First, “normalizing” won’t work. Normalizing (and the Audacity Amplify default) adjusts the volume to maximize the peak levels, but the peak doesn’t correlate well with perceived loudness. Most CDs are already normalized/maximized, and that includes most quiet-sounding tracks.
And, there’s nothing for the CDs,* but if you “rip” to a digital file there are some options:
Some audio player software supports [u]ReplayGain[/u]. ReplayGain pre-scans the files and adds a ReplayGain “tag” to the file. When the file is played, the volume is adjusted to a standard. The actual audio in the file is not touched. iTunes and iPods/iPhones support something similar called [u]Sound Check[/u].
If your player doesn’t support either of these, WAVgain and MP3gain use the same algorithm but in this case the actual audio is “permanently” altered so it works with any player/software.
ReplayGain has an “album” option that adjust the volume of the entire album by the same amount so that quiet songs remain (relatively) quiet and louder tracks remain (relatively) loud, as the producer intended.
Somebody made a [u]ReplayGain Plug-in[/u] for Audacity that’s allow you to “permanently” change the volume of files.
NOTE - Since many quiet-sounding songs are already normalized/maximized and the volume can’t be boosted without clipping (distortion), the only way to match volumes is to make louder songs quieter. If you use ReplayGain (or any other volume-matching method) you’ll find that your music library is generally quieter overall.
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- You could rip the CDs to WAV, apply WAVgain, then burn your own modified copy of the CD. (Audacity doesn’t rip or burn so it won’t help with that unless you wanted to use the ReplayGain plug-in instead of WAVgain.)