by Glenn » Tue Jul 14, 2009 11:35 pm
If you're planning to burn these, your burner software likely has the utility, and is the best choice for that purpose, particularly if your downloaded files are compressed.
Even if you do the peak normalization offered in wavcor or other apps, you may find the levels are still not matched. This is because in addition to peak leveling, the sound levels need to be adjusted for average levels, also known as rms levels. The rms level to peak level ratio is known in the recording industry as "crest factor" (cf) and is largely what determines the perceived volume of the music.
Many recordings, particularly modern pop recordings sound loud because they have a low cf. Older recordings, and also many classical recordings, have a high cf because music in nature sounds this way. If you wish to match perceived volume levels you must match the cf of the different tracks in the mix. Unfortunately, this is not easy to do.
I think it would be a first if Derek could incorporate this into wavcor, particularly as a batch process, but I think it's beyond the scope of what he's trying to offer. I know of one programme, now defunct, that could do this by inputting the desired rms level, but that's not going to help you now.
In the meantime, Audacity has a dynamics compressor that works well enough to achieve this end, but I don't believe the plugin has batch capability - I could be wrong. If it doesn't, you will have to process the tracks individually though trial and error. Once you've matched the cf among all the tracks , you can then use the burning software to perform the peak normalization.
Glenn