Noise reduction

This method works very well if the noise in the second recording is identical prolactin reduction naturally to the noise in the first.
Decreasing Sensitivity decreases the chance of losing sound you want to keep (as indicated by hearing bits of the desired audio in the residue but increases the chance of there being artifacts sounding like "tinkly bells" when applying the effect with Reduce selected.
Duplicating a very short sample of noise in order to get a long enough sample for the noise profile will not help.The length of preview is determined by your setting in Edit Preferences Playback, the default setting is 6 seconds.As with all noise filters, Noise Reduction may not always eliminate all the noise without affecting the quality of the rest of the audio.Case study: Weddings, for difficult lighting, Mark van Dam turns to Photo Ninja.Select a section of the audio track cadeau dragon age origins awakening that includes both sound and silence.Bottom Line, if you use Sound Forge, the Sony Noise Reduction plug-ins are an indispensable addition to your set of tools.Lower values may result in the appearance of artifacts in the noise-reduced audio.Step 1 - Get Noise Profile.Noise Reduction calculates the statistics of the noise.
Then use this as a new Noise Profile.

Audacity learns from this selection what the noise sounds like, so it knows what to filter out later.Set this control to the lowest value that achieves effective noise removal without the introduction of artifacts.This is a case where you can get good results using a notch filter which you will find underneath the divider in the Effect menu.There are many situations where this can be useful.When you are happy that the threshold level is correct, raise the "Level reduction" setting to the highest setting that produces an acceptable amount of gating (the default level of -12 dB usually works well).Listen ko pendant un concours de claques carefully to the result to check that the noise is being cut and the audio is still present.Noise Gate A Noise Gate is a type of "audio gate" that is "open" and allows sounds to pass unaltered when the level is above a "threshold" level.Be sure in Quality Preferences to enable 32-bit Default Sample Format and to disable "High-quality" dither - more explanation here.Greater sensitivity means that more noise will be removed, possibly at the expense of removing some of the desired signal as well.To apply Noise Reduction to the entire track, select all of it by clicking in the Track Control Panel where the Mute/Solo buttons are, or if you only have one track on the screen you can use Edit Select All or the hotkey ctrl.Audacity's Noise Reduction effect is in essence a multi-band digital noise gate, automatically shaped by the Noise Profile you supply.

This is because most Noise Reduction takes some of the music away with the noise, and adds or exposes artifacts in the recording.
Any frequency smoothing you request is applied after time smoothing.