Expression Redirector

Convert Poly Aftertouch and MPE Controller Output to MIDI CC streams.

• This script can convert all forms of MPE expression, plus Channel Aftertouch into MIDI CC streams.
• Data from MPE controllers can include Velocity, Channel Pressure, Pitch Bend, Expression (CC 74), and Note Release. (Seabord calls these Strike, Press, Glide, Slide, and Lift). Some other controllers can send Channel Aftertouch.
• Aftertouch is the pressure on a key after the initial strike. Poly Aftertouch is per-note, Channel Aftertouch is just one value regardless of note. For clarity this program refers to Channel Aftertouch as “Mono Aftertouch”
• Set each type of message to OFF (🚫) or to a MIDI channel. Each enabled message should be on a separate channel to avoid conflicting streams (or not, if you like some chaos 😉). Default is OFF for all streams.
• The note number becomes the CC number, and the message value becomes the CC value sent. Note 0 becomes CC 0, Note 36 becomes CC 36, etc.
• NEW❗️: The last two knobs allow you to override the default MIDI CC assignment for each note.
• IMPORTANT : Keys and CC’s 120-127 are excluded by default. These are reserved MIDI channel mode messages and should not be used. You can enable them by editing the EXCLUDE_CHANNEL_MODE parameter in the OnLoad section.
• Velocity will work from non-MPE sources too. You can use this to send a CC value based on how hard you hit a note.
• You can also choose whether or not to send out Note ON and Note OFF messages. The default is OFF.

SO! What is this good for? Well, for instance it can enable an MPE controller to send up to 128 MIDI CCs for controlling non-MPE synth parameters from the “Slide” expression (usually sliding up and down on the key). Or a controller that sends Poly Aftertouch can control as many MIDI CC’s as there are keys on the device. Even just the AUM keyboard can send up to 128 CC’s based on where you strike the key. An MPE controller with Pressure, Pitch Bend, Expression, and Release could in theory control up to 768 parameters!

I dunno – seems like it could come in handy. Credit to Audiobus forum member @stown for this really great idea. 👏👍🏼😎👏

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  • Category: Utility
  • Revision: 0.5
  • License: The Unlicense
  • Views: 447
  • Modified: 1 year ago
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One comments on “Expression Redirector
  • wim-number37 on said:

    version 0.5 fixes a Poly Aftertouch bug.

    It also excludes CC 120-127, which are reserved Channel Mode Messages that normally shouldn’t be used. You can set the EXCLUDE_CHANNEL_MODE_CC to FALSE to overcome this restriction if you really want to.

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