I know on the EQ-01, the HPF seems to overlap the LPF. I can dial it down and get this mid range sound. Go the other way and boost it with the top knob and its incredibly bright. in fact today I was playing around with it and found this killer jazz bass sound. tons of mids and lows with this burpy growly thing going on. You'll find the more you play, the more sounds you'll find.
