It should also be borne in mind that, in order to limit vertical stylus excursions to a realistic amplitude, commercial recordings have their stereo channels blended together at low frequencies, so there is no advantage whatsoever in reproducing them through separate bass speakers. Without resolving the question, then, we can only say that, regardless of how it is done—with one woofer or two—the SS-1A's bass is better, in terms of naturalness and range, than that of any other system we had heard previously, and is comparable to (although not the same as) that of the FMI J-Modular.
Apart from the question of blending, there is one distinct advantage of having a speaker system's bass unit(s) separate from the upper ranges, and that is the ability to place it (or them) for smoothest possible response in a given room, without in any way compromising the locations of the upper-range drivers.
Our main listening room, although perhaps not typical in this respect, has a tendency to suck out the bass range between 45 and 60Hz with some speakers. When it happens, we have to move them farther in toward the room corners, which doesnt always result in optimal performance through the rest of the audio range, so we usually end up having to test those speakspeakers in two locations and combining the results for a report.
With the SS-1A, we were able to locate the upper-range screens for best overall sound, and then move the bass commode around until we found the spot where it produced the smoothest bottom and the best blending with the screens. No compromise! We emphasize, though, that our room is not your room, and that optimum speaker placement in it is optimum for our room only. (This is why we never publish details about where we place loudspeakers; if we did, too many of our readers would interpret it as a recommendation and try to locate their own speakers likewise.)
We repeat: The only way to find the best location for any speakers in your room is by experimentation. And in the case of bipolar (two-sided) radiators like the SS-1A panels, room placement can be very critical, which is actually an asset as well as a liability.
Because the sound comes from both the front and—as reflections from the wall—from the rear, there is more than ample opportunity for phase interference to cause partial cancellation of some bands of frequencies and augmentation of others. And since many of the wavelengths involved are right in the musical midrange, the result can be pronounced vowel-like colorations. Consequently, the likelihood of an SS-1A's performing at anywheres near its full capability when first fired up is pretty remote. It took us three weeks of pushing the panels around until we hit on what seemed to be good locations, and it took another week for us to realize that a certain deficiency of warmth could be cured by some more adjustments in room placement.
And that turned out to be the hidden asset of the system: The ability to "tailor" its sound to produce a desired result in virtually any listening environment. In this respect, the SS-1A proved (as have other bidirectional systems) adaptable to a wider variety of acoustical environments than are most conventional systems. (Incidentally, we recommend using masking tape or something else reasonably permanent to mark the floor at two corners of any speaker unit after a proper location has been found, so it can be returned to the spot if it has to be moved.)
So, how did the SS-lA perform after we finally got through messing around with it? We would describe its sound as mercilessly accurate—accurate because it tended to verify sonically the things we knew about tapes that we had made ourselves, and merciless because it revealed every flaw in our recordings and, unfortunately, in most commercial recordings.
On our more successful tapes, and on a precious few commercial recordings, the SS-1A system came about as close to re-creating the illusion of honest-to-God, reach-out-and-touch-it reality as it is possible to come via a commercially available system. The high end, as mentioned previously, had that rare combination of softness on strings and woodwinds that gives every audiophile the initial impression of "no highs," and of sharpness on hard transients and the spiky edge of brasses, which came through as though there was no upper limit at all.
A solo violin tape we made (of the concertmaster of a local orchestra) had that incredible sweetness of a fine violin (which it was) with the most subtle, open, resinous sheen at the top that we have heard reproduced. And the rich, wooden warmth of the sound-box was there, too. The performer (who also happens, atypically, to be a very critical audiophile), declared it to be "my violin sound."
The low end, similarly, seemed to have no limit. No matter how deep the musical (or otherwise) material reproduced, from pipe organ or thunderstorm, there was the feeling that the system could have produced even deeper, more floor-shaking lows if called upon to do so. In fact, there was a practical limit to the low end in our room: Oscillator sweeps revealed that the bottom tapered off rapidly below 23Hz, but things in the room were still rattling (until we moved them) at 16Hz, which is as far down as we can tune our oscillator. There was, as a matter of fact, a slight response hump in the room at 28Hz, which did nothing for symphonic music but added a touch more visceral pressure from a few really wide-range organ recordings.
All the more remarkable, then, was the incredible detail of the low end. We almost felt we could, as the saying used to go, "count the cycles," and were readily able (on many recordings) to distinguish between bowed double basses and pipe organ pedals. And never before have we been so much aware of the electronic origin of that "heartheat" at the opening of Pink Floyd's Dark Side of the Moon.
