# Theremin I/O vs Theremin Synth

The clearest difference is rating: Theremin I/O at 4.0 against Theremin Synth's 3.2. Theremin I/O also leads on review sentiment (77% vs 64%) and iOS requirement (8.0 vs 12.1). Theremin Synth's advantage is in-app purchases (none vs 1) and update cadence (every 2 months vs every 24 months). On price, ratings volume, ads and monetization model there is nothing between them.

Theremin I/O costs $2.99 and Theremin Synth $2.99 up front. Theremin I/O sells 1 one-off in-app purchase. Theremin Synth asks for nothing beyond the download.

Theremin I/O holds the better App Store score, 4.0 against 3.2. Both are backed by a comparable volume of ratings — 5 and 6 respectively. Written reviews point the same way: 77% of Theremin I/O's written reviews are positive against 64% of Theremin Synth's.

Theremin I/O ships an update every 24 months, Theremin Synth every 2 months. The most recent releases landed on November 6, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | Theremin I/O | Theremin Synth |
| --- | --- | --- |
| Price | $2.99 | $2.99 |
| Rating | **[4.0 (5 ratings)](https://appshunter.io/ios/app/theremin-io/id669456913/reviews)** | [3.2 (6 ratings)](https://appshunter.io/ios/app/theremin-synth-record-and-loop/id1104816326/reviews) |
| Number of ratings | 5 | **6** |
| Positive reviews | **76.9% of reviews** | 63.6% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 24 months | **Every 2 months** |
| Monetization | Paid | Paid |
| Size | 18 MB | 1 MB |
| Requires iOS | **8.0** | 12.1 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | +4 | 4+ |
| Developer | [FFFF00 Agents AB](https://appshunter.io/developer/288966262) | [Luke Phillips](https://appshunter.io/developer/1104816325) |

## What reviewers say

### Theremin I/O

[App page](https://appshunter.io/ios/app/theremin-io/id669456913)

Transform your iPhone into a touchless musical instrument using your camera and flash. Control sound generation by hand proximity, with options for scales, sound presets, and effects. An in-app purchase enables MIDI controller functionality.

**Highlights:** Touchless instrument control via camera, Adjustable scales and harmony quantization, Multiple sound presets with effects, MIDI controller functionality (in-app purchase), Interactive tutorial overlay

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Network MIDI | $5.99 | one-time |


### Theremin Synth

[App page](https://appshunter.io/ios/app/theremin-synth-record-and-loop/id1104816326)

Create unique soundscapes with this multitouch synthesizer. Record, loop, and overdub your creations, then export them as WAV files to share. Experiment with various waveforms and effects for endless sonic possibilities.

**Highlights:** Multitouch synthesis, Record, loop, and overdub, Adjustable delay, feedback, and scuzz effects, Four waveform options, Export recordings as WAV files, Offline functionality

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

**In-app purchases:** none


## Frequently asked questions

### Is Theremin I/O free?

Theremin I/O costs $2.99, and also offers in-app purchases.

### Is Theremin Synth free?

Theremin Synth costs $2.99, with no in-app purchases.

### Which has better reviews, Theremin I/O or Theremin Synth?

Theremin I/O is rated higher. Theremin I/O averages 4.0 out of 5 from 5 ratings, while Theremin Synth averages 3.2 from 6 ratings.

### Do Theremin I/O or Theremin Synth have ads?

Neither Theremin I/O nor Theremin Synth shows ads.

### Which is updated more often, Theremin I/O or Theremin Synth?

Theremin I/O ships an update every 24 months, and Theremin Synth every 2 months. Most recently, Theremin I/O was updated on November 6, 2026 and Theremin Synth on November 2, 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.*