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?

"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.

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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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?

On 04 Jan 2004 15:38:04 -0600, (Todd H.) wrote:

>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.

thanks for taking time to write. I'm certain it's harmonics too as
pointed out by Arny K. ... I'll experiment more.