LinPlug Spectral - Manual (Page 80)

Velocity to Main Volume
The Vel (Velocity) dial in the bottom right of the Main Section is used to
control the degree to which the played notes Velocity influences the patch
volume. If turned folly clockwise, the volume of the sound do largely
depend on Velocity. When turned fully anti-clockwise the Velocity does not
affect the Volume of the preset.
Master Volume
The Volume control sets the overall Spectral's volume within a wide range.
Please note that Spectral has an internal limiter that prevents the overall
output level to go beyond about +12 dB.
MIDI Controller Assignments page
When choosing “Edit” from the main edit windows “Learn” menu you come
to the page allowing you to edit MIDI Controllers Assigments.