The hum is a very effective signal for dewowing the cassettes so keep a raw transfer as well as the cleaned one.
And after dewow the notch can be more narrow which leaves more music intact.
Please pardon the misspellings and occassional insane word substitution I'm on an iPhone
> On Jul 19, 2014, at 9:58 PM, CJB <[log in to unmask]> wrote:
> Please can someone advise me. I'm using Audacity to digitise a bunch
> of home-taped cassettes. Unfortunately some of them have a pronounced
> hum underlying the music. Is there a way of damping this down.
> Audacity has a bunch of filters written in Nyquist, but I'm not sure
> what settings to use, BTW the hum is likely to be at UK mains
> frequency of 50 hertz. Thanks - Chris B.