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The early days of electrostatic loudspeakers

Early Electrostatic Impressions

The 1950s were horny times. In addition to suffering the hormonal imbalance common to most teenaged boys, our speaker choices were limited. Living in central Illinois, Chicago was our mecca for hi-fi equipment and the largest showroom was at Allied Radio, an electronics supply house, turned partly audio salon. About 90% of the speaker section of my tattered 1958 Allied Catalog describes horn type speakers from the modest 2-way Electrovoice Baronet with an 8-inch woofer and small compression tweeter to audio nervana, the Klipschorn. Amplifiers were small and horns were efficient. We liked the sound energy of horns, but not their often harsh quality and peaky response.

Four technologies changed the sound stage in the late fifties. A startup named Acoustic Research (AR) introduced a new kind of infinite baffle speaker--a 12-inch woofer and dome tweeters in a modest-sized sealed box, and they reached down into the 30-something range. The woofer cone was loosely-sprung and used the pneumatic pressure of the box to reinforce cone return. An air spring reduced distortion, but it was much less efficient.

Transistors were introduced to consumer electronics in 1957 and circuit designers soon found that these devices leant themselves to higher powered amplifiers. These worked very well with inefficient low end drivers that benefitted from better cone control from the higher damping factors offered by many solid state designs.

Electrostatic panels were developed in the late '50s and showed lower distortion and greater transparency than dynamic speakers. They were inefficient, a bad thing in general, but they were happily married to acoustic suspension woofers. Generally, electrostats appeared as high frequency units, perhaps because it was easier to manufacture small membrane panels. I remember only the Quad full-range electrostat until well into the '60s when the KLH 9 appeared, but way beyond the collegiate budget and its low-end disappointed the testosterone influenced ear.

Finally, because stereo disks, introduced in 1958, required two audio channels, amplifier power and speaker radiating area were generally doubled and produced more sound energy in a room. We could afford less efficiency in speaker design, if it promoted sound quality. As stereo sources became more sophisticated, reduced distortion and transparency in speakers became more critical.

All of these technologies came happily together for early adopters of new speaker design. Small speaker enclosures with good bass extension that didn't require a corner, reduced speaker room domination in high quality systems. Several high frequency electrostatic units were offered that could be paired with acoustic suspension low frequency units of similar efficiency, to avoid the Quad bass gap and improve on the often middling mid-range and high-end performance of domed and cone tweeters.

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The First Hybrid Systems

JansZen

A particularly nice combination was the AR-1W (the low frequency driver of the AR-3 mounted in an AR-3 box) and a JansZen 130--four 6x6 electrostatic panels/channel mounted in a canted array to offset some of the electrostat's beaminess. The 130 had a high pass filter and claimed a flat response from 600-20,000Hz, while the AR-1W was flat from about 35 Hz to 900 Hz, then began to roll off smoothly. This allowed inexpensive bi-amping, unless you could hear an efficiency difference between the ARs and the JansZens. This was also fortuitous, because the early solid state amps, nicely tightened up the ARs, but many sounded terribly gritty in the mids and highs, where a Dyna Stereo 70 or Marantz 8B provided smoothness for the electrostats.

I listened to this combination for about four years but was never quite happy, largely because I found some deadness at the crossover between the AR and the JansZen, but it was my first serious system and I still have the ARs, JansZens, Marantz 15 and 7t and Dyna 120. They all still work, when I lapse into a nostalgic mood for vinal and the hormone-laced days of extended adolescense.

Other JansZen models

Competing with the AR-1W / JansZen 130 and 65 combinations were JansZen's own integrated ESL/dynamic systems. Though I am not sure when they began offering hybrid designs, a 1959 edition of Electronics Illustrated Hi-Fi Handbook includes pictures of the Models 65, 200 and 300. JansZen offered the 4-panel Model 130, either in the canted or flat array. A picture of the canted version is shown in the 1959 Stereo Hi-Fi Handbook.

