nixie wrote ...

I believe sound is just as important as the video when recording tesla coil performances.

I'm using the latest hi-end Canon DSLR with an equally good lens. Although it does make for excellent low light video recordings with minimal noise/artifacts, you must use external microphones to achieve a sound recording to equal the video quality. The camera manufacturers never disclose these important details. News crews know it all too well. You can spend $2k for a good camera, and you're left with smartphone quality audio if you use their built-in microphones.
The audio noise (background hiss) level is pretty high on some cameras I looked at, so you have to research it carefully. Microphones won't fix that.

Eric's latest dubstep video was recorded using this camera along with remote studio condenser microphones on suspension stands. Placed with a spread of 20' from a 40' wide audio source. A balanced line converter at the camera converts the XLR signal to a single-ended output at the camera's remote microphone input. AGC is disabled to help recover the dynamic range that makes a coil performance so spectacular in the first place. Of course, if you're listening to it on a smartphone speaker then it does not matter . Headphones will provide the channel separation and bass depth of the original performance.

Hope this helps.

Jeff