I've noticed that in the Solton Club several people are commenting that OS 4 for the X1 is buggy. I never had harmonizer problems on my X1 until I installed OS 4. AJ I've still received no answer from you. If you are still working on the problem please at least say so. It seems like Ketron is losing interest in its older products. There should be an engineer somewhere in the organization that can tell why my microphone loses its effects when I switch to L & R out 3.