MP3Gain does such a great job on MP3 files but what about othet types?
I was wondering if there is such a program for m4a or others (wav, flac, etc?)
or is htere an editor that can do so? (neither Steinberg Wavelab nor Goldwave seem to recognize m4a--unles a plugin I am unaware of is needed)
All you need to do is follow the instructions on the MP3Gain home/news page. Scroll down to the 08 January 2005 entry about AACGain. If you do that, your MP3Gain will work on not just MP3 but also AAC files (which may have .m4a, .aac, or .mp4 file extensions).