[linux-audio-user] Here is my dilemma

I've been lurking on the list for awhile now. I'm fairly good on computers but kind of new with linux. Here's my problem. I'm pretty sure it can be rectified with linux but I don't know how. I recorded an small low-budget cd in a small local studio a few years ago. Although I loved the end result, the cd itself never had the loudness that a regular cd had. I would be playing it at a reletively loud range and then change cd's and always, the other cd would be nearly twice as loud. How can I make these songs louder? On my old recordings there were done with a cheesy four-track, how can I make there cleaner? Some of my old recordings that have been copied over from old tapes are too hot and therefore get a really annoying digital distortion. Can I clean those up too? Chaz