Comparison

Zeeon synth vs Kauldron Synthesizer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Zeeon synth

This app is a virtual analog synthesizer that recreates the sound and feel of classic hardware. It features a detailed circuit-modeling engine, powerful modulation, and multiple filter models for rich, organic soundscapes. Explore a vast array of presets and expand your sonic palette with additional sound banks.

Highlights
  • Circuit-modeling engine
  • Powerful modulation matrix
  • Dual oscillators with variable waveforms
  • Multiple filter models
  • Built-in effects unit
  • Audio Unit v3 support
  • Polyphonic step sequencer
Features
Read full description

Zeeon is a virtual-analog synthesizer built on a deeply detailed circuit-modeling engine. We’ve studied classic and modern analog synths to uncover what gives them their unmistakable character and recreated that essence with precision. The result is a unique instrument that delivers the warmth, movement, and organic depth of true hardware. While many emulations sound flat, Zeeon breathes. Every note is alive, with tight lows and shimmering highs. All audio and modulation are processed at 176 kHz (4× oversampling) for uncompromised quality across the entire spectrum. “Desktop-class sound engine … fidelity of this analog emulation goes beyond everything else on iOS.” – App Store review Features • Audio Unit v3 and standalone application with a simple polyphonic step sequencer • Powerful modulation matrix offering self-modulation and cross-layer modulation, 8 modulation slots, 17 signal sources and 41 targets available, both from modulation modules and audio signal path. This takes Zeeon into semi-modular territory. Imagine oscillator waveform, panning, filter cutoff, resonance or LP-HP mode modulated by oscillators or another layer! • 2 oscillators with continuously variable waveforms, hard-sync and sub-oscillator. Carefully simulated analog drift and PSU influence. • Filter: 3 models available: Transistor ladder low pass, OTA cascade low pass and State Variable Filter with continuously variable LP-HP + BP mode. • 2 low frequency oscillators and envelope generators per voice. • Overdrive: diode clipper, transistor saturation, wave folder, pre and post filter. • Up to 2 layers per voice. Layers can modulate each other. • Effects unit: Circuit modelled BBD chorus, bass booster, zero-delay Phaser, Stereo delay and Reverb. • 280 presets and Tutorials bank. 3 additional banks available as IAPs. Full manual and audio demos available at the BeepStreet website.

About

Kauldron Synthesizer

This app combines classic analog synth warmth with AI-powered sound design. It offers intelligent preset generation, extensive modulation options, and a powerful arpeggiator for creating rich synth textures.

Highlights
  • AI-powered preset generation (SPAWN²)
  • Analog modeling oscillators
  • Extensive modulation matrix
  • Dual XY-pads for control
  • Powerful arpeggiator
  • AUv3 plugin support
  • Over 900 presets
Read full description

Kauldron is where classic warmth meets Artificial Intelligence. One of our toniest and punchiest synths, Kauldron features a completely new analog modeling technology. The full spectrum of rich synth textures is bolstered by the groundbreaking SPAWN intelligent preset generation system that allows new patches to be created at the touch of a button. Abounding with pure hard-hitting tones, Kauldron requires little to no FX or production gimmicks to sound big. 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. Kauldron also 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 A.I. put to benevolent use! Kauldron also includes its AUv3 plugin version so that you can seamlessly run multiple instances in your favorite DAW. Powerful arp with both live & program modes; comprehensive MIDI features with effortless MIDI learn; over 900 presets; recording, sharing, these are just some of the features brewing inside Yonac’s Kauldron. Selected specs include, SYNTH • 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 SPAWN² • 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 PRO FEATURES • AUv3 - use as Audio Unit instrument plugin on iPad & iPhone • Fullscreen AU mode • Extensive MIDI: MIDI learn, aftertouch, MIDI CC map save/share, KB mapping, program changes & more APP • iPhone & iPad Compatibility • 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

Screenshots

Zeeon synth3 screens
Kauldron Synthesizer4 screens

Verdict

The call

The clearest difference is in-app purchases: Kauldron Synthesizer at none against Zeeon synth's 3. Kauldron Synthesizer also leads on price ($9.99 vs $14.99). Zeeon synth's advantage is update cadence (every 2 months vs every 49 months). On rating, review sentiment, ratings volume and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Zeeon synth costs $14.99 and Kauldron Synthesizer $9.99 up front. Zeeon synth sells 3 one-off in-app purchases. Kauldron Synthesizer asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.8 for Zeeon synth against 4.6 for Kauldron Synthesizer. Both are backed by a comparable volume of ratings — 209 and 136 respectively. Written reviews are what separate them: 76% of Zeeon synth's written reviews are positive against 80% of Kauldron Synthesizer's.

UpkeepUpdate frequency

Zeeon synth ships an update every 2 months, Kauldron Synthesizer every 49 months. The most recent releases landed on November 6, 2026 and November 3, 2026 respectively.

