Don't Breathe

Massless Speakers Part 5


Acceptable in the 80's
Not one you can hear

Nelson Pass is a well known and prolific audio designer with his own company Pass Audio.  In 1980 he designed and built a prototype corona wind loudspeaker that he called an Ion Cloud panel, one of the better names of a massless speaker. Stereophile (1980) called him the ionic man.  An often recounted story is that after a few days of demonstrating the device at a trade show he was hospitalised after inhaling too much ozone.  Even in the 80's the toxic effects of ozone were widely known and it is easy to smell before it gets to dangerous levels so perhaps a little more research was needed before using it.

The Ionic Man
Nelson Pass the Ionic Man
This looks to be a fine wire version of a corona wind speaker, apparently Pass had seen the 1960 patent of Townsend-Brown (based on Dr. Tombs' corona wind speaker).  Pass would have been well placed to take this to market with his experience in electronics design so there must have been plenty of factors there to put him off, not least the ozone.  Hear from him in his own words in the excellent Audiophilliac Youtube interview.  He was quoted on the front page of the Wall Street Journal saying "It was the perfect high end audio product: Exotic, inefficient, expensive, unavailable, and toxic."

One massless design that did make it to production was the Plasmasonic by Henri Bondar in 1982.  This is the only set of commercially available massless headphones to have been made.  Patented in 1982 (and a later patent in 1984) the headphones used a small plasma discharge in a ceramic cell with the high voltage amplifier in the headphone itself.  By having the plasma in a headphone its small size was still able to be used as a full frequency driver as it could drive the small volume of air, unlike when used in a speaker system.  The headphones were made by the Audio Reference company with Jean-Claude Fourriere.  Work from Bondar was later used by AHL Tolteque for an intended corona wind loudspeaker (with their own 1990 patent).  This never transpired and an electrostatic version was eventually developed.

Another design that was very nearly realised was a corona wind speaker developed by Alain Deraedt in 1987.  He wrote an excellent  three part series in 1990 for Audiophile magazine, was published in Science & Vie 1987 and a paper in the JAES 1991 as well as writing several 1987 patents.  The prototype was built with Pascal Freulon, a push-pull corona wind panel that looked very close to being produced after a lot of work but unfortunately with no end result, so common when working with massless loudspeakers.

Part 6 - Future Thinking

How Old?
Actual Plasma
A Stiff Breeze
Popular Plasma
Don't Breathe
Future Thinking
 
 
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