Sunday, May 29, 2011

Pendulum Studies

The period of one complete cycle of the dance is 60 seconds. The length of the longest pendulum has been adjusted so that it executes 51 oscillations in this 60 second period. The length of each successive shorter pendulum is carefully adjusted so that it executes one additional oscillation in this period. Thus, the 15th pendulum (shortest) undergoes 65 oscillations.

Inspired by this youtube video, some Supercollider instruments based on periodic fluctuations in amplitude over a series of overtones. The first one mimics the motion in the video - 15 sine waves which oscillate between 51 and 65 hz cycles per minute.

//t is the timing of the pendulum swinging
var t = (51..65)/60;
//p is the pitch, 15 overtones of 60 hz
var p = 60 *(1..15);
//modulate the amplitude of each pitch p by t
{,0,,0,0.5,1,0) * 0.04),,0,1,-0.5)))}.play;

Pendulum-15-60 by Backtrace

var t = (201..328)/256;
var p = 64 *(1..128);
{,0, (1/((p+64)*p.log2)) *,0,0.5,1,0) *48),,0,1,-0.5)))}.play;

You can always add more oscillators to this series:
Pendulum-128-256 by Backtrace