# MuSA_RT vs FD

The clearest difference is review sentiment: FD at 67% against MuSA_RT's 0%. FD also leads on ratings volume (32 vs 1) and iOS requirement (9.0 vs 15.6). MuSA_RT's advantage is price (Free vs $9.99) and rating (5.0 vs 4.6). On update cadence, ads, in-app purchases and device support there is nothing between them.

MuSA_RT is free to download; FD costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

MuSA_RT holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: FD has 32 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 0% of MuSA_RT's written reviews are positive against 67% of FD's, so the app with the better star average is not the one people write more warmly about.

MuSA_RT ships an update every 3 months, FD every 4 months. The most recent releases landed on June 5, 2026 and September 12, 2026 respectively.

## The numbers

| Metric | MuSA_RT | FD |
| --- | --- | --- |
| Price | **Free** | $9.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/musa-rt/id506866959/reviews)** | [4.6 (32 ratings)](https://appshunter.io/ios/app/fd-1-filter-delay/id1448696965/reviews) |
| Number of ratings | 1 | **32** |
| Positive reviews | 0.0% of reviews | **66.7% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 4 months |
| Monetization | **Free** | Paid |
| Size | 3 MB | 61 MB |
| Requires iOS | 15.6 | **9.0** |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Alexandre Francois](https://appshunter.io/developer/506866962) | [Kai Aras](https://appshunter.io/developer/370820899) |

## What reviewers say

### MuSA_RT

[App page](https://appshunter.io/ios/app/musa-rt/id506866959)

This app visualizes music tonality in 3D using advanced algorithms. It analyzes audio from your microphone to identify chords and keys, displaying them with a rotating camera or in augmented reality.

**Highlights:** 3D tonality visualization, Audio analysis for pitch and context, Chord and key identification, Augmented Reality mode, Smooth camera rotation for unobstructed views

**In-app purchases:** none


### FD

[App page](https://appshunter.io/ios/app/fd-1-filter-delay/id1448696965)

This app is a semi-modular audio effect plugin featuring dedicated filter, delay, and modulation sections. It allows for the creation of rhythmic filter sequences and a wide range of complex audio effects through its flexible modulation matrix.

**Highlights:** Semi-modular effect plugin, Modulated filter section, Delay stage, Step sequencer, Low Frequency Oscillator, Mod matrix, Tempo sync

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is MuSA_RT free?

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

### Is FD free?

FD costs $9.99, with no in-app purchases.

### Which has better reviews, MuSA_RT or FD?

MuSA_RT is rated higher. MuSA_RT averages 5.0 out of 5 from 1 ratings, while FD averages 4.6 from 32 ratings.

### Do MuSA_RT or FD have ads?

Neither MuSA_RT nor FD shows ads.

### Which is updated more often, MuSA_RT or FD?

MuSA_RT ships an update every 3 months, and FD every 4 months. Most recently, MuSA_RT was updated on June 5, 2026 and FD on September 12, 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.*