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Artificial Branches


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Artificial Branches
« on: July 23, 2016, 11:43:26 AM »
I've been intrigued by the Mutable Instruments Branches module. Each channel has two inputs and a single output, with a control to determine the probability that a gate signal goes to one output or the other. It seems like a strange module for a small system, as it's 6HP dedicated to something that might not be used very often. So I got to thinking about whether the Branches's functionality could be duplicated with what I already have.

Another Mutable Instruments module, Kinks, rises to the challenge. Kinks has an inverter, a logic (min/max) section, and a sample-and-hold section. All three of these were used for my Branches emulator.

The gate signal (from the Little Phatty) goes into the S&H trigger. Since the S&H source is normaled to Noise, each gate triggers a random voltage. The S&H's output goes to one of the logic inputs. One voltage output of the Triatt, set to bi-polar mode, goes to the other logic input.

Now I've got two logic inputs: one value is known (the one from the Triatt), and the other is unknown (from the S&H). The logic's Max output triggers one EG (a Make Noise Function, actually), and the Min output goes to the Kinks's inverter, where it is turned upside-down and sent to another EG. The idea here is that either the Max output goes high when the random output is higher than the Triatt's voltage, and the (inverted) Min output goes high when the random output is lower.

Each EG goes to its own VCA (the low pass gate and the DSM01), and the outputs are sent to the left and right stereo channel, respectively.

Now, with each gate, the triggered VCA is random. The probability of which VCA is heard for each gate is controlled by the Triatt's knob (but could easily be controlled by CV). All the way left, only the left channel is triggered. All the way right, only the right channel is triggered. In the middle, each channel is heard about 50% of the time.

Edit: Almost, but not exactly like Branches, as described above, because both EGs are often triggered with the same gate. This likely has to do with how much voltage is required to trigger Function. I addressed this quirk by running each logic output through a passive attenuator and making teeny tiny movements to knob until it was just right.
« Last Edit: July 23, 2016, 11:57:50 AM by chysn »
DSI: DSM03; previously: Mopho Keyboard, Desktop Mopho, Evolver, DSM01
Hardware: Eurorack, Moog Little Phatty w/ CV Outs, Arturia MicroBrute, KMI QuNexus
Software: macOS, Ableton, MuseScore
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