Refer to Christopher H.M. Jacques’s “ZS-40” patch: https://patchstorage.com/zs-40-a-polysynth-patch-inspired-by-a-legend/ This version is modified to support MPE (MIDI Polyphonic Expression) and will only work with a MIDI controller that supports this protocol.
Polyphony and MPE
Single-channel (non-MPE) polyphony is straightforward as of 1.13 firmware using the MIDI module configured with multiple outputs and a round-robin priority. Create the individual voices as separate oscillators with separate envelopes, and route the separate pitch and gate outputs from the MIDI module to each voice.
MPE works by moving this round-robin function out of the Zoia and into your MPE-capable MIDI controller. To convert a traditional polyphonic synth into an MPE patch, use multiple midi input devices of consecutive channels, each with a single output.
Determine which set of channels your MPE controller is sending on, and set each midi device’s channel to be one of that set. Typically, one of the channels is reserved for global (all voices at once) control messages. The others are used for per-voice messages.
For example, if your MPE controller is sending on channels 1-16, it may reserve channel 1 for global messages. Note data will not be transmitted on channel 1. Channels 2 – 16 will receive note data, depending on how many notes are depressed at a given moment. Each of those channels will also receive additional CC, pitch, and channel pressure messages pertinent to that note. Setting up this kind of expressive behavior will depend on your controller and what types of control you want to have over the instrument.
To receive those additional expressive control messages, create multiplpe CC, Pressure, and Pitch Bend modules for each of the voice channels, and route them to the appropriate voice’s modulation points.
ZS-40mpe
ZS-40mpe is configured to receive note data on channels 2 through 5, supporting 4 voices. If you press down five keys on your MPE controller, it will be lost to a channel beyond that range that is not receiving on this patch. ZS-40mpe also has a channel pressure for each of those channels 2 through 5. Channel pressure is mapped to the individual voice’s filter-envelope amount multiplier. Additionally, each voice receives a separate pitch bend. You may need to modify the pitch bend % based on the amount of pitch bend being sent by your controller, and the number of semitones you want to bend across in the instrument.
There is one global midi control on CH1 for CC11 (expression). This is routed to the global filter envelope amount that applies to all voices together.
Velocity has been added and goes in small amounts to detune the second oscillator.
The mod-wheel detuning from original ZS-40 is removed in this version.
Plate Reverb is lost and replaced with 2 reverb-lites :(
