John's Aslandis' paintings are Moiré patterns (http://en.wikipedia.org/wiki/Moir%C3%A9_pattern) which Brian May has translated into a generative audio (http://en.wikipedia.org/wiki/Generative_music) soundtrack using simple arithmetic to produce related tones that give rise to beat frequencies (http://en.wikipedia.org/wiki/Beat_%28acoustics%29).
Colours are frequencies in the electro-magnetic spectrum, right? So (if I correctly recall Brian's explanation from last year) he looks at the pallete of colours for a given painting of John's and keeps halving the frequency of each colour until it fits in about the 20-15,000 Hz audio range, then generates a steady audio tone (it might be a sine wave, I can't remember) for each one. But those tones are not all played simultaneously, they fade in and out in various combinations so as to approximate the way the eye would scan the painting. The interference patterns between notes parallels the Moire vibration of the imagery.
Anyhow, I imagine they will clarifying it on the day in their discussion, and you can see/hear it in action. My exposure to this was reluctantly via Brian on a computer screen but that kind of defies the whole point of the way an eye scans a large image so I look forward to the real thing.
For more behind their philosophy and an online catalogue go to John's profile web page...