I have a large collection of foleys that I recorded, and I want to normalize them all, or at least make them all have the same perceived loudness. Is there any program that can do this for me instead of having to go through each WAV individually, and replacing the old one?
I use Sound Forge for this kind of thing. It has a feature that lets you specify a list of processes to run your sounds through, parameters to use, file formats and locations to save to, etc. It will achieve what you need very easily, and it's quite a pleasure to watch it in progress, go away and come back later to find it all done. I recommend it! (It appears to have been bought from Sony by Magix Audio; I have been using (Sony) Sound Forge Pro v10; The latest version retains the feature though - see the "Batch Conversion" section on this page.)