fade out
To decrease in volume, such as at the end of a song, until there is only silence.
Fade out: gradual reduction to zero, not sudden cutoff
A fade out is the gradual reduction of an audio signal to silence over a defined time interval. In electrical terms, this means the amplitude of a waveform decreases linearly or logarithmically until it reaches zero. Unlike a hard mute or switch-off, a fade out is continuous and smooth, typically lasting anywhere from a few hundred milliseconds to several seconds depending on the application and desired aesthetic effect.
In analog audio circuits, fade outs are historically achieved using a potentiometer or variable resistor in the signal path, with the operator manually reducing resistance over time. Modern digital systems implement fades through gain reduction in the audio processor or digital signal processor (DSP), where a multiplier decreases the sample value at each cycle. The fade curve itself matters: linear fades reduce amplitude proportionally across time, while logarithmic fades (equal-loudness curves) account for human perception and often sound more natural because loudness perception is logarithmic, not linear.
Fade outs are standard in music production, particularly at track endings where they serve both practical and artistic purposes. A fade prevents abrupt silence and the audible click or pop that occurs when audio cuts suddenly. Radio broadcast and podcast production rely heavily on fades to transition between segments or to handle material recorded at inconsistent levels. In live sound reinforcement, a fade out can mask unwanted noise or feedback when a performer leaves the stage.
Fade versus crossfade
A fade out stands apart from a crossfade, which involves one signal fading out while another simultaneously fades in. A crossfade requires precise timing and level coordination; a fade out is unidirectional. Both use the same underlying mechanism (gain reduction over time) but serve different purposes in mixing and broadcast workflow.
The term fade out originates from film and theatre, where lighting technicians would dim lights to black at the end of a scene. Audio adopted the vocabulary directly. In hardware mixing consoles, the fader (the physical slider controlling channel level) is the instrument through which fade outs are performed; the term fader and fade became linked in professional audio terminology and remain so today.