Kauldron Synthesizer 4+

Smart Analog Modeling Synth

Yonac Inc.

    • 4.6 • 125 Ratings
    • $9.99



Kauldron is our warmest sounding, punchiest synth yet! A completely new modeling technology, combined with carefully designed features help you create aggressive synth sounds full of rich analog textures with the fewest knob tweaks. The result is a pure, head-on tone that requires little or no FX or post-production to sound big.

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 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.

Selected 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


• 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


• Universal
• Powerful YPAT2 preset management system
• Classic or ribbon key controller
• Ribbon controller: Poly aftertouch into Kauldron
• Ribbon controller: Settable musical key & scale
• Classic KB: Velocity w/ sensitivity setting
• Tapedeck: Record, loop & share
• Metronome
• Tap BPM

Supported Systems

• iOS 11 & newer

What’s New

Version 1.1

• Improves compatibility with certain AUv3 hosts
• Updates related to iOS 15
• Advanced MIDI -> MIDI In & MIDI Input Devices preferences are recalled in AUv3 state
• Other optimizations and improvements

Ratings and Reviews

4.6 out of 5
125 Ratings

125 Ratings


An outstanding offering from a brillant developer

Even at a multiple of the $3.99 into price, Kaudron is a powerhouse of an iOS synth, with a boatload of tone generation, sculpting and performance features. It sounds THICK as a wall made of iron, tons of analog vibe, deep programmability, excellent AU implementation, tons of presets, and did I mention it sounds as thick as a planet made of marzipan, concrete and diamonds, with unlimited musical possibilities? I pretty much buy whatever Yonac releases, but this one has to be the most effortless purchase so far. If you're into iOS music making, don't even hesitate, get it, you will NOT regret it.

Piano Quartz ,

Still no fix for the AUv3 bug

Kauldron is a great standalone iOS synth. Unfortunately, it’s effectively useless as a plugin due to a bug that I reported over a year ago.

When loaded as an AUv3 (I’ve tried it in BeatMaker 3, GarageBand, NanoStudio 2) with a MIDI keyboard connected over Lightning, Kauldron doesn’t conform to the standard behavior of only receiving MIDI notes when its track is selected. Instead, it receives notes regardless of the current track. So if you record a bass line with Kauldron and then try to record a lead with Zeeon, Model 15, or any other AUv3, your lead also triggers notes on Kauldron.

As I said above, I reported this bug over a year ago, and never received a response. It’s disappointing because Kauldron sounds great! I’d love to use it in my iOS production, but I can’t with this workflow-breaking bug.

Developer Response ,

Hello! If you visit our support page on our website, we can help you troubleshoot your issues. It's http://www.yonac.com/support Cheers! - The Yonac Team

GadgetMojo ,

One of my top favs

Though it looks like a simple synth at first glance, it can deliver a good range of sounds. I wouldn’t say it’s my fav synth as it’s hard to judge, but it’s definitely in a group of my faves.

Efficient, has a character, easy/pleasant to use, good sound quality, good presets management (can create banks and rearrange slot-based patches). Has AUv3.

Another excellent synth from these guys is Magellan 2, both are must-have, imho. Very pleasant to use, feels like hardware.

App Privacy

The developer, Yonac Inc., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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