I haven't noticed any high pitched noises coming from the STRDN1080 while it's off but my hearing isn't that great. It wouldn't surprise me if it was.
I do know that the STRDN1080 makes an audible buzz or hum while the unit is on as does all of Sony's latest model A/V receivers, even the ES models are not immune. It's due to an inferior power supply. Even with my less then stellar hearing I was able to hear the buzz all the way from the couch. This was unacceptable to me and it was because of this reason that I returned the unit and went with a quality integrated amp.
I suppose the STRDN1080 would be fine if your priority was movies but if you're serious about music then I recommended passing on all the latest Sony A/V receivers as they just aren't built all that well.