However, you’ll also notice that there are some artifacts in our audio that weren’t there before. The noise is gone, but the voice doesn’t sound natural. To correct this, CMD + Click (Ctrl + Click on Windows) the red line and start to drag it down. You’ll see the line retains the shape of the noise profile, but dragging it up and down will adjust the amount of effect it has on the audio. Pull it down until the voice sounds normal again, even if some noise is slipping through. Like many aspects of audio editing, the trick to getting the best denoising results is to use a few instances of ReaFir each taking off some noise rather than one instance trying to remove it all.

Add a second instance of Reafir and make sure it comes after the first one we set up. Repeat the process of creating the noise profile for this second ReaFir, but this time it is only working on eliminating the noise the first one is letting through. Once again, listen to the resulting audio and pull down the second ReaFir’s noise curve until it is not adding any artifacts to the voice. While often 2 passes of ReaFir will bring the noise level down to an acceptable level, don’t be afraid to use 3 or even 4 passes if you’re going for a really pristine sound. However, I’ve found that after 4 instances of ReaFir you’re probably doing more harm than good to the signal, but in the case of our AC addled example a third pass was warranted. Listen to the original, one instance of Reafir eliminating all the noise, and three instances of Reafir eliminating a bit of noise each, below: