In digital audio production, a crossfade is editing that makes a smooth transition between two audio files. In analog days, crossfades required dubbing the inputs of two source tapes onto a new tape while manually turning down the volume of one source tape while turning up the other, a relatively cumbersome procedure. Crossfading became easier to achieve with the invention of the computer-based digital audio editor. A digital editor allows two or more files to be crossfaded with the fade length limited only by the amount of audio contained in the source files. The edit consists of fading out one source file while fading in the other. This method creates a smooth transition because for a short period of time the listener hears both files playing simultaneously.
A crossfade is the opposite of a butt splice . In a butt splice, the end of the first file is joined to the beginning of the second file.