If you expose yourself to a sound or noise of strength level of or above 85 decibels, then it can cause permanent hearing loss. Perhaps at home or office, you can use an electronic portable noise level meter to find the strength of the sound around you. But you cannot carry it around with you as the device could be cumbersome. A better approach is to install an app called Sound Meter in your Android phone and use it to measure the sound levels of noise or music around you. If you find sound level to exceed the 85 decibels limit, then you can walk away from that location to prevent any damage to your ears.
The Sound Meter app uses your Android phone’s microphone to measure the sound levels it is exposed to. But since the microphones in your smartphone are very small and are basically designed to capture the sound frequencies covering all the ranges of the human voice, this microphone may not work very well for measuring the sound levels very accurately. But it can work for somewhat acceptable accuracy and unless you want to use this app for laboratory, it works alright. You can also connect an external microphone to the 3.5mm jack to enhance the sound frequency capture range.
For measure the sound or noise level in your surroundings, you can launch the Sound Meter app and place it on an even surface. It will display a time-decibel graph for the noise or sound level as measure through the microphone. If the sound level crosses 85 decibel then the music is too loud and you should not stay in such a surrounding for long.
Because of the microphones in all the different phones built differently, they might give different readings for the same sound. To work around this problem, Sound Meter gives the option to calibrate the microphone. In order to calibrate the microphone, you can place the phone in a very quiet location and then decrease the sound level to around 4-5 decibels. In the settings, this app allows you to display the total elapsed time during which the app was measuring the sound level.
Conclusion: Sound Meter can make your phone a handy sound measuring device that you can use to measure the noise level anywhere you go. It is a nice way to keep yourself away from areas full of noise pollution in the city.
You can get the Sound Meter app from https://play.google.com/store/apps/details?id=com.gamebasic.decibel.