Hi
I am seeing this on my new MC8 Pro but also noticed this issue on the MC6 pro as well which I just replaced.
So I have a permanent studio setup where the MC8 Pro has its 4 Omniports all set up as expression ports.
Instead of permanently connecting the Omniports to a physical expression controller I connect all 4 of the ports from my pedalboard into a TRS patch bay sitting in a rack.
This allows me to choose which of my multiple expression pedals or expression devices I wish to use at the time and then I can patch them into the MC8 Omniport as required at the patch bay end rather than on my pedalboard. Saves a lot of awkward plugging and unplugging.
In its usual state the omniports are connected through my pedalboard to the patch bay ports but at the patch bay end they are not connected to an expression controller until I wish to use one of them.
Anyway what happens is this seems to overload the MC8. By this I mean when I create a basic program change preset and test it I have to press the preset button 4 or 5 times before the program change happens. This happens across all my devices on all channels.
I notice the MC8 pro screen cycling through each expression port and displaying values and it seems it can’t handle being plugged in on the controller side but not connected at the other end.
When I disconnect the omniports on the MC8 pro the issue goes away so I know it is due to this configuration.
This behaviour is due to the Tip being left floating for the Omniports when you switch between the Omniports. The expression function reads the voltage at the Tip (of the TRS on the omniport), so if you leave it floating, there’s going to be a lot of noise, which means that the expression function is actually triggering even if there is nothing plugged in. This explains the “cycling through each expression port” and the lag when you try to trigger presets.
I’m not sure how your patch bay is wired, but you should wire it such that when a port is bypassed, the Tip is connected to Ring or Sleeve so that the voltage is stable. The drawback is that the expression port will be set to 100% (if Tip is connected to Ring) or 0% (if connected to Sleeve) when you switch between omniports.
An alternative would be a feature implementation (in a future update) on our side where you can just connect an expression pedal to one omniport, and then we can add a message type that allows you to switch Expression presets that is executed with that Omniport.
For example, by default, Omniport 1 executes Expression Preset 1, Omniport 2 executes Expression Preset 2 etc. We can allow a change of this mapping so you can set it such that Omniport 1 executes Expression Preset 2 when you engage a preset/message-type on the MC.
It’s not a huge drama if that’s the normal behaviour.
Maybe I can normal the 4 ports at the patch bay end and have them connected into some default controllers and then swap things out when I need to use a different controller.
That’s the nice thing about the patch bay as it’s just a quick change of a patch cable to connect a different expression device to the Omni port rather than trying to connect or reconnect things on the pedalboard end.