the ESL63 is a full-range (was designed to operate without a separate woofer) electrostatic loudspeaker, which Peter Walker released after 18 years of development. The operating principle is the same as in the Quad ESL57, but the panel structure is different, and therein lies, I believe, the secret of the ESL63’s headphone-like sound.
A quick reminder. Of the four static panels, the one in top and bottom are bass panels. In between are two midrange/treble panels, the surface of which is divided by wires into seven concentric ring-like areas. Control is done by electrical delay lines so that the input impulse first goes to the middle ring, then progresses alternately to each outer ring until it reaches the outermost one. The structure imitates the theoretical ideal of a point source, the sound propagating as a pulsating spherical wavefront, and aims for precise temporal reproduction between different frequency bands. The ESL63 is not a line array as many other electrostatic and flat diaphragm speakers.
SMOOTH SOUND
The ESL63 is not a perfect speaker, even technically (what speaker is?), but what matters is that it’s able to provide a reasonably flat frequency response over five to six octaves listened from a normal listening position. Other responses (phase, impulse and step) are not bad either, and the distortion unusually low for a loudspeaker, all resulting in a very smooth sonic presentation.
Avid FM radio listeners may wonder how the voice of the announcer, they’ve become familiar with over the years, would sound like face to face? Listen to radio through the ESL63. It still offers one of the most convincing answer to the question. Its sound is, where it matters, so even and sufficiently uncolored. No wonder that many public broadcasting and record companies used Quad ESL63s as monitoring speakers back in the day! Quad’s motto: “The Closest Approach to the Original Sound!” is not far-fetched.
Like with best headphones, the accuracy and nuance of the ESL63’s sound can be illustrated by the old cliché: even familiar recordings reveal subtle details that one doesn’t remember paying attention to before. This happens with the ESL63 all the time. Makes me wonder how it would sound in comparison of with STAX ESL-F81, a static speaker that the headphone manufacturer STAX produced a small batch in the 1980s, and the one Ken Kessler described as the world’s largest headphones!
The sound of the ESL63 may, depending on the reviewer, not be entirely colourless, but it’s wonderfully coherent and consistent. No discontinuities, no articulations, just one big, indivisible sound.
MAXIMIZING THE ESL63’S SOUND QUALITY
The most phenomenal sonic quality of the QUAD ESL63 is its ability to image sound. The listener is able to follow small spatial cues of the music in all directions and accurately navigate in a three-dimensional space. In Kaija Saariaho’s percussion piece Six Japanese Gardens, the instruments are in a semi-circle around the percussion player, at slightly different heights. I don’t know how the performance is recorded (YLE), but the ESL63’s ability to tell with extreme accuracy how far in depth and lateral directions the instruments are, is absolutely crazy!
In terms of tonal balance, and evenness of bass reproduction, the placement of the ESL63 requires a bit of practice. Like dipole speakers in general, it is best to first pull them as far away (minimum > 1m) from all surrounding walls as practical, and then place them in the room as symmetrically as possible. It is also worth considering turning the speaker towards the listening position, depending on what sounds best. I personally ended up directing the speakers crosswise in front of the listener, partly because the stereo image becomes less critical to lateral head movement, but other angles are possible too. Despite all the adjustment, the ESL63 is largely a speaker for only one listener. Just like headphones!
As far as I know Walker originally designed the ESL63 for the floor, and that’s fine for me. But there seems to be consensus about the advantage of raising the speakers to ear level on a stand about 40 cm high for exposing more treble and making listening more headphone-like. To maximize headphone-like listening, one might consider listening semi near-field, from the distance of less than 2 meters.
For some, the ESL63’s treble sounds muffled, especially from off-axis. I’d personally say that the treble is just different. It is kind of misleading to talk about treble separately, as phenomenologically there is only one sound, from which individual frequencies from low to high pop out with the music. In this respect, the treble of the ESL63 reminded me of Manger’s widebandwidth dynamic flat-cone driver, which also radiates sound in a wave-like manner from the center to the edges.
