# Kauldron Synthesizer vs Agonizer

The clearest difference is in-app purchases: Kauldron Synthesizer at none against Agonizer's 3. Agonizer's advantage is update cadence (every 5 months vs every 49 months) and chart position (#194 vs unranked). On rating, review sentiment, ratings volume and ads there is nothing between them.

Kauldron Synthesizer costs $9.99 and Agonizer $7.99 up front. Agonizer sells 3 one-off in-app purchases. Kauldron Synthesizer asks for nothing beyond the download.

Agonizer holds the better App Store score, 4.8 against 4.6. Both are backed by a comparable volume of ratings — 136 and 203 respectively. Written reviews complicate that: 80% of Kauldron Synthesizer's written reviews are positive against 78% of Agonizer's, so the app with the better star average is not the one people write more warmly about.

Kauldron Synthesizer ships an update every 49 months, Agonizer every 5 months. The most recent releases landed on October 26, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Kauldron Synthesizer | Agonizer |
| --- | --- | --- |
| Price | $9.99 | **$7.99** |
| Rating | [4.6 (136 ratings)](https://appshunter.io/ios/app/kauldron-synthesizer/id1292510609/reviews) | **[4.8 (203 ratings)](https://appshunter.io/ios/app/agonizer/id1499426175/reviews)** |
| Number of ratings | 136 | **203** |
| Positive reviews | **79.7% of reviews** | 78.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 49 months | **Every 5 months** |
| Monetization | Paid | **Free with in-app purchases** |
| Best chart rank | — | **#194** |
| Size | 32 MB | 362 MB |
| Requires iOS | 15.6 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Yonac Inc.](https://appshunter.io/developer/288670023) | [Kai Aras](https://appshunter.io/developer/370820899) |

## What reviewers say

### Kauldron Synthesizer

[App page](https://appshunter.io/ios/app/kauldron-synthesizer/id1292510609)

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

**In-app purchases:** none

**What reviewers like**

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

**What reviewers complain about**

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

**Reported bugs**

- Oscillators cannot be set to -1 octave
- Shrill noise
- No Bluetooth speaker output
- Fails to reload with Logic projects
- Cannot load into Logic Pro

**Requested features**

- Bring synths/effects to macOS
- Mac App version
- More comprehensive FX section (distortion/saturation)
- MIDI-out for arpeggiator
- Drum machine, PAD launcher, DAW


### Agonizer

[App page](https://appshunter.io/ios/app/agonizer/id1499426175)

**Currently charting:** #194 Top Paid · Music (US App Store)

This app is a monophonic synthesizer focused on bass sounds, developed with a synth bass expert. It features dual wavetable oscillators, a mangle section, and built-in stereo effects. It supports MPE controllers and various audio/MIDI connectivity options for standalone or app-to-app use.

**Highlights:** Monophonic synth engine for bass, Dual wavetable oscillators, Built-in stereo effects, MPE controller support, Standalone and AUv3 operation, 140+ factory presets

**Features:** Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Neon Nightmare Pack | $1.99 | one-time |
| Chrome Oasis Pack | $1.99 | one-time |
| Circuit Bender Pack | $1.99 | one-time |

**What reviewers like**

- 🎵 Excellent sound quality and unique bass tones
- 🎨 Intuitive and well-designed user interface
- ⚙️ Powerful modulation and sound design capabilities
- 🎛️ Wobulator feature for creative bass manipulation
- 📦 Great presets included with the app

**What reviewers complain about**

- 🐛 Keyboard legato/mono-synth behavior inconsistent
- 🐛 Frequent crashes in host applications (AUM, Cubasis, Audiobus)
- 🐛 No sound output in GarageBand and some AU hosts
- 🐛 App freezes on splash screen with iOS 18.3
- 🐛 UI responsiveness issues and knob lag

**Reported bugs**

- Keyboard does not properly handle legato/mono-synth note priority
- Crashes in Audiobus, AUM, and Cubasis host applications
- No sound output when used as AUv3 plugin in hosts
- No sound in GarageBand integration
- App freezes on splash screen with iOS 18.3

**Requested features**

- Polyphony mode or toggle between mono and poly
- Envelope drawing capability instead of preset selection
- Menu-based waveform selection instead of cycling
- Arpeggiator function
- Preset browser search and favorites filter


## Frequently asked questions

### Is Kauldron Synthesizer free?

Kauldron Synthesizer costs $9.99, with no in-app purchases.

### Is Agonizer free?

Agonizer costs $7.99, and also offers in-app purchases.

### Which has better reviews, Kauldron Synthesizer or Agonizer?

Agonizer is rated higher. Kauldron Synthesizer averages 4.6 out of 5 from 136 ratings, while Agonizer averages 4.8 from 203 ratings.

### Do Kauldron Synthesizer or Agonizer have ads?

Neither Kauldron Synthesizer nor Agonizer shows ads.

### Which is updated more often, Kauldron Synthesizer or Agonizer?

Kauldron Synthesizer ships an update every 49 months, and Agonizer every 5 months. Most recently, Kauldron Synthesizer was updated on October 26, 2026 and Agonizer on October 29, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*