Oxo Synth2 brings Synth1 back as a free, open-source synth for Mac and iPad

Oxo Music has released Oxo Synth2, a free, open-source recreation of Synth1, the virtual analog synth from Daichi Laboratory that thousands of musicians have used since the mid-2000s. The goal is simple: keep the countless Synth1 presets found online playable on current machines, now that the original is no longer updated. This article is based on the official Oxo Synth2 page and the source code repository. The release was reported on November 5 by KVR Audio.

Why recreate Synth1

Synth1, by Daichi Laboratory, is free but closed source, and it appears abandoned: according to Oxo Music, there have been no updates for years and no replies to email. On the Mac it only runs on Apple silicon through Rosetta, the translation layer for Intel apps, which Apple has said will be phased out; Oxo Music places that at macOS 28. Without a successor, the preset banks the community has built up would become unplayable.

Oxo Synth2 therefore keeps the same parameters and the same interface, with no changes to the sound engine. The additions are about workflow: MIDI Learn (map any control to a MIDI controller in one move) and interface themes with an editor. Above all, Synth1 .sy1 presets and zip banks load as they are. The developer says every parameter was modelled one by one, from about 3 GB of measurement data generated with the help of an AI model, and publicly invites Daichi to release his own code under an open licence.

What is inside

• Polyphony up to 32 voices, mono and legato modes, portamento.
• Oscillators: two oscillators plus a sub oscillator, oscillator 1 detune, frequency modulation (FM), ring modulation, hard sync and noise.
• Filter: five types (LP12, LP24, HP12, BP12, LPDL), with saturation, key tracking and velocity control.
• Envelopes for amp and filter, plus a modulation envelope targeting pitch, FM or pulse width. They follow the ADSR model, explained in our envelope guide.
• Two LFOs with six waveforms, tempo sync and key sync.
• Arpeggiator: up, down, up and down or random, over 1 to 4 octaves, locked to host tempo.
• Effects: ten types (two analog distortions, digital distortion, decimator, ring modulator, compressor, four phasers), an equalizer, tempo-synced delay (stereo, cross, ping-pong) and chorus/flanger.
• Unison up to 8 voices, with detune, stereo spread and pitch.

The developer’s side-by-side comparison, Synth1 versus Synth2:

Formats and compatibility

No CLAP or AAX version has been announced, so Pro Tools users will need another synth. The differences between these formats are covered in our plugin formats guide.

Who it is for, what it costs, what it competes with

Who it is for: first, Synth1 users on the Mac, who keep their preset banks playable without Rosetta. Then iPad musicians, who get an easy-to-program subtractive synth in AUv3 along with a huge catalogue of existing sounds. Beginners also get a good learning tool: one page, every control in view, and a classic two-oscillator, one-filter architecture.

What it costs: nothing. It is released under the MIT licence, one of the most permissive open-source licences: the code can be reused, modified and redistributed, including by other developers.

What it competes with: among free synths, Vital (in its free tier) and Surge XT, also open source, go much further in modulation and wavetable synthesis, but neither loads Synth1 presets. On Windows, the original Synth1 remains usable until the port arrives. So Oxo Synth2 is not trying to be the most powerful free synth: its value is compatibility with a large body of presets, now backed by code anyone can maintain. Other recent free releases, such as Push and Groove’s Micronix, are collected in our Free and Open Source section.

The macOS download is on the Oxo Synth2 page; source code and contributions go through GitHub.