was cluttered with pipes!
History of:
Wright/St.George Laboratories Inc.
Previous Work
I had (with another friend from high school) started a company to custom install High Fidelity equipment in (long suffering) friends homes. We started this in late 1951. My first project (for myself) was to build a replica of a Klipchorn from photo's. It took over five months as I had to use hand tools. I found that I was able to purchase the requires drivers from a Winnipeg based company, Electrical Supplies Ltd., who sold HiFi stuff from the basement of their store. Down there, they dealt in equipment used in broadcast studios and PA companies. By the late '40's, more of this type of stuff began to be imported from England where some returning soldiers found that they couldn't get jobs. These people had received excellent technical training. They seemed to have come from Yorkshire or the surrounding areas.
In the winter of 1955 I built a tweeter based on the use of 'shade sceening' which was hooked up to a Williamson amplifier (it had a WWFB output transformer) with the electrodes connected to the output tubes. To boost the bias voltage, I used an old HV power supply from a scrapped oscilloscope. It took me less than two days to build he ESL and while I waited for the cement to set, I was able to build a veneered plywood cabinet for the dipole. Buffs from the '50's will recognize the the black grill cloth that had a gold 'dribbled' pattern (this grill material could be easily identified because or its acrid smell). When everything was finished I had to postpone playing it as we had a power outage from a winter storm which blew down a tree between Reditt and Minaki.
The power was restored about 7 PM the next day. The first record I played was Boyd Neal's rendition of Greensleeves. Although it wasn't loud, I was hooked by the fidelity. As I returned to Boston by train I couldn't take it back with me. But after the summer vacation I shipped a lot of other audio gear back to MIT in the fall of 1956.
The ESL I built the first ESL in Minaki is shown in the photograph - it is the small unit hanging on the wall.
When I played the tweeter
in conjunction with an ElectroVoice 'Aristocrat enclosure' using a Vitavox
speaker, several friends suggested that I start a company (Wright Electroacoustics
- as foreign students at MIT we were limited as to how much we could earn;
So at the suggestion of my advisor, some of us started companies
to employ other US students). I had already built several power amplifiers
that were in use in small Boston recording studios. I the basement
of my Commonwealth Avenue apartment, I built a much larger ESL with the
same construction. It is the large unit in the foreground. As the ceiling
height was limited, the ESL had to be placed on its side to take the photo!
Of course. this ESL was to be used as a stereo pair - standing upright
on either side of a door. The bare frame of the other speaker is standing
upright as the rest of the basement ceiling
was cluttered with pipes!
When it was completed the results were spectacular for the period. I had built a special cascode amplifier that didn't use an output tranformer. It uses four 807 transmitting tubes with floating filament (heater) transformers. This amplifier weighed over a hundred pounds as I used (cheap) war surplus stuff to build it. I was able to convince Winchester Transformers to make a step-up tranformer as well as a high voltage power supply.
As an aside, many of the current ESL's follow the same curved construction
By the spring of that year, we had assembled and tested five tweeters and seven full size systems. We felt that we were ready to book exhibit space at a major show! (Here someone else picks up the narrative).
New York Hi-Fidelity Show
The exhibit was trucked down from the company's plant in Newton Lower Falls. The truck was a closed sided truck covered with a tarpaulin. Because the confirmation on the space came at the last moment, it was the only truck available no other vehicle available. After the truck left the plant, there was a cloudburst. Apparently the rain was following the truck. Wright was in a panic because of the rain. The stuff was unloaded at The Hotel New-Yorker and set up to dry out. The next morning the ESL's were turned on at 7:00 AM. At 8:30 the power to the ESL's was turned on. By the show opened, even the sputtering had ceased.
One of the attractions was a seven foot square stereo ESL using two large area full range panel arrays operating ar a twenty degree angle to each other.
This photograph was taken at the show. In the back, you can see the large stereo ESL. At the left side is one of the smaller electrostatic speakers, on the floor. It used a slightly vertically curved woofer ESL made out of 'micro-louvred shade screening' mounted on a phenolic frame using a special adhesive. The two electrodes were spaced from each other by the use of lucite strips (both on the back and front) of the Saran diaphragm (tm). The conductive coating used a modified detergent which had to be diluted with deionized water. This was essential to make it permanent. It was operated as a constant-charge resistive element. The resistance was ~60 Megohm per square. The ESL woofer spacers were five micro-louvre units on centers. the woofer was four bays wide.
