Shimmer is a tricky one. It is an algorithm with a complex routing; a little different from the other H90 reverbs.
Here are a few old posts about Shimmer / Freeze. They focus on the Space ‘Factor & H9 pedals, but the same concepts apply to the H90 algorithm:
https://www.eventideaudio.com/forums/topic/h9-shimmer-pitch-decay-etc/
https://www.eventideaudio.com/forums/topic/space-freeze-mode-in-shimmer/#post-135430
https://www.eventideaudio.com/forums/topic/freeze/#post-146755
That last link mentions DualVerb, but the same will apply to Shimmer. You are actually ‘freezing’ part of the reverb signal, not your input.
