Walk the independent claim. Apple's grant US11546687B1, "Head-tracked spatial audio" (issued January 3, 2023; inventors including Symeon Delikaris Manias and Juha Merimaa), is a granted patent — the B1 kind code indicates a grant without prior publication. Its CPC tags H04R 1/326 and H04R 1/323 are directional-transducer classes, with spatial-rendering classes alongside.
The element that does the work is the head-to-soundfield coupling. Plain stereo moves with your head; head-tracked spatial audio does the opposite — a virtual speaker stays anchored in the room as you turn, because the renderer continuously adjusts the soundfield to your head's measured orientation. The claim's contribution is that closed loop between head tracking and rendering.
What it reads on is the spatial-audio feature in Apple's earbuds and headphones — the experience marketed where audio appears to come from a fixed point regardless of head movement. The directional-transducer classification ties the claim to the physical audio hardware as well as the rendering.
Scope discipline: the claim does not own spatial audio, and it does not own head tracking. It protects the recited coupling of the two as claimed. A system that renders fixed stereo, or that does spatial audio without head-locked anchoring, operates outside it. The defensible element is the head-position-to-soundfield link.
Granted status makes US11546687B1 a live consideration in a contested space — Apple, Meta, Sonos, Dolby, and Bose all hold spatial-audio IP. For anyone building head-tracked audio into earbuds or a headset, this grant is part of the freedom-to-operate map on the head-tracking-plus-rendering combination.
For a strategist, the patent marks Apple's claim to the specific experience it popularized. The category is broad, but the head-locked-anchoring effect is the part consumers notice — and the part this claim is built around.