# KASPAR vs Agonizer

The clearest difference is in-app purchases: KASPAR at none against Agonizer's 3. Agonizer's advantage is update cadence (every 5 months vs every 16 months) and rating (4.8 vs 4.6). On price, review sentiment, ratings volume and ads there is nothing between them.

KASPAR costs $19.99 and Agonizer $19.99 up front. Agonizer sells 3 one-off in-app purchases. KASPAR 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 — 91 and 203 respectively. Written reviews point the same way: 75% of KASPAR's written reviews are positive against 78% of Agonizer's.

KASPAR ships an update every 16 months, Agonizer every 5 months. The most recent releases landed on October 6, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | KASPAR | Agonizer |
| --- | --- | --- |
| Price | $19.99 | $19.99 |
| Rating | [4.6 (91 ratings)](https://appshunter.io/ios/app/kaspar/id1245045964/reviews) | **[4.8 (203 ratings)](https://appshunter.io/ios/app/agonizer/id1499426175/reviews)** |
| Number of ratings | 91 | **203** |
| Positive reviews | 75.0% of reviews | **77.8% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 16 months | **Every 5 months** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 64 MB | 362 MB |
| Requires iOS | 11.0 | 11.0 |
| Devices | iPad | **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

### KASPAR

[App page](https://appshunter.io/ios/app/kaspar/id1245045964)

This powerful synthesizer app offers 8 polyphonic engines with extensive morphing, layering, and modulation capabilities. Create complex sounds with 24 oscillators, 8 filters, and built-in stereo effects. It integrates seamlessly with DAWs and other music apps.

**Highlights:** 8 polyphonic synth engines, Multi-Engine Automorphing, Extensive modulation system, Poly aftertouch support, 2 stereo FX busses, Audio Unit plugin integration, Inter-App Audio and Audiobus support

**In-app purchases:** none

**What reviewers like**

- ✨ Incredible power and depth
- 🔊 Amazing and unique sound quality
- 👍 Easy to use and intuitive UI
- 💡 Highly configurable and flexible
- 🎛️ Advanced sound shaping possibilities

**What reviewers complain about**

- 🐛 Occasional crashes and instability
- 💻 High CPU usage
- 🐞 Bugs in AUv3 implementation
- 🖼️ UI scaling issues in some DAWs
- 🤔 Presets can be uninspired or limited

**Reported bugs**

- Sound muted in solo mode for some synths
- Synth crashes when loading as AUv3 in Roland Zenbeats
- FX chain not working
- Program change messages not followed as AUv3 in Cubasis internal track
- UI does not scale to full screen in Cubasis 3

**Requested features**

- Add a step sequencer
- Improve preset variety and inspiration
- Fix AUv3 program change issues
- Address UI scaling problems in DAWs
- Implement MIDI out functionality


### Agonizer

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

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 |
| --- | --- | --- |
| Chrome Oasis Pack | $3.99 | one-time |
| Circuit Bender Pack | $3.99 | one-time |
| Neon Nightmare Pack | $4.99 | 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 KASPAR free?

KASPAR costs $19.99, with no in-app purchases.

### Is Agonizer free?

Agonizer costs $19.99, and also offers in-app purchases.

### Which has better reviews, KASPAR or Agonizer?

Agonizer is rated higher. KASPAR averages 4.6 out of 5 from 91 ratings, while Agonizer averages 4.8 from 203 ratings.

### Do KASPAR or Agonizer have ads?

Neither KASPAR nor Agonizer shows ads.

### Which is updated more often, KASPAR or Agonizer?

KASPAR ships an update every 16 months, and Agonizer every 5 months. Most recently, KASPAR was updated on October 6, 2026 and Agonizer on October 14, 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.*