Anyone know of some software (win32) to cleanup mp3's generated from old, old cassettes.
First things first:
You shouldn't perform the cleanup on the MP3 files. MP3s are "lossy compressed", meaning that some (very slight) sound quality has been lost in the compression. If possible, you should work with the original wave files as they were ripped from the cassettes, not the compressed MP3 files.
In order to clean up the MP3s, you would have to decompress them into wave format, edit the wave, then re-compress them into MP3. MP3-compressing a wave twice can induce some unwanted artifacts.
(Note that many modern wave editor programs will directly open an MP3 file for editing, and will also save directly to MP3. They are still doing the steps I described above, they're just doing it under-the-hood to make the process simpler. They are still doing the same double-recompression I just described and this should still be avoided if possible.)
Okay, with that out of the way, the next question becomes: Why do you need to edit cassette copies of something anyway? If this is an old cassette of a commercial recording, you're better off just buying the CD version. I'm assuming that these are cassettes of something not available in CD form, so on to the next question:
Is there any way to re-grab the audio data on better equipment, or from a better original source? For instance, were these cassettes made from some other master source such as a reel-to-reel tape? You'll get much better quality if you can go back to that for your source. And if these cassettes were grabbed from a cheap cassette player on a cheap sound card, you'll have quality problems there that could be resolved by performing the grab on better equipment.
Finally, to answer your real question: What software is available to clean up analog recordings to make them sound better? The answer is that just about any high-end wave editor program will do: Cool Edit, Sound Forge, etc. These programs all have noise reduction functions, EQ's, dynamic compressors, normalizers, and all the other tools needed to edit a wave file. Many CD-recorder drives also come with some simple wave editing software designed to remove pops and scratches from LP record rips and normalize them for CD burning.
But in all of those cases, "cleaning up" a recording is an art in itself. There's nothing that can magically restore the recording to its original state. It's a GIGO system- if you feed it a bad recording to begin with, you're just polishing a turd. The art comes in making the turd stink a little less. For that, you need to spend a lot of time playing with the filters and monitoring the results on a very good set of speakers. If you're willing to do that, then I'd suggest Cool Edit or Sound Forge.
___________
Tony Fabris