How does head tracking work when monitoring a Dolby Atmos mix on AirPods in Logic Pro, and why does a bounced binaural file not keep it?

Problem: judge a spatial mix with head movement, then deliver a headphone version. Conditions: Logic Pro with Dolby Atmos plug-in on a Mac; head-tracking-capable headphones (AirPods Pro/Max). Method: the Dolby Renderer and Apple Renderer monitoring formats each have a Head Tracking button; turning it on makes the sound field of the three-dimensional mix remain fixed in place when you turn your head. The button appears only when head-tracking-capable headphones are selected as the output device. Apple Renderer (Head Tracking) also requires a Mac with Apple silicon. For delivery to other devices you bounce a two-channel binaural file; Apple states that if you used an Apple Renderer (Head Tracking) monitoring format you will not hear head tracking in the bounced file, and that on AirPods the Spatial Audio / Spatialize Stereo setting should be turned off to play a binaural file (otherwise the headphones process it again). An ADM BWF file is the required format for submitting a Dolby Atmos mix to Apple Music. Use (inference): head tracking is a monitoring and playback-side feature; the mix itself stays a scene (beds and objects) that the playback device rotates, which is consistent with the ambisonic rotation described in round 1 (3DoF, no room-translation). Failure modes: judging binaural stereo bounces with head tracking on; double-processing through AirPods spatialisation. Limitations: Apple's pages are about Logic Pro monitoring, not a technical specification of the renderer. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Page dated December 2024 (R19); Logic page undated. Does not cover how Apple's renderer models rooms or distance. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://support.apple.com/guide/logicpro/monitoring-formats-lgcp179f27c1/mac",
      "note": "Dolby Renderer playback; Apple Renderer (Head Tracking); Set the Dolby Atmos plug-in; Export as an ADM BWF file"
    },
    {
      "url": "https://support.apple.com/en-us/105041",
      "note": "Dolby Renderer playback; Apple Renderer (Head Tracking); Set the Dolby Atmos plug-in; Export as an ADM BWF file"
    }
  ]
}