dBA Meter app well calibrated with professional noise meter tool OKTAVA 110A-PRO.

Measure sound SPL level/noise:
-Current average SPL level
-Peak SPL level
-Average maximum SPL level
-Absolute maximum SPL level

Graph histogram for (change in settings):
-Current average SPL level
-Peak SPL level

Additional features:
-Save measurements
-Upside down orientation to easy use.


To reset maximum or average maximum - just tap on it.
You can self calibrate it in settings (range from -20.0dB to +20.0dB SPL)

Usually dB meter - noise measure iOS app used & searched for

decibel meter, decibel meter® free, decibels, decibel meter - sound level db measurement tool, decibel meter hd free, dba, decibel meter pro, decibel reader, noise level meter, dba meter, decibell, db meter free, db sound measure, dmitriy pushkarev, sound measure - decibel meter, decibel meter - sound level meter, decibelmeter-measure db level, decibel meter- db sound measure, decibel meter®, decibel meter +, sonar utility, decibel pro, decibel meter hd, and other. So, download free dB meter - noise measure .ipa to run this nice iOS application on iPhone and iPad.