Experiences with Plasma tweeters?

Hi from New Zealand.

About a month ago I had the pleasure of hearing some Acapella speakers from Germany which use plasma tweeters. These produced the only sound I have heard from speakers that I could say really sounded like live cymbals, so I'm hooked. The fact that they use
A) valves,
B) tesla coil principles
also makes them a hell of an interesting.

There is a good site on the web about peoples experiences with making these (is easy to find if you search on Google or I can find it if you need). I'm just wondering if anyone here has had a go at designing such a thing (and lived!).

Thanks

Murray
 
State of the art is (still?) Plasmatronics Type 1. I almost bought a pair, kind of regret it that I did not when I had the chance. These are rare, require helium gas til function and cross over at 700Hz (switchable to 1000Hz). Very nice. I understand some homes in California have full range units integrated into the house. Watch out for ozone -- several people have had trouble with ozone poisioning. The emission of UV light is less troublesome -- sunscreen is cheap.

Petter
 
I would think it would be possible to use a sort of ventillation hood. Perhaps something like a funnel above the driver with air evacuation. It'd be a nuisance in the practical sense, but I could probably talk myself into it...after all, I never set out to have a set of water lines on my listening room floor, either, but there they are.
As cyclotronguy and I were saying backstage, I seem to recall seeing that you can make a driver using an ordinary candle flame. The carbon particles--i.e. the glowing part of the flame--supposedly are able to be coaxed into action by plates on either side. No, I haven't tried it. I suspect that it would be horrendously inefficient. But it's something I'd like to take a poke at one of these days when I have time. At least candles aren't health hazards as long as you don't set the house on fire.

Grey
 
Ozone generation certainly seems to be a downfall of this type of tweeter. One web site talks of some one setting a speaker up and leaving it overnite only to arrive to bleached room in the morning. We have a little experience in making high power ozone power supplies - a little leak from a hose carrying off test generated ozone totally bleached grass around the spot it leaked from. Its nasty stuff as an oxidant(though I haven't researched its other effects on life) but the makers of Acapella speakers use some catalyst to get it to return back to O2. Obviously there is an answer since (a few) comercial tweeters are out there. A bigger problem actually I suspect would be integrating its response with a decent midrange (eg Seas excel Mg cone types)and preseving phase and linearity. Any thoughts?

Murray