Stumbled upon this free and open source synth for linux, OSX and Windows. It looks lovely but more importantly; if you are just getting started with coding synths and want to have a look under the hood of completed project this is a nice source to look at.

Helm features

  • 32 voice polyphony.
  • Interactive visual interface.
  • Powerful modulation system with live visual feedback.
  • Dual oscillators with cross modulation and up to 15 oscillators each.
  • Unison and Harmony mode for oscillators.
  • Oscillator feedback and saturation for waveshaping.
  • 12 different waveforms.
  • 7 filter types with keytracking.
  • 2 monophonic and 1 polyphonic LFO.
  • Step sequencer.
  • Lots of modulation sources including polyphonic aftertouch.
  • Simple arpeggiator.
  • Effects: Formant filter, stutter, delay.

Helm is a free download for Windows, Mac, and Linux. A debian package download, and source code for mac/pc is also available from Github.

Download the compild version here;