Noise reduction
This advanced filter suppresses unwanted noise in any audio clip. The filter responds dynamically to the changing noise conditions within the clip. The preset you choose provides the starting point from which the adaptive algorithm proceeds.
You can often further improve your results by adjusting the Noise reduction and Fine tuning parameters. There is a lag of about a second before any new setting has an audible effect, so you should make changes in small amounts then pause to check if there is an improvement.
Noise reduction: When a camcorder is used outdoors with the actors distant from the microphone, the “source noise” may be very high, and to make matters worse the internal noise of the camcorder may be amplified to intrusive levels. If a lapel microphone connected to the line input of the camcorder were used when taping the scene, however, the source noise could be quite low. Adjust this control to match the noise conditions of the actual signal.
Fine tuning: This controls the amount of cleaning to be used. It is only needed when the Noise reduction level is low, since at higher levels the noise has already been eliminated.
Auto adapt: When this option is checked, the filter automatically adjusts to changes in the type or amount of noise in the clip. The Fine tuning is not used when Auto adapt is active.
Remove wind: This checkbox engages a filter that reduces wind noise and similar unwanted background sounds in the audio clip.
Note: The Noise reduction filter will help with a wide range of material, but it is not a panacea. Your results will vary depending on the original material and the severity and nature of the problems.