Using standard BT into my car audio receiver. No aptx or LDAC in the car. My iPhone at half volume sends BT louder to my car stereo than the M9.
I was always under the impression that the receiver controlled the volume output of a BT stream, not the transmitter, but clearly that’s not the case. I was also under the impression a dap like the M9 would have a more powerful BT output than a phone, but again that doesn’t seem to be the case.
I can see the benefit of using a dedicated BT receiver like a BTR3 in the car, but then I wouldn’t need the M9. In any case I’m finding my phone more useful for music on the go in the car, especially with streaming services like Tidal, so I’ve pulled the M9 off car audio duties now.