Helm GUI



Helm is an open-source realtime monophonic/polyphonic softsynth developed by Matthew Tytel at It comes in both 32-bit and 64-bit versions, and can be run as an LV2 plugin or as a standalone instrument. It also includes cross-platform patch loading and saving capability.

Helm consists of two richly-sounding oscillators that each offer 11 different (anti-aliasing) waveforms. Cross-modulation is provided, as well as detuning and transposition for each wave. A sub-oscillator with shuffle wave shaping and noise are also included, and all four sound sources have discrete amplitude signal level controls.

The filter section allows adjustment among lowpass, highpass, bandpass, high-shelf, low-shelf, band-shelf and allpass filter types. Cutoff and resonance slider controls are provided along the filter graph's x and y axes, respectively. A very useful formant filter with X-Y axis control is also available. Two monophonic LFOs and one polyphonic LFO are included.

Helm also includes a very useful arpeggiator function with gate, octave range and pattern controls, as well as a step-sequencer section.

There are several useful effects provided as well, including reverb, stutter (resamples part of the audio signal and repeats it), delay, distortion and feedback. Global controls include pitchbend, polyphony amount (up to 32 voices), portamento with legato option, and velocity tracking.

Patches and Manual:

Helm Manual in pdf format at

Helm Patchbank (updated August 29, 2017). A rolling bank of my own presets. Extract the tarball to your preferred "Presets" folder located in your home directory's ".helm" folder.


Helm Website