Hello,

Back in the 70's I read an article in a magazine, I don't remember if it was Elementary Electronics, Electronics Illistrated or Popular Science (or some other mag), but they had plans for a "Flame Speaker". You could make a gas flame and seed it with some chemical(s) and then insert electrodes into it, apply apmlified audio and it would produce sound waves. I never tried this. Maybe the guys could give it a shot???

Sincerely,
H. Mark Newman