I have the Sony MDR 10RBT and the Sony MDR 1RBTMK2, and also the Harman Kardon BT, all of them are bluetooth headphones with aptx. Now, I know the two Sony have Hi Res Audio, not sure about the Harman Kardon BT.
I have been doing a search to try to find out what this Hi Res Audio is all about, and how can I get started in listening to that format.
More searching, and I am sure I will come with the answers.
BTW, there is no question of the 3 headphones, the MK2 Sony is the best, with the lower Sony taking up 2nd, and the Harman Kardon taking up the rear...