Here I hope to fill in the gaps and link to the information I have on this site and on other sites on the
I will list inventors, speakers, companies and anything else that I end up with some linked information
Dr. D.M. Tombs, Gerald Shirley and the Corona Wind Loudspeaker
I have Dr. Tombs (great name) in the theoretical section as the designer of a
Corona Wind Loudspeaker in 1955. Later he passed the project over to an American
called Gerald Shirley (with a view to commercialising it, which I can't find any evidence of). It appears that
neither of them patented any aspect of the design, but it was well published in the following articles (full
details in the references section): Nature 1955 ,
Radio and Television News 1956 , Electronics 1957 ,
I am personally quite keen on the work that they did as it was the first of these types of loudspeaker that I
discovered, mentioned in a chapter of an old 1950's electronics book. There are only occasional mentions on the web
of this work, for example in the GIFs at the bottom of this French article, and a ref in this paper.
Siegfried Klein, The Ionovac and Magnat
Siegfried Klien was a prolific inventor and developer of many plasma tweeters
from the '50s through to the '80s. He developed and has many patents on the DuKane
Ionovac, the Ionophone and the Magnat MP series of plasma tweeters, all listed in the commercial section of this site. There is no point in me going in to too much detail here, as
www.ionovac.com has an enormous amount of information on it, including
historical detail, and www.plasmatweeter.de has some nice pictures of
Nelson Pass, Threshold Audio Inc., Ion Cloud Panel
Nelson is a well known and prolific audio designer and designed and built a prototype corona wind loudspeaker (in the theoretical section) that he
called an Ion Cloud panel. Here are pictures, the front cover and article from Stereophile Vol.6 No.1 (early 80's) calling him the ionic man and
recounting the gas and ozone issues he had with the speaker. It looks like it's another design that nearly made it
to production, but not quite.
I know little of this theoretical design apart from this one french article that was sent to me by Pascal Freulon. It appears to be a corona wind design. He also has a 1979 patent.
Jean-Claude Fourriere, Henri Bondar - Tolteque and PlasmaSonic
Henri Bondar designed the Plasmasonic headphones which did make it commercially,
for a few hundred at least. Patented in 1982, in his own words here, click "acoustics" on the left. It appears that this
may have been more of a corona wind effect than a plasma, difficult to tell - but the only headphones so far made.
Jean-Claude Fourriere managed the Audio Reference company that made the Plasmasonic, then went on to AHL Tolteque
in 1990. It appears that a theoretical corona wind version
of the electrostatic speaker was intended, but again it didn't deliver the goods as a commercial product.
Dr. Hill developed this classic commercial (although not that many made)
loudspeaker that contained a really very good multi-point to plane plasma tweeter which operated in a helium atmosphere to get around the gaseous safety issues. Good detail and photos on it on www.plasmatweeter.de. Patented 1979. An article on it
Otto Braun, Corona Acoustic
Otto Braun developed the commercial Corona Acoustic plasma tweeter, which went through a variety of models before the design was taken up by
Lansch. Unusually, this tweeter can still be purchased.