Auxetophone

[strawman]

This is the kind of thing geeks in my area enjoy playing with:



This is one unique method of amplifying sound prior to vacuum tubes and transistors.

 

[Eriol]

Fascinating. Thanks for the video.

 

[PatrThom]

So it's essentially a pneumatic transistor?

You might want to check out what people are trying to do with gasoline-powered speakers as well.
Pump a stoichiometric mixture of gasoline and air into one end of a tube, use a spark plug to generate high-pressure sound waves. Modulating the spark isn't too hard, the trouble is with regulating the combustion mixture.

Sorry, no video link. I tried to find some, but no dice.

--Patrick