What the hell is that one? Once in while you see those 3-d drawings and depending on the angle you look at them, they switch depth. I met this in a Sonar project. Everything set to make the trumpets sound from behind and sometimes they do (most of it), but in very loud passages they seem to be just in front of me and the violins at the back. Yes, thus flipped in spatial perception....... is this the right word for it?

Any explanation for this, or is it just my "ever older ears" ?