Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!ucsd!sdcc6!calmasd!jnp
From: jnp@calmasd.GE.COM (John Pantone)
Newsgroups: sci.electronics
Subject: Re: Flame Speaker Demo.
Message-ID: <43@calmasd.GE.COM>
Date: 30 Aug 88 19:10:56 GMT
References: <3376@crash.cts.com>
Organization: GE/Calma, 9805 Scranton Rd., San Diego, CA 92121
Lines: 40
In-reply-to: guhsd000@crash.cts.com's message of 29 Aug 88 22:21:05 GMT


(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