This clip is from the 2007 Duckon Sci Fi convention in Naperville IL, USA. The show consisted of 2 Tesla coils making lightning for patrons to enjoy. The musical Tesla Coil turned out to be a big hit.
The coil in this clip is a solid state musical Tesla coil constructed by Steve Ward. The Tesla coil stands 7 feet tall and is capable of putting out over 12 foot of spark. The sound pressure level is well over 110dB. The coil is powered by 240 volts and can draw over 40 amps. The coil resonates at a frequency in the 45 KHz range, and is modulated by a microprocessor sending out trigger pulses over a fiber optic link. The fiber optics are used to provide electrical isolation for the control electronics. The high voltage sparks are making the notes that you hear. Every note of the music is a burst of sparks at the note's frequency.
Here is a video of the coil from a different angle from a earlier run of the coil.
http://www.youtube.com/watch?v=3ff_AXVlo9U
Video captured by Terry Blake edited by Jeff Larson.

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