Tips to Remove AC Hum?

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KenO
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Tips to Remove AC Hum?

Post by KenO » Mon Feb 18, 2013 7:21 pm

Am helping a friend edit some audio recordings that have severe AC hum.

We checked the Tips and found the detailed "Audacity Noise Removal" http://wiki.audacityteam.org/wiki/Noise_Removal which also includes Notch Filter and Noise Gate.

Since we are just beginners, would be interested in what has worked best for others.

Will add we are open to all suggestions.

Thanks

Ken

kozikowski
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Re: Tips to Remove AC Hum?

Post by kozikowski » Mon Feb 18, 2013 7:44 pm

severe AC hum.
That may kill you right there. What country are you in? Severe hum or buzz causes other distortions than just covering up the sound. It actually distorts the music or voices so if you do get rid of the interference, the music that's left can be badly damaged. You're not going back to the studio recording.

No matter which tools do the work, notch filter or noise removal, the musical tones associated with the hum or buzz will be removed. For example, if the singer hits 360Hz (in the US) in a song, that note will be horribly distorted because 360 is one of the musical tones in 60Hz (in the US) buzz. It's not magic. The tools try to remove the musical tones that can be either hum or voice.

If the buzz is severe enough, you will not be able to use Noise Removal. Nose Removal works in two steps and the first step is to find and select a portion of the show with all hum and no show. You will not be able to find that.

Select a portion of the show with noise and export it as WAV or FLAC and post it here.

http://forum.audacityteam.org/viewtopic ... 49&t=64936

Just a parting shot that we can't do forensics. No CSI tools here.

Koz

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