[linux-audio-user] Gnome Wave Cleaner, muffled to normal?

[ed orphan]

I'm using the Gnome Wave Cleaner 0.20-07 to clean up
an old LP before burning it to CD. I've very impressed
with GWC. However, I do have one problem that 
GWC seems unable to solve. There is one area of a song 
that's muffled and I can't see any way to bring back the
"brighness" to match the rest of the song. I guess its highs
have been clipped in some way, probably from my 
blundering ( this is my first LP with GWC ) but from the
screen I can't see any damage. I've tried the Edit->Amplify
command, but though it gets louder, it's still muffled. And
it's way to late to for the Undo command to help.
   Does anyone have any ideas how to return the
brighness to a muffled section of a song?  Would something
like Audacity help? I've no experience with sound editors,
so any information would be very welcome.