Plasma speakers (sometimes called flame speakers if the source of the plasma is
combustionrather than gas ionization) are a form of loudspeakerwhich vary the intensity of a plasma, rather than using a magneticfield to push or pull a conventional driver, to create compressionwaves in air (which a listener perceives as sound).
In a normal loudspeaker design, the
inertiaof the driver will resist an instantaneous change in its position as the magnetic field varies with the input. This decreases the fidelityof the speaker, as the input is distorted due to the physical limitations of the device, particularly for strong high frequencies. (This limitation is one of the reasons why tweetersare so much smaller than woofers.) In a plasma speaker, this limitation effectively does not exist, as the air itself is driven directly by expansion of the plasma as the current through it varies. ( Ionizationof a gas causes its electrical resistanceto drop significantly; see for example the "Jacob's ladder" for an explanation.) Plasmatronicsproduced a commercial plasma speaker that used a heliumtank to provide the ionization gas; other designs (some of which date to the 1950s) use combustion of natural gas or even candlesFact|date=February 2007 to produce a plasma, through which current is then passed as in the gas plasma designs (though combustion designs do not require the initial high-voltage to create the plasma).
The plasma speaker design is a member of the family of so-called
A "plasma arc loudspeaker" or "plasma-dynamic loudspeaker" is a loudspeaker that creates sound by varying air pressure through a
corona dischargeor electric arc. It is an evolution of William Duddell's "singing arc" of 1900 and, in recent times, modern research into spacecraft propulsion in the form of the ion thruster.
Plasma tweeters are claimed to be an improvement on traditional tweeter designs because the "driver" has very little mass, and so low
inertia, reducing distortion and increasing transient response. Because of their inability to move large volumes of air, they are limited to reproducing only very high frequencies, and are therefore usable only as tweeters. Most of those who have heard them claim they are notably sharp and clear.
The operation of the speaker requires a continuous supply of ionizable gas. One model used
helium; with the attendant problems of handling and refilling the gas cylinders. The plasma by-product, ozone, can reach hazardous levels in closed rooms. Due to their high cost, limited range, frequent maintenance requirements, and limited utility, they are rarely used in modern loudspeaker equipment, and are instead considered a novelty, perhaps with desirable aesthetic characteristics.
* [http://www.audiocircuit.com/index.php?cc=908&sort=brands The Audio Circuit] A site tracking, among other things, past and present brands of ionic speakers.
* [http://www.nutshellhifi.com/library/speaker-design1.html The Art of Speaker Design]
* [http://www.enjoythemusic.com/magazine/equipment/1002/acapellavoilin.htm A loudspeaker with a plasma ion tweeter]
* [http://uk.youtube.com/watch?v=cEeWtBAE5LY An inspiring attempt at a working DIY plasma loudspeaker - well worth watching]
* [http://www.obsolete.com/120_years/machines/arc/ William Du Bois Duddell and the "Singing Arc"]
* [http://www.plasmatweeter.de/ The Plasma Speaker Homepage]
* [http://www.ee.vill.edu/ion/p13.html History]
* [http://www.swtpc.com/mholley/PopularElectronics/May1968/Flame_Amplification.htm May 1968 Popular Electronics "Flame Amplification"]
Wikimedia Foundation. 2010.
Look at other dictionaries:
Loudspeaker — For other uses, see Loudspeaker (disambiguation). An inexpensive, low fidelity 3½ inch speaker, typically found in small radios … Wikipedia
Tweeter — A tweeter is a loudspeaker designed to produce high frequencies, typically from around 2,000 hertz to 20,000 hertz (20,000 Hz, generally considered to be the upper limit of the human hearing). A few tweeters can manage response up to an octave or … Wikipedia
Plasmatronics — was a company, founded by former Air Force Weapons Laboratory (now Phillips Laboratory) scientist Dr. Alan E. Hill, which produced a plasma speaker design. This was first demonstrated at the 1978 Winter CES show  .The product was effectively a … Wikipedia
Plasmahochtöner — Ein Plasmahochtöner ist ein Hochtonlautsprecher ohne Membran. Die Schwingung wird durch eine Plasmaflamme erzeugt. Plasmahochtöner mit geöffnetem Frontgitter. Obwohl er auch oft Teslahochtöner genannt wird, wurde der Plasmahochtöner weder von… … Deutsch Wikipedia
Ölkühlung — Mainboard wird mit Rapsöl gekühlt Unter Ölkühlung versteht man eine Reduzierung von Temperatur mittels Öl. Inhaltsverzeichnis 1 Starkstromtechnik 2 … Deutsch Wikipedia
Singing Tesla coil — Video of the Museum of Science (Boston) s coil The singing Tesla coil is a form of plasma speaker. It is a variation of a solid state Tesla coil that has been modified to produce musical tones by modulating its spark output. The resulting pitch… … Wikipedia
Pioneer Corporation — Infobox Company |DVD EURO company name = Pioneer Corporation ja. パイオニア株式会社 company company type = Public K.K. (tyo|6773) slogan = sound.vision.soul foundation = Tokyo, Japan (1938) location = key people = Tamio Sudo, President industry = Consumer … Wikipedia
Vorkosigan Saga — The Vorkosigan Saga is a series of science fiction novels and short stories set in a common fictional universe by American author Lois McMaster Bujold. Most of these were published between 1986 and 2002, with the exceptions being “Winterfair… … Wikipedia
List of Amherst College people — This is a list of some notable people affiliated with Amherst College.Notable alumniCollege founders and presidents*Edward Jones 1826, Principal of forerunner of Fourah Bay College (the predecessor of the University of Sierra Leone) (Africa)… … Wikipedia
List of University of Illinois at Urbana-Champaign people — This is an incomplete list of notable people associated with the University of Illinois at Urbana Champaign in the United States of America. Bill Gates noted in a February 2004 speech that Microsoft hires more alumni of the university than from… … Wikipedia