Can somebody please explain to me the difference between Volume and Velocity that is used in the SMF Makeup Tool?

I understand what Volume is, but Velocity ...?

This can be found in the Owner's Manual of the BK-9 on page 98.

Velocity is how hard you hit the keys and is normally marked as dynamics on home keyboards.
How the sound responds to how hard you hit the keys is determined by the velocity setting of the sound.

Bill