# OpeNoise vs CJDecibel

The clearest difference is rating: CJDecibel at 5.0 against OpeNoise's 4.0. CJDecibel also leads on update cadence (weekly vs every 7 months) and review sentiment (100% vs 86%). OpeNoise's advantage is ads (none vs shown) and monetization model (free vs ad-supported). On price, ratings volume, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

CJDecibel holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 4 and 2 respectively. Written reviews point the same way: 86% of OpeNoise's written reviews are positive against 100% of CJDecibel's.

OpeNoise ships an update every 7 months, CJDecibel weekly. The most recent releases landed on October 13, 2026 and October 3, 2026 respectively.

## The numbers

| Metric | OpeNoise | CJDecibel |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.0 (4 ratings)](https://appshunter.io/ios/app/openoise/id1387499991/reviews) | **[5.0 (2 ratings)](https://appshunter.io/ios/app/cjdecibel-noise-detection/id6479873232/reviews)** |
| Number of ratings | **4** | 2 |
| Positive reviews | 85.7% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 7 months | **Weekly** |
| Monetization | **Free** | Ad-supported |
| Size | 12 MB | 37 MB |
| Requires iOS | 15.0 | **11.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Arpa Piemonte](https://appshunter.io/developer/1317255035) | [炽金 练](https://appshunter.io/developer/1523269489) |

## What reviewers say

### OpeNoise

[App page](https://appshunter.io/ios/app/openoise/id1387499991)

This application measures real-time sound pressure levels, displaying minimum and maximum values. It offers advanced analysis like third octave and FFT, with options to save data, calibrate, and share measurements with a community. Note: it is not intended for professional use.

**Highlights:** Real-time A-weighted sound pressure level measurement, Minimum and maximum level tracking, Third octave and FFT analysis, Data saving in text file, Calibration functionality, Measurements displayed on a map, Community sharing of calibration and measurements

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

**In-app purchases:** none


### CJDecibel

[App page](https://appshunter.io/ios/app/cjdecibel-noise-detection/id6479873232)

This utility app offers real-time, high-precision decibel measurements to detect noise levels. It features a minimalist interface for easy operation, allows recording of detection locations, and enables sharing or exporting of historical data.

**Highlights:** Real-time decibel measurement, High-precision detection, Location recording, Data sharing and export, Detection history viewing

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is OpeNoise free?

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

### Is CJDecibel free?

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

### Which has better reviews, OpeNoise or CJDecibel?

CJDecibel is rated higher. OpeNoise averages 4.0 out of 5 from 4 ratings, while CJDecibel averages 5.0 from 2 ratings.

### Do OpeNoise or CJDecibel have ads?

CJDecibel shows ads; OpeNoise does not.

### Which is updated more often, OpeNoise or CJDecibel?

OpeNoise ships an update every 7 months, and CJDecibel weekly. Most recently, OpeNoise was updated on October 13, 2026 and CJDecibel on October 3, 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.*