I don't see a forum for the CP300, so I thought I would ask here.
The insertion effects have very detailed parameters but most of them do not appear to be accessible through the menus on the machine. Usually only Wet/Dry balance is in the menu.
Am I correct in concluding that these are MIDI-only accessible?
Example: AutoPan LFO Frequency.
Yes, you are correct. If you look in the CP300 Owner's Manual page 115-122 EFFECT PARAMETER LIST, the parameters charts for each Effect Type are shown. The parameter with the black dot in the "Control" column, is the parameter designated as the one that can assigned for real time control (using the CP300 Assignable controllers).
All other Effect parameters are addressable via System Exclusive parameter change messages, only. (Starting on page 128)
Thank you for the clarification! 🙂