The above editing tools all involve arrangement of audio regions. Audacity also has valuable tools to process or change the qualities of the regions themselves. Commonly used effects for home recording include:
- Amplify: Increases the volume of a region by a designated amount.
- Compressor: Lessens the difference in volume between the loudest peaks of a region and the quietest parts.
- Fade In / Fade Out: Gradual increases or decreases the volume in a region.
- Graphic EQ: Increases or decreases the bass or treble of a region.
- Noise Reduction: Removes ambient room noise from a selection.
- Normalize: Adjusts overall volume of a region so that loudest peak reaches maximum volume without degrading.
To apply effects, at least one audio region must be selected first. To select all regions within a track, left click on the desired track’s info box at the very left of the track. To select a single region, double click on it with the selection tool.
Pictured is Audacity's Equalization tool. The user has chosen to silence bass frequencies below 35 Hz and treble frequencies above 7000 kHz.

For more on Audacity effects, click the link below.