A crossfade overlaps a fade-out on one sound with a fade-in on another so that the two sounds change over smoothly. It is commonly used to hide clicks and sudden level changes at edit points.
When to use a crossfade
Crossfades are useful when joining takes in a comp, removing sections of dialogue, looping audio, or connecting sound effects. The same principle is used over a much longer duration when moving between songs in a DJ mix.
Choosing the length
A few milliseconds may be enough to remove a click. A vocal breath or sustained instrument note may need a longer overlap. If the crossfade is too long, both sounds can become audible at once and expose timing or phase differences.
Choosing the curve
Linear, equal-power, and S-shaped curves change the perceived level in the overlapping section. Try an equal-power curve if the middle sounds too quiet. If the overlap becomes louder than either source, use a gentler curve or shorten the fade.
Points to watch while editing
A transition placed directly on a drum attack or consonant can double the sound’s leading edge. Whenever possible, move the edit into a decay or a nearly silent point. When overlapping similar sounds, also check the result in mono for phase cancellation.
How it differs from a fade
A regular fade smooths the beginning or end of one item. A crossfade transfers between two overlapping items and is closely related to comping and loop editing.
