Ionophone is a generator of sound oscillations, for the emission of which a corona or arc discharge is used in gases. The hot arc very quickly heats up and ionizes the gas, in our case air. The air begins to expand rapidly, creating a pressure jump, i.e. shock wave or cotton, which we hear. If we light a discharge with the frequency we need, and "pumping" the amount of energy we need (the amplitude of "cotton") into the channel, we will get music. https://www.youtube.com/watch?v=-vU0D-s8gvo https://www.youtube.com/watch?v=7r-4d6rtHq8