Apple uses the term “spatial audio” to describe its immersive, 360-degree sound technology, but this term is also used more generally. Different sounds are projected out from different origin points to give you the chance to be immersed from every angle. Listeners are engulfed by each sound as it emanates from them in all directions.
Spatial audio head tracking keeps the sound channels in place no matter how you move your head, as if you were standing in a sound room with speakers all around you. According to reddit user, earlier the Spatial audio head tracking settings used to be granular in iOS 15.0 – Off, Video Only & Audio and Video. Now in iOS 15.1 it has been updated to an all-or-nothing setting. Some users have reported being able to easily control the head tracking option straight from the control center inside the volume menu. Therefore, users interested in spatial audio can enable the feature for videos and turn it off for music.
You can also go to the Settings app -> tap on Accessibility -> select AirPods to get the previous setting. When you listen to Dolby Atmos music, you need to turn off head tracking. Afterwards, if you want to watch something with head tracking on your AppleTV4K, you need to re-enable it.