Calibrating 'Sound Meter' App from Google Play

[Mystery Reader]

Hi,
Can anyone who has this app tell me how to properly calibrate it to my phone? Or does it automatically calibrate when you turn it on? I haven't used it yet because I want to make sure it is set to its best accuracy.

I found the calibration screen but not sure if I'm supposed to "plus" or "minus" -- or is that dependent on where one is at any given time?

Thank you!

Mystery Reader

 

[RingerBell]

@Mystery Reader
Yes, basically app readings should be calibrated or atleast verified somehow. The app could be pre-calibrated for some smartphones, but as there are so many models using Android, so it's very difficult to have it pre-calibrated for all models.

I guess, if one wishes to estimate the reliability of the dB-meter app on smartphone, it could be good thing to calibrate it against a reliable dB-meter in multiple environments, with different sources of sound. Sometimes dB-meter can be be even lend from some local public administration office.

Smartphone microphones are probably most sensitive in the human speech range and not meant for recording at high levels of sound pressure. That might affect the performance in environments which are heavy on the frequencies ranges, where the phone microphone isn't sensitive, like environments with high amount of low frequency noise, or in loud environments where the sound pressure level is high. If the sound pressure level exceeds the maximum level that the phone microphone can record, then the app will show this maximum value, not the true sound pressure level.