Eliminating hum

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vannuysd
Posts: 17
Joined: Thu Jun 18, 2015 10:12 pm

Eliminating hum

Post by vannuysd »

I've been bedeviled lately by a background hum that is difficult to diagnose. I think it may be coming from the fan of my new computer. My old computer didn't have a fan so it was never an issue. I'm referring to background audio hum on my audio podcast. Is there a tool in Amadeus that would eliminate or reduce this hum without distorting my voice?

CDJonah_alt
Posts: 379
Joined: Thu Mar 15, 2007 3:57 pm

Eliminating hum

Post by CDJonah_alt »

Try doing a fourier analysis of your data where you aren't speaking. If
there appear to be sharp peaks, set up notch filters to eliminate those
frequencies.

Chuck

On 9/28/15 10:41 AM, vannuysd wrote:
I've been bedeviled lately by a background hum that is difficult to diagnose. I think it may be coming from the fan of my new computer. My old computer didn't have a fan so it was never an issue. I'm referring to background audio hum on my audio podcast. Is there a tool in Amadeus that would eliminate or reduce this hum without distorting my voice?




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Jim Edgar
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Eliminating hum

Post by Jim Edgar »

The best way to deal with something like that is at the time of recording. In other words, fix it at the source. Put the computer in a closet, move the mic further away, isolate the recording space in some way.

Also - identifying the noise source and type is important.  Strictly speaking, "hum" (low frequency tone) is different than pitched "noise" (random frequencies) and the approaches to fixing them are different.   A fan more commonly creates "noise" with a pitch center.  You can use a parametric at the center frequency, but you'll still end up with a lot of other garbage in the signal.  And if that main frequency is in the range of your voice, it will affect that as well. Which is why it's best to eliminate/fix at the source. 

The most common flaws in podcasts (and recording in general) include:
- Room resonance (echo/reflection)
- Lack of separation from the noise floor (usually a recording level issue)
- Background noise from the space
- Environmental noise from outside the space


You can use a front-end noise gate, but all that happens is that as soon as you begin talking, the gate "opens" and you hear all of that background noise.  


There are also microphones which have more directional pickup patterns (you should at least be using a cardioid pattern pickup, rather than "omni"), called hyper cardioid or super cardioid, generically "shotgun" microphones.


best of luck,


- Jim

Jim Edgar

jimedgarvoices@gmail.com (jimedgarvoices@gmail.com) - @jimedgarvoices
http://www.jimedgarvoices.com  -  http://about.me/jimedgar

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