Spatial Audio
Head-tracked surround sound.
Spatial Audio places audio sources in a fixed virtual room and uses head-tracking (in compatible earbuds/headphones) to keep them anchored as you turn. Apple's implementation runs on AirPods + iPhone/iPad/Mac; Dolby Atmos is the open mastering format powering most spatial-audio content on streaming services. Best-perceived effect is on movies, weakest on legacy stereo music.