guhsd000@crash.cts.com (Paula Ferris) (08/30/88)
I have been meaning to ask about this for a long time, also this may need to be forwarded to a physics forum. I once saw a demonstration of a flame of burning gas used as a device for sound reproduction (Simply: A Speaker). All I remember was the flame was passed through a ring at mid-flame, and possibly a contact at the base of the flame. In the demo, all they did were simple tones, I think it could be used for more complex sounds though. Does anyone have any information on this? I always though it would be a great item for a party (outdoors!) and a great conversational piece. -- ====================================== End Of Message UUCP: (cbosgd, hplabs!hp-sdd, sdcsvax, nosc, inhp4)!crash!guhsd000 UUCP(pnet): (cbosgd, hplabs!hp-sdd, sdcsvax, nosc, inhp4)!crash!pnet01!guhsd000 ARPA: crash!guhsd000@nosc.mil INET: guhsd000@crash.CTS.COM CIS: 73717,226 TELEX: Temp. Disabled ...Where the streets have no name. -U2 EL CAJON, CALIFORNIA, USA (That's really close to San Diego, if you didn't know.) ======================================
jnp@calmasd.GE.COM (John Pantone) (08/31/88)
(Paula Ferris) writes: >I once saw a demonstration of a flame of burning gas used as a device >for sound reproduction (Simply: A Speaker). All I remember was the >flame was passed through a ring at mid-flame, and possibly a contact >at the base of the flame. ... Does anyone have any information on >this? I always though it would be a great item for a party >(outdoors!) and a great conversational piece. WOW! I haven't even thought about this for almost 20 years! In days of old (late 60's) while at college my buddies and I built one of these flame speakers - I think from an article in Popular Science, or some such magazine. The flame we used was a bunsen burner fed from a propane tank (like the ones used for torches, etc.). Copper sulfate solution was put into a bowl and a wick (from an oil lantern) was placed so that it would draw on the Copper sulfate and feed it into the base of the flame. This of course turned the flame a wild green color, and provided copper ions. A transformer was fed from the stereo (tubes, natch.) and if I'm not mistaken the secondary impedence was 4ohms. We simply hung one lead from the output into the flame at the base, near the wick, and another higher up - and varied the distance until the sound seemed best. I seem to remember the distance at about 1 inch. The flame tended to reproduce treble very well, but bass rather poorly - if at all. Iron Butterfly and the Jefferson Airplane sounded pretty shabby on the "Flameker" as we called it. Voice was O.K. though. This was in Michigan - during the school year - so instead of going outside into 3 feet of snow we did the whole thing in my dorm room! I don't think I would recommend that location, though :-) -- These opinions are solely mine and in no way reflect those of my employer. John M. Pantone @ GE/Calma R&D, 9805 Scranton Rd., San Diego, CA 92121 ...{ucbvax|decvax}!sdcsvax!calmasd!jnp jnp@calmasd.GE.COM GEnie: J.PANTONE
aboulang@bbn.com (Albert Boulanger) (09/01/88)
There was an Amateur Scientist column on how to produce sound from flames that came along in the 70's sometime. I think it was when the original columnist was still conducting. By the way, these monthly columns were the hosts of many construction projects. Here are some laser projects that I recall: Dye Laser CO2 Laser Pulsed Nitrogen Laser Argon Laser Ah, the good ole days, Albert Boulanger BBN Labs Inc. ABoulanger@bbn.com (arpa) Phone: (617)873-3891
davea@hpscdc.HP.COM (Dave Angelini) (09/01/88)
There are two companies at least that made flame speaker. One was Ionovac
and the other escapes me at this time. They do sound excellent and I am
they would compete with anything out there presently.
Dave
How much $ for fire insurance?michiel@idca.tds.PHILIPS.nl (Michiel Fierst van Wijnandsbergen) (09/02/88)
In article <3376@crash.cts.com> guhsd000@crash.cts.com (Paula Ferris) writes: > >I once saw a demonstration of a flame of burning gas used as a device for sound >reproduction (Simply: A Speaker). > >Does anyone have any information on this? I always though it would be a great >item for a party (outdoors!) and a great conversational piece. There is a German company actually building serious speaker systems that use a flame-speaker for the high frequencies. It is sold in the high end audio market in Europe. The company is called MAGNAT. I am not sure if they still build these speakers but they were popular in Europe a few years ago. The sound was pretty good, although I personally didn't like the speakers because their high end was to strong. That is, by the way, not due to the fact that they used a flame-speaker, but due to the German taste. Most German speakers have stronger high tones than, for instance, British speakers. MAGNAT called their system the plasm speaker I think (I'm doing all this from memory). MAGNAT is well known in Europe as a company building high end audio equipment. If anybody wants more information, let me know. I will try to find some papers about this product... -- # Michiel Fierst van Wijnandsbergen Internet fierst@idca.tds.philips.nl # # Philips Telecomm. and Data Systems UUCP ...!mcvax!philapd!fierst #
rkarlqu@hpscdc.HP.COM (Rick Karlquist) (09/14/88)
I think there is some confusion here between the flame loudspeaker of Popular Electronics in 1968 (yes we built one in my high school too) and the corona wind speaker first described in 1955 or so. The Ionovac and I believe the Magnat are corona wind speakers, not flame speakers. I have a copy of the original paper describing the design. You put high voltage bias across a spark gap creating a corona wind. You then modulate this corona wind with a "grid" element which was actually a ring surrounding the spark gap. The audio connects to the "grid". A serious disadvantage of the device is the large amounts of ozone produced. In 1955, they were still selling ozone generators to "freshen the air, like after a thunderstorm" and only later learned that ozone is an irritant with no beneficial health effects (unless its in the upper atmosphere :-( I wonder if there's some way to make a speaker out of those "negative ion generators" that seem to have replaced ozone generators.