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)

c1ferrari's picture


remlab's picture

A plasma tweeter crossed over at and allegedly flat down to 700hz? Is that a typo? The modern Lansche plasma is crossed over at almost 3 times as high.
Reread the review. It's obviously not a typo. Wow!

bpw's picture

I heard the Hill Type 1 at a couple of shops back in the 70s.

At WCES '92 in the old Sahara Bi-Level a pair of prototype full range (!) cold air plasma speakers were demonstrated by Tolteque AHL of France, but the company went out of business not long afterward. Each speaker was 9' tall by 5' wide.

remlab's picture

I already stated that it wasn't a typo.
If it took 500 watts to get a plasma tweeter down to 700hz, I can't imagine the power it took to go "full range". There must be something on the internet mentioning this speaker. All I can find so far is this..
J.M. Willigens on the Tolteque: Their manufacturer, AHL, a subsidiary of a steel mill in Haut Languedoc (south of France) went out of business around 1995. Their product line included three different Tolt'que models, differing only in height and called "americain", europeen and japonais to reflect the differing ceiling heights required to accommodate them. The Tolt'ques were originally meant to use the "cold plasma" ionization technology, which proved unpracticable, but a lot of the research work, particularly concerning transformers and isolation, was used for an ESL development.

bpw's picture

I wasn't disagreeing with you, merely reiterating.

Somewhere I may still have the brochure on the plasma speaker. They were using a pair of big McIntosh amps, I think 750 watts, which were definitely breaking a sweat (the front panel VU meters were clearly getting way up there) just playing light classical music at modest volume. The people from the company, who spoke almost no English, said something about not having the necessary voltage out of the wall (they were expecting 220V?) to enable the speakers to play louder. They estimated a price of $80k for a pair, assuming they would ever be produced.

You are unlikely to find anything more on the web about the company and products because they are long forgotten.

remlab's picture

Was it horn loaded? I would imagine it would have to be.

bpw's picture

No, it wasn't. The ionization chamber (active driven area of the speaker) was about 4 inches square. I really don't remember much. After all, that was over 22 years ago.

audiolab's picture

Shame... that the world is running out of helium

yaka24's picture

more expensive electronics than in the picture (emotiva) were used it would sound better

remlab's picture

..the high value leader right now. Amazing stuff for the money. Stereophile definitely needs to review some of the electronics in their lineup.

corrective_unconscious's picture

Typed by hand from the manuscript / magazine issue or from a Tandy computer file?

"(An ion is an atom having more than or fewer than its usual complement of electronics.)"

If that is the original text then there should be a "[sic]" put in.

If it's a transcription error than it should be fixed. Same for the word "od" which you can find in the review proper. Maybe others - I've only scanned the first page.

We don't want W.D. going on a rant about how "Stereophile" hates electrons, now do we?

John Atkinson's picture
corrective_unco... wrote:

Typed by hand from the manuscript / magazine issue or from a Tandy computer file?

Ran a scan from the original magazine through a text recognition app, then cleaned it up by hand.

corrective_unco... wrote:

If it's a transcription error [then] it should be fixed. Same for the word "od" which you can find in the review proper.

Both fixed. Thanks for the proof reading.

John Atkinson
Editor, Stereophile

corrective_unconscious's picture


You're messing with my mind again.

remlab's picture

Anality to the point of banality. Ugh!

corrective_unconscious's picture

You should learn what an ellipsis is.

If you merely stutter then I apologize, naturally.

remlab's picture

Thiss iz geting funn!

hexguitar's picture

I was 25 years old in 1979 when I stumbled upon Audiovision in Dallas.

This was my first glimpse of true high end audio.

Audiovision had two large rooms.

The largest contained lower to mid-priced high end gear. There were speakers from DCM (Time Window), Magnapan (MG-I, MG-IIA), Mordaunt Short, etc. Electronics were from NAD and Harmon-Kardon. Sources were from NAD, Eumig, and Denon.

The second room, which was about 20 by 35 by 12 contained the high priced gear. This room had Threshold, JVC Pro (imported directly from Japan), and Beveridge electronics. The Beveridge pre-amp in the main system had two chassis. One chassis had the power supply. The other contained all of the rest of the pre-amps guts.

Speakers in this room included Magnepan Tympanis and Beveridge hybrid electrostats.

Here is where I saw and heard the Hills.

My initial reaction was similar to virtually everyone I subsequently observed hearing (and seeing) Hills for the first time. I was startled.

When first fired up (sorry, I couldn't resist the pun), the plasma emits a small "pop" as it forms. It also visually produces a blue flame between the nozzles that seems to dance in the air.

Then the music started and I was again startled by the clearest, most life-like reproduction of recorded music I'd ever heard. The recording being demoed was a solo A Capella contra-basso male voice.

The image produced could have fooled me into believing the invisible man was singing in the room.

I ended up talking the owner into giving me a job. We sold three pairs of Hills in the 10 months I worked there. In late 1979, the owner announced that he was bleeding money and had to close.

The Hills did have maintenance issues. Guy Oliviera, who was the store manager, did tech work on the store's Hills. They broke down frequently.

But when they functioned, they played better than anything I've ever heard.

Steven Kastner

psteet's picture

When the store went under, Todd, the owner, came back to Austin and stayed with me while he looked for another place. He ended up trading me the speakers for rent and I owned them for another twenty years. Other than the expense and inconvenience of the helium, they were a joy to have and listen to. To this day I have never heard speakers with better high end. I finally sold the tweeters to a man in Canada as he did not want the whole speaker and offered and remarkable amount of money for them. I am happy to have been the owner of one of the most unusual and downright remarkable pieces of audio gear ever produced.

Plasmatony's picture

I worked for Alan Hill all those years ago. I have a pair of plasma drivers and have revived them with new electronics. It is such a joy to have them back in operation. Alan is still alive and kicking and rumor has it that he has plans...

remlab's picture

Pretty freakin crazy! Horrid music on the video. Have your own plasma speaker for $100.00!

Bob Henry's picture

I likewise attended WCES '92 and stumbled upon the Tolteque plasma loudspeakers.

So large they nearly occupied the entire room.

And so wide (each unit 5 feet) that stereo imaging was imperceptible.

As for the Hill Plasmatronics, I first heard them in Los Angeles at Ken Mavrick's Audio One store.

The violet-colored flickering plasma was something to behold. And the sound reproduction was freakishly real given the right source material (e.g., human voice, acoustic instruments played at moderate levels).

Made me covet them over my Harold Beveridge loudspeakers, whose mid-range naturalness and "3-D" imaging was first-rate.

As for other cutting edge loudspeaker designs, I never auditioned John Iverson's Electro Research "force field" loudspeaker. (One WCES display anecdote I heard was that the ozone it produced made listeners nauseous and/or gave them a headache.)