Helm is a free, cross-platform, polyphonic synthesizer that runs on GNU/Linux, Mac, and Windows as a standalone program and as a LV2/VST3/AU plugin.

This is a custom fork of Helm aimed at keeping its build systems and dependencies up to date. New features will not be developed in this repo.

• 32 voice polyphony
• Interactive visual interface
• Powerful modulation system with live visual feedback
• Dual oscillators with cross modulation and up to 15 unison oscillators each
• Sub oscillator with shuffle waveshaping
• Oscillator feedback and saturation for waveshaping
• 12 different waveforms
• Blending between 12 or 24dB low/band/high pass filter
• Low/Band/High Shelf filters
• 2 monophonic and 1 polyphonic LFO
• Step sequencer
• Lots of modulation sources including polyphonic aftertouch
• Simple arpeggiator
• Effects: Formant filter, stutter, delay, distortion, reverb

To build everything:

cmake -S . -B build
cmake --build build -j$(nproc)

To build one type of plugin:

cmake --build build --target HelmPlugin_<PLUGIN_FORMAT>

Where <PLUGIN_FORMAT> is one of: LV2, AU, or VST3.

To build the standalone:

cmake --build build --target HelmStandalone