SUBWOOFER OR NOT SUBWOOFER?
The Quad ESL63 has received most criticism from later generations for its limited bass and dynamics, s well as modest maximum sound pressure. That is a fair judgement given that the speaker was designed sound transparency, non-coloration and low distortion in mind. The fact that the ESL63 offers useful (- 6dB) bass down to 40 Hz (depending on the listening room) is just what the speaker was expected to do. So does the ESL63 need a dedicated subwoofer? Not in the sense that it would be a bad speakers without one. But it’s true that a sub would not only bring the response down to 20 Hz, but also reduce inter-modulation distortion when the stator panels are relieved of the task of reproducing frequencies below 100 hertz.
One such commercially available sub is Gradient SW63, a dipole subwoofer with two Peerless 300 mm woofers and active low-pass filters. Good news is that due to inquiries from around the world, Gradient is restarting the production of the SW63 again! This sub not only solves the loudness problem by increasing the max SPL by 10 decibels, but also works as an ideal stand with its ready-made inserts.
I’ve personally never missed a sub, one reason being the music I’m listening with it, and the way I listen to it. Music (eg. string quartets) rarely dives deeper than 40 Hz. Another thing is that the sub would take away a portion of the speaker’s headphone-likeness. It is my experience that in hybrid systems, the subconscious tends to sense a separate sound sources, no matter how well the integration is implemented. On the other hand, I’ve heard the ESL63s assisted by an active Gradient subs beneath, and a Townshend ribbon super-tweeter on top, and had no problems with the performance whatsoever!
THE AMPLIFIER AND THE SOURCE
One eternal ESL63 theme is what would be an ideal amplifier for it? Reportedly, Peter Walker drove his 63’s with a 15-watt tube amplifier, and was satisfied. I did the same but wasn’t too happy. It is generally believed that the 85 dB sensitive, six-ohm (min. 3.5 ohm) speaker thirsts for an output power of at least 50 transistor watts into 8 ohms, and preferably double that into 4 ohms. I’m inclined to agree. Quad’s own proposal for the ESL63 was the 80 watter (100 watts into 4 ohms) 405-2, manufactured from 1982 to 1993. Many consider the 2 x 140 W Quad 606, launched in 1987, to be even better.
I tried QUAD’s 45 watt (8 ohms) Vena II Play, a mid-fi amp from QUAD’s current product range, a Class AB engine with linear power supplies, but without Quad’s original current dumping topology. It proved to go reasonably well with the ESL63’s. In the Kyrie part of Mozart’s Coronation Mass, the combo produced solid percussion sounds, and otherwise held the music (choral and orchestral) in a good control. Shorter and longer echoes of the Zurich Tonhalle were clearly conveyed as Jean Guillou played Mussorgsky’s Pictures at an Exhibition on his organ. When I played sample CDs from the Diapason music magazine, 100-year-old French chansons from the depths of the Internet, and contemporary ambient music from a Dutch classic music online radio station, the ESL63/Vena combo recreated a freely flowing midrange that served especially well vocal music with a fine-grained precision and that soft and smooth 3D QUAD sound. When I replaced the Vena with a much higher power integrated amplifier by Musical Fidelity, music sounded a tad more refined, plus the grip on the bass panels was further improved.
TOP VALUE FOR MONEY
Quad Musikwiedergabe in Germany sells refurbished ESL63s for over 5,000 euros per pair. It’s not nothing, but given what value is available for the money, not excessive either. A used pair of ESL63s in good condition can be found for 1000 – 1500 euros. A very tempting option indeed.
If I remember correctly, The Absolute Sound magazine once (long time back) asked its editors to assemble a system from all the devices on the market in different price categories. In the ‘under five thousand’ dollar category, Dr. Robert E. Greene chose a system with a $100 portable CD player and a cheap amp, 90% of the money going to a pair of Quad ESL63!
