Akai MPC X User Manual page 251

The third Envelope tab contains the pitch modulation envelope.
Global Semi lets you transpose the keygroup up to 36 semitones up or down. This will affect the length of the
sample (if Warp is off). This is the same as the Semi field on the Global tab.
Fine provides fine-tuning of each layer by cents. This will affect the length of the sample (if Warp is off). This is the
same as the Fine field on the Global tab.
The Pitch Envelope controls affect the keygroups's pitch change over time. Use the fields or tap and drag the
"handles" of the envelope to shape the envelope or time-variant modulation output. Adjust the envelope's influence
on the pitch with the Depth slider. See the later Anatomy of an Envelope section to learn about the envelope
parameters.
The Velocity Modulation control determines how much the velocity affects the pitch envelope (Pitch).
When you press a pad softly, only minimal modulation is applied. When you press it harder, the modulation amount
also gets stronger depending on the setting of the Pitch slider.
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