danboid wrote: ↑Tue Dec 27, 2022 1:11 am
I know how to use a Linux box as a BT speaker for a phone. I've got that working for both PA and ALSA. I'm wanting to use an Android phone as a BT speaker for another phone.
Yes, you've said this already.
For the phone to receive BT audio like you want it must expose A2DP Audio Sink. Does your phone do this? Don't know you won't tell. If it doesn't it could be because the hardware doesn't support it, manufacturer chose to not compile support into system, chose not to support profile or any and all combination of these. Seems like it is not something normally supported on Android Phone. I only ever see Audio Source on phones I've had.
Since you actually want the audio sent to stereo and not the phone BT audio receiver device as suggested for you is a simple solution.