
Overtonium, a new additive synthesizer
Overtonium is a free, open source synthesizer laid out like a 32-channel mixer. Every channel is one sine oscillator locked to a harmonic of the note you play, with its own tuning, envelope and modulation. The control worth reaching for first is TUNE, which sweeps each partial continuously between equal temperament and just intonation: At one end the partials sit at exact whole-number ratios and the stack fuses into a single timbre, at the other they fall to the nearest semitone and the same stack smears into a chord. There are VST3 and Standalone builds for macOS, Windows and Linux, an Audio Unit for macOS and an LV2 for Linux.











