Expander
The Expander effect is used to expand the dynamic range of an audio signal. Expander boosts high-level signals and attenuates low-level signals. If you select a part of the file with the mouse, this effect will be applied to this exact part of the file. Otherwise the sound of the whole file will be altered.
In the Properties Window you can change the effect properties. It's possible to select the necessary preset from the dropdown list or set the necessary Threshold, Ratio, Root Mean Square (RMS) and Post Amplify values.