Akai MPC TOUCH User Manual page 165

Silence
This process replaces the region between the start point and end
point with silence.
Extract
This 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.
Normalize
This 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.
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