MPE can sound like a new technology, yet it runs on ordinary MIDI. Understanding how it works makes controllers, plugins and DAW settings far less mysterious. This guide covers the basics, the current specification and a simple way to start.
MPE is still MIDI
MIDI Polyphonic Expression uses the same protocol as every other MIDI device. The difference is how it distributes data. In standard MIDI, pitch bend, pressure and similar messages apply to a whole channel, so they affect every note on that channel equally. MPE gives each note its own channel, so each note can carry its own pitch bend, pressure and control data. As Boris FX's MPE guide puts it, MPE is still MIDI at its core.
The practical result is that you can bend or press one note in a chord without touching the others.
The dimensions of expression
MPE controllers typically capture several per-note gestures:
- Strike: how hard you hit the note.
- Pressure: how much force you apply after the strike.
- Glide: left and right finger movement, usually mapped to pitch bend.
- Slide: forward and back movement, often mapped to timbre, filter or effects.
- Lift: how quickly you release, which can shape the tail of the sound.
The MPE 1.1 specification
The MIDI Association published MPE v1.1 in May 2022. It is an editorial revision of the original January 2018 specification, and the announcement states that no technical design changes were made. The working group addressed ambiguities that developers had reported, consolidated the implementation rules into one detailed section and expanded the best-practice appendices with examples. The group also named a MIDI 2.0 profile for MPE as the next step, aimed at automatic configuration between senders and receivers. You can download the specification from the MIDI Association's MPE page.
What you need to get started
You need three things: an MPE controller, an MPE-capable host and an MPE-capable instrument.
- Controller. Popular choices include the ROLI Seaboard, LinnStrument, Expressive E Osmose and Ableton Push 3.
- Host. Ableton Live (since Live 11), Logic Pro, Bitwig Studio and REAPER all handle MPE.
- Instrument. Surge XT and Vital are free and support MPE. Commercial options include Arturia Pigments and Serum 2.
Setup tips
Most problems come from a few settings:
- Enable MPE on the track. Many DAWs need MPE mode switched on per track or per instrument.
- Match the pitch bend range. The controller and the plugin must agree on the per-note bend range. A mismatch is the most common cause of notes that sound out of tune when you glide.
- Check your channel layout. MPE normally uses a manager channel and a block of member channels. Make sure the zone is configured the same way on both ends.
- Record the expression. Capture MPE data in clips, so you can edit each note's gestures afterward.
Try it in ten minutes
Load Surge XT or Vital on an MPE-enabled track, pick a patch with obvious timbre movement, and play a three-note chord while moving only one finger. If that single note changes while the others stay still, MPE is working. From there, explore how slide and pressure map to the parameters you care about.
MPE rewards experimentation. Once the technical pieces are in place, the instrument stops feeling like a keyboard and starts feeling like something you shape with your hands.