In short, we were stupefied by the performance of the SS-1A, when reproducing decent material. But with typical recordings, we are sorry to have to report that the SS-1A revealed every nuance of what it is that ails most recordings: Steely, sizzly violins, whumpy mid-bass, pinched trombones, advancing and receding woodwinds, excessive closeness and lack of depth, and an overall solid-state hardness which soon had us working (not too successfully) with equalizer and treble control.
We couldn't help but speculate as to what those commercial recordings might have sounded like had the recording studios themselves been set up with monitor speakers as accurate and revealing as these. Considering what they must be using, though, there is some question as to whether many listeners might not be happier either using a cartridge that is more "polite"-sounding than the Decca, or a speaker system which tells more-flattering lies about the program material fed to it.
If you want to hear exactly what a recording actually sounds like, the SS-1A will tell you, but until something is done about commercial recordings in general, maybe you would prefer not to know. Personally, we'll grit our teeth and put up with, in exchange for the privilege of knowing that, when the ultimate recording comes along, the SS-1A will reproduce virtually every iota of it.
The only real weakness of the SS-1A is its stereo imaging. Center fill and imaging stability are not as good as they could be, and there is a slight "Vertical Venetian Blind" effect as we move across the listening area—instrumental locations seem to shift back and forth a bit—but at least there are no treble "hot spots" (as in many systems with electrostatic tweeters), and the system does not tend to make a guitar sound as wide as a grand piano. It reproduces original sizes fairly accurately.
The SS-1A is also—or at least can be, at its best—nearly perfectly neutral in perspective. Its sound tends to be slightly forward (fig.1), as is appropriate for a system that will almost certainly be used in a fairly large listening room, where the listening location will be 8' or more distant. The forwardness serves to place a very closely-miked sound source slightly in front of the system rather than right at it, producing a marked "in-the-room" illusion, but without any of the raucousness normally observed in systems that "project the sound forward. Thus, close-up recordings sound close, while distant ones have a perspective very similar to the actual distance of the microphones from the performers.
Fig.1 Infinity Servo-Statik 1A, subjective frequency response (5dB/vertical div.).
Under the circumstances, we were not surprised that the SS-1A reproduced depth and perspectives very faithfully, which is one of the things that makes it so revealing of the gross multimiking used for most commercial domestic recordings. Flat recordings sound very flat. In addition, the SS-1A has a truly phenomenal transparency which, again, reveals mercilessly any graininess or veiling of the program source.
Blending between the SS-1A's drivers was excellent. No crossover was audible between the tweeters and midrange panels, and the mating of the midrange sections and the woofer was dependent on room placement. We were able to locate things so that not one of our listening group was able to guess (prior to being told) where bass/midrange crossover was taking place.
There is only one other speaker system we have encountered that is really comparable with the SS-1A, and that is the FMI J-Modular. They don't really sound the same—the Js have what we would characterize as a warmer, rounder sound—but at their best, they are actually more alike than dissimilar. Highs are virtually identical, both have about the same bi1ity to reproduce depth and perspective, and while the J's bottom is a shade fatter, the SS-1A's bottom is a shade tauter. And both, under their best conditions, can sound astonishingly realistic. If we were forced to rate them, we would be inclined to give the SS-1A top honors for absolute accuracy, with the qualification that many listeners may find the FMIs a bit easier to live with.
All in all, though, it is our feeling that the SS-1A sets sets a new standard for performance in a commercial speaker design, and that its only drawback is a direct result of this:
It makes your typical commercial recording sound just as bad as it really is. A sweet-sounding pickup cartridge (like the Denon or Supex) can ameliorate matters, and you can always switch cartridges when playing a really good recording, but if you want to know the unvarnished truth about your program material and—we might add, about the mistracking proclivities of your cartridge—this system can give it to you like none other that we know. But as we said before, don't skimp on the electronics. "Almost as good as the best tubed stuff" isn't going to allow the SS-1A to perform at its best, and if you happen to be one of those souls who have a gut feeling about the inherent superiority of solid-state, and won't pay the price of a pair of switching amps, you would probably do better to investigate another speaker system, because to crud up the top of the SS-1A with the typical solid-state hardness and grit would be a crime against reason.
The only crucial question about the SS-1A at this time is, will it prove to be as durable and as dependible as a $4000 super-system should be expected to be? The persistent reports of midrange panel failures are not reassuring, even though replacements (when obtained) are easy to install, and our SS-1A has been working steadfastly for several months now. We can only hope, fervently, that the reports are exaggerated or, if not, that Infinity can remedy the situation instanter. It would be most unfortunate were a product as good as this to fizzle out because of one intractable production problem.—J. Gordon Holt
Manufacturer's Comment
Editor, your review of the SS-1A is certainly one of the most detailed and complete reviews I have had the pleasure to read. Furthermore, most of your conclusions about the SS-1A itself concur with our own remarkably well. I do however have a few comments concerning some other points in the review.
