"Last week we made a music CD from a live digital recording the
easy and simple way. Today we're going to fix volume levels and do
graceful fades and transitions using Audacity and normalize. Give
yourself a lot of disk space, make copies of your original sound
files before you start, and remember that Audacity has Undo and
Redo commands, so don't stress out over making mistakes.
"Normalization is a term you hear a lot, and it has two
different meanings. One is to adjust all tracks to the same volume
level, so that you're not surprised by a loud song following a soft
song. Another meaning is to amplify a single track proportionally,
or part of a track, making it as loud as possible while preserving
its dynamic range. Audacity does the latter, but it cannot
normalize a diverse batch of songs. For that we use the excellent
command-line tool, normalize..."