Helm
by Matt Tytel

A pay-what-you-want, GPL-licensed polyphonic synth that runs standalone or as a plugin on Windows, macOS and Linux.
Helm is a polyphonic synth from Matt Tytel, the developer who later made Vital, and it runs standalone or as a plugin on all three desktop platforms. It is Free Software under GPL-3.0 with no DRM, offered on a pay-what-you-want basis where free is a valid option. Development has been quiet for years but the downloads still work and the synth holds up.
In action
Video plays from YouTube when started.
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