A) We appreciate your candor and fairness in presenting an admitted sticky situation concerning the midrange modules tor the SS-1A. It should be said that, for a period of over three months, we did not ship any of these systems (even facing an enormously overbloated inventory of SS-1A parts). The reason was that we had recently discovered defects in the chemical composition of our grid laminate which would cause subsequent deterioration of the modules. We know at this time that even some of the systems in the field would suffer at some time due to this defect.
It must be emphasized at this point that the total number of SS-1As shipped into the field before this defect was noticed was under 15 systems. Of these 15, only 3 have gone to consumers, and each of these is operating properly! The balance of the systems are in dealers' showrooms, and some of these were down for a period of time while we were solving this dilemma.
It has been brought to our attention that the word is spreading about SS-1A owners committing acts of violence against their continually failing SS-1As. We can prove that this is only distorted hearsay, with no basis in fact. At the tine of this writing, we can state that we have solved the problem and are shipping modules to dealers to render their SS operable. Thank you for being so patient; we really appreciate it.
We now believe we can offer superb reliability on the SS-1A, although as clearly explained by J. Gordon Holt, it will never have the reliability of a few cones in a box. It is exactly analagous to a Ferrari being as reliable as a Dodge Dart.
B) The second point I should like to mention is that the switching amplifier JGH had when reviewing the SS-1A was one of the earliest pre-production prototypes. Even this amp, JGH suggests, has a better high end than the D-76A. We agree with the comment that it is a waste of money to buy an SS-1A and not utilize the best associated equipment. It is in this spirit that we suggest that, at this point in our progress on the class-D amplifier, it is the only amplifier that, when used on both midrange and tweeter, makes the SS-1A become totally alive. JGH has been shipped the latest version of the amplifier and will evaluate it in some future issue.
We do agree, however, that the ABC tubed amplifiers do a very fine job indeed. We have not heard the new Vertical-FET power amps or the Stax class-A amp on the SS-1A, but there is indication that these are excellent possibilities. At the time of this writing, it is our finding that there are other preamps that do as good or better a job as the ARC. The ones that I have heard that qualify are Infinity's FET, the Stax FET, Levinson's JC-2, and Thaedra from GAS.
C) The last point I should like to make is about the standing battle between two camps of audiophilia: the pro-Deccas and the anti-Deccas. I must confess I used to be among the pro-Decca group—very staunchly. At this point, I am not totally in the anti-Decca camp, either. The Decca cartridge in a Decca arm on a few select records sounds magnificent. However, generally its hot upper midrange and horrible tracking ability make it very tedious on a speaker as revealing as the SS-1A. If you indeed have Decca-itis, as does JGH, then the SS-1A will reveal all those ugly things on most recordings, as suggested in the review.
From our research at Infinity, we really suggest a cartridge like the Denon with a spherical stylus in a very low-mass arm such as the Grace 707 or the Rabco ST-7 'table/arm. This will yield not only very satisfactory results on most records, but also will excite you on the very best discs.—Arnold Nudell, President, Infinity Systems
Reviewer's addendum:
Such is the effectiveness of the audio grapevine, we had become convinced that Infinity must have delivered at least 23,000 SS-1As, 22,741 of which had suffered midrange panel failures. We are glad to hear the situation isn't quite that bad, and are even more glad to hear that Infinity feels that they have now solved the problem. Now, only time can tell.
We should add here that, since initial tests of the SS-1A and the FMI J-Modulars (also reviewed in this issue), the Js underwent yet another modification that has obliged us to reassess the relative ratings of the systems. At this time, we must admit that we are undecided as to which of them is actually the more-nearly-perfect reproducer. The final word must wait until the next issue.
As for the Decca pickup/tube amplifier "controversies," we continue to like the Decca, despite its obvious tracking problems (which are, incidentally, more conspicuously noticeable on the SS-1A than on any other system we know of), because it is still the only cartridge we have found whose overall sound duplicates the brightness and aliveness of original tapes. And we still find the best tubed equipment to be more musically natural than any solid-state components we have tested to date.—J. Gordon Holt
Sidebar 1: What If You Lose a Midrange Panel?
Failure of a midrange panel in the SS-1A is an annoyance but by no means a disaster. If you have a mental image of pryotechnics reminiscent of starship Enterprise taking Klingon fire, forget it. Yes, there's 4000 volts DC on those panels, but it is only a static charge, with no more potential for violence than the charge you build up walking on a carpet in dry weather. When a midrange panel goes out, it may cause clicks or distortion in the sound, but in most instances, that's all there is to it. The panel is easily replaced, and you can even continue to use the system until the replacement panel arrives. (The tweeters rarely fail, but the following applies to them too should one of them go out.)
