Akai MPCX User Manual page 128

The Silence process replaces the region between the start point
and end point with silence.
The Extract process deletes the regions before the start point and
after the end point and saves it as a new sample (with a name you
enter) in your current project.
Tip: This is useful if you recorded a drum loop and wanted to
remove just a snare drum hit, a kick drum hit, etc. to use separately
in the project.
The Normalize process increases a sample's level to the highest
level possible without distortion. This is essentially a kind of digital
gain optimization, so you do not have to worry about excessive
level settings when working with samples with a wide range of
amplitudes.
The Reverse process reverses the region between the start point
and end point.
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