Have a look at this interesting Plasma Arc Vortex Speaker. Unlike the regular plasma ark speakers that you have seen in the past.
Via: Hackaday
“After replacing the power supply and adding an RC snubber across the flyback transformer primary, my plasma speaker is already much louder. The addition of a more powerful PSU, it allowed me to also reduce the number of turns on the primary, which increased the voltage output. The RC snubber not only protects the MOSFET from the inductive spike of the flyback transformer, but it also drastically reduces the ringing associated with the capacitance between the MOSFET drain and source and the leakage inductance of the flyback transformer. The music your hear is only from the arc and nothing else. There are no other sources of music in the room. It works by using a 555 timer to convert an audio input signal into a frequency modulated signal used to drive a flyback transformer.”