I melted three candles together, lit them and took 1 photo a minute.
Combined the images in After Effects and used a preset written by Satya Meka on ae.tutsplus.com to extract keyframes from an audio spectrum. I then used expressions to link the frame number of the candle comps to the relevant frequency of audio.
The preset by Satya creates keys from the colour levels in a determined area of an already rendered spectrum, another approach would have been to use trapcode sound keys which, as far as I can tell, can create keys directly from audio. This second method may have potentially been less temperamental but the first method is free therefor I was willing to put up with a few quirks.
