Hi Blake
Actually yes... I do hear it when I tilt. I have taken a photo and marked where the sound seems to emanate from. Also, have managed to get a recording by placing the mic at this spot and adjusting an exposure slider.
I noticed that when I turned over the machine and listened I could hear a similar sound while it was busy installing a windows update too... without any other activity.
I've attached the photo and recording.
Your help is much appreciated
Den