The mid-range panels in the SS-1A are largish flat rectangles, and there are six of them per screen, in two vertical rows of three. The failure of one of them will usually be immediately audible in one of several ways:
1) The sound from one stereo channel (only) will become sputtery or shattery at high listening volume, as though one channel of the power amplifier were overloading,
2) There will be a series of small but very sharp clicks from one channel, usually occurring at regular intervals,
3) One channel, again at high listening levels, will emit a "pop" followed by a sudden temporary loss of level in that channel. If there are clicks or pops involved, you can easily zero in on the bad panel by placing one ear close to the offending screen and moving it around until you locate the click source. Use a spot of white chalk on the front grille (easily vacuumed off later) to mark the spot.
In very rare instances, a midrange panel may fail in such a way as to temporarily disable all the midrange modules in that screen, at which time tracking down the defective panel becomes a bit more of a chore.
Turn off the entire system and unplug the defective screen from its AC supply. (Infinity, incidentally, recommends leaving the screens fired up at all times, to prevent moisture condensation and keep them at full charge.) The rear cover is removeable by four screws. If you have already located the bad panel, disconnect the three terminals fastened to the rear of it. This involves only the removal of three small hex nuts. If all the midrange panels are dead, or drastically down in volume, it will be necessary first to disconnect the outside two terminals from every midrange panel. Use a strip of cellophane mending tape to fasten the loose wires to the center of each panel so the disconnected terminals don't touch anything but are close enough to their panel screws to reach them.
Now, plug in the screen's AC supply and turn on the main system (balance control at center) so the functioning screen is playing at very low volume. Then turn that screen off with the balance control. (Although the polarizing supply is safe to touch, high-level signals from the power amplifier can produce lethal voltages across the panels.)
To avoid a safe but unpleasant shock from the polarizing supply, stand on a rubber mat or wear dry sneakers and, with the signal still feeding the screen, use one hand (with the other in your pocket) to reconnect each panel in turn, starting its terminal nut with your fingers to hold the terminal on. You should start to hear midrange output from the first panel reconnected. If not, that is probably the defective one. If so, reconnection of another one will eventually cause a spark and loss of midrange level, and that will be the bad panel. If you still can't seem to locate it, don't try to trouble-shoot the system further than that. Call your dealer for assistance.
If you locate a bad panel, disconnect all three wires from it and use sticky-tape to fasten them to the rear of the panel where they can't touch any other metal parts, and order your replacement panel from your dealer. Replace any other disconnected wires and make the nuts as tight as you can get them from finger pressure alone. You can now continue to use the system until the replacement panel arrives—which may, if the experience of some previous Infinity customers was typical, be quite some time.
Operation with one module (or even two, for that matter) does no harm and has little effect on the sound. It does however have some sonic effect: it knocks down the low-end response of that screen, and will cause a slight dip in the system's mid-bass range. So do make the effort to replace a defective panel.
To replace a panel, remove the wooden strip at the outer edge of it and gently pry it out. Slip the replacements inner edge (terminals at the bottom edge) under the center retaining strip and work it into place, then reinstall the wooden edge strip with its screws.—J. Gordon Holt
Sidebar 2: Specifications
Description: Three-way stereo loudspeaker system consisting of two electrostatic screens and a single common-bass woofer "commode" (18" cone drive-unit), with a separate line-level crossover/100W amplifier (1968), a separate line-level crossover (1975). Crossover frequency: 100Hz (1968); 70Hz, 2kHz (1975). Nominal impedance: 16 ohms.
Dimensions: Screens, 36" H by 28" W by by 7" D; woofer 24" H x 24" W x 24" D (1968); Screens 60" H by 22" W x 8" D; woofer 19" H x 22" W x 22" D (1975).
Price: $2000, including crossover and bass amplifier (1968); $4000, including electronic crossover (1975); no longer in production (1978 onward).
Manufacturer: Infinity Systems, Inc., Chatsworth, CA 91311 (1968); Infinity Systems, Inc., Canoga Park, CA 91304 (1975); Infinity Systems, Inc. (a division of Harman International), 250 Crossways Park Drive, Woodbury, NY 11797. Tel: (800) 553-3332. Fax: (516) 682-3524. Web: www.infinity.com (2003).
It could, in fact, be said with some truth that, if you wanted close-up, high-powered sound, you chose a good horn system or a similarly inclined cone type, and that if you preferred a more distant listening perspective, with the more subtle attributes of detail and transparency, you opted for electrostatics.