AudioKit Synth One, a free and open-source iPad synth, is now available for download in the Apple App Store, developer Matthew Fecher has announced. The Synth One, which Fecher describes as “the largest free and open-source iOS music project in history,” is a professional-level polyphonic synth created by a team of over 100 volunteers over the course of several years.

The Synth One is a robust piece of free software, and many of the volunteers involved are professional sound designers and techs who have worked with artists like Neon Trees, Rihanna, M83, and software companies like Valhalla DSP. Right now, it works with audio routing tools Audiobus 3 and Inter-app Audio so you can bring the sounds into other apps like Cubase and GarageBand, but the team says it also plans to add AUv3 and Ableton Link support down the road (the ETA on this, however, is unknown).

In a video that describes the inspiration behind creating a free, open-source synth, Fecher says, “there’s millions of people in the world with iPads that can’t even afford five or 10 dollars for a music app. Millions of people receive free iPads from schools and other charity organizations. Many don’t even have credit cards, putting a 99 cent app out of reach.”

The Synth One comes with over 300 presets, has five oscillators (FM with mod wheel, sub, noise, and two digitally controlled oscillators), two assignable LFOs, touchable ASDR envelopes for amp and filter, mono glide and legato, high pass and band pass filters, and more. It can also be controlled with a MIDI keyboard. You can check out the whole list of features on AudioKit’s website. At some point in the future, AudioKit says it will add MPE (MIDI Polyphonic Expression), opening up fun possibilities to use it with things like the Roli Seaboard.

If you want to get a feel for what the Synth One sounds like, music app reviewer Tim Webb has already posted a video showing off some of the app’s capabilities and how sonically interesting it can get.

The whole project will soon be available on GitHub after AudioKit finishes cleaning up some of the source code, and will hopefully have a manual, provided a volunteer steps up to the task. Once posted, other developers will be able to mess around with the code (done in Swift and C++) to make their own synths or perhaps, as one Synth One volunteer suggested, work on porting it to Android.

AudioKit’s Synth One is available for free today in the App Store for iPad users.