I know we have some geeks on this board, so check this out.
Ladies and gentlemen ...
The MUSICAL TESLA COIL!
It's pretty complicated, but something like this:
A tesla coil builds up an electrical charge until the potential is high enough to arc out to something grounded. Kinda like lightning.
Each time it arcs out it makes a pop. Kinda like lightning.
Well, these guys have programmed their coils to arc out at various frequencies. So if it created 440 discharges per second, it pops 440 times in a second. 440 times per second = 440 hertz = A(above middle C)
More discharges/second = higher pitch, fewer discharges/second=lower pitch.
They sometimes use a guitar with midi interface to the computer to control the pitch.
So it really is the discharge of electricity making the music.
There actually was an orchestra that came to town that had a big, elaborate setup with multiple Tesla coils. I was going to go, but the tickets were a little pricey. I imagine it was to cover energy costs.
Nikola Tesla was a genius, BTW. The man single-handedly invented almost every aspect of our modern life. Satellites, laser beams, wireless devices (radio, television), microwaves, even electricity itself (AC current that powers everything we know) was all invented by Tesla. The man had is wealth and reputation destroyed by the banking elite at the time because of some of the inventions he had that we never used. He is greatly under-credited for his contribution to society. If it weren't for those banksters, we would all have electricity wirelessly transmitted to us everywhere we go. It would be free. Instead, we have to get it on a copper wire (which costs money) and they charge us for the electricity we use. J.P. Morgan one, Nicola Tesla nothing. If you aren't familiar with the story of Nikola Tesla, look him up. His story can explain a whole lot about the world you think you know.