MIDI FX vs GSDSP MMMm
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
MIDI FX
This app allows you to control and process MIDI signals for music creation. It offers features like harmonization, transposition, and sequencing, enabling you to control external or virtual synthesizers and create complex musical arrangements.
- MIDI signal processing
- Harmonize and Transpose
- Sequencer for synths
- Delay and Looper
- Filter notes by velocity
- Internal instruments
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Buy once and get the iOS and Mac apps (with Family Sharing) Control your MIDI signals and process them in any combination of ways: Harmonize, Transpose, Arpeggiate, etc... Or use the Sequencer to play any external or virtual synth. Use a MIDI interface to unlock the power of the app to control multiple synths with one keyboard, play one note and generate chords, basslines, etc... Use the delay/looper or filter notes based on velocity or other parameters to send to different synths/effects. A MIDI workstation in your pocket (or your iPad/Mac) You can also use some internal instruments (drums sampler, piano or synth) if you are away from your MIDI gear, and sequence whole songs inside the app, or use other synth apps as input/output for MIDI FX. Your imagination is the limit!
GSDSP MMMm
This app provides a powerful MIDI modulation engine to control various plugins, hardware, and instruments. It offers a range of modulation sources like LFOs and random generators, and includes a dedicated performance skin for live use. It's a MIDI-only FX version for hosts requiring pure MIDI processing.
- MIDI CC control for plugins and hardware
- LFO, Random, Envelope Follower modulators
- XY pads for modulation
- Dedicated Performance Skin for live use
- AUv3 MIDI FX plugin
- Desktop versions available
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A powerful MIDI modulation engine for controlling plugins, hardware, and instruments using LFOs, random sources, macros, and audio-based modulation. Modulate Everything MMMm is a MIDI controller and modulation workstation designed to control any parameter that accepts MIDI CC — software instruments, plugins, external hardware, or any MIDI-capable device. Create modulation using LFOs, Random Generators, Envelope Followers, XY pads, and more. No more drawing of automation curves, keep your audio dynamic and exciting with ease. Perform Live MMMm includes a dedicated Performance Skin designed for low-light and stage environments. It uses a restrained, red-accented color palette that preserves focus and minimizes visual distraction while performing. The interface remains clear and readable in dark settings, ensuring stable workflow during your live performance. MMM vs MMMm MMM includes audio input, enabling Envelope Followers, audio-reactive modulation, and audio output — ideal when used as an audio plugin. MMMm, by contrast, is a MIDI-only FX version for hosts such as Logic Pro or AUM that require a pure MIDI processor. Both versions support MIDI input and output and provide the same core modulators. MMMm is an AUv3 midi effect plugin compatible with Logic Pro, AUM, Cubasis, GarageBand and many more. A Desktop version is also available for Windows and macOS (VST3 / AU / AAX). More information here: https://gs-dsp.com/products
Screenshots
Verdict
The clearest difference is in-app purchases: GSDSP MMMm at none against MIDI FX's 1. GSDSP MMMm also leads on ratings volume (16 vs 5). MIDI FX's advantage is update cadence (every 9 days vs every 5 weeks). On price, rating, ads and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. MIDI FX sells 1 one-off in-app purchase. GSDSP MMMm asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for MIDI FX against 4.9 for GSDSP MMMm. Both are backed by a comparable volume of ratings — 5 and 16 respectively.
MIDI FX ships an update every 9 days, GSDSP MMMm every 5 weeks. The most recent releases landed on October 23, 2026 and October 27, 2026 respectively.
| Parameter | MIDI FX | GSDSP MMMm |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (5 ratings) — better | 4.9 (16 ratings) |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 5 | 16 — better |
| Update frequency | Every 9 days — better | Every 5 weeks |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod, Mac — better | iPhone, iPad, iPod |
| Requires iOS | 14.7 | 13.0 — better |
| Further details — not scored | ||
| Size | 263 MB | 44 MB |
| Age rating | 4+ | 4+ |
| Developer | Jorge Arroyo | Gustav Scholda |
Customer experience
MIDI FX
GSDSP MMMm
In-app purchases
MIDI FX
- Unlock app$9.99
GSDSP MMMm
No in-app purchases









