Quad ESLs: Then and Now
Can a loudspeaker be
all things to all people? Probably not, but the Quads take a damn good
shot at it and I'll dispute anyone who says otherwise.
Igor, It's Alive!
It is rumored that when introduced at the London Audio Show in the mid-1950s, the speaker we now call the ESL-57 caused many conventional speaker manufacturers to wonder how long they, themselves, would survive. "Walker's Little Wonder" was a remarkable achievement, even measured by today's standards.
Put in perspective, we must remember that the unit was originally meant to be used as a monophonic reproducer in the close quarters typified by the average British home of the time. It was designed for music lovers at a time when other system components lagged far behind, and the notion of 'high end' was inconceivable. Cartridges, tonearms, turntables, and recordings were just emerging from what we now call the 'historic' period dominated by 78 r.p.m. shellacs. Was Walker anticipating the development of stereo with its demands for phase accuracy and wide frequency response? In my mind, this is a certainty.
The phase coherency and the consistent frequency response of the ESL-57 are its basic strengths. These qualities made it an outstanding reproducer even in the early days. Coupled with shocking transparency, they allow one to overlook the shortcomings of the speaker even today.
The Sound (of One Speaker
The musical limitations of the design are primarily a result of physics and technology. The reproduction of bass frequencies is the biggest challenge the designer faces. Obtaining response extending into the octaves below 100 Hz requires increasingly larger panels. As the panel grows, it becomes more demanding on the electronics, to the point of economic and physical impossibility. Walker took a different tack, and cleverly blended three panels into one unit capable of delivering wide frequency response with near-seamless coherence. The result was a musically satisfying design with surprisingly good imaging and quite acceptable dynamic capabilities. In addition, huge amounts of power were not required to achieve good listening levels. This was certainly a bonus for owners of the 15 Watt Quad II (Quality Unit Amplifier Domestic) amps sold at the time.
In comparison to the ESL-63, the bass is dryer and not quite as fulfilling. Dynamics are less pronounced and some drummy resonances from the metal screens are excited in the loudest passages. A slight congestion in the midrange imparts a legato effect on some recordings. This was evident while auditioning Bach · Kreisler · Ysaye, a solo violin recording on Water Lily Acoustics [WLA-WS-07] by Arturo Delmoni. A sensible limit on listening levels is necessary unless one is willing to risk arcing, which will damage the Mylar panels now said to be unavailable from Quad. Any good quality amp between 8 and 30 Watts with a stiff power supply is suitable for driving these speakers without harm, provided one exercises reasonable caution.
The highest treble is very directional and this means that the speakers must be angled inward, towards the listener or they will sound excessively dull and closed-in. This is probably the most contentious issue surrounding the ESL-57: the "beamy" treble and the restricted listening position it causes. Sadly, no solution exists for this, so resign yourself to hours of solitary listening or constant scrimmages for the sweet spot.
On the plus side, their transparency is astonishing and something once heard, never forgotten. The sound just seems to come from somewhere in and around the speakers and one can - given the right associated equipment - see into the soundstage with exceptional clarity.
Where it exists on the recording, ambiance reproduction is excellent, and the atmospheric Delmoni recording mentioned above is an outstanding example of this. What this indicates is a superb ability to resolve the subtle details of decaying sounds, and is a natural outcome of the speaker design.
Some will say that the imaging is slightly diffuse, but I hold this to be consistent with what we experience at a live concert, where the sounds are blended by the hall acoustics. This too, contributes to the realism of the picture the ESL-57s paint. The RCA Classics pressing of Claire de Lune [LSC-2326] conducted by Agoult is a mellow, seductive tour de force for these speakers. Speaking of seduction: I've got to say that the reproduction of the human voice is the true forte of the Quads, old, and new. If you've got it, give a listen to the classic They Can't Take That Away From Me on Windham Hill Jazz [WH-0116] as sung by Patti Cathcart in a smoky, jazz mezzo voice while Tuck Andress strums through the changes on his Gibson in a spacious acoustic. What the Quads do with this cut will leave you breathless.
Enter: FRED, Lord of the
The first major difference between the old and new Quad speakers is the dipolar radiation pattern chosen for FRED. The ESL-57 was designed to radiate only from the front, and this makes it quite easy to set up in confined quarters. A true dipole has sonic advantages and will sound more spacious and airy, particularly in the lowest octave, but it needs more room to breathe. Many people think that ESL-63s are bass shy. The speakers are in fact, capable of prodigious bass. They must be positioned five feet or more from the back wall so that the rear wave does not have a canceling effect on the front wave at low frequencies.
The second innovation incorporated into the ESL-63 is the concept of the delay-line signal path. Imagine concentric rings of conducting wire (electrodes) covering the surface of the speaker panel. The feather-light membrane at the heart of the speaker is induced to vibrate by the alternating music signal traveling through the electrodes on the front and rear panel. As the music signal is fed first to the centre section of electrodes and then to each ring in turn, the music emanates from the centre to the edge of the panel like ripples from a pebble dropped into a pool of water. The effect mimics a point source of sound focused about twelve inches behind the plane of the speaker. The result for the listener is a speaker that is remarkably open, quick, and natural.
Many other weaknesses were addressed as well. Any amplifier between 50 and 200 Watts that is stable into 8 Ohm capacitive loads can be used with confidence. The ESL-63 has a vastly increased tolerance for volume demands and protection circuits that will shut down the unit to prevent damage to the panels. Great attention has also been paid to making the signal phase response more accurate and coherent. This has resulted in improved decay characteristics that make the speaker sound quicker, clearer, and more realistic, especially in the reproduction of percussive transients. This has also meant better midrange detail and an overall improvement in transparency.
A perfect example of this is the recording of Toru Takemitsu's Waterways by the ensemble, Tashi [RCA ARL1-3483]. The group consists of clarinet, piano, violin, cello, harps, brass, and a variety of percussion instruments. The piece was recorded in a large studio with simple microphone techniques. The music is spare and evocative, depending more on timbre and dynamics than rhythm to express the composer's ideas. The ESL-63s present a spacious vista sparsely populated with islands of sound ranging from a piano echoing in the darkness, to the thunder of a bass drum and raucous blasts from the brasses.
The new speaker has the ability to handle a wide spectrum of music from solo wind instruments to strings, brass, percussion, and symphony orchestra with conviction and aplomb. The excellent Solti recording, Venice [RCA-2313] is a great example of how adept the ESL-63s are at handling the breadth, depth and dynamics of an orchestra going full tilt. Listen to the overture to Rossini's Semiramide. The Orchestra of the Royal Opera House stretches beyond the bounds of the speakers. Depth is exceptional. What a roller coaster of dynamics. Hang on and enjoy the ride!
What really distinguishes them is their overall balance in every area: the ability to play as loudly as one can reasonably expect; a realistic tonal balance in which no area is unduly emphasized; a sensational sweetness in the mid-band and finally, standard-setting transparency in the treble.
|Copyright © 1998 Audiophilia Online Magazine|