Competing with the AR-1W / JansZen 130 and 65 combinations were JansZen's own integrated ESL/dynamic systems. Though I am not sure when they began offering hybrid designs, a 1959 edition of Electronics Illustrated Hi-Fi Handbook includes pictures of the Models 65, 200 and 300. JansZen offered the 4-panel Model 130, either in the canted or flat array. A picture of the canted version is shown in the 1959 Stereo Hi-Fi Handbook.

The Model 200 includes the flat 4-panel electrostat array, a 12-inch low frequency driver, the electrostat's power supply and crossover in a 2.5 cubic foot box. The omnipresent 50s style tapered legs were included at no extra charge.

The JansZen Model 300 is smaller, with an 11-inch low frequency driver, two electrostatic panels the power supply and crossover. Though the Model 300 has the same ESL components as the Model 65, the 300's panels are mounted in a concave pattern. Note that on both the 200 and 300, the ESL panels are tilted up slightly for a better axis.

The Model 300 was also available as a panel system for custom mounting. Here you can also see driver details.

The JansZen panels were also used in EPI's Stat 450 and the KLH 9s, the first large panel electrostats were designed by Arthur Janszen.

Lafayette

Lafayette Radio offered an ESL high frequency unit in a design similar to the JansZen 65s except with three panels, the center of which was narrower.

Pickering

Pickering, a company that produced early high quality phono cartridges, also designed an ESL high frequency unit. Their brochures promised a companion low frequency unit, but I never saw these advertised or available. I would be interesting to have more information about the panel's curved design.

Radio Shack

Radio Shack may not be the source you think of first for high quality speakers, but over the years they have marketed several units that have been exceptional for the price.

The First Full Range Systems

Quad

The first full range electrostat was the Quad, introduced in England in 1955. While some dealers in large U. S. cities may have had a source for these, generally they were obtained from England and required a sea voyage before they became part of American sound systems. While they were on American radar, some owners did not understand the profile that ESLs presented to amplifiers. In 1961, the first year I find these included in the 'hi-fi annuals', stereo disks had only existed for three years. Listeners were struggling to duplicate their single channel systems. 30- to 40- watt amplifiers were the high average. Macintosh offered a 60 watt monoblock and Marantz had the stereo 40 watt model 8B at $198. The Quads speakers were well-suited to their companion Quad amps, but these were modest-sized units. Quad owners learned to live with limited dynamic range and bass extension.

At university, I became acquainted with a professor whose primary eccentricity was that he had filled his house to overflowing with LPs (the 78s were stored in the basement). I remember being able to request any recording from a sizable fraction of the Schwann catalog to be auditioned on Quad ESL-57s, driven by Quad electronics. In the roughly six preceding years, my audio taste had progressed from a 1948 RCA console with a 45 rpm changer and 8" unbaffelled speaker with a peg board back, through moderate sized horn systems to entry level acoustic suspension systems. My maturing ear remembers the Quads as being exceptional, especially compared to horn designs and even good acoustic suspension systems, on chamber music and opera. This early experience formed a taste for the transparent, articulate sound that I find in current ESL technology.

Quad equipment was not expensive in the sixties. The Quad ESL sold for $158 per side. When you consider the price of the AR-1W and JansZen 130 combination at $145 and $180 per side, the Quads represented an alternative with more seamless spectral balance but within a more limited range.

KLH

Attraction to living partners usually is not based on such insubstantial issues as taste in reproduced sound, but more than one partnership has been strained or broken by audio arrangements in the living room. KLH 9s were among the first such temptations for audiophiles that challenged this issue. To add to the insult of door-sized speakers, ESLs aren't happy until they have intruded themselves well into the room they inhabit.

I have an indistinct recollection of hearing a pair of KLH 9s in a showroom in Chicago in the mid-60s. I believe they were being driven by either a Mac 275 or a pair of Marantz 9s. I was attracted because I was then listening to Janszen 130s, which was approximately the tweeter section that the KLH 9 employed. Like the Janszen, I recall the high end being a bit reticent and with considerably more low end than the Quads.