With the automation box open, the velocity is fully adjustable. Double-click the note to open the automation box. By dragging the velocity line down with the "hand" tool, you lower the overall volume of the MIDI note.
The automation box has a grid. The vertical axis represents volume, and the horizontal axis represents time in beats and measures. There is a base line just above the bottom of the box. This represents zero velocity, or silence. There is also a line representing the current velocity, for reference. Click your cursor on the top-left of the grid,. This establishes a starting point for the volume-automation curve. The curve joins between the start point and the end point; it represents the increase or decrease in volume, relative to the zero-velocity line. For a fade-out, end the curve below the zero line.
Do the reverse of a fade-out. Start the velocity curve below zero and finish it level with the current velocity.
Click near the top of the square for a loud starting point. Click below the zero line to make a steep gradient. This creates an abrupt drop in volume. Plot a zig-zag automation pattern by making high and low automation points. This will create a chopped up, or staggered, sound as the volume peaks and dips rapidly.
Plot a slightly smoother and less steep zig-zag for a gentler "pulsing" volume modulation, similar to a tremolo effect.