When an mp3 file is opened in Cool Edit it is internally converted to wave which must be stored somewhere. If the mp3 files are large, this may be the problem.
Having said that, Cool Edit is the wrong tool for your task. Although it may not be obvious, the file is being converted to wave and then back to mp3, which results in a further loss in quality. This will also be true of any audio editor.
Have a look at
mp3gain which is designed to do exactly what you want without any quality loss. It will also operate on many files in one batch, which will allow you to process large proportions of your job unattended, e.g. overnight.
Thanks very much for your response!
It doesn't seem to be a function of file size per se, because these are basically pop songs, with a maximum size of under (usually well under) 10M, so unless Cool Edit is trying to read all the .WAV versions of the files into RAM at once I wouldn't think that was the problem.
MP3Gain does seem to be very promising, although I find their approach a bit different. Performing the tasks without having to re-compress is perfect, but the whole idea of mixing up the concepts of compression and peak normalization is counter-intuitive to me.
Compression is actually not a bad thing at all, considering that I'm processing these files for radio broadcast, but is there a way to batch the process of 1) compressing all the files to a given perceived loudness level, then 2) doing a peak normalization to a given percentage of maximum digital volume level? I find their model of targeting an arbitrary peak dB level odd. I understand that their target audience is mostly people trying to create tracks suitable for playing on a portable device in high-noise environments, so it may work for that purpose.
Thanks for your help!
Richard