Background Noise

[boomcat]

What are the best tools to reduce background noise? I'm trying to clean up a lecture and I want to keep the speech but cut out the coughing and crap. The noise removal button would cut out the lecture and the coughing. Can you guys suggest something?

[alatham]

There is no magical tool that will help you. The Noise Removal doesn't work because it's only really useful for constant background noises (like tape hiss and hum noises).

You may have some luck by carefully looking at the Spectrogram (drag the track so it's as large as the display allows and click on the track name and select Spectrum). You might find that the speech occupies a specific set of frequencies that you can carefully filter around, but I doubt it. Single voices are very difficult to isolate using a computer, your ear is much better at doing that.

The only other thing you can do is crawl through the audio very slowly and use all the tools at your disposal to edit out as much junk as possible. But that kind of thing takes forever, especially if you're learning along the way. For an hour long lecture, I would estimate between 10 - 15 hours of editing to reduce as much noise as possible.

[steve]

The low-tech solution: ask your lecturer if you can put your recorder on the table in front of them.

[storyleader]

It might be worth trying the Gate effect (from the SWH collection of LADSPA plugins). If the coughs, etc., are quiter than the lecture, set the threshold so that you hear the lecture but not the coughs.