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Reducing AC hum ?



 
 
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  #1  
Old January 4th 04, 06:32 PM
JeB
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Default Reducing AC hum ?


Anybody have "tricks" for reducing AC hum in voice recordings?
I'm working with 30-50 year old recordings with very noticable amounts
of hum (some 60hz recordings, some 50hz). Sound editor's "noise
reduction" works fairly well but the leftover artifacts are distracting.
Any other suggestions?


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  #2  
Old January 4th 04, 07:55 PM
Arny Krueger
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Default Reducing AC hum ?

"JeB" > wrote in message

> Anybody have "tricks" for reducing AC hum in voice recordings?
> I'm working with 30-50 year old recordings with very noticable amounts
> of hum (some 60hz recordings, some 50hz). Sound editor's "noise
> reduction" works fairly well but the leftover artifacts are
> distracting. Any other suggestions?


The FFT filter in Adobe Audition can be used to build very selective filters
for the power line frequency and harmonics. Generally, I find that filtering
through the 7th to 9th harmonic is necessary.


  #3  
Old January 4th 04, 10:38 PM
Todd H.
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Default Reducing AC hum ?

JeB > writes:
> Anybody have "tricks" for reducing AC hum in voice recordings?
> I'm working with 30-50 year old recordings with very noticable amounts
> of hum (some 60hz recordings, some 50hz). Sound editor's "noise
> reduction" works fairly well but the leftover artifacts are distracting.
> Any other suggestions?


A tight 60Hz comb filter may be worth a try.

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  #4  
Old January 5th 04, 05:01 AM
JeB
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Default Reducing AC hum ?

On Sun, 4 Jan 2004 13:55:29 -0500, "Arny Krueger" >
wrote:

>"JeB" > wrote in message

>> Anybody have "tricks" for reducing AC hum in voice recordings?
>> I'm working with 30-50 year old recordings with very noticable amounts
>> of hum (some 60hz recordings, some 50hz). Sound editor's "noise
>> reduction" works fairly well but the leftover artifacts are
>> distracting. Any other suggestions?

>
>The FFT filter in Adobe Audition can be used to build very selective filters
>for the power line frequency and harmonics. Generally, I find that filtering
>through the 7th to 9th harmonic is necessary.
>


thank you for the feedback.

do I understand that you can "build" a filter with steep stops at each
harmonic or you do multiple passes?

 




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