Hill Plasmatronics Type 1 loudspeaker Page 2

Sonic details are reproduced with clinical clarity, which is dandy with superb source material but a liability with the majority of recordings. Bass is deep, tight, and gut-shaking, and the seams between the drivers are virtually imperceptible—quite an accomplishment in view of the fact that two of them are cones, with appreciable inertial mass, while the other, widest-range one is completely massless (footnote 3). Without running any curves, we would guess the low end to be effectively flat to around 35Hz in a room of adequate proportions. (The one we listened in was not. The tightest, deepest low end was only audible in an adjoining room, which did at least prove that the system was capable of producing that kind of bottom.)

Our only cavil about the sound concerned the system's brightness, which was too much. Dr. Hill assures us that the system measures flat out to the bat's radar region, and indeed it sounded flat when we listened with the cartridge of his choice (a GAS Sleeping Beauty Shibata). But with original tapes, and a cartridge we have found to provide comparable brightness, we felt the sound from the Type 1 to be brilliant almost to the point of stridency (although without the teeth-setting edge that betrays the presence of spurious odd-order harmonic content). For this reason, the system never quite captured the correct musical timbres of most musical instruments—an attribute few audiophiles seem attuned to anyway. (Take an audiophile to a concert and his first reaction is, almost invariably, "My God, where are all the highs?")


With most speaker systems, some degree of exaggerated treble is necessary to help overcome the innate deficiency of detail. It is not necessary with the Plasmatronics, although we can well understand how that brightness may be necessary to sell these speakers to the kind of listener willing to pay $7000 for speakers alone (many of whom are locked into cartridges whose own brightness range is attenuated).

If we had our druthers, we would like to see (and hear) this system equipped with a switch that would provide, in one position, the kind of sound that we heard (by which we cover ourselves against the possibility that it may sound less bright in other rooms), and in the other position,, a more neutral musically felicitous sound.

Considering the current chaotic state of the high-end" audio field, few listeners will get any real idea of what these speakers can and cannot do until digital program sources become more widely available. Anyone endeavoring to evaluate the Plasmatronics at a dealer's will be at the mercy of the dealer's often-misguided choice of associated equipment. There is, in fact, more than just a possibility will sound better than it really is, because of the current popularity of deadish but tipped-up phono cartridges that will tend to offset the speaker's brightness and underscore its remarkable detail.

The Type 1's literature specifies a maximum output level of 107dB, which looks pretty good but not outstanding. In truth, we found it possible to achieve clean signals up to a peak SPL reading of 116dBA before overload became audible. That may not be disco-type output level, but to any other listener it is one hell of a lot of noise—particularly when we consider that live music form acoustical instruments rarely exceeds 100dB when heard from an audience seat, even a very close one.


Incidentally, "overloading" the Type 1 system does not cause the usual startling snap or crackle of amplifier clipping or voice-coil bottoming. When overloaded, the system—literally—runs out of gas and progressively limits the amplitude of signal peaks, in much the same unobtrusive manner as the peak limiters used for years by virtually all commercial record companies.

Is this loudspeaker worth its $7000 price tag? Maybe. There is no doubt but that there is $6500 worth of technological know-how and constructional hardware in a pair of Plasmatronics Type 1s, but whether or not they are worth that much to you as a consumer depends on what you value, and how much. If you are hyper-critical of imaging, inner detail, transient response, and high-end openness, be assured that this system will give you more of those things than any other currently available system. If you are a bass freak, these won't disappoint you, though they may not make you as happy as a large transmission-line system or a monumentally dimensioned horn system.

But if you are more of a music listener than a detail fanatic, you may well find that there is much in the grooves of most discs that is best left unheard. And if you are picky about the accurate reproduction of timbres, you may also—depending on the characteristics of your program sources—be more or less put off by the Plasmatronics' brightness. We suspect, though, that most audiophiles will find these speakers to provide the most mind-blowing listening experience they have ever known.

Further Thoughts
Although not the perfect transducer, the Plasmatronics Type 1 represents a significant advance in the state of the audio art because it eliminates, once and for all, the need for detail "enhancement" in the program material an ancillary electronics. If, and when, this standard of detail reproduction filters down into the lower-priced equipment areas, multimiking and the use of "hot" microphones to offset detail smearing in playback systems will no longer be necessary. This could pave the way for a new kind of audiophile recording, in which performing groups can be presented at a natural distance, to provide blending of the sounds without loss of definition. The result will probably be what we've all claimed to be seeking: The sound of live music. Whether or not we will all like that sound is moot. . .

Footnote 3: Well, not quite completely. The gas mixture has some thermal inertia, which causes a gradual rolloff of frequencies above about 30kHz. However, the rolloff is much less rapid than the rolloff that occurs above the resonance frequency of a mechanical transducer.
Plasmatronics, Inc.
Albuquerque, NM 87106 (1979)
Company no longer in existence (2014)
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