Genesis And Design Notes - Noise Engineering Cursus Iteritas Manual

Noise Engineering
Cursus Iteritas
Dynamically generated wavetable oscillator using orthogonal functions.

Genesis and Design Notes

This module started many years ago when Scott Jager and Yasi Perera turned me onto Walsh
functions.
The big question was how to reduce the large number of variables (32 harmonic volumes for a 32
band Walsh synthesizer) into a reasonable control set. Bandpass filter-like controls seemed to be a
good solution and there already exist similar controls in the various existant Harmonic Oscillators. A
software prototype was written that proved that a sequency bandpass control scheme was usable.
The then project went to sleep for a couple years as other modules took priority.
When I started working on it again I wanted it to have three modes much like our other current
modules so I went searching for other orthogonal function sets that could fit in the same control
scheme.
The Fourier Series was an obvious second set of orthogonal functions to use which perfectly
mapped to the bandpass-like controls.
Modern mathematics have given us an ocean of orthogonal function sets in wavelets so that seemed
another good place to look. The Daubechies 4 wavelet fit the bill being easy to compute and having
an interesting—and somewhat sawtooth-like—waveform. The controls were a little less natural
since this wavelet has more time precision and more frequency redundancy. With some work
however it worked out quite naturally.
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