Hum in Podcast Audio

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Permalink Reply by Allan Newsome on January 22, 2010 at 6:10am

A laptop plugged in can cause the DC hum you're talking about. You'll need to try some of the methods you likely found when you googled the issue and find one that works for your laptop setup. You'll want to do that before you record because it's always better not to have the noise to begin with that to attempt to remove said noise after-the-fact.

Trying to remove the hum from an already recorded audio file will result in the tinny effect you mentioned.

If you must use the audio, try running Audacity's Low or High Pass filter (depends on the "hmm" which will work best but play with it). It *will* change the audio file but you may be able to get usable sound quality. I've had to use the Low Pass filter on old (late 1990's) audio interviews I did on cassette tape to attempt to remove the 'hiss" that tape causes and was able to make them "okay" for use. Had the interviewees still been living, I'd much rather have talked to them again but that wasn't an option.

Good luck!

--Allan Newsome
Two Chairs No Waiting - Andy Griffith Show Fan Podcast
http://mayberry.com/podcasts/

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Permalink Reply by Daniel Hadaway on January 22, 2010 at 8:01am

A low pass or high pass filter will work, but only if the hum is at the top end or high end of the spectrum... If the hum is at, say 200Hz, the filters will make your audio sound tinny (if you use a high pass filter) or muffled (if you use a low-pass). In this case you'd need to do some surgical EQ to take out only the frequency range that the hum exists in - if you can do this, your audio will still sound relatively natural.

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Permalink Reply by Bobby Brooks on January 22, 2010 at 11:00am

Dear Allan,

Thank you for the great tips!

By the way, I am a big TAGS fan and fan of your site.

Sincerely,

Bobby

http://www.KeepingThemEngaged.com



Allan Newsome said:

A laptop plugged in can cause the DC hum you're talking about. You'll need to try some of the methods you likely found when you googled the issue and find one that works for your laptop setup. You'll want to do that before you record because it's always better not to have the noise to begin with that to attempt to remove said noise after-the-fact.

Trying to remove the hum from an already recorded audio file will result in the tinny effect you mentioned.

If you must use the audio, try running Audacity's Low or High Pass filter (depends on the "hmm" which will work best but play with it). It *will* change the audio file but you may be able to get usable sound quality. I've had to use the Low Pass filter on old (late 1990's) audio interviews I did on cassette tape to attempt to remove the 'hiss" that tape causes and was able to make them "okay" for use. Had the interviewees still been living, I'd much rather have talked to them again but that wasn't an option.

Good luck!

--Allan Newsome
Two Chairs No Waiting - Andy Griffith Show Fan Podcast
http://mayberry.com/podcasts/

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Permalink Reply by Bobby Brooks on January 22, 2010 at 11:02am

Dear Daniel,

Thank you for your great tip!

Sincerely,

Bobby

http://www.KeepingThemEngaged.com


Daniel Hadaway said:

A low pass or high pass filter will work, but only if the hum is at the top end or high end of the spectrum... If the hum is at, say 200Hz, the filters will make your audio sound tinny (if you use a high pass filter) or muffled (if you use a low-pass). In this case you'd need to do some surgical EQ to take out only the frequency range that the hum exists in - if you can do this, your audio will still sound relatively natural.

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Permalink Reply by Allan Newsome on February 6, 2010 at 2:01pm

Hey Bobby,

I was just wondering if you were able to knock our the DC hum? I was able to do it on my laptop by plugging it into an extension cord that had the "ground" prong broken off. (I'm NOT TELLING FOLKS TO DO THIS...it "could" mess up your equipment...but that is what I did to get the hum out)

Hope all is well and working for you.

--Allan Newsome
Two Chairs No Waiting - Andy Griffith Show Fan Podcast
http://mayberry.com/podcasts/

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Permalink Reply by Bobby Brooks on February 23, 2010 at 4:07pm

Dear Allan,

I was able to get the DC hum taken care of my keeping the laptop unplugged during the recording. My latest podcast episode reflects a better quality recording because of your tip.

Thank you for all of your help.

Sincerely,

Bobby Brooks
Student Engagement Consultant & Speaker

http://www.KeepingThemEngaged.com

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Permalink Reply by Allan Newsome on February 26, 2010 at 5:15am

I'm glad it worked for you.

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