Helix Floor and M-Audio EX-P
I'm just posting this because this thread popped up when I was searching for the correct setting to get this going.
I just got my M-Audio EX-P today (1/4/2021). It works great after doing the following two things (no modifications to EX-P required):
1) Switch on bottom of EX-P set to "other"
2) In Global settings on Helix, under EXP Pedals, set whichever expression pedal input you've plugged into, to Polarity=reversed
It seems to work no matter where the knob on the side of the EX-P is set, up, down, or anywhere in-between.
Of course you need to assign the pedal to control whichever device/parameter you wish it to control in the Helix. Normal Helix rules apply for max/min settings.
Works like a champ!
FWIW, I have not tried this on my HX Stomp... and I don't have an LT.
UPDATE: [10/12/2022] Just to be clear, this works on my Helix Floor (and I would guess an LT, but I don't have one to test). I did try it on my HX Stomp and it does NOT work there. This may be where modifications to the pedal are needed.
I forgot I posted this and was happy to rediscover my own post to remind me of these settings. You may need to check the global settings after a reset/update!