Emax

Yes you can on an Emax I SE keyboard version, I do it all the time.

You assign the Right Wheel to control the Filter Cutoff.  You can 
assign the Right Wheel to control lots of things and one of them is 
the filter cutoff.

I haven't got the Emax in front of me to tell you which module you 
need to go into, probably analog processing, but it is very straight 
forward if you look at your operating graphics.

You can then set up an arpeggio with a nice unfiltered Moog bass 
sample and then filter it to your hearts content in realtime.

However,  I don't know if the rack version lets you use your master 
keyboards mod wheel to achieve the same effect over MIDI.

regards

synthasy2000