The only plasma speaker I ever heard about turned out to have ozone emission problems and was making people ill if they were in a closed room with them... but I cannot remember the name of the company as this was around 10 years ago... |
There was a plasma speaker on e:Bay last summer. I believe it was called the Hall Plasmatronic. It was supposedly a complete & operating pair. I believe the reserve was between 2 & 4K. I don't think the reserve was met...
I think it was designed by Dr. David Hall. Hope this helps...
Daniel |
That might be the Hill Plasmatronics.
Acapella Audio of Germany incorporates "ion" tweeters
into their designs. |
The name of the speaker was the Hill "Plasmatronic", and it did emit a lot of ozone as a byproduct; very hard on the lungs and other vital tissues. It was a fascinating concept speaker, but quite literally a health hazard. |
While i've never heard a Plasma tweeter, i've been told by others that i trust that there are NO other options once you've experienced them first-hand. Their speed is unmatched by any type of driver based on a physical material. In specific, the Hill Plasma drivers were bone flat out to 40 KHz and remained linear out to appr 100 KHz if i remember correctly.
I know that our friend overseas ( the magical and mystical Detlof ) uses Plasma tweeters with E-stats for mids and large planars for bottom end. He's a good guy and would probably be glad to fill you in on specifics such as benefits, drawbacks, safety precautions, etc...
I can dig up a site where a guy had several hybrid dynamic / plasma speakers for sale. Some were still new in the box if i remember correctly. Drop me an email if you're interested and i'll try and hook the two of you up... Sean
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Acapella audio of germany is currently producing three models with horn loaded plasma tweeters (and they've apparently figured out away around the ozone problem). This is your best bet. It may be something like acapella??.de Nelson Pass (of Pass Labs) built one back in the '70's called the Ion Cloud so he may be a source of information. I have seen one or two other units that looked to be current production models: one a japanese company and the other using TAD drivers. |
I own a pair of the before mentioned A-Capella Ion speakers and I'm still very much alive.
They have the ozone problem licked a hundred percent and there are no precautions to be taken. I see no drawbacks except the price, which is hideous! (About $ 3500 to 4000 a pair, if you can get them at all, because A-Capella does not sell them singly, but only together with their speakers.) The advantages are a far better sound stage rendering, much more depth and you can listen far deeper into the soundstage. They take careful placing and blending, but which speaker doesn't and to these ears they beat every tweeter I have ever listend to. (Decca & Sequerra ribbons especially, which I know best). You can adjust the frequency, where they set in. Besides they go up so high, that with certain music you have amorous bats clamouring to get inside! (-; You'll get more information through www.acapella.de
Cheers and a merry X-mas to you all!
Detlof |
There's a big difference between the Hill Plasma type of
speaker and the "Ionovac/Ionophone" horn loaded style of
"plasma" speaker.
The former used a large gas plasma that was directly
modulated by AF at high voltage.
The latter uses an RF signal to generate a very tiny (and
hot) plasma which is indirectly modulated by AF high
at high voltage.
Both are similar in terms of needing a plasma, but the
latter case must deal with the effects of horn loading,
and limited LF response.
Both have some background hiss from the plasma itself.
The Hill had the single most impressive mids and highs
that I can recall - fantastically coherent and dimensional.
Their bass was less wonderful. The Hill used "Argon"
welding gas to create the plasma, so it "leaked" into
the room (presumably on the floor, as it is heavier than
air), so they are safe with an exhaust route for the remaining
gas to get out of the room.
Neither make excessive amounts of Ozone. There's more ozone in the air in any major city than these are likely to produce in your listening room.
Magnat made a pure plasma tweeter many years ago, it was an
omni from what I understand - never heard one.
I did an on paper design of a wide range omni, direct radiator
plasma driver some years back...I think it would work.
I don't know about the Acappela tweets, anyone got a URL?
Are they horn loaded??
_-_-bear |
Bear, they are hornloaded, don't hiss and the URL is
www.acapella.de |
Thanks Bear. The Magnat's were the ones that i was thinking of but couldn't remember the name. I'm still looking for the address, but the guy had several pairs of various models, some still sealed in the box.
I remember seeing some stuff about the Hill woofer. It supposedly had the fastest transient response / most linear output at 30 Hz of any woofer available at the time of production. Even with that good of a woofer, the mass of a 14" dynamic driver will always sound slow and out of synce when mated with what we would consider a "massless" radiator.
I have a friend with a TON of the Dukane Ionovac's. Some have never been fired and are still in the original packaging. Would it be worth hitting him up for some of these ????? Sean
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Yeah, I remember those crazy Hills. I think that there also might have been dangerously high voltages on exposed elements of the plazma drivers...this was the reason that the F.T.C. banned these speakers (but maybe that was just the rumor mill B.S.) But I think that these speakers used Nitrogen not Argon to create the plasma. Happy Tunes! |
Bear- if you are not willing to have a little argon gas and stray high voltage roaming around the living room you simply aren't a serious audiophile. |
Clueless, there are excellent modern designs around, which do neither as you suggest. You're talking ancient history. |
Detlof my friend (i like your posts), I'm talking poor humor - I was just joking. |
Oh heck, my sincere apologies!...amd I thought I'd detect humour, whenever it raised its wonderful head...just goes to show!!!! Regards, Detlof |
just goes to show!!!! how poor my humor is... undetectable. They don't call me clueless for nothing. |
LOL, selfirony, o wily one, is the best of humour!..and now stop please making me feel guilty! Twice is enough, don't you think? (: |
Twice is enough???? That's the same dry line my wife gives me.
