DigiDesign Pro Tools 8.0 Reference Manual page 530

If a region references insufficient data to ex-
ecute a selected fade or crossfade, you are
prompted to either skip those fades or to ad-
just the bounds of the selection to be able to
execute those fades.
Standard Crossfade (Centered)
splice
fade-out curve
point
region 1
crossfade selection
Centered crossfade
This type of selection creates a crossfade on both
sides of the splice point, which affects the vol-
ume of region 1 and region 2. It is the most
common type of crossfade.
This crossfade type requires that region 1 con-
tain audio material beyond its end point, and
region 2 contain audio material before its start
point.
Pre Crossfade
sp lice sp lice
point point
region 1 region 1
crossfade selection crossfade selection
Pre crossfade
512 Pro Tools Reference Guide
fade-in curve
region 2
region 2 region 2
This type of selection creates a crossfade before
the splice point. This lets you maintain the vol-
ume of the very beginning of region 2 instead of
fading across it, which is useful if there is a
strong attack at the beginning of region 2 that
you want to preserve. When making selections
for crossfades that occur on the border of two re-
gions, you can use the Tab key to move the cur-
sor to the exact beginning or end of a region.
This crossfade type requires that region 2 con-
tain audio material before its start point.
Post Crossfade
sp lice
point
region 1 region 2
crossfade selection
Post crossfade
This type of selection creates a crossfade after
the splice point. It is useful if you want to main-
tain the amplitude of region 1 until its very end.
When making selections for crossfades that oc-
cur on the border of two regions, you can use
the Tab key to move the cursor to the exact be-
ginning or end of a region.
This crossfade type requires that region 1 con-
tain audio material beyond its end point.