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Morph Controller Wavetables


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Morph Controller Wavetables
« on: May 08, 2021, 08:12:10 PM »
Most of the time, wavetables in the Pro 3 are used for audio. The built-in wavetables can also be used as oscillating bi-polar modulation sources, either at audio rates or low-frequency rates (in LFO mode). Here, I'd like to introduce a new type of wavetable that's designed to precisely modulate other control signals.

The inspiration here is the discontinued Doepfer A-144 Morph Controller eurorack module ( The A-144 has a single CV input and four outputs. The panel diagram shows the relationship between the input and each output. For example, as the input increases, Output 1 starts at 0V and moves linearly to peak, then falls linearly to 0, where it stays for the highest 2/3 of the input range. This wavetable is an emulation of the A-144's Output 1:

If you dial this wavetable up and try to listen to it, you'll hear no audio. That's because morph controller wavetables do not oscillate. Each reference waveform represents a static voltage that can be used to control other levels. You scan through these static voltages by modulating Osc 3's shape.

Morph Controllers Can Control Levels

For a specific demonstration of how a morph controller wavetable can be used, follow these patch design steps, starting from the Basic Program:

(1) Select the morph controller wavetable "MC: Out1"
(2) Set Osc 1 Level to 64 and Osc 2 Level to 0
(3) Use the mod matrix to assign Osc 3 to Osc 1 Level at amount of -64
(4) Use the mod matrix to assign Osc 3 to Osc 2 Level at amount of 64
(5) Assign slider to Osc 3 Shape Mod at amount of 127
(6) Set Osc 1 and 2 shapes to taste (but much different values for best results)

Play the patch while moving the slider to scan through the morph controller wavetable. Since its reference waveforms don't oscillate, the control relationship remains constant for each slider position. It should be easy to hear how the oscillator mix corresponds to the A-144 Output 1 diagram at various slider positions. Note that the wavetable's output is always 0 or positive.

Morph Controllers Can Control Distribution

Another example is the Gaussian distribution morph controller:

This can be used to mix waveforms using the slider like the other one, of course. But it gets interesting when the Osc 3 shape is controlled by a random LFO. Consider this patch, again starting from Basic Program:

(1) Select the morph controller wavetable "MC:Gauss"
(2) Set LFO 1's shape to S&H
(3) Set LFO 1's destination to Osc 3 Shape Mod at an amount of 127
(4) Set Osc 1 shape to 0 (triangle)
(5) Use the mod matrix to assign Osc 3 to Osc 1 Shape at an amount of 127

Unlike regular S&H, in which every voltage has the same probability of occurring, the use of the Gaussian morph controller will impose a normal ("bell curve") distribution, centered around the sawtooth shape, upon the "random" voltage.

One More Morph Controller (For Now)

The Triangle morph controller is similar to the Gaussian morph controller, but it's an actual uni-polar triangle, which is ideal for morphing equally between two sources, or uniformly scanning a single source:
« Last Edit: May 08, 2021, 08:28:57 PM by chysn »
Pro 3 #1640
macOS, Ableton, MuseScore2, Serum, Pianoteq

Re: Morph Controller Wavetables
« Reply #1 on: May 08, 2021, 08:21:33 PM »
Very cool!