I sit right below mine and no issues with noise when audio is playing. Its just like white noise when quite in the room though.
You can set the input you want and lock it, but mine still takes a bit longer to lock onto it than I would like. I usually get a blue screen and flcker and then hourglass while I hear audio already for a few seconds until video kicks in.
It will usually do this with skipping a preview too. One of my minor annoyances with this unit, but not a deal breaker