Switching output sink(?)

[Mandar Mitra]

Hello,

I can use the mate volume control applet to switch between the builtin speakers 
on my computer and an external speaker connected via bluetooth. Other 
applications like Firefox and mpv (played from the command-line) send the 
output to whatever is currently selected as the sound sink, but emms seems to 
always send output to the default builtin speaker, even when a bluetooth 
speaker is connected and selected in the volume control applet.

I can probably use the discussion here

https://askubuntu.com/questions/71863/how-to-change-pulseaudio-sink-with-pacmd-s
et-default-sink-during-playback

and cobble together an elisp function to run the necessary shell commands, but
don't know how to integrate this into emms.

Could you please give me a hint or two -- maybe point me to which .el files I
should look at for more info? Or let me know that this is not easily doable?

I've just upgraded to EMMS 6.0, but this happened with earlier versions as well.

Thanks,
Mandar.