Modal SKULPTsynth SE User Manual page 22

MPE
MIDI Polyphonic Expression (or MPE) is a method of using MIDI to enable expressive electronic
musical instruments to control multiple dimensions of sound polyphonically. In MIDI, channel-
wide messages (such as pitch bend, CCs, and channel aftertouch) are applied to all notes
being played on a single channel; therefore, in MPE each note is assigned its own channel so
that those messages can be applied to each note individually.
An MPE instrument typically has three dimensions of expression / control – left-right (X-axis);
front-back (Y-axis); and pressure (Z-axis) – each axis can be mapped to various parameters of
sound and be applied on a per-note basis.
SKULPTsynth SE is an MPE-compatible synthesiser, which means any valid MPE instrument can
control multiple parameters of SKULPTsynth SE's sound engine polyphonically. The majority of
the SKULPTsynth SE parameters can be controlled by MPE.
Setting up MPE on SKULPTsynth SE
Enabling SKULPTsynth SE to respond to MPE involves the following steps:
1. Turn on MPE Mode. This can either be done on the SKULPTsynth SE device or on
MODALapp. To set it on the device:
• With SKULPTsynth SE powered off, hold the MEG button.
• Power on the device and wait for the power-on animation to finish.
• Press any touch pad in the range of 9-16 to turn on MPE Mode, or press any touch pad in
the range of 1-8 to turn off MPE Mode. The touch pad LEDs will show the selected mode.
• Release the MEG button once selected the MPE mode.
2. Using MODALapp, set 'MPE Master Channel' to match that of your MPE instrument. Your
MPE instrument may refer to this as its 'MPE Zone' – 'Lower Zone' uses channel 1 and
'Upper Zone' uses channel 16. Some MPE instruments may not specify a Master Channel
/ Zone – in this case the most likely value to use here is '1'. Please refer to the MPE
instruments settings or documentation for more information.
3. Using MODALapp, set 'MPE Number of Channels' to match that of your MPE instrument.
Some MPE instruments may not specify a Number of Channels – in this case the
most likely value to use here is '15'. Please refer to the MPE instruments settings or
documentation for more information.
4. Using MODALapp, set 'MPE Pitch Bend Range' to that of your MPE instrument. Your
MPE instrument may refer to this as its 'Pitch Bend Sensitivity'. Some MPE instruments
may not specify, or use, a fixed Pitch Bend Range – in this case use this value to set your
preferred semitone range of the MPE X-axis. Please refer to the MPE instruments settings
or documentation for more information.
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MPE
Each MPE dimension is mapped to the SKULPTsynth SE sound engine as follows:
• Left-right / X-axis (sent as MIDI Pitch Bend) – This controls the pitch of the note, with the
range set using the 'MPE Pitch Bend Range' global setting (see above).
• Front-back / Y-axis (sent as MIDI CC 74) – This controls the SKULPTsynth SE Mod Wheel
modulation assignments.
• Pressure / Z-axis (sent as MIDI Channel Aftertouch) – this controls the SKULPTsynth SE
Aftertouch modulation assignments.
As the MPE Y and Z dimension assignments are built into SKULPTsynth SE's existing
modulation matrix, these assignments are saved and recalled with each patch.
Using MPE on SKULPTsynth SE
If using MODALapp / MODALplugin please ensure that you are running the version (or above)
of MODALapp / MODALplugin released with SKULPTsynth SE firmware v2.0 to ensure correct
communication between the app / plugin and the SKULPTsynth SE.
If using in conjunction with non-MPE MIDI controllers or software, please set their output MIDI
channel to match the SKULPTsynth SE's 'MPE Master Channel' to ensure correct behaviour.
SKULPTsynth SE MPE limitations:
• If Y+ or Aftertouch is assigned to any global sound parameters (LFO1 and Delay
parameters) then these parameters will change for all notes / voices and only the latest /
newest MPE note will have control of these parameters.
• MPE is not available in Polychain mode
• MPE expression data cannot be recorded into the SKULPTsynth SE sequencer, and any
MPE notes recorded into the sequencer are converted in 'master' notes.
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