A macOS native (Apple Silicon and Intel) VST3 / AU synthesizer plugin that emulates the Atari ST's YM2149 / AY-3-8910 PSG sound chip.
If you came here looking for "ymVST for Mac", "ymVST macOS port", "Atari ST YM2149 VST for Mac", or "AY-3-8910 plugin for macOS" — this is a spiritual successor to Gareth Morris's classic Windows-only ymVST (2003), rebuilt from scratch for modern macOS in C++ with JUCE.
- 3 square wave tone channels with per-channel fine tune, on/off, and tone/noise mixing
- Noise generator (5-bit period, 0-31)
- Hardware envelope generator with all 16 YM2149 envelope shapes
- User-drawn amplitude waveform editor (32-step, 4-bit volume) with one-shot or loop modes
- Arpeggiator with sync, speed, and length controls
- Portamento (pitch glide)
- Sound bend / Noise bend (gradual pitch shifting)
- Tremolo (LFO amplitude modulation)
- SID hard-sync mode (channel 1 syncs to channel 0 for metallic tones)
- Mono / 3-voice polyphony toggle
- 27 factory presets covering leads, basses, kicks, snares, hihats, FX, and chord patterns
- Full DAW parameter automation
- State save and restore (including the user-drawn waveform)
- MIDI CC mapping compatible with the original ymVST
- QWERTY computer keyboard input in standalone mode (Renoise / tracker layout)
- Retro Atari ST GEM desktop-style UI with custom 8x8 pixel font
- macOS 11 or later (Apple Silicon native, Intel x86_64 universal binary supported)
- Compatible with Renoise, Logic Pro, Ableton Live, Bitwig, REAPER, GarageBand, and any host that supports VST3 or AU plugins
Download the latest release from the Releases page and copy the plugins:
cp -r macYM.vst3 ~/Library/Audio/Plug-Ins/VST3/
cp -r macYM.component ~/Library/Audio/Plug-Ins/Components/The binaries are not codesigned, so remove the macOS quarantine flag once after copying:
xattr -dr com.apple.quarantine ~/Library/Audio/Plug-Ins/VST3/macYM.vst3
xattr -dr com.apple.quarantine ~/Library/Audio/Plug-Ins/Components/macYM.componentThen rescan plugins in your DAW.
- macOS with Xcode Command Line Tools (
xcode-select --install) - CMake 3.22 or later
# First-time configuration downloads JUCE (~2 min)
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --config ReleaseThis produces all three targets: VST3, AU, and a standalone app.
To rebuild quickly after making changes:
./build.shTo build a specific target:
cmake --build build --target macym_VST3 --config Release
cmake --build build --target macym_AU --config Release
cmake --build build --target macym_Standalone --config Releaseln -sf "$(pwd)/build/macym_artefacts/Release/VST3/macYM.vst3" ~/Library/Audio/Plug-Ins/VST3/
ln -sf "$(pwd)/build/macym_artefacts/Release/AU/macYM.component" ~/Library/Audio/Plug-Ins/Components/open build/macym_artefacts/Release/Standalone/macYM.appThe standalone app accepts QWERTY keyboard input using the standard tracker / Renoise layout:
Lower octave (C-3): Z X C V B N M (white keys)
S D G H J (black keys)
Upper octave (C-4): Q W E R T Y U (white keys)
2 3 5 6 7 (black keys)
Extended (C-5): I O P (white keys)
9 0 (black keys)
Esc triggers the panic button (all notes off).
Gareth Morris's original ymVST is a beloved Windows-only freeware VST plugin from 2003 that recreates the Atari ST's iconic chip-tune sound. It's a SynthEdit-built 32-bit plugin and has no macOS port. macYM exists to give Mac users access to the same family of YM2149 / AY-3-8910 sounds, with the original UI aesthetic and feature set, but as a native modern plugin (Apple Silicon, VST3, AU).
- Gareth Morris — original ymVST for Windows (2003), the inspiration for this project's feature set, UI design, and MIDI CC mapping.
- Peter Sovietov — ayumi, the YM2149 / AY-3-8910 emulator at the heart of this plugin (MIT license).
- JUCE — framework for cross-platform audio plugin development.
macYM is released under the GNU General Public License v3, due to the JUCE free license terms. Source code is included; redistributions must remain GPL v3. See LICENSE for the full text.
The bundled ayumi library is MIT licensed.