PolyForce

A polyphonic wavetable synthesizer that runs natively inside MPC on the Akai Force.

PolyForce is a VST2 instrument for MPC OS's built-in plugin host, with its own touchscreen pages and Q-Link sets. Its feature set tips its hat to a certain buzzing desktop wavetable synth 🐝, squeezed into the CPU budget of a standalone groovebox. The name, DSP, wavetables and presets are all PolyForce's own.

Note

Preview. Milestones 1–7 are complete and pass the full test suite on x86 and under ARM emulation. It runs on an Akai Force (MPC OS 3.x): the pages, browser and buttons have been checked on the device, a full on-device test round is still to come. The plugin ID (PlFc) and the file name (polyforce.so) stay; the parameter list may still change before v0.1.

Highlights

• 8 voices · Poly, Duo, Mono and Legato · four steal modes with click-free fades · glide
• Two wavetable oscillators with up to 8× unison, classic waves, sub oscillators and a noise source
• Two filters — LP, BP, HP, notch, peak, comb and vowel — serial or parallel, three engine characters
• Deep modulation — two LFOs, a 12-slot matrix (28 sources, 36 targets) with modifiers, four XY pads
• Arpeggiator, 16-step sequencer and four shape sequencers, locked to MPC's transport
• 30 built-in wavetables — analog, FM, digital, vocal, acoustic and chip — plus your own (Serum-format WAVs) from the plugin folder or the SSD, with a browser, favorites and recents
• 205 factory presets in 14 categories, level-matched; user presets, Init and Randomize, .tun / .scl microtuning
• Built for the Force's CPU — NEON vectorisation, a profile-guided build, and a CPU guard that sheds release tails before the audio drops out

Effects are deliberately left out: use MPC's insert effects on the track.

Documentation

Document	What's in it
User guide	The pages, the sound engine, wavetables, presets, tunings, MIDI
Factory content	The 30 built-in wavetables and 205 factory presets
Building	Toolchain, make targets, tests, device bench, packaging
Architecture	Source layout, threads and real-time rules, saved state
Performance	CPU budget, optimisation passes, measurements, CPU guard
Interface	Touchscreen design and the skin pipeline
Roadmap	Milestones, what's next, decisions
Milestone 1 design	Design record: wavetable library, loader, browser

Requirements

• An Akai Force. Other first-generation (32-bit ARM) MPC OS devices may work but are untested.
• Root SSH access to the device (for example through MockbaMod). Stock MPC OS has no way to install third-party plugins.
• MPC OS 3.x for the touchscreen pages. Release builds need glibc 2.30, so MPC OS 2.x loads them too, but it doesn't draw third-party plugin pages yet.

Installation

Use a release package (PolyForce-<version>-mpc-armv7.zip, built by CI: every run of the build workflow keeps one), or build one with make plugin-package (see Building). Unzip it and follow the INSTALL.md inside. In short:

scp -r PolyForce-<version> root@<device-ip>:/tmp/
ssh root@<device-ip> sh /tmp/PolyForce-<version>/install.sh

The installer stops MPC (save your project first), copies the plugin into /sdcard/Synths, backs up and edits MPC.settings, and starts MPC again. Running it again upgrades in place and keeps your own wavetables, presets, tunings and favorites. Then add PolyForce to a track from MPC's instrument plugins.

Building from source

On Linux or WSL (developed on Ubuntu 24.04):

make test            # the full test suite under ASan/UBSan
make arm-plugin      # build/arm/polyforce.so for the device
make plugin-package  # dist/PolyForce-<version>-mpc-armv7.zip

Toolchain, every make target and the on-device bench are described in docs/BUILDING.md.

Status

Stage
Phase 0 — engine spike: oscillators, filters, WAV import	✅
Milestone 1 — wavetable library and browsing	✅
Milestone 2 — voice modes, stealing, glide	✅
Milestone 3 — subs, classic waves, routing, noise	✅
Milestone 4 — comb and vowel filters, engines, NEON filters	✅
Milestone 5 — LFOs, mod matrix, XY pads	✅
Milestone 6 — arpeggiator, step and shape sequencers	✅
Milestone 7 — presets, microtuning, interface redesign	✅
Factory content — 30 built-in wavetables, 205 presets	✅
Second performance pass — control rate, PGO, CPU guard	✅
Third performance pass — output stage, 16-bit tables, frame cache	✅
On a Force: pages, browser, wave view; device bench (11.1% at 8 × 8)	✅
Release build in CI (glibc 2.31, PGO), passing the plugin catalog's check	✅
Full on-device test round: Q-Links, project save and reload	🔜
v0.1 — first release, parameter list frozen	⬜

Details in the roadmap.

License

PolyForce is released under the MIT License. Third-party components keep their own licenses (below).

Credits

• Skin generator, previews and installer: sd88me/mpc-vst-plugins (MIT), vendored in third_party/mpc-vst-plugins with a few small, marked patches.
• Interface font: Titillium Web, SIL Open Font License 1.1 (surface/fonts/OFL.txt).

PolyForce is an independent project, not affiliated with or endorsed by Akai Professional / inMusic or Steinberg. Akai, Force and MPC are trademarks of inMusic Brands; VST is a trademark of Steinberg Media Technologies GmbH.