New in Poly-Ana 1.3.2, improved MPE (MIDI Polyphonic Expression) support!
Version 1.3.2 of Poly-Ana and L’il Poly-Ana AU/VST adds improved support for MPE, the newest addition to the MIDI specification. Multi-channel control allows for the synth’s voices to have separate, unique and independent pitch-bend and other MIDI CC controller messages sent per note/channel rather than shared across all voices on a single MIDI channel as with a typical keyboard controller. Poly-Ana’s multi-channel MIDI-Guitar mode has already supported most of MPE before this update. (In fact, most of MPE was supported by Poly-Ana long before the MPE specification was even proposed! We’ve been proud to have been mentioned on several pages listing MPE compatible synth products right from the very start of MPE!)
We’ve now added a few new features, most of them automatic with one new setting in the Options Dialog, to improve MPE compliance. To keep the classic multi-channel MIDI-Guitar behavior, leave the new MPE (ON)/GUITAR MULTI-CHANNEL MODE switch in the Options Dialog set to Off. To enable improved MPE compatibility, turn it On. Usually that’s all you’ll need to think about, just set the option to match the kind of multi-channel MIDI controller you’re using. (Note that for Guitar mode you will typically want to use a patch set to Poly Mode: UNIson with either 1 or 2 voice Polyphony, but this isn’t strictly necessary so we don’t force or require the setting.)
The main difference is in how events on the MPE Master Channel are interpreted. With MPE mode activated, changes to MIDI CC modulation sources on MIDI Channel 1 are shared to all voices sounding on all other MIDI channels as well. Additionally, the WHEEL modulation source (mod wheel) is made unique per voice/channel when “MPE (ON)…” is activated, where it was shared between all voice/channels in the older Guitar Mode. The other modulation sources that can be unique per-channel are IN-1, IN-2, EXPR and PRESS (channel aftertouch only, polyphonic aftertouch only applies to channel 1 which will be your MPE Master Channel for Zone 1 when in MPE mode). These other four modulation sources, plus pitch-bend, all work with multi-channel input in either MPE or Guitar modes, only the Mod WHEEL behavior is different between the two modes (unique Mod Wheel control only being offered in MPE mode). This distinction is necessary for backward compatibility due to how Poly-Ana traditionally mapped the Mod WHEEL MIDI CC (control-change) message to the Wheel front panel parameter/control where the other four common modulators were assigned CC number sources in the Options Dialog with no corresponding front panel “depth” controls. (Though you can always make a depth control by using Poly-Ana’s Mod Mixers! Usually by multiplying one of the other Mod Sources by the WHEEL source.)
As Poly-Ana is a mono-timbral instrument (poly-timbrality is easily achieved by adding additional plug-in instances to your project) MPE Zones are not currently supported so only MPE streams containing Zone 1 should be sent to Poly-Ana. As well, Poly-Ana has a maximum of 12 voices, so your MPE controller should be set to send a maximum of 12 channels (or fewer, generally you’ll want to set your MPE controller’s number of channels to match the Polyphony setting of the Poly-Ana program you’re controlling).
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Poly-Ana also doesn’t currently respond to MPE messages defining Pitch Bend range or Mono/Poly Modes, preferring instead to adhere to the front-panel program settings. While this can be somewhat less automated to set up, it’s ultimately the choice we prefer as it puts control completely in the user’s hands and avoids any automatic behavior making changes to the patch/program that the user might not be immediately aware of.
If you’re not using either type of multi-channel MIDI control you can safely ignore this new setting as your MIDI will typically be input all on Channel 1 and all MIDI pitch bend and CC controllers will be shared across all voices triggered on the single MIDI channel. (In fact, if you’re not using multi-channel Guitar or MPE at all, you can safely skip this update.)