Infinity Servo-Statik 1 loudspeaker Page 3
For our tests of the complete Servo-Statik 1 system, we used the Crown DC-300 for the midrange electrostatics, and started yith the Crown D-40 on the tweeters. Both power amplifiers were operated with their own input gain controls full-up at all times. The bass commode was left in its previous position in the room, and about four hours of experimentation resulted in a panel placement that seemed optimum to us. The crossover level controls were set to provide what we felt to be the most natural balance from moat program material.
During this initial balancing-out procedure, we observed two subtle but persistent colorations from the panels. the sounded like a broad responSe hump at around 1kHz, the other sounded like a narrower one at around 8kHz, and both were judged to be very small in actual magnitude. The 1kHz one was clearly audible with the tweeters turned off, and although correct mid/upper balance caused it to recede into the background, it remained faintly audible on white (pink?) noise and was no doubt contributing something, however subtle, to the system's overall sound.
The 8kHz one also tended to disappear when the balance controls seemed properly adjusted, but it too remained faintly audible and may have caused some of the slight steeliness we observed subsequently in massed-violin sound.
To a listener accustomed to the KLH Nine, the most immediately obvious characteristic of the SS-1 was its closeness. The Nine places sounds slightly farther away than they were recorded, producing from most symphonic recordings a richness and warmth that one normally associates with a moderately distant seat in the concert hail.
The SS-1 has what we would judge to be a more neutral perspective, so that closely-miked recordings sound close-up, distantly-miked recordings sound distant but not remote.
As mentioned earlier, the KLH (properly installed) is what could be called a "polite"-sounding speaker, and is almost incapable of sounding raw or vulgar. The SS-1, by comparison, seemed better able to convey the actual "flavor" of the music, sounding rich and sweet or snarly and aggressive depending on the music itself.
Probably because of its closer sound, the SS-1 seems to reproduce noticeably more inner detail in the sound than the Nine, although it is arguable whether or not the enhanced audibility of squeaking chairs and grunting cellists adds anything of musical worth to the reproduction. That it does add realism is however beyond 4uestion.
The SS-1's incredible detail, though, carries with it a distinct liability: The system reproduces the distortion fed to it with even more merciless clarity than does the Nine. Since it does not sweeten up the high end, the power amplifier used to drive its tweeters is a crucial factor in the system's sound. Most solid-state amplifiers have a more-or-less hard sound, and these the SS-1 does not need. The Crown D-40, which we used for most of our tests, has less hardness than most, and was judged to work quite satisfactorily. Since, however, practically all recordings have some characteristic hardness of their own, we feel that listeners who like live string tone may prefer to use a treble amplifier with even less of this quality than the D-40. We have not as yet found a solid-state unit of appropriate power rating that really fills the bill—we're still looking—but we did find that the old, tubed Dynaco Stereo 70 is ideal for the purpose, if it doesn't offend you to sully your solid-state system with tubes. Oddly, the Stereo 120, which sounds so touch better than the Stereo 70 on most speakers, did not seem to work as well as the Crown D-40 on the SS-1's tweeters.