I have Bluetooth headphones connected. Volume control is limited to the headphone control itself. How can I control the volume using the Play volume knob?
I think you cannot, as the BT has its own volume management, and that is: the connected device controls it.
I'm sure the question has been asked before, but I'm damned if I can find the thread... And the proposed solution!
If this was on the A6, I think the advice would be to ensure that any digital output has been selected so that the digital volume control is in effect, this should also then control the digital feed to the Bluetooth output stream. Assuming here we are talking about BT output engineered via the settings shortcut apk or equivalent.
Hmm - selecting coaxial output kills the squeeze connect setup. Only speaker output works, but there's no Bluetooth volume control. Guess it's not possible.