sunSurgeAutomata

The title refers to a passage from Lewis Thomas’ book The Lives of a Cell where he describes the “steady surge of energy pouring out from the sun into the unfillable sink of empty space by way of the earth”, resulting in the “improbable ordered dance” that we call life on Earth.

All sounds in the piece are derived from “clicks” organized using one-dimensional cellular automata (the most familiar example of a cellular automaton is a 2D version called Conway’s Game of Life).

One of my goals was to create a computer-generated piece that was not based on a model of ‘instruments’ playing ‘notes’; instead, the structure arises from the self-organizing patterns that emerge when you apply the simple (local) cellular automata rules to pulses or as a signal processing algorithm.

sunSurgeAutomata was the first piece created with the CERL Sound Group Platypus Digital Signal Processor (for more on the history hardware development at the CERL Sound Group, see page 14 of Looking Back, Looking Forward). To make the piece, I wrote a microcode implementation of a one-dimensional cellular automaton as a rhythmic pattern of clicks using Stephen Wolfram’s rule 90; another microcode where I used the cellular automaton as a pattern of gates on a record- ing of my voice speaking the Lewis Thomas text; and yet another microcode where I tried to apply the cellular automaton rules to a stream of samples by taking an input stream of samples and forming each output sample as a function of the previous and next samples in a buffer (which ended up being pretty close to a Karplus-Strong type resonator). Each custom-written microcode was a sequence of very long instruction words for the Platypus. I loaded one
of the microcodes into the Platypus at a time and recorded the output of the digital-to-analog converter through the analog-to-digital converter and onto the SCSS (a disk system designed by Kurt Hebel for the School of Music).

Some listeners claim to have heard another “life” reference in the ending of the piece — a musical pun referring to ending of the Beatles’ A Day in the Life, but any resemblance is entirely coincidental.