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Author Topic: An interesting or perhaps peculiar relationship in Icarus...  (Read 3162 times)

Burkuagh

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I have stumbled upon a relationship between the directionality of waveforms and the resonance of filters. 

Using the "reverse" option in the phase section of the osc editor can often produce little to no difference in the sound output of a waveform, though in some cases it can have intense ones, such as in the case of offset waveforms that are far from symmetrical.  but... in even the waveforms that seem to sound the same no matter what their direction the amount of squeltchieness or scream you get out of the resonance of the filters can be drastically altered.

A quick example.  Open an init patch in Icarus with a simple saw waveform going the traditional direction, starting at top left and ending at the bottom right.  Then turn on the Curtis analog filter, set the resonance knob to half so that its line is pointing straight up... now hold down a note while sweeping the cutoff across its whole range.  You'll notice that only at the top 25% or so of the cutoff range you get that resonant scream out of it. 

Now reverse the direction of the saw waveform so its starting at the bottom left and ending at the top right and again do the filter sweep.  This time you will notice that the resonant scream spans almost the entire range of the cutoff knob.

This affects many filters in different ways.  I have been having a lot of fun exploring this and just thought i'd share

Markus Krause

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Re: An interesting or perhaps peculiar relationship in Icarus...
« Reply #1 on: July 28, 2017, 10:00:25 AM »
The reason for this kind of effects is the nonlinearity in the analog filters. The saturation effects introduce chaotic behaviour to the filters. This makes them interesting to experiment with.
It affects all filters with nonlinear elements. In Icarus this are the anlog types (Cartis, analog, scream, 303, Tone2, Butter) and the Fractal types.

The sound of the filter does also depend on the volume of the osciallators