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androidaudiodecibel

Calculate Decibel from amplitude - Android media recorder

How to calculate decibel from maxAmplitude, I wrote an android application to get maxAmplitude at regular interval, I need to show the o/p to the user in decibels.

Solution

  • Decibels are a relative unit, they express the power of your signal relative to some reference power.

    If you are working with amplitudes, then the formula is:

    power_db = 20 * log10(amp / amp_ref);

    (See http://en.wikipedia.org/wiki/Decibel#Field_quantities).

    Note also that maximum amplitude is not usually a very good indicator of loudness (or even of power). More typically, you should measure the RMS power of your signal, and convert that to dB instead.