# EQ550b vs GSDSP MMMm

The clearest difference is in-app purchases: GSDSP MMMm at none against EQ550b's 1. EQ550b's advantage is update cadence (every 2 weeks vs every 6 weeks) and iOS requirement (10.0 vs 12.0). On price, rating, review sentiment and ratings volume there is nothing between them.

Both are free to download. EQ550b 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 — 4.8 for EQ550b against 4.9 for GSDSP MMMm. Both are backed by a comparable volume of ratings — 13 and 14 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

EQ550b ships an update every 2 weeks, GSDSP MMMm every 6 weeks. The most recent releases landed on September 1, 2026 and September 11, 2026 respectively.

## The numbers

| Metric | EQ550b | GSDSP MMMm |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (13 ratings)](https://appshunter.io/ios/app/eq550b/id1507176549/reviews) | **[4.9 (14 ratings)](https://appshunter.io/ios/app/gsdsp-mmmm/id6450306205/reviews)** |
| Number of ratings | 13 | **14** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 2 weeks** | Every 6 weeks |
| Monetization | Free with in-app purchases | **Free** |
| Size | 19 MB | 44 MB |
| Requires iOS | **10.0** | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [RRS, OOO](https://appshunter.io/developer/1486125568) | [Gustav Scholda](https://appshunter.io/developer/1642323227) |

## What reviewers say

### EQ550b

[App page](https://appshunter.io/ios/app/eq550b/id1507176549)

This audio effect plugin emulates a classic American equalizer from the late 1960s, offering four bands of equalization with selectable frequencies and proportional Q. It provides a wide range of tonal variations for professional audio manipulation and can be used as a standalone app or an AUv3 plugin.

**Highlights:** Modeled vintage EQ, Four bands of equalization, Selectable frequency centers, Proportional Q filter, Stereo, Mid, or Side EQ modes, AUv3 plugin compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| RRS EQ550b Unlimited | $4.99 | one-time |


### GSDSP MMMm

[App page](https://appshunter.io/ios/app/gsdsp-mmmm/id6450306205)

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.

**Highlights:** 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

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is EQ550b free?

EQ550b is free to download, with in-app purchases available.

### Is GSDSP MMMm free?

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

### Which has better reviews, EQ550b or GSDSP MMMm?

GSDSP MMMm is rated higher. EQ550b averages 4.8 out of 5 from 13 ratings, while GSDSP MMMm averages 4.9 from 14 ratings.

### Do EQ550b or GSDSP MMMm have ads?

Neither EQ550b nor GSDSP MMMm shows ads.

### Which is updated more often, EQ550b or GSDSP MMMm?

EQ550b ships an update every 2 weeks, and GSDSP MMMm every 6 weeks. Most recently, EQ550b was updated on September 1, 2026 and GSDSP MMMm on September 11, 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.*