Remove muffled audio?

[escarlate]

Anyone know a good program or a method to remove hiss, muffled audio, like audio recording tape cassette?

[davexnet]

Try Audacity, free audio editor.

[escarlate]

do not know if this issue has already been reviewed here but I think it is not so simple as treating the audio, I use some plugins to the program sound forge more'm not finding a way to do this
Audacity is that there is a way of acting as if it s my doubts?

[AlanHK]

See http://wiki.audacityteam.org/index.php?title=Noise_Removal

[escarlate]

thankyou for help