Reply To: Random Question: Need help with recordings and MP3 files

[nakchak 5539xp 0]

@mage you can think of it background noise filtering like this:

Imagine the recording is a group photo, but you only really want the two people in the middle in the others are “noise”.  You put a piece of paper on top of the photo and trace the outline of the two people you want in it, and cut the outline out.  Now when you put the piece of paper on top of the photo you have masked the “noise” (other people) out.

When @doctorether says you sample the background noise, you are in effect creating a mask to filter noise that matches the background sounds out, you would then apply the mask to the recording to remove the majority of background sound out, thus emphasizing  the subject of the recording, in this case your voice and what ever your talking about, instead of say road, animal and other environmental noise.

From a mathematical point of view you are trying to zero the equation, in other words you want the sum to equal zero, and you do that by adding a negative version of the sound you don’t want to the recording, i,e, 2 + -2=0 where 2 is the background noise and -2 is the noise cancelling version of the background noise.

That’s the basic principles of noise cancellation anyway (and adjusting white balance on a camera, just a bit further up the electromagnetic spectrum, and deflector shields in startrek lol), a very similar thing is done by noise cancelling headphones and microphones, its just that they do it automatically, while its something you have to manually do in Audacity.