Replacing certain amplitudes with silence

[emm.de]

Hey, I wonder if anyone knows how to replace (within the mp3-file) certain low amplitudes with silence? I have a large mp3-file with spoken word but there is an annoying low volume backgroud music too, and I want to replace that, with silence. I tried the noise removal and that worked OK, but not entirely. Anyways, whats the trick?
//Emm

[justinburnett]

Unfortunately, because music is all over the map in terms of frequency, it's tough to get rid of. If it's really quiet, you might first try using a Noise Gate, with the threshold set just above the volume level of the music. That, combined with some noise reduction woill probably do the trick. Depending on how high you set the threshold, it may make the talking sound a little strange, so experiment with the balance between the Noise Gate and the noise reduction until you find a sweet spot that you can live with.

Take care
-Justin-

[kozikowski]

Audacity 1.3.12 either has a noise gate or one can be added (if I can find it). See if there's one in the Effects menu near the bottom. That's not going to work because nothing can get rid of the noise during a spoken word. The Noise Gate will create cavernous silences between bouts of noisy words. Noise Reduction will create perfectly quiet, well behaved Donald Duck words.

You compound the problem with the MP3 file. MP3 creates sound damage and makes post production and file management much more difficult than if you had shot the work yourself.


Koz

[justinburnett]

I agree with what Koz has to say. Even if you find the perfect balance between Noise Gate and noise reduction, the result is never going to be pretty. You can be a lot more brutal than you could if you were trying to reduce noise in music, since all a recording of speech really has to be is intelligible. But is is going to sound weird. Noise reduction is one of those areas of audio where there has yet to emerge a real magic bullet for the masses.

[emm.de]

thanks guys. actually, the combination of noise gate and noise removal worked quite fine. the annoying music in the background is gone (except when the guy speaks) and his voice do a little pitching here and there, but overall, I was actually a bit impressed. gonna do some more experimenting… shukran.