I was wondering how long it would be before someone
mentioned that....<g>...flame speakers have been around
since the 1800's....after all, flame is ionized so by
using an electrostatic modulation, its a simple
matter to jerk it back and forth at audio rates.
They were even sold commercially as speakers back in the
1960's/1970's...I used to know a lawyer who had a pair
he paid something like $1500 for them...they used propane
gas to produce a flame, had two electrostatic deflection
plates and a cavity to reflect the sound....the response
is said to be from 0 up to light...<g>...I never heard
them in operation.
I don't the efficiency of those would be sufficient to
fulfill the needs of the original post...everything
resonates to every frequency, but is most efficient when
near resonance....so even piezo transducers can carry all
the frequencies you would need and would of course have
a 'Q' at their maximum resonance.
The Chladni tables, akin to the early 'eidophones', had
sound sung or spoken into a horn that focused the sound
onto a plate so it could vibrate and move sound and form
the beautiful geometries now called 'cymatics'...so a
speaker under such a surface or a piezo affixed to it
could be driven to produce the many fascinating patterns.
Of course one or more FIXED tones will generate very stable
geometries although altering their relationships to each
other will produce motion and even patterns such as swirls,
expansion, etc...as so beautifully shown by the late Dr.
Hans Jenny and more recently by Russian scientist Dr. Yuri
Ivanov as posted here;
http://216.60.190.54/spider/b-100e.htm
another related post (after a fashion);
http://www.escribe.com/science/keelynet/index.html?mID=2350
t
There are many marvelous ideas and devices that have long
been lost or forgotten....such as 'musical fountains' where
water jets spray at audio rates to make music simply as
long as the fountain runs.
Joseph Hiddink wrote:
>
> I remember reading something about the "Singing
> Flame" in old Radio/Electronics magazines, and
> that was already in the twenties or thirties. I
> believe I read it in Hugo Gernsback Magazine.
> So, how come that Nasa invented that?
> Joe Hiddink vliegschotel@yahoo.com
>
> --- MILLENNIUM PROJECT <infonet@home.com> wrote:
> > I searched nasa's site and couldn't find
> > anything about flame speakers.I
> > found one page with a definition of a flame
> > speaker.Nothing else
> > yet.Heres the page I found
> >
> http://www.exploratorium.edu/xref/exhibits/flame_speaker.html
> > This website has some intresting index.
> >
> >
> ----------------------------------------------------------------------
> > Warren writes:
> > Yes, that is it. I will try and find my files
> > on it and cut you a
> > copy with diagrams. E-mail me if I should
> > forget.
> >
> >
> >
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