The tweeter was centered above the woofer. This ESL used a similar construction with a horizontally curved electrode structure with a single micro-louvre screen - the spacing rods were about an inch apart - allowing the tweeter to be about five inches high (plus the plastic frame). The tweeter is visible at the left side of the photograph
Some of the stereo material was played on a borrowed two track Ampex tape deck but a stereo pickup was also used to play a selection of disk recordings using a Fairchild belt-driven (3-speed turret type) turntable. A pair of 120 watt Macintosh power amplifiers were used being switched between the two different stereo ESL systems.
The company used two Dynakit's with a stereo adapter.
A large number of dealers and manufacturer's
attended the show. During the show Sherman Fairchild invited Wright to
visit his plant and his chief engineer, Ruben Carlson asked him to visit
his home lab.
Time magazine covered the show. Here is what was said:
ELECTRONICS
Stereo Grows Up
To the 1958 High Fidelity Music Show in Manhattan last week trooped more than 5o,ooo audiophiles who wanted to hear "the new dimension in sound," stereophonic records and tapes. Spread over five floors, the 125 exhibitors concentrated on showing the fast growth of the new art. General Electric showed only stereophonic components; Massachusetts' small Wright St. George Laboratories displayed an inexpensive ($65), thin (1 3/8 in.) picture frame speaker that can be secreted behind curtained walls or prints, is well suited for stereo,* which requires at least two speakers some distance apart. This year, sales of such stereo gear will help swell the music market by $50 million, to $450 million or more.
Ampex, Revere, Bell Sound Systems, Wollensak, Webcor are selling stereo tape players. Stereo record players (price: $12 5 to $2,500) are being pushed by Pilot, Columbia, Zenith, RCA Victor, Emerson and others. Into the market for stereo records have come Columbia, RCA, Angel, London, Audio-Fidelity.
* Stereo achieves a full
concert-hall quality by reproducing two separate sound tracks, which the
human ear combines, just as the eyes do for stereo photos to create a better
image. In recording, at least two microphones are used, each stationed
at different points to pick up the varying shades of sound.
RCA's BURNS & Stereo
TAPE
New
dimensions for old sounds.
Yet many music lovers have held back from buying stereo because there is such a wide variety of systems to choose from, and buyers are wary lest they get trapped in a battle of speeds such as the old 33i-45-78-r.p.m. fight in records. Last week's show demonstrated that the industry has -pretty well shaken down to playing two systems.
For records, companies agreed to adopt the "45/45" system, in which each record groove is pressed with two sound tracks, angled at 45'. Thus one machine will play most stereo records. Stereo sounds richer on tape, although sales of stereo tapes this year will hit only about $3,000,000 because they are tough to thread and are expensive (about $16.95 for 60 minutes' playing time). But major companies are now planning a simplified tape system.
Blades Before Razors. RCA Victor last week brought out a magazine-load cartridge that eliminates the shortcomings of spool tape. This month RCA will put on the market a broad library of classical and popular stereo magazine tapes in four sizes and prices, from $4.95 for 22 minutes to $9.95 for 60 minutes. Player sets for the cartridge tapes will come out later because producers, such as Motorola, insisted that RCA first put out enough tapes to make a market. RCA's own magazine tape playing system will come out by Christmas, retail for $295 to $450.
To spur stereo broadcasting, the Federal Communications Commission granted permission for FM stations to test stereo "multiplexing," a system that sends the two separate signals over a single radio frequency. New York City's-WBAI started to broadcast stereo last week; WRCAFM will begin next week. Manhattan's two-year-old Madison Fielding Corp. last month put out a multiplex stereo adapter that can be attached to any FM radio, turn it into a stereo set. Price: $49-95.
RETAIL TRADE Blue Chips to Live With
Manhattan society turned out in black tie this week at the opening of an antique shop: the plush new quarters of French & Co., oldest and largest U.S. dealer in antiques. What the champagne-sipping Manhattanites saw was a $10 million display of furnishings ranging from Boucher tapestries valued at $175,000 to a Louis XV desk insured for $250,000. French's splashy housewarming was only part of an antique boom that has sent a stream of pre-183o European furniture to the U.S. (1957 imports: $14.2 million), has even sent European buyers scurrying here to shop.
Part of the appeal of antiques is purely financial: they represent a hedge against inflation, have increased in value as the dollar has declined. U.S. museums spend from $10 million to $20 million a year on new purchases, thus leave the market thinner. Even tax rulings contribute. An antique buyer may sign over his purchase to an institution that will receive it upon his death, take a deduction each year while he keeps it in his home and continues to ``````
(Page 86)
When the NY show was over, the exhibit was trucked up to New England, and, Wright-St.George Labs exhibited in the New England Hi Fidelity Show held in Boston.
Many of their ESL's were sold in the New England area. As David Hafler was able to produce a 80 k output transformer for the Dynakit, several systems were produced using 80 K output transformers.
