
In my experience, Apple has great sources and has great encodings of those sources, so Apple Music is going to deliver the best, or at least match any other service. So to that end, considering re-encoding and transcoding degrade the quality, what you want is the best quality encodings of 256kbps AAC (not all encodings are equal and neither are their sources). If it's an analog source, it will be converted to 256kbps AAC with the analog to Lightning cable.

If it's a higher digital source, it will be downconverter to 256kbps AAC before streaming over Bluetooth.


What a lot of people are missing is that whatever the source is, by the time it hits the APM, the best quality file/stream is going to be 256kbps AAC.
