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Natural Science Forum / Physics / Acoustics / August 2006Cold Plasma Speakers
Hi: Where can I find info on cold plasma speakers? Thanks, Radium > Hi: > > Where can I find info on cold plasma speakers? Go to the nearest blood bank; that's what they use in their freezers. Bob M. >Hi: > >Where can I find info on cold plasma speakers? --- Google "Antarctic Vampire Orators"  SignatureJohn Fields Professional Circuit Designer > Hi: > [quoted text clipped - 3 lines] > > Radium Can't you use Google? > > Hi: > > [quoted text clipped - 5 lines] > > Can't you use Google? No luck http://www.google.com/search?hl=en&lr=&safe=off&q=%22cold+plasma+speakers%22&btn G=Search http://www.google.com/search?hl=en&lr=&safe=off&q=%22cold+plasma+speaker%22&btnG =Search > > > Hi: > > > [quoted text clipped - 7 lines] > > No luck Strange that isn't it ? Graham >> > Hi: >> > [quoted text clipped - 11 lines] > > http://www.google.com/search?hl=en&lr=&safe=off&q=%22cold+plasma+speaker%22&btnG =Search Here: http://membres.lycos.fr/plasmapropulsion/Basic%20course_&_models/Corona_Acoustic _theory.html > Hi: > [quoted text clipped - 3 lines] > > Radium I ask because I am looking for a type of speaker that does not use a diaphragm and does not get too hot to touch. > I ask because I am looking for a type of speaker that does not use a > diaphragm and does not get too hot to touch. Any electrosttic or piezoelectric speaker should work for you. Angelo Campanella >> I ask because I am looking for a type of speaker that does not use a >> diaphragm and does not get too hot to touch. > > Any electrosttic or piezoelectric speaker should work for you. > > Angelo Campanella Both electrostatic and piezoelectric speakers require/utilize a diaphragm to produce the required SPL. > Both electrostatic and piezoelectric speakers require/utilize a diaphragm > to produce the required SPL. All efficient speakers will use a diaphragm. If efficiency can be sacrificed, then the bare piezoelctric can be used. It is my undersanduing that electrostaic speakers are flat and are all transducer (or all diaphragm if you declare that the element itself is a diaphragm). Ang. C. Hadn't Elac a plasma tweeter? Not cold, of course. And after playing Dark side of the Moon there was so much ozon in the room it caused lung diseases. :-). Why are we taking this Radium serious? > > Both electrostatic and piezoelectric speakers require/utilize a diaphragm > > to produce the required SPL. [quoted text clipped - 7 lines] > > Ang. C. > Hadn't Elac a plasma tweeter? > Not cold, of course. > And after playing Dark side of the Moon there was so much ozon in the room > it caused lung diseases. :-). > Why are we taking this Radium serious? Primarily because this is sci.electronics.basics, where there is no such thing as a stupid question. And please learn to bottom-post. Thanks! Rich > Hi: > > Where can I find info on cold plasma speakers? LMAO ! Hey, I've met your namesake Archimedes Plutonium recently. He's as barking mad as you are ! Graham > > Hi: > > [quoted text clipped - 6 lines] > > Graham AP's still around? Yeesh! Ain't seen him in forever! (Not that I've WANTED to, but...) SignatureDon Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist, or the subject of the message doesn't contain the exact text "PopperAndShadow" somewhere, any message sent to this address will go in the garbage without my ever knowing it arrived. Sorry... <http://www.sonic.net/~dakidd> for more info > Hi: > [quoted text clipped - 3 lines] > > Radium >> Hi: >> [quoted text clipped - 3 lines] >> >> Radium Guys, he's a troll, ignore him! >>> Hi: >>> [quoted text clipped - 5 lines] > > Guys, he's a troll, ignore him! A sociopathic swine, and contemptable piece of human waste, by the name Mike (Porky) Rieves, who is demonstrably devoid of moral conscience and all generally accepted standards of ethical behavior, just farted and bestowed upon us the above echo. > Hi: > [quoted text clipped - 3 lines] > > Radium I don't think there is such an animal, today. There have been a few plasma loudspeakers sold. One of them was by Plasmatronics (in the early 80's, iirc), however, they weren't "cold". It used an inert gas (helium, I believe) to create 'fingers' of plasma. Each finger was about 3" long and glowed bright blue. This was only for the upper midrange and highs, and the need for a large tank of helium was a real pita, plus the low end was a conventional dynamic speaker. I was also fortunate enough to have seen and heard one that did not (apparently) use an ignited plasma. It didn't play too loudly and was never produced commercially. It also created large amounts of ozone. It had response down to dc. Its mode of operation was probably similar to those plasma-based air cleaners. I've considered getting one of these air cleaners, then apply the appropriate modulation, but I don't think it would produce the type of sound that would sell (plus the ozone problem is still there). Here's a link that may give you some more info. http://en.wikipedia.org/wiki/Plasma_arc_loudspeaker Bob > I don't think there is such an animal, today. There have been a few plasma > loudspeakers sold. One of them was by Plasmatronics (in the early 80's, [quoted text clipped - 3 lines] > need for a large tank of helium was a real pita, plus the low end was a > conventional dynamic speaker. The device was born as an "ionophone"; a classmate in the '50's (Fuji Oda) built and evaluated one as his masters thesis around 1955. He had to make the transducer itself from fused quartz because it ran white hot (about a kilowatt of input power; as an RF carrier at 27 mHz. The transducer shape was basically like an eyw cup with an electrode on either side wall, connected dorectly to the output transmission line from an RF transmitter. Amplitude modulation (AM) of the rf carrier produced sound and some light from the plasma and hot quartz at the time for that coonfiguration. Ozone; yes.. smelled it often. Plasma TV screens use a low pressure gas sealed in an envelope. The gas glows when milliamps of current flow through it. The place where the glow occurs is around the cathode or anode (I