Tuesday, October 28, 2008

Week 10 Audio Arts - Additive Synthesis

Can I have the award for artistic patching? Impressionism vs bidule layouts....

Audio Demo


It's a midi controlled additive synth. You get 6 oscillators, and you get to choose the ratio of their frequencies to the midi note, their amplitude, and their wave type. There is a simple amplitude envelope to control the shape of the sound. It's polyphonic.

More Extreme Additive Synth (pictured)
There are 16 oscillators, each contained in a group. The oscillators are automatically mapped as harmonics in relation to the defined fundamental, however if you want a rougher tone, they can be scattered slightly using the "Freq Freakout Factor".

The amplitude of each oscillator is determined by a set ratio of the previous oscillator, creating a decreasing exponential curve. For example, if the "amp taper factor" is at 0.5, then every harmonic will be half the value of the previous one.

The amplitude of odd and even harmonics can be boosted and cut.

Frequency, pan, and amplitude can be varied individually using random value generators for each oscillator, creating evolving textures.

It's all pretty processor intensive, cause there are a total of 64 oscillators running simultaneousy (including the random modulators).

Reference: Christian Haines. "Additive Synthesis." Lecture presented at the Electronic Music Unit, University of Adelaide, 21 October 2008.

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