Using MPE With Eurorack Modular Synthesizers

Endorphines shared this video, demonstrating how to use their Shuttle Control, with the latest firmware, to support Multidimensional Polyphonic Expression (MPE) with a Eurorack modular synthesizer.

The Shuttle Control is a USB MIDI-to-CV converter module, with 16 arbitrary assignable channels. Having this many outputs available makes it possible to take advantage of the range of expression available with MPE controllers, like the ROLI Seaboard Rise 25.

Here’s what Endorphines has to say about the technical details:

The general idea behind the MPE is an updated MIDI protocol in which every voice has its own MIDI channel with the multi-dimensional controls.

There is a lot of control from various kinesthetic actions, which we daisy-chained to two Shuttle Controls to increase the overall amount of CV outputs up to 32. Every column of 8 jacks logically correspond to each voice, and modules correspond to the same voices in an allocation grid: first one, second, third and fourth. So far, each Shuttle handles two voices.

Every pressed key on Seaboard is a voice that generates the following MIDI data:
– Note translated into 1 volt per octave Pitch CV on the separate MIDI channel.
– Horizontal movement of the finger on the key or wave surface defines a pitch bender: X-axis control
– Z-axis (or depth) corresponds to channel aftertouch – how much finger pressure is applied to the key.
– Third dimensional Y–axis is vertical position of the finger on each key. By default it is assigned on CC number 74 and is called “timbre”.
– Note on/off and velocity as on a usual MIDI keyboard

Every one of the actions takes is 4 times, since we have four voices.

The final output of Furthrrr Generator is patched into the Gate input.

Pitch CV1 is patched into the Key input of the Carrier VCO of the Furthrrrr Generator.

CV2 is an identical voice pitched CV as CV1 and is patched into the Key input of the Modulator. It is important for frequency modulation that both oscillators track to the same pitch and frequency ratio to obtain harmonically pleasant results.
Those CV outputs are already merged with pitchbender with 48 semitones or 2 octaves range as by MPE standard.

CV3 is assigned for separate pitchbender output but we don’t use because already have merged it with CV and for less cables.

CV4 is patched into the Check in – trigger input of the envelope. Uni-polar envelope output opens the filter’s cutoff – X CV input and the corresponding red knob is set to the 3 o’clock. Turn a bit of resonance using the blue Y knob to add spice.

CV5 is assigned to velocity – to react to how fast the key is pressed. We patched it into the Mood index of the Furthrrrr Generator and adjusted the blue knob to 3 o’clock and the red knob to 12 o’clock. We also turned the frequency switch on.

CV6 is assigned to aftertouch and is patched into the Furthrrr’s waveshaper CV input with the blue knob on 2 o’clock.

CV7 is assigned to a timbre – vertical movement of the finger over the key and is patched into the Order of Carrier in the Furthrrrr Generator. We set the blue order knob to 12 o’clock.

Finally, CV8 and 16 are assigned to the note gates of other voices than the current Shuttle control has assigned above, so it will cycle properly thru all 4 voices.

We repeat the procedure above for remaining 3 voices.

Both Grand Terminals route their stereo outputs into the Cockpit mixer and its output is recorded into the camera. Cabin pressure and fever are set by taste.

We connect the Seaboard directly into the first Shuttle Controls host connection. To daisy chain another Shuttle Control we check ‘device-to-host’ checkbox for the current preset, and connected another Shuttle Control to the ‘device’ socket.

Before the performance we have to tune all our oscillators. Since all voices are cycling, we just press 4 times any A-note and then manually tune all 8 oscillators, until both LEDs light up. Now we are ready to play.

Details on the update are available at the Endorphines site.

If you’ve using MPE with your modular synth, share the details of your setup in the comments!

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