Scorecard4 real differences · 6 level
Zeeon synth versus Kauldron Synthesizer: the parameters behind the verdict, then further details
ParameterZeeon synthKauldron Synthesizer
Price$14.99$9.99 — better
Rating4.8 (209 ratings) — better4.6 (136 ratings)
Positive reviews76.0% of reviews79.7% of reviews — better
Number of ratings209 — better136
Update frequencyEvery 2 months — betterEvery 49 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.615.6
Further details — not scored
Size27 MB32 MB
Age rating4+4+
DeveloperBeepStreetYonac Inc.

Customer experience

Zeeon synth

All ratings209 ratings
Positive93.8%
Neutral2.4%
Negative3.8%
Written reviews167 reviews
Positive76.0%
Neutral7.2%
Negative16.8%

Kauldron Synthesizer

All ratings136 ratings
Positive88.2%
Neutral6.6%
Negative5.1%
Written reviews74 reviews
Positive79.7%
Neutral9.5%
Negative10.8%

User reviews

Zeeon synth

From 209 App Store ratings

What we love

  • 🎨 Excellent sound quality
  • 🎹 Intuitive and well-designed interface
  • 🔧 Flexible and deep sound design capabilities
  • 💻 Seamless integration as an AUv3 plugin
  • 🎚️ Smooth and responsive controls

Room to improve

  • 🐛 Stability issues, crashes on some devices
  • 🔌 Compatibility problems with newer iOS versions
  • 📂 Preset management could be improved
  • 🔀 Lack of MIDI learn and sequencer features
  • 🖥️ UI scaling issues on larger iPad displays

Kauldron Synthesizer

From 136 App Store ratings

What we love

  • ✨ Warm and rich sound
  • 👍 Easy to use interface
  • 💡 Great presets included
  • 🚀 Powerful sound engine
  • 🌟 High quality emulation

Room to improve

  • 🐛 Buggy AUv3 implementation
  • 🔊 Shrill noise issue
  • 🔇 No Bluetooth speaker support
  • ⚠️ Strange behavior/no reset
  • 📉 Lacks oomph/personality

Bugs and requests

Zeeon synth

Reported bugs

4 issues
  • Preset settings not retained after app restart
  • Synth reverts to default settings when reopening Logic Pro project
  • Crashes and freezes on certain iOS 14+ devices
  • Inability to access in-app purchases from within the app

Requested features

5 requests
  • Add MIDI learn functionality
  • Implement a more robust preset management system
  • Include a built-in sequencer with save/load capabilities
  • Improve UI scaling and layout for larger iPad screens
  • Provide better integration with inter-app audio and Audiobus

Kauldron Synthesizer

Reported bugs

15 issues
  • Oscillators cannot be set to -1 octave
  • Shrill noise
  • No Bluetooth speaker output
  • Fails to reload with Logic projects
  • Cannot load into Logic Pro
Show 10 more
  • Starts and quits on latest iOS
  • AUv3 bug: receives notes regardless of track selection
  • AUv3 implementation flaky, random crashes
  • AUv3: plays all instances simultaneously
  • Bug with Garageband: duplicates patterns
  • MIDI learn functions not saved
  • Sometimes glitchy
  • XY pad movements not recorded as automation
  • CPU killer on iPad 4
  • No function to share sounds

Requested features

11 requests
  • Bring synths/effects to macOS
  • Mac App version
  • More comprehensive FX section (distortion/saturation)
  • MIDI-out for arpeggiator
  • Drum machine, PAD launcher, DAW
Show 6 more
  • Browser download feature
  • Sequencer in Kauldron
  • Effects tool
  • Version history
  • More developer responses/support
  • Dark mode option

In-app purchases

3 purchases

Zeeon synth

One-time3
  • OI - Exploration Vol. 1$3.99
  • BB Z-Space$4.99
  • BB Synthwave$4.99
None

Kauldron Synthesizer

No in-app purchases

Questions

Is Zeeon synth free?
Zeeon synth costs $14.99, and also offers in-app purchases.
Is Kauldron Synthesizer free?
Kauldron Synthesizer costs $9.99, with no in-app purchases.
Which has better reviews, Zeeon synth or Kauldron Synthesizer?
Zeeon synth is rated higher. Zeeon synth averages 4.8 out of 5 from 209 ratings, while Kauldron Synthesizer averages 4.6 from 136 ratings.
Do Zeeon synth or Kauldron Synthesizer have ads?
Neither Zeeon synth nor Kauldron Synthesizer shows ads.
Which is updated more often, Zeeon synth or Kauldron Synthesizer?
Zeeon synth ships an update every 2 months, and Kauldron Synthesizer every 49 months. Most recently, Zeeon synth was updated on November 6, 2026 and Kauldron Synthesizer on November 3, 2026.

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