How cool is this?! Big thanks to Steven Polonsky for bringing this to our attention!
The YouTube channel Franzoli Electronics explains in their bio, "The main loud music really comes from the tesla coil sparks. They are literally playing the music due to the programmed phase, pulse width and firing frequency! So, there are no speakers, no audio / video special effects. It looks even better in person and sounds almost the same, just without the beat / percussion backing track."
Photo: Franzoli Electronics/YouTube