Fade

In audio engineering, a fade is a gradual increase or decrease in the level of an audio signal. The term can also be used for lighting in theatre, in much the same way.

A recorded song may be gradually reduced to silence at its end (fade-out), or may gradually increase from silence at the beginning (fade-in). For example, the song Bittersweet Symphony by The Verve fades in from the beginning, while the songs "Born to Be Wild" by Steppenwolf and "Hey Jude" by The Beatles both fade out. However, "Born to be Wild" fades out in a matter of seconds, whereas "Hey Jude" takes over 2 minutes to completely fade out. Fading-out can serve as a recording solution for pieces of music that contain no obvious ending.

The term fade is also used in multi-speaker audio systems to describe the balancing of power between front and rear channels.