Noise Reduction in Audacity
Question:
I used the Noise Reduction function from the Audacity Effects menu to reduce the annoying “hissing” sound when recording from audio cassettes.
It works out fine but the only question I have is do I need to keep doing the same process (“teaching”Audacity between good and bad sound) for each song I convert? Or will it have learned this by doing this just once and applying it to all songs that get converted?
Answer:
Yes: For best results, you’ll have to “train” Audacity each time you want to do Noise Reduction for a particular piece of audio.
Here’s a simplified version of what happens. Let’s assume you’ve got some recordings of audio recorded with a lot of background noise. One recording has background noise of people talking. Another has background noise from outside, like some wind blowing on the microphone.
When you select a piece of audio in Audacity for noise reduction training, you’re telling Audacity to remove anything that sounds similar to that clip from your entire audio recording. So in our examples above, you don’t want to target the noise of people murmuring in the background, when the actual background noise is from wind blowing on the microphone. The result will confuse Audacity and give you a result of Audacity’s noise reduction not working.
Finally, keep in mind that Audacity won’t “remember” the training after you close it. So training done on one day will not carry over to the next.
The short answer? Yes, train Audacity each time you use the Noise Reduction function.
