Comparison

VOLT 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

VOLT Synth

This app is a virtual analog synthesizer designed for expressive sound creation. It supports multidimensional polyphonic expression (MPE) and offers a variety of synth voice features, built-in effects, and keyboard layouts. It's compatible with MPE hardware and software, as well as standard MIDI controllers.

Highlights
  • Virtual analog synthesizer
  • Multidimensional Polyphonic Expression (MPE)
  • Expressive synth engine
  • Multiple keyboard layouts
  • Built-in stereo effects
  • 100+ factory presets
  • Standalone and AUv3 support
Features
Read full description

VOLT is a virtual analog synthesizer designed to create classic synth sounds while emphasising expressive play. With full support for multidimensional polyphonic expression (MPE) - VOLT is a great companion to any Seaboard player. Overview: * Polyphonic Virtual Analog Synthesizer * Expressive synth engine with MPE, poly-, channel aftertouch & 4D touch keyboard * 5 Keyboard Layouts (Classic, Uniform, String, Scale & Chord) * Built-in stereo effects * 100+ fine tuned factory presets * Supports ROLI Seaboard, LinnStrument, Geoshred and others out of the box * Standalone operation with support for USB audio interfaces, wired, network & bluetooth MIDI * Audio Unit v3 Extension * Inter App Audio support * Audiobus support * Ableton Link Synth Voice: * Variable waveshape * Variable pulse-width (on all waves) * Detunable sub & noise source * SEM style state-variable filter * LFO per voice * Dual ADSR * Poly drive (per voice distortion) * 8x Polyphony / Unison * Detune / Slop * Pan Spread * Arpeggiator Effects: * 3x stereo effect units * Vintage Chorus * Digital Delay (syncable) * Epic Reverb Input/Expression: * MPE MIDI hardware including but not limited to ROLI Seaboard Rise, Seaboard Block, Lightpad Block * MPE MIDI software including but not limited to Geoshred, Geoshred Control * Regular MIDI keyboards featuring channel or poly aftertouch, pitch- and mod wheels * Onscreen 2D Touch Keyboard (supports slide and glide) * Plain MIDI Input Presets: * Factory bank including 100+ expressive presets ready to play out of the box * Preset Management with Templates & Categories * Shared User Presets between Standalone and AUv3 versions * Preset Export & Import via Files.app, Airdrop etc. * iCloud Drive Support Connectivity: * Standalone * AUv3 Instrument * Inter-App Audio Instrument * Audiobus Instrument

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

VOLT Synth4 screens
Kauldron Synthesizer4 screens

Verdict

The call

The clearest difference is price: Kauldron Synthesizer at $9.99 against VOLT Synth's $19.99. Kauldron Synthesizer also leads on in-app purchases (none vs 3) and review sentiment (80% vs 63%). VOLT Synth's advantage is update cadence (every 2 weeks vs every 49 months) and iOS requirement (9.0 vs 15.6). On rating, ratings volume, ads and device support 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

VOLT Synth costs $19.99 and Kauldron Synthesizer $9.99 up front. VOLT 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 — 4.6 for VOLT Synth against 4.6 for Kauldron Synthesizer. Both are backed by a comparable volume of ratings — 193 and 136 respectively. Written reviews are what separate them: 63% of VOLT Synth's written reviews are positive against 80% of Kauldron Synthesizer's.

UpkeepUpdate frequency

VOLT Synth ships an update every 2 weeks, Kauldron Synthesizer every 49 months. The most recent releases landed on September 20, 2026 and September 24, 2026 respectively.

Scorecard6 real differences · 4 level
VOLT Synth versus Kauldron Synthesizer: the parameters behind the verdict, then further details
ParameterVOLT SynthKauldron Synthesizer
Price$19.99$9.99 — better
Rating4.6 (193 ratings)4.6 (136 ratings)
Positive reviews62.9% of reviews79.7% of reviews — better
Number of ratings193 — better136
Update frequencyEvery 2 weeks — betterEvery 49 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS9.0 — better15.6
Further details — not scored
Size92 MB32 MB
Age rating4+4+
DeveloperKai ArasYonac Inc.

Customer experience

VOLT Synth

All ratings193 ratings
Positive89.6%
Neutral4.1%
Negative6.2%
Written reviews62 reviews
Positive62.9%
Neutral14.5%
Negative22.6%

Kauldron Synthesizer

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

User reviews

VOLT Synth

From 193 App Store ratings

What we love

  • 🎶 Great sounds
  • ✨ Intuitive UI
  • MPE integration
  • 🎵 Expressive
  • 💻 Good for travel

Room to improve

  • 🐛 Crashing frequently
  • ⚠️ Unstable on newer iOS
  • 🎛️ Cumbersome sound switching
  • 📉 Poor performance
  • unresponsive controls

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

VOLT Synth

Reported bugs

18 issues
  • No MIDI input after 30 seconds
  • Crashing when using multiple AU instances
  • Presets disappear after iOS 14 update
  • Standalone mode broken on recent iOS
  • AU3 not working in Cubasis/NanoStudio 2
Show 13 more
  • Crashes with iCloud Drive for patch storage on iOS 13
  • Preset scroller not accessing sounds
  • Stability issues on iOS 12
  • UI issues in AU mode on iPhone
  • No sound after last update
  • Presets not loading
  • AUv3 UI lacks preset selection slot
  • Preset saving crashes app
  • Digital readout under controls obscured by finger
  • Latched key graphic disappears
  • Legato mode doesn't work with aftertouch
  • Pitch bend limited to 12 steps
  • Global pitch bend setting disappeared

Requested features

7 requests
  • Two fields for sound forward/backward
  • New features and sounds for MPE
  • Dedicated strings section in presets
  • Randomize function for LFOs/envelopes
  • Larger fonts in preset display
Show 2 more
  • Improve envelope snappiness
  • Improve modulation routing options

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

VOLT Synth

One-time3
  • Dub PackFree
  • haQ attaQ paQ$3.99
  • Red Sky Lullaby Pack$3.99
None

Kauldron Synthesizer

No in-app purchases

Questions

Is VOLT Synth free?
VOLT Synth costs $19.99, and also offers in-app purchases.
Is Kauldron Synthesizer free?
Kauldron Synthesizer costs $9.99, with no in-app purchases.
Which has better reviews, VOLT Synth or Kauldron Synthesizer?
VOLT Synth and Kauldron Synthesizer are both rated 4.6 out of 5 on the App Store, from 193 and 136 ratings respectively.
Do VOLT Synth or Kauldron Synthesizer have ads?
Neither VOLT Synth nor Kauldron Synthesizer shows ads.
Which is updated more often, VOLT Synth or Kauldron Synthesizer?
VOLT Synth ships an update every 2 weeks, and Kauldron Synthesizer every 49 months. Most recently, VOLT Synth was updated on September 20, 2026 and Kauldron Synthesizer on September 24, 2026.

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