• • • Decibel Ultra • • •

- Would you like to know how loud the TV, music or the environment is?
- Or your neighbour is too loud? With Decibel Ultra you know it exactly!

- Decibel Ultra measures the volume and helps you figure out how big the noise level compared to reference values.

- Calibrate with Decibel Ultra all your surround speakers to the same level.

Decibel Ultra measure the sound pressure level (SPL) in dB professional frequency weightings: A, B, C, D ,Z (flat) and time weightings: Fast, Slow, Impulse.

- Perfect to tune guitars.
- Send the results quickly via email.
- interested how loud you are?
- Ultra-precise measurement of frequencies, a sine of 1000.0 Hz appears really as 1000.0 Hz!
- Calibrated to the internal microphone, equipment enclosed headphones, MicW microphone or with line-in. Decibel Ultra is calibrated to standard 94dB at 0776 Vrms / 1000 Hz.

Decibel Ultra was calibrated with a Class 1 Sound Level Meter and calibrator! From device to device, it may still be fluctuations around a few dB (2-3 dB). The app set the device into a special, best possible measurement mode. The automatic gain control (AGC) will turn off to get clean measurement without distort signals. On some older devices, the AGC can not turned off by software, it will then automatically corrected in the calculation.

Depending on the unit generation, it varies how sensitive is the device. For example the current iOS devices e.g. iPhone 6 (plus) the internal microphone of an iOS device can not perform any measurement below 30 dB. Measurements below 40 dB with an external microphone or via the headphone jack supplied line output, are not possible with this current devices. The headset that came with the iOS device, cannot measure below about 44 dB. This is a limitation of the current device. But hey, 30 dB is already really sensitive!

Highly recommended is the MicW i436. It has a very linear frequency response and dynamic, ideal for precise professional measurements.

Continuous noise can be a potential hazard to your health!

I would like to thank the company MicW Audio and Synthax GmbH for their kind support.

Free version. The ad-free version is called "Decibel Ultra pro" here in the iTunes Store.

What's New

Version 3.5

- bug fixes
- calibration data for iPhone 8 and iPhone X
- support for iOS 8 - iOS 11.x

Ratings and Reviews

3.7 out of 5

6 Ratings

6 Ratings

Very good app!


I work as a Maintenance Engineer for a hospital. We have a very expensive Db meter that is hard for a novice to use (very complicated) this gets almost exactly the same readings and very easy to use. I love the email function. I would give it 5 stars if you add more instructions for us users that don't have the knowledge or experience to understand all the settings. Thank you for creating the app! I will be buying the Pro version (to rid myself of the adds) are the differences between this version and Pro just the Adds?
I'm amazed that this app was even close to our our real, expensive Db meter. It made a believer out of me.

Love the idea and interface....but accurate?

ss ZHO

I love the idea of this app. The interface is very nice also. And is FREE!!!

It lacks in accuracy however. :/

I am an automotive test engineer. I have experience evaluating the noise levels of automotive products. I decided to test this app out compared to a sound level meter (only took a very quick walk around lab and office). I found that the numbers did not match up very well (I believe it was within 10 dB, however). I think the strongest reason for the inaccuracy was due to lower frequency sounds. To properly measure low frequency, a larger microphone is needed. I dont know the size that comes with the iphone, but I can not imagine it being that large.

My recommendations for future updates:
Consider allowing different frequency weighting scales (dBA is very popular).
Consider a weighting scale for the iphone microphone (if mic does not pick up lower frequency very good, you may be able to digitally amplify the expected signal at that frequency)
Consider specifying the frequency range that this app is good for.



After trying all the dosimeter/decibel meter apps on the market, this app is the most accurate and easy to use. It is frequently updated by the developer to support the latest devices and operating systems unlike the vast majority of competing apps. As a tinnitus sufferer, this app is vital to my hearing health to prevent further hearing damage. Thank you for developing and maintaining this app, you have no idea how much it has impacted my life.


Patrick Schaefer
18.4 MB
Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.
English, French, German, Italian
Age Rating
Rated 4+
© 2017 Patrick Schaefer


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