Central Processing Unit has released CPU Micron, a schematic-accurate emulation of the 1983 Roland MC-202, as reported by Synth Anatomy. The report does not mention MPE support, so this is not a launch story about expressive features. It is, however, a good excuse to talk about something many MPE owners run into: how to play a monophonic synth from a multidimensional controller.
What CPU Micron offers
Based on the coverage, the emulation includes:
- A single CEM3340-based oscillator with square and saw waveforms, plus a sub-oscillator reaching down two octaves and a source mixer.
- An IR3109-modeled low-pass filter with cutoff, resonance, envelope-to-filter, LFO-to-filter and keyboard tracking.
- One syncable LFO with rate and delay, and one ADSR envelope routable to the filter and VCA.
- A two-channel sequencer, where the second channel can write MIDI notes back to the DAW.
- A preset browser with included sounds.
Availability is split in two. The desktop version (macOS, Linux, Windows; standalone, VST3 and AU) is listed at 39.99 GBP, while the App Store version (iPadOS and macOS, AUv3) is listed at 14.99 USD. The App Store listing is here.
The mono problem for MPE players
MPE assigns each note its own MIDI channel so that pressure, slide and pitch bend can be applied per finger. A monophonic synth, by definition, plays one note at a time. That raises practical questions:
Which finger controls the sound? If the plugin ignores MPE, it may treat everything arriving on the member channels as ordinary notes, and gestures can behave unpredictably.
Where does pitch bend go? MPE controllers commonly use a wide per-note pitch bend range. A synth expecting a different range will make slides sound too small or far too large.
What do pressure and slide control? Without per-note destinations, nothing happens unless you map them.
Practical approaches
Here are workable ways to get expressive results from a non-MPE mono instrument:
- Use a single-channel or "mono" mode on your controller. Many MPE controllers can send everything on one channel, so pitch bend and pressure become global. With a monosynth that is usually exactly what you want, since only one note sounds anyway.
- Match the pitch bend range. Set the controller's bend range to what the plugin expects, commonly 2 semitones for standard bend wheels, or adjust the plugin if it offers a setting.
- Map pressure to filter cutoff. The MC-202 character comes from its filter, so channel pressure routed to cutoff via your DAW's MIDI mapping can add a convincing swell to a bassline.
- Use slide for a second destination. If your DAW or a utility plugin can convert CC74 into another controller, it can drive resonance or LFO depth.
- Record the gestures. Capture the performance as MIDI so you can edit the curves later, then re-record any takes that need work.
Check the plugin's manual for exactly which MIDI messages it accepts, because the announcement does not spell this out.
Why monosynth emulations still matter
Plenty of classic bass and lead sounds were monophonic, and part of their appeal is the way a single voice responds to a performer. Playing them with a controller that can slide, press and glide gives you phrasing that a plain keybed cannot, even when the synth itself is not MPE-aware.
For players who want full per-note control, the better route is a polyphonic instrument built for MPE. For a focused, characterful bass voice, a well-configured mono emulation can be a fine complement.
Key takeaways: CPU Micron emulates the Roland MC-202 on desktop and iPad, MPE is not mentioned in the coverage, and the best way to play it from an MPE controller is usually a single-channel setup with pressure and slide mapped to filter-related controls.
Sources: Synth Anatomy, CPU Records, App Store.