Using Sox to volume Level

[Linux for blind general discussion]

there is the normalize-audio package, which works on wav, mp3, and ogg
vorbis according to it's description in Aptitude, and might work on
FLAC given that it recommends the flac package. I've never used it
directly, but persumably, it'll be more straight forward than using
Sox given that it does specifically what you want whereas sox is more
of a general audio editing toolbox.