Once you open up an application, such as VLC or MPV or maybe even Chromium and you want to choose which audio output device is going to be used, you would do the following:
- Open the application you want to use and begin playback
- Check for the 'speaker' icon on your toolbar (in my case, bottom right of screen in tray)
- Click on speaker
- In '18.04' release you will see the application open and you can click under it to open the audio options for that application. Once the mixer opens, select the box next to 'audio stream on' and select Atom/Celeron/Pentium Processor x5-E8000/J3xxx/N3xxx Series or similar 4a. In 18.04 you will need to fix the setup of Pulseaudio: speaker-test -D hw:0,X -c 2 -r 48000 (where X is 0, 1, 2, etc.)
If one of the selections produces sound, then add the following lines to the end of /etc/pulse/default.pa
load-module module-alsa-sink device=hw:0,X (where X is the number from above test that worked)
set-default-sink output 0
Next, in the volume control panel set the device profile on the configuration tab to 'Off'.
Restart/reboot.
Source: https://dlidirect.com/community/champ/forums/1778-atomic-pi-user-forum/topics/4888-pulseaudio-not-working
4b. If you in '18.10' you can simply click the speaker, choose 'Mixer' at the top of the pop-up and switch the audio stream as noted without having to fix Pulseaudio.
- This also applies to using bluetooth audio, once you have paired the device, you will need to go through steps 1-3 as above, but instead select your headphones / speaker from the list.
Cheers!