Sound Meter for Android allows you to measure environmental noise with your mobile phone.
SPL(Sound Pressure Level) meter uses your phones microphone to measure noise volume in decibels(db)and shows a graph for you to visualize the measurement.
Note that mobile phone microphones were aligned to human voice at 300-3400Hz (40-60dB).
The maximum values are LIMITED by phone manufacturers, so very loud sound at 110+ dB may not be very accurate.
***How to use***
The app automatically displays the SPL measurement when you start it, the graph shows you the maximum and minimum values within 8 seconds.
You can also view the overall maximum value that get displayed while the app is running.
To calibrate the app, select the settings menu icon at the top and continue by pressing the arrows accordingly. Once calibration is complete, you can save it. The calibration is stored so that you do not need to calibrate next time you open up the app.
The Sound Pressure is the force (N) of sound on a surface area (m2) perpendicular to the direction of the sound. The SI-units for the Sound Pressure are N/m2 or Pa.
Sound is usually measured with microphones responding proportionally to the sound pressure - p.
The power in a sound wave goes as the square of the pressure.
added Chinese language