Sound Meter help

For the iPhone and Android apps and the web app at sound.hertzmc.com

How accurate is it?

It's a good guide, not a certified sound level meter. Phone microphones differ, so readings can be a few dB off, and very loud sounds (over about 110 dB) can be more than the microphone can take. For the best reading, hold the phone still with the microphone (bottom edge) uncovered and pointing toward the sound.

Calibration

If you have a real sound level meter, put both side by side, tap i, then use − and + next to Calibration until Sound Meter matches it. Otherwise leave it at 0.

What Min, Avg and Max mean

Min and Max: the quietest and loudest moments since you opened the app or tapped Reset.
Avg: the average sound energy over that time, the way sound level meters average (one loud moment counts a lot).
The graph shows the last minute, one bar per half second. Green is under 70 dB, yellow 70 to 84, red 85 and up.

It says "Microphone is off"

iPhone: Settings → Sound Meter → turn on Microphone.
Android: Settings → Apps → Sound Meter → Permissions → Microphone → Allow only while using the app. If your phone has a microphone switch in quick settings, make sure it's on.

The number doesn't move

Another app (a call, a voice recorder, a video app) may be using the microphone. Close it and come back. If it still says "No sound from the microphone", check the microphone switch in quick settings (Android) and that nothing covers the microphone.

The apps are free and show one small banner at the bottom. See the privacy policy for what the ad collects. Sound Meter never records or sends any sound.

Contact

Email soundmeter@hertzmc.com.