Prime Composition

A short piece based on the decomposition of successive numbers into their prime factors. Each prime is represented as a harmonic partial. For a number N, only those prime harmonics which are factors of N are played.

For example, the number 66 has prime factors 2, 3 and 11, which are the 1st, 2nd and 5th primes. With a fundamental (base) frequency of 60hz, this would therefore trigger sine partials of 60hz, 120hz and 300hz. The fundamental frequency cycles through a triadic sequence every 64 numbers - the only compositional decision besides the underlying structure.

Factors are visually represented as logarithmically-scaled circles, with hue determined by their value. A flash is seen upon reaching a prime number (whose sonic representation is a single partial, corresponding to its single prime index).

Visual programming done in Processing (www.processing.org), communicating with SuperCollider for synthesis (supercollider.sourceforge.net). Full source code available at: http://www.erase.net/projects/prime-composition/