AudioKit Synth One J6 is one of the best free synthesizers available for iPhone and iPad. It has now arrived on Mac, too, bringing its vintage-inspired sounds and hands-on controls to both Apple Silicon and Intel computers.
You can use Synth One J6 as a standalone instrument or load it as an AUv3 plugin in a compatible Mac DAW. It’s free to download, with no subscription or paid feature tier.
Synth One J6 has an inviting interface built around dedicated sliders and knobs. Its controls are arranged across seven tabs, so you can start by browsing presets and playing, then explore the deeper sound-design features when you’re ready.
There’s a built-in step sequencer and arpeggiator, dual touch pads for real-time effects control, and onboard effects including delay, reverb, chorus and bit crush. Three LFOs can be routed to more than 60 destinations, including other LFOs. You also get MIDI Learn, tempo-synced controls and a record button for capturing a sound or musical idea without leaving the app.
That balance makes it approachable if you’re new to synthesis, while offering enough modulation and performance control to keep experienced players busy. Connect a MIDI keyboard, choose a preset and play, or start shaping the sound yourself.
An analogue-inspired sound engine
Synth One J6 takes inspiration from classic analogue synthesizers, including the Juno-6 and Jupiter series. AudioKit says it recorded oscillators from vintage Juno-106 and Jupiter-8 hardware and used machine learning to study their characteristics while developing the app’s sound engine.
The result is a collection of warm pads, basses, keys and leads, with subtle variation intended to give the sounds an analogue feel. You can hear that character in the presets, then use the filters, modulation and effects to make them your own.
AudioKit has always had a strong community focus, and Synth One J6 reflects that. Its library includes more than 400 presets created by a range of sound designers and music creators. I was fortunate to contribute some presets to the app, alongside many other talented musicians and YouTubers.
The app was also made with accessibility and music education in mind. AudioKit says it wanted to give students and aspiring musicians access to a full-featured instrument even when they can’t spend money on music apps. The Mac version includes VoiceOver improvements, and the app supports playing with an external MIDI controller.
The Mac version works as a standalone app or as an AUv3 instrument. AudioKit says it has tested it with Ableton Live, GarageBand and Logic. The current App Store listing requires macOS 12 or later and supports both Apple Silicon and Intel Macs. Preset Sync can also carry sounds between Mac, iPhone and iPad when enabled on each device.
Synth One J6 is a generous release from AudioKit: a free synth that’s easy to enjoy straight away, with enough depth to reward further exploration. If you make music on a Mac, you can download Synth One J6 from the App Store. You can also find the feature list and background on the official AudioKit Synth One J6 page.