If you are using the H90 in Dual Mode, you can think of it as 2 separate processors: Path 1 = I/O 1-2 , Path 2 = I/O 3-4. Any combination of Presets can be placed on either path. If you are using it with a switcher that allows you to rearrange the order of the loops, then you could place Path 1 or Path 2 at different points of your signal path to be Pre or Post.
