For people who listen to music on their computer, a big problem is the varying volume which the sound comes out of the speakers. This problem is especially bad with headphones. As an example, someone is listening to Nirvana and they have adjusted the volume to their liking. Nirvana's song ends and Soundgarden comes on. Soundgarden's music file may specify a different volume, making the sound very loud or very quiet.

Volume normalization attempts to take care of this. By analyzing the volume on each file, it can try to compensate for the ones which are louder or softer, making them come out of the speakers all at about the same volume.