I wondered the same thing about the AirPods Pro Atmos head tracking (which just came out for music, in iOS 15 I think). If you turn your head and leave it there

I wondered the same thing about the AirPods Pro Atmos head tracking (which just came out for music, in iOS 15 I think). If you turn your head and leave it there, after about 5 seconds the soundstage will start to move toward your new orientation, and fully recenters in about 10 seconds.