Must be a different Nyquist or Nyquist on a different day because the usual rule attributed to Nyquist has nothing to do with hum removal.
Sent from my iPhone
> On Jul 20, 2014, at 10:13 AM, CJB <[log in to unmask]> wrote:
> Many thanks for Yyou guys' input. And there is a special Nyquist
> 'effect' for Audacity to remove hum or whatever. First you teach
> Audacity what the 'hum' consists of and then apply the effect.
> Never done this before so I'll let you guys know what happens. Then
> you can download the file and see for yourselves!!
> Chris B.
>> On 20/07/2014, Don Cox <[log in to unmask]> wrote:
>>> On 20/07/2014, Paul Stamler wrote:
>>>> On 7/19/2014 7:58 PM, CJB 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.
>>> Does Audacity include a spectrum analyzer? It could tell you whether
>>> the hum is 50Hz or 100Hz.
>> Probably both components will be present, and perhaps other harmonics of
>> 50Hz too.
>> Don Cox
>> [log in to unmask]