Filter: Lowpass 24 dB. Bring the Cutoff down to about Noon and turn the Res up until it starts to narrow the sound and make it stick out a bit.
Filter Envelope: Start with a small Mod Amount. Bring the Attack up a little until you get a smooth bubbly attack shape. Then bring the Sustain to 0, and set a medium-long Decay.
Velocity: Turn the Filter Envelope Mod Amount back to 0, and route the Velocity to the Filter Envelope Mod Amount. Turn up the Velocity amount and start playing around on the keyboard. You want harder presses to create a brighter bubble attack, lighter presses to create no bubble.
Voice: Legato with a decent amount of Portamento
Reverb: modest amount of Wetness, and medium-large Size.