Each FX Chain has eight Function knobs to which you may assign any parameters of algorithms enclosed within the FX Chain.
The global option would be an expression pedal or MIDI control, if you wanted to assign parameters across FX Chains. Of course, you could program Function knobs in each Fx Chain and control them simultaneously by assigning them the same MIDI CC# number. This method requires external control from an actual controller, expression pedal or DAW, for example.
