If you enjoyed this piece of music, please consider donating to the Albert Kennedy Trust, who work with homeless LGBT young people.
For this piece, I used Risset bells with a long decay. I used a Dissonance-curve style analysis of the partials to generate a tuning based on the timbre. Rather than use the method outlined by Bill Sethares, I compared the partials to look for good just tuning ratios. I then picked the 8 most in-tune partials (using a moving window system, so make sure they weren’t all next to each other). This is part of my TuningLib quark, which is available to SuperCollider users. (See the justScale method for DissonanceCurve)
Then I used an mp3 of the Bell Carol, but very slowly. I also adjusted the tuning of every partial by up to 10Hz and delayed all attacks by up to 60 milliseconds. This creates weird beating effects, as two identical bells are just slightly out of tune with each other. Their attacks are also often just a bit too far apart to be simultaneous.
I have ambitions to generalise harmony in terms of dissonance, so that it’s applicable to bespoke tuning systems, but ended up not applying that to this piece. This track is part of a larger project, ’12 days of Crimbo’, which will raise funds for homeless and/or LGBT charities.