The New York Hi-Fidelity Show was first written up in Time magazine. The company was invited to the Toscanini home by his son, Walter, who had a mastering studio in the basement. He was impressed by the sound of the large stereo system as shown in the photo. The Maestro used to sit in the large high ceiling hall to listen to his recordings. The system's speakers were a large Altec Lansing system with front horn-loaded dual 15" woofers combined with a bass-reflex and using a special high frequency (horn-loaded) pressure driver.
Percy Wilson also heard the speakers in a Boston Audio Store (The Listening Post) and visited the factory in Newton as well.
TECHNICAL- TALK
Column Loudspeakers - a correction
I am afraid that the sketch I sent across the Atlantic for last month's issue was too crude for the editorial staff to follow accurately; and unfortunately I missed out one important dimension in the text: the length of the throat unit. In my case it is actually 6 in. high and is made of four boards 13 in. by 6 in. chambered to an angle of 45 degrees at the 6 in. edges, so that it fits together with internal dimensions 12 in. by 12 in. by 6 in.
The Keene's cement is then built-up as shown in the sectional diagram herewith.
(see page 336 of the December issue for the complete sketch of the column)
I have actually used a similar box to contain the disperser unit as shown; but I fancy that a vertical dimension of 8 in. or even 9 in. might be better.
I also have the idea that the loading and the dispersion might be better if the -speaker unit were reversed so that the magnet is above the baffle board in the throat unit; there is room for it provided the disperser does not project too far into that unit, and in that case the disperser might terminate in a flat of the same diameter as the magnet, pot, instead of in a point. I have not yet had opportunity to try this modification, but it clearly has merits.
Stereo and Mono
Anyway, even with the arrangement as so far described, I am more than pleased on my return. I have heard nothing either here - e.c. America that I like quite so well for stereo. I have confirmed my impression, by the that, provided that the pickup cartridge good one, the best way of playing monophonic records is as though they were stereophonic Some people have argued that when they played that way the "pinch effect" is bound to give rise to harmonic distortion which will apparent in. the vertical channel. But I sure that that is not so: any distortion seems cancel out in the two 45/45 channels.
Terminology
You will, no doubt, have observed the new description "monophonic". I discussed question of terminology with many –friends across the Atlantic and we were all agreed that monophonic is a much better term than monaural. The latter is a hopeless misnomer, for, after it really relates to the listener and not to record, and the listener always (I hope) list with both ears. Stereophonic and monophonic on the other hand are quite balanced terms I fancy, however, that they will in practice contracted to stereo and mono respectively. much the better. But in any case I do I everyone over here, technicians, advertisers E musicians alike, to refrain from using the word monaural.
An Omission-Turntables
Since I saw the printed version of my report on the Montreal Audio Fair, I have been wondering where the section on Turntables got to. I must have mishandled it in my hotel before dispatch. For it contained one of most pertinent things of all my comments: ubiquity of the Garrard turntables. Everywhere I went, both in Canada and in the States,, Garrard 301 and the Garrard Record Changer were in demand. None of the American Record Changers that I saw come up to the standards of 'the RC98/4 and I only noticed one Transcription Turntable-the Rek-O-Kut---which would stand comparison with the Garrard 301. No, that is wrong: I did notice three others, they are either not yet available to the public or are only just becoming available -- the Weathers, the Fairchild and the Grado.
Over there, too, there are many more Hi-Fi fans using Record Changers than there are over here. My impression is that this difference will not last long; in my view, Record Changers are on the way out owing to the more intolerant demands of stereo. It has hardly been appreciated as yet how troublesome vertical rumble can be. Therefore, I fully expect that some recording companies will deliberately reduce (if they do not do so already) the vertical sensitivity to frequencies below, say, 200c/s or even 100 c/s in order to minimize the effects of rumble and the troubles caused by too deep a vertical cut. This attenuation will of coarse be facilitated if a vertical/lateral system of record cutting is adopted by summing and subtracting the 45/45 signals; it is not so easy with a direct 45/45 cutting head.
This is a modification of Peter Goldmark’s suggestion last March that the vertical amplitude be reduced at all frequencies. This proposal was put forward to secure a greater compatibility – i.e. so that stereo discs could be played more easily with ordinary pickups thereby avoiding the necessity of two recording standards, stereo and mono. But many objections were raised to it at the R.I.A. Convention and I understand that his firm , "American Columbia) have not pursued it.
To revert to the turntable question. I did notice that the Garrard 4HF, which is intermediate 'in standard and in price between the 301 transcription and the ordinary single record player, such as the TA, was much admired in the Technical Report of the model is included in this issue and I have also seen it in production at Swindon and was much impressed by the testing line along which each individual sample must pass.
