Hi, Using latest version of Logic Pro X . When I select multi-device output in audio preferences, it works just fine but slowly starts to add echo or delay to one of the outputs. If I de-select, then re-select it, it works for awhile, then slowly starts to echo again. Ideas?

Hi - What you're describing sounds like it could be feedback gradually building up. but I don't understand what you mean by "multi-device output in audio preferences" -- could you be more specific? Are you referring to an Aggregate Device [set up in Audio MIDI Setup] that's being used as the audio output in Logic's Audio Preferences? If it is feedback, that would result from an output being fed back into the input of the same source -- you might want to check your various i/o settings on the channel strips to see if that could be happening..? If your audio interface has its own routing utility, that would be another place where a feedback loop could conceivably happen. But it's hard to say without seeing or knowing more about your setup and mixer routings..