How do I normalize the audio volume of my FLAC collection?

Question

It seems that some CDs have a much lower general audio volume than others. This is not a problem if listening to an entire album, but it becomes a problem, when listening in shuffle mode: there is a constant need to reach out for the volume knob.

Of course, sometimes a title is gentle quite intentionally, but that's mostly occuring in classical albums or musicals, which are not intended to be listed to in shuffle mode.

However, on my wife's flower power collection, this is quite annoying.

Hence the question: How do I automatically adjust the volume level of all the 1000+ FLAC tracks in a folder without loss of quality, possibly using a script?

(Interestingly, when playing her collection via her new Sony walkman there is no noticeable volume difference; they must have a way to adjust the output volume automatically, perhaps on-the-fly.)

Answer 1

"normalize" to FLAC means to make a permanent change in the sound, in the file, thah will be no longer "original", so dont change lossless audio, and if it does, just for personal use, at least do not try to share it as if outside the original file intact. However there is the option to tell the player to play it as if it were normalized, adding a tag to the file, see replay gain tag:

http://wiki.hydrogenaud.io/index.php?title=ReplayGain

https://en.wikipedia.org/wiki/ReplayGain

I recommend normalizing lossy audios only. you can do this with the command line program called "normalize"

http://normalize.nongnu.org/