forget which) in the case of DC current. If AC current is used, both glow alternately. Such gas discharges are highly nonlinear; there being no current until breakdown occurs, the abundant current and light. That's why an AC carrier, which can be modulated at an audio rate, was used in the beginning. The audio performance is entirey due to the expansion of the gas being heated by the quantity of current flowing through it (I^2*R heating). On an audio wave peak, the temperature and volume are greatest; on an audio wave valley, the tempreature and volume are least. I think it is really a clumsy way of productings ound, inherently nonlinear for moderate to loud sound levels. > I was also fortunate enough to have seen and heard one that did not > (apparently) use an ignited plasma. It didn't play too loudly and was never > produced commercially. That's what Fuji concluded. > It also created large amounts of ozone. Yup. > It had > response down to dc. Its mode of operation was probably similar to those > plasma-based air cleaners. I've considered getting one of these air > cleaners, then apply the appropriate modulation, but I don't think it would > produce the type of sound that would sell (plus the ozone problem is still > there). It's just a toy. Ang. C. >[SNIP] > The audio performance is entirey due to the expansion of the gas being [quoted text clipped - 3 lines] > a clumsy way of productings ound, inherently nonlinear for moderate to > loud sound levels. I am not sure I should be posting on this thread but just a couple of points that may be of interest. Plasmas in air have two mechanisms for directly producing sound. The first is a monopole caused by expanding/contracting due to a varying temperature and the second is a dipole caused by varying the stream of charged particles rapidly moving between the electrodes and transferring some of their momentum to the particles of air. There have been a number of commercial designs of plasma speakers over the years and several DIY projects which can be found on the web. I believe a hifi company in Germany is still producing a tweeter for the "audiophile" market: http://www.acapella.de The principle of operation is nonlinear but then so is electrostatic attraction/repulsion. If the pros outweighed the cons I suspect engineers would find ways of handling the nonlinearity. However, it is hard to see an application where the cons do not outweigh the pros. > >[SNIP] > > The audio performance is entirey due to the expansion of the gas being [quoted text clipped - 6 lines] > I am not sure I should be posting on this thread but just a couple of > points that may be of interest. > Plasmas in air have two mechanisms for directly producing sound. The > first is a monopole caused by expanding/contracting due to a varying > temperature and the second is a dipole caused by varying the stream of > charged particles rapidly moving between the electrodes and > transferring some of their momentum to the particles of air. I wonder if a plasma loudspeaker could use a mechanism similar to a stun gun. The spark from a stun gun does not produce any perceptible heat in close proximity because -- despite being a 100,000 volts -- the power is not enough to raise temperature sufficiently to burn the skin. That being said, the stun gun does make sound when it sparks. I assume that an equipment similar to the stun gun could be engineered so that it could produce sparks that would cause the intended sound [e.g. speech or music]. Conventional plasma speakers produce sparks that reach as high as 2,000 Celsius. If an high-voltage, low-amperage electric current of 1,000 Hz frequency is passed through air, a 1,000 Hz tone will result. > There have been a number of commercial designs of plasma speakers over > the years and several DIY projects which can be found on the web. I [quoted text clipped - 5 lines] > engineers would find ways of handling the nonlinearity. However, it is > hard to see an application where the cons do not outweigh the pros. > I assume > that an equipment similar to the stun gun could be engineered so that > it could .......... be stuck up your arse ? I bet that would make some noise ! Graham > Where can I find info on cold plasma speakers? First, you have to figure out where in Hell you can get some "cold plasma". Plasma is hotter than hot, almost by definition. Cheers! Rich > > Where can I find info on cold plasma speakers? > [quoted text clipped - 3 lines] > Cheers! > Rich Sorry. I think "plasma" is the wrong word, then. By "plasma speaker", I meant a speaker that generates sound by using electricity of an analogous frequency and passing the electric current through the air. In order for electricity to flow through a tough insulator, like air, the voltage needs to be at least 50 kV. If the electric current flowing through the air, has a frequency of 1,000 Hz, it will produce an audible 1,000 Hz tone. >> > Where can I find info on cold plasma speakers? >> [quoted text clipped - 11 lines] >through the air, has a frequency of 1,000 Hz, it will produce an >audible 1,000 Hz tone. 2000. Try it. John >2000. Try it. --- Very nice. Just like incandescent lamps. :-) SignatureJohn Fields Professional Circuit Designer >>If the electric current flowing >>through the air, has a frequency of 1,000 Hz, it will produce an >>audible 1,000 Hz tone. > 2000. Try it. True if you drive the plsma arc with straight audio. But when a carrier is used, or - if there is a calass A amplifier mode available - the zero audio state is a 50% current AKA "Bias". Then the audio, ac wise, modulates the current to be greater or lesser.. etc. Angelo Campanella > >> > Where can I find info on cold plasma speakers? > >> [quoted text clipped - 13 lines] > > 2000. Try it. Of course ! Power has no polarity. Graham > > > Where can I find info on cold plasma speakers? > > [quoted text clipped - 11 lines] > through the air, has a frequency of 1,000 Hz, it will produce an > audible 1,000 Hz tone. Look here Mr Pea Brain. You appear to recognise that this 'plasma' will need both volts and amps. That means power, which means heat. So, no cold plasma. Graham |
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