MATLAB: What kind of signal is the return value of audioread()

audioaudio processingAudio Toolboxaudioread

Hello everyone!
I tried to figure out what kind of signal the return value of audioread() is exactly. I could only figure out that the matrix displays the data sample. However, what exactly is displayed? Loudness? Pitch? Some other signal? What is the unit of the signal?
I googled a lot but could not find an answer. There are also additional functions for loudness and pitch, therefore I assume the data points do not display these kinds of signals.
In my example the input to the function was a .m4a file.
Thanks a lot for your help!

Best Answer

The value returned by the audioread is the amplitude of the audio signal. This is equivalent to the loudness of the sound. If all other properties of the two signals are constant, then the one with more amplitude will be louder. You can think of its as the amount of distance the diagram of a speaker needs to move from the rest position to generate that sound.
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