Music 220b, Homework #2, Matt Wright
This is a "Modulation Song", a piece using modulation synthesis and controlled by cellular automata.
Here is the code. It requires the FM Violin instrument
.My modulation-song-generating procedure is ms-stereo and it has 4 parameters:
Here are some settings I like. Each has a link to a wav file example. Since the cellular automata used to make this piece start with random values, you'll get a different (but very similar) version of the "piece" each time you call ms-stereo
;; Fast stacatto 7/8 (sound file) (ms-stereo 15 7 0.1 0.09) ;; Mushy overlapping (sound file) (ms-stereo 15 7 0.05 0.2) ;; Much slower (sound file) (ms-stereo 4 20 0.2 0.2)
The basic idea: The cells of the 1-dimensional cellular automaton correspond to the different beats within a bar. On each cycle we play the current bar, and if a given cell is alive in that cycle we play a note on that beat, otherwise not. We play a low tone at the beginning of every bar, and move it up by 1, 2, or 3 half-steps every bar. The pitches of the notes within each bar are successive harmonics of the low note, and the fm C:M index also increases throughout each bar.