# Isotope MIDI Keyboard vs FrequencyCat

The clearest difference is price: FrequencyCat at Free against Isotope MIDI Keyboard's $6.99. FrequencyCat also leads on review sentiment (100% vs 80%). Isotope MIDI Keyboard's advantage is update cadence (every 2 days vs every 40 months) and ratings volume (10 vs 1). On rating, ads, in-app purchases and device support there is nothing between them.

FrequencyCat is free to download; Isotope MIDI Keyboard costs $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 4.9 for Isotope MIDI Keyboard against 5.0 for FrequencyCat. That said, the two scores are not equally well evidenced: Isotope MIDI Keyboard has 10 ratings behind it against 1, so its average is the more settled of the two. Written reviews are what separate them: 80% of Isotope MIDI Keyboard's written reviews are positive against 100% of FrequencyCat's.

Isotope MIDI Keyboard ships an update every 2 days, FrequencyCat every 40 months. The most recent releases landed on October 7, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | Isotope MIDI Keyboard | FrequencyCat |
| --- | --- | --- |
| Price | $6.99 | **Free** |
| Rating | [4.9 (10 ratings)](https://appshunter.io/ios/app/isotope-midi-keyboard/id1667140170/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/frequencycat/id6448219399/reviews)** |
| Number of ratings | **10** | 1 |
| Positive reviews | 80.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 days** | Every 40 months |
| Monetization | Paid | **Free** |
| Size | 3 MB | 3 MB |
| Requires iOS | 16.0 | 16.0 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Jaewon Choi](https://appshunter.io/developer/1324431041) | [Xuesong Zhang](https://appshunter.io/developer/1684075008) |

## What reviewers say

### Isotope MIDI Keyboard

[App page](https://appshunter.io/ios/app/isotope-midi-keyboard/id1667140170)

This app offers an intuitive and accessible way to play music and learn music theory. Its unique isomorphic grid layout simplifies chord playing and understanding note relationships, making it ideal for both beginners and experienced musicians.

**Highlights:** Isomorphic grid layout for intuitive playing, Built-in Element sound engine, Audio Unit v3 plugin support, MIDI and MIDI over Bluetooth connectivity, Velocity-based touch and accelerometer input, Customizable themes and layouts

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### FrequencyCat

[App page](https://appshunter.io/ios/app/frequencycat/id6448219399)

Transform your photos into unique sound art using advanced image-to-sound technology. Explore, enjoy, and share your creative audio-visual pieces. Embrace your inner artist and discover the unexpected.

**Highlights:** Morph images into sound art, Create spectrogram oddities, Share sound art creations, Unique audio-visual experience

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Isotope MIDI Keyboard free?

Isotope MIDI Keyboard costs $6.99, with no in-app purchases.

### Is FrequencyCat free?

FrequencyCat is free to download, with no in-app purchases.

### Which has better reviews, Isotope MIDI Keyboard or FrequencyCat?

FrequencyCat is rated higher. Isotope MIDI Keyboard averages 4.9 out of 5 from 10 ratings, while FrequencyCat averages 5.0 from 1 ratings.

### Do Isotope MIDI Keyboard or FrequencyCat have ads?

Neither Isotope MIDI Keyboard nor FrequencyCat shows ads.

### Which is updated more often, Isotope MIDI Keyboard or FrequencyCat?

Isotope MIDI Keyboard ships an update every 2 days, and FrequencyCat every 40 months. Most recently, Isotope MIDI Keyboard was updated on October 7, 2026 and FrequencyCat on October 6, 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.*