Developer Benjamin Dehli has introduced Overtonium, a free additive synthesizer plugin for Linux, Mac & Windows.
Overtonium approaches additive synthesis like a 32-channel mixer, with each channel representing a sine oscillator locked to a harmonic of the played note. Each partial has its own tuning, envelope, modulation, velocity, aftertouch, panning and level controls, while a separate noise channel provides additional non-pitched sound.
A central feature is the TUNE control, which continuously moves each partial between its equal-tempered position and its exact whole-number harmonic ratio. The instrument also separates this partial tuning system from keyboard temperament and inharmonic stretch, with six keyboard temperaments available: equal, just, Pythagorean, quarter-comma meantone, Werckmeister III and Young.
The instrument supports MPE, channel pressure and polyphonic aftertouch, along with per-partial pitch and amplitude modulation, random pitch drift, two-stage envelope behavior and global effects including wobble, tape echo and reverb. Twenty-eight presets are included.
Features:
- 32 sine-wave harmonic partials
- Separate noise channel
- 32 channel-style partial strips
- Individual tuning for every partial
- TUNE control that moves partials between equal temperament and just harmonic ratios
- Inharmonic STRETCH control
- Six keyboard temperaments
- Adjustable keyboard root and reference pitch from 415 to 466 Hz
- Keyboard tracking
- Per-partial phase control
- Per-partial pitch modulation with eight waveform shapes
- Per-partial amplitude modulation with seven waveform shapes
- Per-partial random pitch DRIFT
- Individual delay, attack, decay and sustain envelope controls
- Separate KEY OFF envelope
- Independent velocity response for every partial
- Independent aftertouch response for every partial
- Channel pressure and polyphonic aftertouch support
- MPE support
- Per-partial stereo panning
- Individual mute, solo and level controls
- Global WOBBLE effect
- Tape echo with two paths
- Global reverb
- Master level control
- Twenty-eight factory presets
- User preset saving and folder-based preset organization
- macOS, Windows and Linux support
- AGPLv3 open-source license
Pricing & Availability:
Overtonium is available now as free software under the GNU Affero General Public License v3. The complete source code is available through the project’s repository.
