# Decibels vs M

The clearest difference is rating: Decibels at 4.3 against M's 2.5. M's advantage is in-app purchases (none vs 1) and update cadence (every 2 weeks vs every 30 months). On price, ratings volume and ads there is nothing between them.

Both are free to download. Decibels sells 1 in-app purchase, starting at $3.99 per month. M asks for nothing beyond the download.

Decibels holds the better App Store score, 4.3 against 2.5. Both are backed by a comparable volume of ratings — 22 and 21 respectively. Written reviews complicate that: 22% of Decibels's written reviews are positive against 38% of M's, so the app with the better star average is not the one people write more warmly about.

Decibels ships an update every 30 months, M every 2 weeks. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Decibels | M |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.3 (22 ratings)](https://appshunter.io/ios/app/decibels-sound-level-db-meter/id1590741461/reviews)** | [2.5 (21 ratings)](https://appshunter.io/ios/app/m-efcs/id6470352068/reviews) |
| Number of ratings | **22** | 21 |
| Positive reviews | 22.2% of reviews | **38.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 30 months | **Every 2 weeks** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 20 MB | 238 MB |
| Requires iOS | 17.0 | **14.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 9+ |
| Developer | [Real Vision Ltd](https://appshunter.io/developer/1447773149) | [Sinco Audio](https://appshunter.io/developer/1576180489) |

## What reviewers say

### Decibels

[App page](https://appshunter.io/ios/app/decibels-sound-level-db-meter/id1590741461)

Measure sound levels in decibels using your device's microphone. View real-time graphs and historical data to detect noise pollution and protect your hearing. Calibrate for accurate readings across various environments.

**Highlights:** Measures sound in decibels (dB), Displays sound samples on a graph, Detects loud and low environmental noise, Calibrated for accuracy, Shows min/avg/max decibel values, Saves data and view history, Calibrates decibel for each device

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| dB Meter Full App Access | $3.99 | per month |


### M

[App page](https://appshunter.io/ios/app/m-efcs/id6470352068)

This app offers comprehensive control over guitar effects pedals. Users can manage impulse responses (IRs), reverb, delay, modulation, amplifier simulations, and noise gates to shape their sound.

**Highlights:** IR switching for cabinet simulation, Extensive reverb effects, Customizable delay settings, Various modulation effects, Amplifier sound simulation, Noise gate for clean sound

**In-app purchases:** none


## Frequently asked questions

### Is Decibels free?

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

### Is M free?

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

### Which has better reviews, Decibels or M?

Decibels is rated higher. Decibels averages 4.3 out of 5 from 22 ratings, while M averages 2.5 from 21 ratings.

### Do Decibels or M have ads?

Neither Decibels nor M shows ads.

### Which is updated more often, Decibels or M?

Decibels ships an update every 30 months, and M every 2 weeks. Most recently, Decibels was updated on October 24, 2026 and M on October 25, 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.*