Generate complex and variable waveshapes.
This Oscillator combines two methods of waveshaping and shape modulation.
There is a DAM Waveshaper on the output of each VCO, and there is the facility to Morph between two waveshaping formulae, the sum of the formulae, and the difference between the two formulae. The phase of the second VCO is also variable, and if required there is a quantized input to raise or lower the second VCO in octave steps. The sum of the two Waveshapers is achieved when the Morph point is mid way between the ASin h and ATan h points.
The only reason I chose to use the two particular methods of waveshaping (ASin h and ATan h) were that they gave the widest, and most useful range of waveshapes at the output (feel free to experiment).
The bias voltage on the audio signal input allows further variation in the output waveshape. The phase of the second oscillator also affects the resulting shape when the output is the sum or difference of the two waveshapes. So we can introduce more harmonics and waveshapes into the output I have included a third oscillator which is not used in the audio, but just to phase modulate the second audio oscillator. The High Pass Filters are all set with their pitch/voltage at the 1 kHz/Volt setting to save calculating the frequencies. These are merely for blocking LF rumbles and DC from the audio output.
Note: Taking the Bend 1 and CVs outside the -4.5 to + 4.5 volts would be of no benefit as this will result in very little output.
Note: There is a High Pass Filter in the output to prevent DC or very low frequencies resulting from the Phase Modulation (this can produce large amounts of aliasing, so there is the possibility of reflected “harmonics” and DC).
Note: I did briefly experiment with using a Feedback (Volts) module to use the audio output to produce the phase modulation, but this proved to be too extreme and unpredictable in it’s results.
Note: I used the HD Oscillators from the Community Modules download from the Synthedit website as these give a slightly better waveform with a greater harmonic range.
Note: Don’t bother trying oversampling on this structure, I experimented and found that if anything it decreased the range of sounds (less high frequency content)
As you can see from the screenshot below this structure produces some interesting waveforms, and harmonic (and inharmonic) structures, which with the correct low frequency CV’s can produce some more unusual (and possibly un-musical) audio outputs..
Note: Although the VCO’s allow selection of Pink Noise, White Noise, and Pulse waveshapes none of these produce any interesting outputs (to me anyway).
The prefab for this module can be found on the files section of synthedit@groups.io (click link to download).
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