Lorenz Attractor

How does one compose a soundtrack to chaos? For “Weather and Chaos: The Work of Edward Lorenz,” I generated musical themes and ideas using the math and simulations from director Josh Kastorf’s film. Continue on to learn how, and watch and listen to some demonstrations.

(You can also listen to the full soundtrack or watch the short film, “Weather and Chaos: The Work of Edward Lorenz.”)

The Lorenz Attractor
The piano, cello and synth parts from the Lorenz Attractor sequence are a music emulation of the attractor equations and visualization in the film. The notes played correlate to the distance of the data points from the center of the attractor.

To do this I extended the visualizer Josh created in Processing, an open source software development tool for the arts created by MIT. This extension converts the data points from the attractor into midi notes, allowing me to control parameters such as the scales and ranges of the parts, the duration and velocity (roughly volume) of the notes and the granularity of the conversion between the data and notes. (I often modified the velocities afterwards to either make the performance more musical or adjust the mix.) These sequences were then sent to my digital audio workstation and recorded in real time.

This allowed me to control the general tonality and pacing of the music, as well as the ranges of the individual parts. I could not control the specific voice leading or harmonies. (Although I could pre-determine the possibilities to some degree.) This resulted in something pandiatonic – music that uses diatonic scales without the expectations of functional harmony.

You can see this process in the video above. With the piano and cellos parts coming from the equations, I filled in the inner voices with sustained strings to provide some resonance and harmonic movement. The resulting opening flourish in the piano provided a memorable melodic element to tie this significant point in Lorenz’ career back to moments about his personal story.

The Lorenz Attractor

The second section of the attractor sequence in the film shows multiple trails proceeding through, starting from different initial conditions. As you may notice in the first video above, I recorded several synth parts concurrently with the piano and cello, having set them up with slightly varied initial conditions. By the time I faded these into the mix for the multi-trail visuals, their paths through the attractor had separated from the piano and each others’, illustrating the nature of chaos theory. The result is this pandiatonic synth-wash that became a reoccurring thematic texture representing chaos, particularly in regard to the weather.
Double Pendulum

The Baba O’Riley Effect

The Who’s “Baba O’Riley” (aka “Teenage Wasteland”) is not only the first song I ever played in a rock band (hey, three chords) – it’s also the first piece of popular music to use a sequencer. [Some electronic music composers/nerds/friends may come up with something else? In any case, this is what they taught at Berklee, and Pete seems to agree.]

The basic effect, heard at the opening and then as background texture for the studio version of the song, comes from superimposing two circular patterns of notes that are similar but of different lengths. They start off together but quickly diverge, creating varying patterns as their relationship to each other evolves. That seemed like a pretty good way to illustrate the double pendulum and the concept of sensitive dependence on initial conditions. Making the lengths of the patterns prime numbers maximized the amount of time between when the two would synch up. Have a look/listen in the clip above.

Thank you for reading this post – I hope you found it interesting. There are a couple of other nice uses of chaos math in the score. If readers express interest, I can add examples of those in the future.


  • September 13, 2018
  • Very cool, Rob! Sounds great. I look forward to seeing the film.

    September 14, 2018
  • This super interesting! Thanks for sharing the concepts behind your score.

    September 14, 2018
  • Rob,

    Without pretending to understand what goes into the compositions, I can say that I really enjoy both the music and the visuals. I could imagine reclining in a dark room, mid to late evening, with the visuals on a screen and the music looping for an hour or two. Really impressive. I hope you get to continue your work along these lines.


    September 14, 2018
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