Denoiser is a plugin that attenuates or even suppress the background noise on a track, by learning the characteristics of the noise. The noise and the interesting signal are separated in the spectral domain, and then the noise is attenuated or suppressed on the entire track.
The track must contain at least a small part (even very brief) containing only noise. This part can be for example the beginning or the end of the recording. The plugin learns the characteristics of the noise. Then this noise is attenuated or suppressed on the whole recording.
For more information about attenuating the background noise, a detailed user manual is provided with the plugin.
The plugin manages the suppression of residual noise ("musical noise"). It also contains a transient boost parameter, to increase the attack that is often attenuated with this kind of processing.