Sincerely, I remain |
Well, don't worry, we ain't married. Tell her it's not the numbers, its the duration.....(-; |
Those green tanks for the Plasmatronics were filled with HELIUM, not argon, as I recall (and you and I heard the same ones at the same time, Bear!) |
The ozone emitting speakers you guys are talking about was called Dayton-Wright. They were big, heavy, and sounded great. I understand that the membranes failed pretty readily, so they went out of business. The original speaker that Joe Grado used as reference was AR1Ws for the low end, Janzen electrostats for the mids, and the Ionivac supertweeter for the highs. |
The Dayton-Wrights were electrostats, not plasma speakers. The diaphragms were enclosed in "bags" containing (as I recall) sodium hexafluoride gas, so I doubt they emitted any ozone (which results from breaking down AIR or other gas containing oxygen, not sodium hexafluoride) |
I've heard, though only briefly, the Acapella. The tweeter is very nimble and nice sounding. The Hill I heard MANY years ago (around 1979). The Hill required a bottle on inert gas that is injected into the ion tweeter to prevent corrosion of the electrode that ionized the gas. You would get a wiff of ozone being discharged by the speaker.
A few years ago, the DIY magazine AudioXpress (at least I think it was this magazine) had an article on how to make your own plasma tweeter. Their design did not require injection of a gas around the electrode. The electrode had a quite limited life, but, it was cheap and fairly easy to build spares. |
Dayton Wrights had "cells" enclosing the membranes and containing sulfur hexafluoride (SF6) gas. There is no mention of ozone being produced in the documentation, since the gas filled enclosures were not intended to leak (a Schrader valve on the bottom of each speaker, similar to one found on a car or bicycle, was present for adding SF6 if ever needed). The most frequent cause of failure (leaks) were cats, mentioned in the manual. Cats like to jump to high places, and the punctures of the enclosures were a certain distance off the floor where the cat(s) dug their claws in. The XG10s I have work perfectly, never a leak in their history, I was told by the previous, original owner.
Back on topic, the Acapella tweeter produces ozone which is dissipated in the throat of the horn before it escapes to the room. I don't know about other manufacturers, but ozone production is a very significant problem to be dealt with (ask Nelson Pass or Alan Hill). |
Where I work.....a large Semiconductor Manufacturer, we use SF6 in plasma etchers...to etch Silicon. I wouldn't want a cylinder in MY house! Not to mention the EPA showing up to monitor emissions from my Stereo, of all things.
My cats NEVER went near my Maggies....which is supposed to be a problem.
Fluorine compounds in the house? No way! |
Magfan, to each his own...ESLs are strongly preferred here over other planar technologies, especially for low level detail. SF6 is more difficult to get these days but not impossible. It does have some benefits. Bias voltage can be much higher than with air (the XG10s with XIM-11 pro unit run around 15-16 kV), and the speed of sound through it is about 1/3 that through air. Wright used that characteristic in the matching XW10 subwoofers (and Watson Labs woofer modules) which have two special 10" woofers and (you guessed it) bags filled with SF6 inside the sealed enclosures. Flat to 20 Hz. |
oops sorry...I could swear........ |
What anyone prefers is OK by me! My entire professional career in semiconductor processing / fabrication has been spent around an absolute AlphaBet soup of Chemistry. I will NOT have any Fluorine or Fluorinated compounds in my house.
With the possible exception of Floride Toothpaste!
While I believe in, and practice good sound, I won't take any chemical risks. Even Helium, an 'inert' gas and technically non-toxic (no chemical reactions) is an asphyxiant.
http://www.solvaychemicals.us/static/wma/pdf/9/8/4/1/Sulfur_Hexafluoride.pdf
Above link is for MSDS (Material Safety Data Sheet) on SF6 |
What info are you after? From your very brief post it sounds as if you want info on where you can buy a working unit.
Only TWO companies make and sell plasma tweeters - Acapella and Lansche. Both are German. Acapella used to sell the plasma tweeters individually but I think they now only sell them as part of their speakers. Lansche is the same, but they closed the door on tweeter sales many years ago. Unless I am very much mistaken, you will not be able to buy these from the factory.
I think that Brian Ackerman from AAudio Imports is a member of Audiogon, so he may be able to advise you on whether you could buy one.
Your other route is to DIY a pair. I have seen circuit diagrams on the web. My own skills are very modest - I can't even put together a doorbell kit from Radio Shack let alone tackle a project like this!!
Going on specs alone the Lansche is more desirable. The plasma flame is twice the size of the Acapella, consequently it can go lower - 5kHz for the Acapella, 2.5kHz for the Lansche. Neither unit tolerates low frequencies beyond the stated crossover point very well, so steep filters are necessary. The Acapella has a crossover built in - the point and slope are configurable by changing internal components. Not sure about the Lansche.
If you want to know what they sound like - I have a pair of Acapella Violons. |
Amfibius' information coincides perfectly with mine. I would have a source for the a-Capella tweeters in Europe. No commercial interest on my side. If you are interested drop me a mail and I'll give you a contact address. |
I heard the Plasma I at a hotel suite at CES in 1979. They sounded incredible - but the technology is what mesmerized me.
Best part of this was listening in on a conversation between Dr Hill and Dr. Oskar Heil - the inventor of the FET and the Heil Air Motion Transformer. Dr Heil showed up just after me, and the 3 of us listened for a while - Heil's first time listening to them or meeting Dr. Hill. The next hour was a long passionate conversation on the physics of sound from 2 of the pioneers. A pretty good day for a 19 y.o. kid. |
It was Heil Plasmatronics. They burned a helium. $7k a pair in 1976. I actually heard them at a store called Absolute Audio in Santa Ana. Fabulous sound. The best speakersvI have ever heard. No cones to produce sound above 600 hz. Hence no distortion from lag time of paper cones . It was strange watching a flickering purple gas emit music. Impressive. The inventor is a laser physicist. They took them off the market as they posed a slight health risk.
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