[linux-audio-user] spectral correction

[joke]

Hello & Happy new year!

I am actually working on a master with the trio Ardour-Audacity-Rezound, 
It works fine as usual!

The master is good, but there is some artefact I want to erase in the 
spectre itself without losing too much of it. I mean without erase some 
frequencies in the spectre. But I would like to erase just the little 
artefact, working if possible on the graphic itself - the spectral 
representation.

Do you know a free software which could do this kind of job?

Thanks a lot for you answer

cheers

Julien