If you are interested in measuring the sound level, the sound level meter application is a decibel meter that uses the built-in microphone on your device to measure the sound volume in decibels (dB).

At the bottom it shows the evolution of the decibel level in a graph that allows great detail and that you can enlarge or reduce by touch (with two fingers on the screen).

It is important to note that the performance of the microphone will be different for each device. Therefore, before its first use, it is necessary to calibrate the sound level meter. If the device needs calibration, go to a quiet place where hardly any sound is heard and modify the correction until you reach a value between 10-20 dB.