No, you don't activate/deactivate that setting on the H9. You do that on your ES8 by changing the MIDI CC yout ES8 sends out. For example, you can map MIDI CC 1 to the expression pedal, and MIDI CC 2 to the output volume on H9 (or in H9 Control. See attached image). Then you switch the MIDI CC messages by pressing a footswitch on your ES8.
Oh ok thanks! That helps a lot. I just assumed the “assign expression value aka hot knob” was just for toggling between the default preset and the hot knob value.
I’ve been messing with using expression to control input volume and I get a pretty noticable digital step/sweep sound and it’s not the most smooth volume control ever. Is there anything I can tweak to make the digital stepping noise go away?