Yonac are one of the original iOS developers. There from almost the very start of the app store, and I think that they were the first to bring a synth to iOS before it was even iOS (it was miniSynth if you’re interested, and is now miniSynth 2). Since then they’ve brough high quality apps to the store on a very regular basis and have developed some of the most innovative apps I’ve seen.

Today they bring us a new synth, Kauldron, which they describe as  “our warmest sounding, punchiest synth yet!” They go on to explain that this new iOS synth is based on a wholly new modeling technology, combined with carefully designed features help users create aggressive synth sounds full of rich analog textures with the fewest knob tweaks.

Kauldron pushes every available iOS technology to the max: it is not only fully universal (you can run it natively on your iPad and iPhone), but also an Audio Unit plugin. In fact, it is one of the first fullscreen AUv3 plugins for iOS: with iOS 11 and a compatible DAW, you can enjoy all the great Kauldron features on a nice, big spread.

Kauldron debuts the next generation of our Artificial Intelligence preset creation system, SPAWN². Completely reimagining the groundbreaking SPAWN algorithms in our hugely popular Magellan, the new SPAWN² gives you unprecedented control over generating presets. In the expert mode, you can accomplish anything from subtle ‘variations on a theme’ to bold new sounds. In the basic mode, where Kauldron does all the thinking, you get preset after usable preset with just a touch. This is not simple randomization: it is the power of machine learning put to benevolent use!

Kauldron is designed with modulation and fine dynamic control in mind. The two fully-featured LFOs and the mod envelope combine with a wide variety of MIDI learnable controls to manipulate multiple parameters. Everything is easily set up in a clearly laid out ‘mod matrix.’ The dual XY-pads can be used for controlling modulation or a wide range of synth parameters. MIDI aftertouch can be routed via the matrix for even greater control over expression and tonality.

Powerful arp with both live & program modes; comprehensive MIDI features with effortless MIDI learn; over 900 presets; recording, sharing, IAA, Audiobus 3, Ableton Link — these are just some of the features brewing inside Yonac’s Kauldron.

Kauldron Specs


  • 3 analog modeling oscillators w/ multiple waveforms & true PWM
  • FM via Osc 2
  • Maximizer module with drift, spread & voice count for huge, stereophonic all-synth sounds
  • New vAnalog filter design w/ ‘dirt’ overload for even warmer, harmonically complex tones
  • Dedicated filter ADSR envelope
  • Filter tracking, contour & more
  • Pink/white noise generator
  • Osc. phase reset & sync
  • Retro & modern glide algorithms
  • Virtual VCA envelope with 2 attack types
  • Poly/mono operation
  • Legato mode for buttery smooth passages
  • Extensive modulation options via the ‘mod matrix’
  • 2 LFOs w/ BPM sync, keytracking, trigger mode & more
  • Assignable mod envelope
  • 23 mod targets
  • 11 mod controllers, including aftertouch, velocity & keytracking
  • 2 XY-Pads for controlling mod targets or synth parameters
  • Arpeggiator with live & program modes, 11 algorithms, gate, swing, note value, octaving & more
  • Stereo mod effect with chorus & flanger modes
  • BPM-syncable stereo delay
  • Studio quality reverb w/ 7 room types, damping, time & mix
  • 900+ presets in a wide variety of styles & sounds


Before going into what SPAWN is, I think it’s worth saying that this is one of the most interesting features here, and almost certainly one of the best uses of this kind of AI technology in the synth space, irrespective of whether it’s used in an iOS app or any other operating system for that matter. Here are the details:

  • Automatic preset generation via artificial intelligence
  • Generate infinite new, usable presets at the touch of a button
  • Expert mode lets specify Variation & Autonomy for each major synth module
  • 3 unique A.I. algorithms
  • Auto arp programming in any listed scale


  • AUv3 – use as Audio Unit plugin on iPad & iPhone
  • Fullscreen AU mode in compatible DAWs & iOS versions
  • Extensive MIDI: MIDI learn, aftertouch, MIDI CC map save/share, KB mapping, program changes & more
  • Inter-App Audio
  • Audiobus 3
  • Ableton Link

Kauldron is supported on iOS 10.3 & newer, and on iPad Air, iPad Mini 2, iPhone 6, 6 Plus, & newer devices.

Kauldron costs just $3.99 on the app store now: