You don't need to explain, I know the subject. Compression acts on the amplitude of the entire audio signal, not "quiet frequencies". You can start here: https

You don't need to explain, I know the subject. Compression acts on the amplitude of the entire audio signal, not "quiet frequencies". You can start here: https://en.wikipedia.org/wiki/Dynamic_range_compression https://en.wikipedia.org/wiki/Dynamic_range_compression Normalization as it normally is used is offline process where you up the gain of the whole audio so that the loudest noise is 0dB.