"Decibel X PRO" is one of very few sound meter apps on the market that has highly reliable, pre-calibrated measurements and supports frequency weightings: ITU-R 468, A and C. It turns your iOS device into a professional noise meter, precisely measures the sound pressure level (SPL) all around you. This extremely useful and beautiful tool will not only be a great tool for many uses but also bring you a lot of fun. Have you wondered how quiet is your room or how loud is a rock concert or sport event? "Decibel X PRO" will help you answer all of those.


- Trusted accuracy: the app is tested and pre calibrated for all Apple devices. The precision is matching with real SPL devices
- Apple Watch support: see noise level right from your wrist
- Frequency weighting filters: ITU-R 468, A, B, C, Z
- Powerful, smart history data management:
+ Recording data can be saved into a list of history records for future access and analysis
+ Each record can be exported as hi-res PNG graph or CSV text via sharing services
+ iCloud support which synchronize all history records across your Apple devices
+ Fullscreen mode to give overview the whole history of an record
- Dosimeter with NIOSH, OSHA standards
- FFT and BAR graphs to display real time FFT. Those are very useful for frequency analysis and musical tests. Real time predominant frequency is also displayed.
- WAVE graph with 2 display modes: Rolling & Buffer
- InstaDecibel to capture your dB report overlaid on photos and easily shared via popular social networks (Facebook, Instagram, Messages, etc.).
- Support both Portrait and Landscape layouts
- Beautiful, intuitive and carefully crafted UI design
- Optimized for iOS 11


- Standard time weightings (Response Time): SLOW (500 milliseconds) and FAST (200 milliseconds)
- Trimming calibration from -15 dB to 15 dB
- Standard measurement range from 30 dBA up to 130 dBA
- HISTO graph for plotted history of the recorded values
- Real time scale level chart
- Display Current, Average/Leq, and Max values with both nice and clear digital and analog layouts
- Quick reference text to help you compare with real-life examples
- "Keep Device Stay Awake" option for long duration recording
- Reset and clear current recording at any time
- Tap on Max value to reset at any time
- Pause/Resume the tool at any time


- Please do not expect a quiet room reading will be 0 dBA. The range 30-130 dBA is the standard usable range and an average quiet room will be about 30 dBA.
- Although all devices are pre-calibrated, custom calibration is suggested for serious purposes requiring higher precision and accuracy. You will need a real external device or calibrated sound meter as a reference, then adjust the trimming calibration until the reading matches with the reference.

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What's New

Version 6.5.1

● Fixes random crashing issue of Insta Decibel
● Fixes UI issue on iPhone X family devices
● Fixes an issue where there now should open a warning message when sharing via Instagram, Facebook services but those apps are not installed yet
● Several minor fixes & performance improvements

Thanks for using Decibel X! Please be sure to rate this new version and leave us a review on the App Store. Your feedback is greatly appreciated. We're listening to your feedback and working hard to improving Decibel X.

Ratings and Reviews

4.6 out of 5
2.9K Ratings
2.9K Ratings
mr. nemoto

Good but has a few bugs.

I use this app for training and assessing vocal intensity for Parkinson's patients. There are 3 problems that need to be fixed. One is the data on the summary report doesn't fit on the "page" so the numbers are hard to read. The second problem is that when data is cleared, it immediately starts recording again and the pause button has to be hit quickly. And finally, even the slightest upward swipe (always on accident) flips you into a different screen which is annoying and disruptive.


Great noise monitor

I occasionally need to monitor noise levels at home or in classrooms when I’m substitute teaching. So I’m a novice at this, although I am a scientist in other areas. This APP does everything I need: records noise levels, lets me adjust the parameters, such maximum acceptable noise level, and I can download the data. It defines & explains everything. It is calibrated. The only thing it has no effect on is my 4 cats’ level of meowing. If only it could feed them.... I’m thrilled with this APP!


Latest iPhone Version

I’ve been using this app for a few years and it’s never let me down ... until now. The app is useless on my iPhone X now. Since the latest update, the app crashes upon launch. If I repeatedly relaunch the app I may get lucky after 5 or 6 attempts to launch. Yet after it finally opens its unstable if I switch to a different app and usually crashes as well. Contacted support, 2 weeks ago and there has been no response. Hope someone is reading these reviews because I’d really like to know if I should burn this bridge and find another solution.


SkyPaw Co. Ltd
22.2 MB
Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.
English, Dutch, French, German, Italian, Japanese, Korean, Portuguese, Simplified Chinese, Spanish, Traditional Chinese, Vietnamese
Age Rating
Rated 4+
© 2018 SkyPaw


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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