Calibrate Mobile Phones to Measure Sound Levels

  • For sound level measuring, we can use a mobile phone. There are many mobile apps. We will use the application Sound meter.

    If we measure the same situation with more mobile phones, we find out that
    displayed data are different.



    To create a noise map of the town, we need to use more mobile phones.
    So we have to calibrate them.


    In a big room, we put the best sound meter far enough from a speaker
    and next to it we put a phone which we want to calibrate.
    The microphones of both devices must be facing the same direction.

    The calibration process:

    1. We will create a white noise.
    2. We will gradually set PC's volume so that the sound meter shows values
      of 30, 40, 50, 60, 70, 80 dB
    3. We will note data from the sound meter into a table.


    We will put the measured data into LoggerPro program and
    we will examine which function is suitable for the description of dependance.

    Suitable function:

    Unsuitable function

    For our calibration is suitable the function y = ax+bx which has parameters a, b
    X- data measured from a phone    Y - real accurate data


    For every phone it is important to make a table of measured data and
    create a special calibrating equation.





    In conclusion we will test given methods.
    In a room we will create a sound of constant volume.
    We will prepare 2 different phones and we will read shown data.
    The phones have these calibrating equations:



    We will input the measured data into calibrating equations and
    there should appear almost the same results.







    Is it difficult for you?
    Try the simple, easy method.