Two American Loudspeakers
I mentioned last month that I had arranged for special auditions of the Wright/St, George electrostatic and the K.L.H. loudspeakers. The latter audition did not take place owing to extreme pressure on my time and I only managed to get in the former during the afternoon before my plane left Boston. But I did hear a pair of K.L.H.'s in Harold Schonberg’s flat in New York and found them be very good indeed. When I saw that H.S. them, I expected nothing less, for his monophonic reproducer which I heard was without doubt of top quality. He now has best American stereo pickup, one of the three best American makes of amplifiers and an impressive battery of loudspeakers, so that respect his verdicts on records even more than I, have had occasion to do in the past (and that was not a little). I hope he will forgive me for saying this, but it is just as well to know where we stand. I believe that he will have Every satisfaction with his pair of K.L.H.'s, even though they are not so massive in the bass as his 15 cubic ft. corner enclosure with coaxial speaker unit. How I wish that, somehow, we could manage to get a pair over here for a full-dress review!
The same remark applies, perhaps a fortiori, to the electrostatic which I both saw in construction and heard. The engineering of it is superb and I believe that the technique on which it is based is sound. It certainly has a range from below 30 c/s to beyond audibility limits and its sensitivity is up to good dynamic standards; that is, it will sound just about as loud as a good moving coil unit in a large enclosure from the same signal input.
It is in two parts: a large bass unit about '3 ft 6 in. by 2 ft. at the
bottom and a curved treble unit about 2 ft. 6 in. by I ft. 3 in. above.
he whole is contained with the polarisirig and matching units in a box
about 3 ft. 6 in. by 3 ft. by 5 in. deep.
I wish of course that I could have had
a direct comparison with the Quad, but that was not possible. In my recollection
I should say it had much the same characteristics. But there were two differences:
the Wright/St. George was rather more pronounced in the bass, and in the
particular model I herd had a bit of hiatus at the crossover frequency.
The latter quality was hardly noticeable until we used the white noise
test; and of course it is only a matter of adjustment. I have an idea,
indeed, was due to a mishandling by a noise merchant who had just been
pumping a 120 watt signal into it just before I arrived. No wonder that
the demonstrator seemed a little anxious, for a signal of that magnitude
should have been sufficient to tear the thing apart. Evidently it had stood
the punishment extremely well.
This speaker seems
to me, to have an auspicious future, particularly as it can be used in
a variety of forms, e.g. built up in multiple array into an auditorium
wall, or used in pairs hung from a picture rail. I should expect, however,
that the latter arrange present some difficulties at high volume level
since the response pattern is a figure 8 and the rear signal might cause
reflection from the wall.
Amongst ordinary tweeters I heard nothing of comparable quality to our Kelly Ribbon unit. That, in my view, is in a class by itself.
Another speaker system that attracted attention was the Tannoy "Belvedere”. This is a comparatively small enclosure (not available in Britain) designed to take the Concentric. Notwithstanding the tendency in recent years to go in for bigger and bigger units-15 in., 18 in., and even 21”for some purposes----I found that the 12” dual had established a considerable reputation, as had also the corresponding W/B 12” Concentric unit. I found also that there tendency coming along for even smaller units. Is that the back-lash of stereo? Anyway, I am quite sure that before long there will be a strong demand for an 8” Dual Concentric unit. I would love them for my columns.
American Pickup Cartridges
I said last month that before I had hoped to get hold of a Weathers Ceramic which, seemed to have useful qualities. I failed. In fact, the only one I heard, or s Boston Fair. None of the magazines—Audio, Radio Electronics and High Fidelity –whose Editors I visited, had been able to obtain one. So I suppose we shall have to wait a while. There were, however, two other cartridges that specially interested me (Fairchild and Grado) and I have brought samples home with me. And there were two others, the E.S.L. (Ortifon) and the Shure, which I only heard casually, but which I want to know more about—the latter is a moving magnet type, I understand. The Decca had not been released, though it had been announced by H. H. Scott.
I saw both the Fairchild and Grado made up from incredibly tiny parts at their respective laboratories, and I actually measured the characteristics of the latter as it was, and when it had been, assembled. I have had it in continuous use, too, since I came back am obtaining fantastically good results from it. But more of that more anon. I have not yet doe more than just try out the Fairchild to ensure that it in working order. Both are twin moving coil cartridges and both therefore avoid difficult problem which is presented to the moving iron (variable reluctance) of having to keep the moving element accurately centralized between four pole piece thus an advantage to start with in linearity. There is, however, difficult problem in the matter of moving mass, as referred to the stylus, resonates-------
© 1959 Gramophone Magazine -- used courtesy of Gramophone Magazine
© 1980, 1999 Wright
Electroacoustics