Legendary synthesizers, rebuilt in the open.
Audio Tools recreates classic instruments as free, open-source plugins for macOS and Windows. Each one is modeled from the original documentation and measurements, and anyone can read, check and improve the code.
1978
AT20V
The semi-modular that screams.
Semi-modular synthesizer modeled on the 1978 Korg MS‑20. Two filters that scream, a 35-jack patch bay with cables that hang, a vocoder for the audio input, polyphony and 51 presets.
1982
AT101V
The bass line machine.
Monophonic synthesizer modeled on the 1982 Roland SH‑101. The IR3109 four-pole filter, a sub-oscillator, an arpeggiator and a 100-step sequencer with a visual editor, accents, slides and 43 presets.
2023
AT42
Twenty oscillators. One slow storm.
Ambient drone machine modeled on the Elta Music SOLAR 42. Twenty drone oscillators with light orbs, two noise voices, two VCOs, dual Polivoks filters, a 13-cartridge effector, a touch keyboard, a 62-jack patch bay and 28 presets.
1976
AT700
The modular that filled a wall.
Modular synthesizer modeled on the 1976 Roland System-700. The 17-module Main Console with its internal buses, the duophonic 701A keyboard, the 717A sequencer of 3 × 12 steps, 137 jacks, spring reverb, phaser and 31 presets.
1998
ATFS1
The synthesizer that talks.
Formant and FM synthesizer modeled on the 1998 Yamaha FS1R. Sixteen operators per voice with eight spectral forms, 88 algorithms, Formant Sequences you can make from any recording, 32 voices with their filter, a working 1U front panel and 32 presets.
Which one is yours?
Why open source.
Synthesizers are cultural instruments. Records were made with them, sounds were designed on them, and people learned music on them. When a commercial plugin is discontinued or stops running on a new operating system, the songs and presets built with it can disappear too. Open source is how an instrument outlives the company that made it.
Preservation
How a classic circuit behaves is knowledge that belongs to musicians. Written down in code that anyone can read, it cannot be locked away.
Learning
Every filter equation, calibration constant and design decision is visible. A student can follow how an analog circuit becomes software.
Trust
No accounts, no license servers, no telemetry. You can check exactly what runs in your studio.
Longevity
Anyone can rebuild the plugin for the next operating system, in ten years or in thirty.
Collaboration
Owners of the original hardware can measure, compare and correct the model. Each improvement is shared with everyone.
Every Audio Tools instrument is free software under the GNU Affero General Public License v3, the same license as the JUCE framework they are built on. You can use them, study them, change them and share them. If you distribute a modified version, you share your changes under the same terms.
The source code will be published here soon.
One synth at a time.
Each new instrument gets the same treatment: the original documentation, measurements, a faithful model and the features a modern studio expects. AT20V, AT101V, AT42, AT700 and ATFS1 are the first five.