I'd like to use changes in filter cutoff as an expressive device. If the changes are slow enough to do by hand, I can program the modulation wheel or use the front panel knob. No problem. If they're faster --- e.g. eighth-notes as: open-close open-close ..., or eighth-note triplets (3 to a beat) as open-close-open open-close-open ... I can't do it by hand. It won't do to program key velocity to control the filter cutoff as I want to use velocity independently to control volume.