# sumFX vs isxynth

The clearest difference is review sentiment: isxynth at 100% against sumFX's 55%. isxynth also leads on price ($7.99 vs $9.99). sumFX's advantage is rating (4.4 vs 3.7) and update cadence (every 6 months vs every 34 months). On ads, in-app purchases, monetization model and device support there is nothing between them.

sumFX costs $9.99 and isxynth $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.

sumFX holds the better App Store score, 4.4 against 3.7. Both are backed by a comparable volume of ratings — 12 and 3 respectively. Written reviews complicate that: 55% of sumFX's written reviews are positive against 100% of isxynth's, so the app with the better star average is not the one people write more warmly about.

sumFX ships an update every 6 months, isxynth every 34 months. The most recent releases landed on September 7, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | sumFX | isxynth |
| --- | --- | --- |
| Price | $9.99 | **$7.99** |
| Rating | **[4.4 (12 ratings)](https://appshunter.io/ios/app/sumfx/id6450494474/reviews)** | [3.7 (3 ratings)](https://appshunter.io/ios/app/isxynth/id6450951503/reviews) |
| Number of ratings | **12** | 3 |
| Positive reviews | 54.5% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 6 months** | Every 34 months |
| Monetization | Paid | Paid |
| Size | 44 MB | 8 MB |
| Requires iOS | 12.0 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [OSC Audio](https://appshunter.io/developer/1693533681) | [Alexey Nadzharov](https://appshunter.io/developer/729549192) |

## What reviewers say

### sumFX

[App page](https://appshunter.io/ios/app/sumfx/id6450494474)

This app is a versatile audio effects processor for musicians. It offers a modular design with multiple high-quality FX modules and customizable slots, allowing for quick creation of unique sounds. Focus on your music with intuitive controls and visual feedback.

**Highlights:** Modular multi-FX processor, 8 high-quality FX modules, 8 FX slots with Wet/Dry control, 2 LFOs per slot, 50+ cross-platform presets, Pre/post waveform view

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

**In-app purchases:** none


### isxynth

[App page](https://appshunter.io/ios/app/isxynth/id6450951503)

This music effect plugin allows spectral cross synthesis and morphing between two input signals. It separates noise and tone components, offering controls for blending, freezing, and time-based delays. Gestures on controls can be recorded and played back for dynamic sound shaping.

**Highlights:** Spectral cross synthesis, Morphing between two input signals, Noise and tone component blending, Freeze control for spectral blurring, 3-second delay lines per input, Gesture recording and playback

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

**In-app purchases:** none


## Frequently asked questions

### Is sumFX free?

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

### Is isxynth free?

isxynth costs $7.99, with no in-app purchases.

### Which has better reviews, sumFX or isxynth?

sumFX is rated higher. sumFX averages 4.4 out of 5 from 12 ratings, while isxynth averages 3.7 from 3 ratings.

### Do sumFX or isxynth have ads?

Neither sumFX nor isxynth shows ads.

### Which is updated more often, sumFX or isxynth?

sumFX ships an update every 6 months, and isxynth every 34 months. Most recently, sumFX was updated on September 7, 2026 and isxynth on September 24, 2026.

---

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