Thanks for the rapid reply! Apologies, my question was vague in hindsight, but your answers very helpful and reviewing the materials you shared plus some extra research, I have straightened out my understanding. I'm new to iOS and navigating the various audio APIs. I am building an iOS app, audio-only (no VR/AR/game engine) with a UI to play back head-tracked audio using third order ambisonics (i.e. binauralising using head position with reference to the more detailed positional information in 3OA). I'm looking to overlay other spatialised audio features which are a bit much for this thread as it's focused on ASAF and the codec, but basically I've been seeking to understand which APIs support ambisonics and where ASAF/APAC fits into the existing picture. Now I've got a grip on APAC compatibility and conversion method (I came across this as well: https://developer.apple.com/av-foundation/Apple-Positional-Audio-Codec.pdf), I'll take this away and have a play. I've also familiarised myself with ambisonic implementations in AVAudioEngine i.e https://developer.apple.com/videos/play/wwdc2019/510/?time=363 and https://developer.apple.com/documentation/coreaudiotypes/kaudiochannellayouttag_hoa_acn_sn3d I'll jump into Resolve to get some hands-on experience with ASAF - don't suppose this is coming to a DAW near you anytime soon (i.e. Logic, ProTools, Cubase?) Also - any chance ambisonic support will be added to the AmbientMixer in the PHASE engine? Best, Plight