Infinity Servo-Statik 1 loudspeaker J. Gordon Holt October 1975 part 3
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.