I have a feeling the point that everyone is missing is the conversion when it comes to AirPods...
Production studio creates the Master File, then that is converted to whatever is served on the streaming service (AAC/ MP3 whatever) then that is decoded to digital audio steam inside the phone and -when talking about wireless headphones - that is reconverted to bluetooth digital stream and then decoded inside your headphones DAC.
Resolution / Bit Depth and Lossy/Lossless are two different things. Resolution is something that only MIGHT matter in the production studio since higher sample rates and bit depth allow for better harmonic overtones and headroom that affect the effect processors you work with and can possibly create marginally better results. You can think of it as having a 30" 4K Display 1 meter away from your eyes and displaying 8K content on it (192KHz) vs 4K content on it (48Kz) - all other things being equal.
Lossless files contain bit by bit the exact audio stream. If it's 44,1Khz / 16 bit depth then it has 44100 samples per second of which each sample can take a position of either of 16bits. On the other hand all lossy files are essentially psychoacoustic filters that encode the audio into a data file, not an audio stream. They remove from the audio stream stuff that your ears won't easily notice to reduce file size without reducing the audible quality and that's why a lossy file needs decoding. When your DAC is decoding that lossy file, it tries to piece together the missing info to produce an analog signal as close as possible representing that original lossless file and it does a pretty damn good job at it, but of course there are missing info that we just don't hear / notice. On the next step to transfer the audio to the wireless headphones, when you re-encode / re-decode a file stream for wireless playback then you are trying to use that psychoacoustic filter again on a file that's already processed by it, therefore it's much easier to introduce artefacts, skew the transients, add mild distortion all very minute though and very un-noticeable as far as normal listening goes (If you A/B then you might possibly understand the differences but even there it will be hard).
Even if the link from the iPhone to the AirPods Max or Pros isn't lossless in that case, a lossless file on my iPhone will instead suffer only 1 conversion from lossless to lossy, that of the bluetooth link. It's bound to be better even if it's going to be a small amount / un-noticable to most people (if not all people for that matter, but that's not the story here).
All Apple is doing is being technically correct and saying that you cannot have 192KHz lossless playback on your Headphones. But you know what, the DAC on the Headphones allegedly is capable of 48KHz / 24 bit playback - and that is lossless too! Hell 44100Hz / 16 bit can be lossless too! Can you have the bluetooth connection stream the file directly to the headphones to avoid the AAC conversion? Maybe some AirPlay update is in the works to allow that. But even if it never happens, having one less A/D to D/A conversion in the chain is appreciated for me. Especially when it's for free.
support.apple.com
