Once a .wav file has been converted into an MP3, regardless of bitrate, is it possible to do anything to the new .mp3 file that will enhance or improve the quality of it?

I assume that using some software such as Cool Edit, SoudForge, Waves etc., that something should be possible...

THANKS!:)

other than use e.g. MP3Gain to avoid clipping: NO.
possible, but not to improve objective quality. using an audio editor on an already encoded file involves trancoding almost all the time, which is bad. you might not notice the degradition though, depends on your hearing.

No. Sorry. Not that I know off.

The only lossless change that you can do to an MP3 file if to change the relative volume at which it's played (using MP3Gain). Any other change to it (as noise removing, wave edting, etc...) will only decrease the quality of the file.

Of course everything is relative. Are you talking about an specific sound sample with a lot of background sound or similar? In that case some sound-cleaning software can give you a sample more "listeneable" or "understandeable", but probably not more quality.

If you're aware of a specific bug in the encoder, and you're aware of what the decoded output is supposed to be, then in theory you could identify when the bug is being hit and correct for it. The only example I can think of for this that isn't entirely theoretical is mitigating the HF boost in Vorbis through equalization. It ought to be utterly unrealizable for LAME and all other modern encoders.

You'd probably have to encode the orginal wav file to get that information though, so theres probably not anyway you could fix the file given only the knowledge that it was broken in certain places (unless it was something like a bad header or tag).

Different decoders can be used to improve quality. There was a link to an ABX I saw around here a while ago that put foobars decoder ahead of a few others which were tested (MAD, Winamp's built in decoder, etc).

LAME can also decode the files it makes (which I think should result in the best quality, since it made them in the first place), however it wasn't tested.

I've never conducted a similar ABX myself though.

Here.

That's the one. Thanks.

I can't read French, so I can't tell how objective the test was. It also looks like it relied more so on classical samples, than a wider range of genres :/

I did this test, and wrote the text.
I choose very low volume sample, in order to have something to test. Samples are still available:
http://foobar2000.net/mp3decoder/page3.htm (links are in table)

I picked up Magix Audio Cleaning Lab Deluxe the other day. It claims to be able to refresh mp3's. How and why I do not know as this is not why I brought the product. I will give the manual a read!

That page translated with Google. http://translate.google.com/translate?hl=e...%3Doff%26sa%3DG

Ha! LAME translates to BLADE in French!

Guru, I take it that the foobar2000-decoded samples had "Dither: strong ATH noise shaping (recommended)" enabled in the Playback preferences? It seems to imply this, but it is never mentioned specifically.

EDIT: Foobar2000 sounds significantly worse than WinAmp on my computer, with dithering on OR off. There is no need at all to use ABX, the effect is not subtle. It's like there's some distortion, present no matter what settings I use. And when the dithering is turned on I can hear it quite clearly in softer pieces as a harsh static. Is there something wrong? I don't have any sound-modifying settings activated except ReplayGain & dither.
EDIT2: Nevermind, I found that switching the output method to WaveOut fixes the sound issues I was having.