I can read it but it gives me a headache. I would rather not have to do this on any sort of regular basis.
$ sox source.flac -b 16 dithered.flac
$ sox --combine merge source.flac dithered.flac loud-difference.flac remix 1,3i 2,4i norm -1 spectrogram # assumes stereo input
$ open spectrogram.png
$ open loud-difference.flac
$ sox source.flac -b 16 quiet.flac gain -100
$ sox quiet.flac loud-again.flac norm -1
$ open loud-again.flac open my $fh, '<', 'input.txt' or die;