Apple is currently rolling out Space Audio and Lossless Audio for Apple Music. Later this year, however, Apple will also bring dynamic head tracking to songs in the Apple Music catalog.
From the FAQ section of a supporting document Apple reveals that dynamic head sensing spatial audio will be coming to Apple Music in autumn. Dynamic Head Tracking will be able to create an even more immersive experience for spatial audio. This feature will be available on AirPods Pro and AirPods Max connected to a compatible iPhone or iPad.
Spatial audio uses the gyroscope and accelerometer in the headphones and iOS device to track head movement and device position. By comparing the movement data it is able to remap the sound field so that it remains “anchored” to the device even if the head moves.
Apple Music videos with Spatial Audio enabled already support dynamic head tracking, but in the case of audio tracks, no visual elements are involved. For this reason it is plausible that Apple has a different implementation in mind that will create more depth in the listening experience.