if it is a consant sound like an air conditioner or background noise like traffic etc the noise tools in STP should be able to clean it up
in the sample editor window select a section of audio that is just the noise you wanna remove
go to the process menu and select set noise print
select the whole section of audio you want to clean and go to the process menu and select reduce noise and adjust the settings to get the results you want
David at Movies Rock in Toronto
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