You can switch—or smoothly crossfade (morph)—between the presets of the upper manual. See Use Vintage B3 Morph controls.
Important: Morph controls are spread across two windows. Click Main in the control bar, then click the Preset button at the lower right to view the Morph slider. The Options window contains advanced Morph controls.
Upper Morph slider: Drag left or right to control the switching or morphing. You can also assign and use a MIDI controller such as your keyboard modulation wheel to control the Morph slider.
Select via Keyboard buttons: Click the On button, then play a lower and upper key to set the range of Preset keys affected by the morph. Click Off to disable the morph range that is set up.
Mode switch: Click Step to abruptly switch, or click Linear to smoothly morph (crossfade), between presets.
Range pop-up menu: Choose a range of keys for morph presets.
MIDI Controller pop-up menu: Assign a MIDI controller to the Morph slider. You can choose any MIDI controller number shown (or channel aftertouch). You can also click Learn to teach the Morph slider to respond to any incoming MIDI message.