What's New

Thanks for using Decibel X! Here's what's new for the version 8.0.4:
∿ Fix a bug which makes the app start/resume very slow on new iPhone 11
∿ Fix a crash when changing to BAR graph
∿ Support iOS 13 and new iPhone 11 devices
∿ Component upgrades
∿ Minor improvements & fixes

What to expect in the next version:

∿ Record WAVE data along with the dB measurements data and it can be replayed later
∿ Set alarm when exceeded a preset threshold
∿ More powerful data management and export

App Description

"Decibel X" is one of very few noise meter apps on the market that has highly reliable, pre-calibrated measurements and supports dBA, dBC. It turns your iOS device into a professional sound level 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" 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.

Get Decibel X Premium and enjoy:
- Permanently remove all advertisements
- Unlock ITU-R 468, A, B, C frequency filters
- No limits when saving data

* Choose from different subscription options. Our standard subscription options are:
1-month Subscription
1-year Subscription

* Subscription payments will be charged to your iTunes account at confirmation of your purchase and upon commencement of each renewal term. Subscription with a free trial period will automatically renew to a paid subscription. You can cancel your subscription or free trial in the iTunes settings at least 24-hours before the end of the free trial period. The cancellation will take effect the day after the last day of the current subscription period and you will be downgraded to the free service.
* Please note: any unused portion of a free trial period (if offered) will be forfeited when you purchase a premium subscription during the free trial period.

* Privacy Policy: http://www.skypaw.com/decibelx/privacy_policy.html
* EULA: http://www.skypaw.com/decibelx/terms.html

iPhone Screenshots

(click to enlarge)

Decibel X: dB, dBA Noise Meter screenshot 1 Decibel X: dB, dBA Noise Meter screenshot 2 Decibel X: dB, dBA Noise Meter screenshot 3 Decibel X: dB, dBA Noise Meter screenshot 4 Decibel X: dB, dBA Noise Meter screenshot 5

iPad Screenshots

(click to enlarge)

Decibel X: dB, dBA Noise Meter screenshot 6 Decibel X: dB, dBA Noise Meter screenshot 7 Decibel X: dB, dBA Noise Meter screenshot 8 Decibel X: dB, dBA Noise Meter screenshot 9 Decibel X: dB, dBA Noise Meter screenshot 10

Apple Watch Screenshots

(click to enlarge)

Decibel X: dB, dBA Noise Meter screenshot 11

App Changes

  • November 16, 2011 New version 1.0.1
  • February 26, 2012 New version 1.1.0
  • September 07, 2012 New version 3.5.0
  • October 01, 2012 New version 3.6.0
  • October 13, 2012 New version 3.6.1
  • April 15, 2013 New version 3.6.2
  • August 01, 2013 New version 3.7.0
  • October 07, 2013 New version 3.8.1
  • February 21, 2014 New version 3.8.2
  • July 15, 2014 New version 3.8.4
  • July 18, 2014 New version 3.8.5
  • November 15, 2014 New version 4.0.0
  • November 22, 2014 New version 4.0.1
  • December 29, 2014 New version 4.1.0
  • February 16, 2015 New version 4.1.1
  • May 27, 2015 New version 4.1.2
  • September 23, 2015 New version 4.2.0
  • September 24, 2015 New version 4.2.2
  • October 07, 2015 New version 4.2.3
  • February 04, 2016 New version 4.3.0
  • February 19, 2016 New version 4.3.1
  • February 19, 2016 New version 4.3.1
  • July 05, 2016 New version 4.3.5
  • November 07, 2016 New version 4.3.6
  • December 04, 2016 New version 5.0.0
  • December 14, 2016 New version 5.1.0
  • December 17, 2016 New version 5.1.1
  • December 20, 2016 New version 5.1.2
  • June 13, 2019 New version 7.0.0
  • August 28, 2019 New version 8.0.0
  • September 04, 2019 New version 8.0.1
  • September 11, 2019 New version 8.0.2
  • September 24, 2019 New version 8.0.3
  • September 30, 2019 New version 8.0.4