When a new synth plugin lists "polyphonic aftertouch" in its feature sheet, it is easy to assume it works with your MPE controller. Often it does not, at least not fully. A fresh example is Colapso, the atomic-themed additive synthesizer from Imaginando, released this week.
What Colapso offers
Colapso builds sound from the spectra of 22 chemical elements. Each voice has three oscillators, and each oscillator draws on up to two elements as its spectral source. Up to eight voices can run in mono, poly or unison mode. A multimode filter models nine circuits, there are four drawable LFOs and four drawable envelopes, four macros, two insert effects, a send and a bus compressor. It ships with over 200 presets in standalone, VST3, AU and AAX formats for macOS and Windows, at an introductory €69 (regular €89) until November 1, 2026.
The coverage we have seen mentions polyphonic aftertouch as a modulation source, but does not mention MPE support. That is the point of this article.
Two ways to get per-note expression
Polyphonic aftertouch is part of the original MIDI 1.0 specification. A single channel carries a pressure value for each individual note. It gives you one extra dimension of per-note control, pressure, and nothing else.
MPE (MIDI Polyphonic Expression) takes a different route. It assigns each note its own MIDI channel, so every note can carry independent pitch bend, channel pressure and CC74 "slide" in addition to velocity. That is what lets you glide one note of a chord, press another harder and slide a third up and down a key's surface at the same time.
You can read more about the specification at the MIDI Association's MPE page.
Why the difference matters in practice
If a plugin supports only polyphonic aftertouch, then with an MPE controller you may find:
- Per-note pitch bend does not work. The plugin may treat bend as a global message, so one finger's glide bends the whole chord.
- Slide has no destination. CC74 per-note data goes nowhere.
- Pressure may arrive in the wrong form. Many MPE controllers send channel pressure on each note's own channel, not polyphonic key pressure.
Some hosts and controllers can convert between these formats, and a few controllers can output polyphonic aftertouch instead of MPE. That can rescue the pressure dimension, but you lose per-note bend and slide.
What to check before buying
Before you spend money on a synth for an MPE rig, look for explicit wording on the product page, such as "MPE support" or an MPE toggle in the settings. Then:
- Try the demo with your actual controller, if one is offered.
- Test per-note bend with two held notes and glide one of them.
- Check the manual for how slide and pressure are routed to modulation.
- Ask the developer. Small teams often respond quickly, and a request can move MPE up the roadmap.
Where this leaves Colapso
None of this is a criticism of Colapso. It is a distinctive additive instrument, and polyphonic aftertouch is a legitimate expressive feature for keyboards that send it. But if you play an MPE surface, treat it as an open question until the developer confirms support. We will cover any announcement from Imaginando if MPE arrives.
The broader lesson is simple: "per-note expression" is not one feature. Pressure, bend and slide are three separate dimensions, and a plugin may support one, two or all three. Knowing which you are getting saves frustration and money.
Sources: Synth Anatomy, Imaginando.