Helm – create electronic music with this polyphonic synthesizer

Last Updated on July 11, 2021

helm is an open source MIDI enabled polyphonic music synthesizer with an easy to use parameter modulation system with real-time graphical feedback.

helm can run as a standalone synthesizer or as an LV2, VST, VST3, AU or AAX plugin.

helm has a subtractive synthesizer engine with three oscillators with 15 anti-aliased waveforms, cross modulation, 32 voice polyphony, a low-pass, high-pass, band-pass, notch, low-shelf, high-shelf and all-pass filter. There is also a formant filter, stutter, delay and reverb effects, patch browsing, MIDI learn and more.

Features include:

• Modules:
  • Oscillators with waveform selector, cross modulation, tune/transpose, and unison.
  • Sub with waveform selector, shuffle, octave down.
  • Mixer – controls the gain of each oscillator sound score and a white noise source.
  • Feedback  a very quick delay line/comb filter inserted into each voice.
  • Filter – boosts or reduces different frequencies in each playing voice. Each type of filter has different characteristics: Filter response, Filter type, Filter blend, Filter drive, Envelope depth, and Key track.
  • Stutter – samples a section of input audio and repeats it.
  • Formant – a type of filter that sounds like a person’s mouth. Create different vowel sounds by picking different spots in the X/Y pad.
  • Distortion – set the style of the distortion with soft clip, hard clip, linear fold, and sine fold.
  • Delay – essentially an “echo” effect”. It takes the input audio and repeats it while reducing the gain of each consecutive repeat.
  • Reverb – simulates audio reflections of a room or space by having many delay lines overlaid upon each other.
  • Modulation – change an audio or performance control over time to make dynamic/morphing patches.
  • envelopes in Helm are ADSR (attack→decay→sustain→release) envelopes. They are polyphonic (one instance per voice) and are useful for bringing in and fading out a value like the amplitude or filter cutoff of a voice.
  • LFO – low frequency oscillator
  • Step Sequencer – a modulation source that cycles through a series of steps.
  • Graphical keyboard – with aftertouch, note, velocity, mod wheel, pitch wheel, and random mods.
• OpenGL interface.
• 32-bit and 64-bit versions.
• Cross platform support – runs under Linux, Mac OS X, and Windows operating systems.

Website: tytel.org/helm
Support: Manual, FAQ, GitHub code repository
Developer: Matt Tytel
License: GNU General Public License v3.0

helm is written in C++. Learn C++ with our recommended free books and free tutorials.

Return to Synthesizers Home Page

Explore Linux
	Best Free and Open Source Software - A huge collection of recommended free and open source software covering every major category.
	In-depth Linux Software Reviews - Detailed assessments of Linux software covering features, usability and overall quality.
	The Big List of Active Linux Distros - An extensive collection of actively developed Linux distributions.
	Open Source Alternatives - Alternatives to software and services from Google, Microsoft, Apple, Adobe, IBM, Autodesk, Oracle and others.
	Essential Linux System Tools - Indispensable utilities for monitoring, maintaining and managing Linux systems.
	Linux Productivity Tools - Useful utilities for improving productivity and streamlining everyday tasks.
	Alternatives to Popular CLI Tools - Modern alternatives to familiar command-line utilities supplied with Linux systems.
	Awesome Free Linux Game Tools - Tools, utilities and companion software that improve gaming on Linux.
	Machine Learning on Linux - Machine learning and deep learning software, self-hosted applications and practical tools.
	Saving Money with Linux - Practical ways to reduce electricity consumption and lower computing costs with Linux.
	Linux Candy - Fun, entertaining and sometimes delightfully quirky software from the lighter side of Linux.