I've seen this problem on the forums before, and on the net in general, but it was never completely addressed here and I can't find a satisfactory reply elsewhere, so apologies for the repeated topic. When using the i/o plugin to inject an external effect processor into Logic, I get terrible feedback. My audio interface is an EVO 16 from Audient, and the effect is an Eventide H9. I've tried everything I can possibly think of: software monitoring on/off, changing inputs and outputs, mix settings in the effects processor, digital clock settings, rebooting the mac, having a coffee, meditating, but nothing works. It should. I know I've used this function before, but not since 10.5 (I think !). All I can get is extremely loud feedback. The Eventide on its own works fine. Any thoughts ? Many thanks. N