I am interested in what is the purpose, i.e. the benefit, of using dual expression pedals? Thanks!
You can control different parameters that you want to be available without affecting each other. I.e. wah and delay mix on the same preset.
I have multiple instruments going into my QC at all times, guitar (channel 2), Moffenzeef synth (channel 1) and sometimes my Moog Theremin (channel 1 as well).
I have two expression pedals (sliders in my case) hooked up to my QC. One controls the wetness and decay of the reverbs. The other controls the rate of the tremolo, but also the envelope filter on channel 1 (synth). It’s really flexible and they can be programmed to do different things, depending on which block I have activated.
I use one for Wah & one for Whammy. Having two just means that you can control two separate parameters or devices independently.
I run two EXP.
EXP 1 is connected to Volume + Whammy and those blocks are mapped to stomp so when I stomp on it the EXP control audibly affect volume and then Whammy.
EXP 2 is per-preset. On an ambient preset it controls my freeze + looper volume or a character effect like vibrato amount. On a live preset it controls reverb amount.