No audio after new case, how do I set the audio device back to HDMI?

Hi,

weird issue for me: I run Ubuntu 16.04 with kodi 17 rc2 and configured everything according to this minimal Ubuntu guide. After a few small hiccups everything worked fine. I had a very small case and wanted to add my hard drives, therefore I bought a new case. After transfering my mainboard and plugin in the front-panel audio panel, my audio stopped working in Kodi. I’ve now tried to unplug the front panel, but “the damage is already done”.

Now I’m a beginner with everything linux, and all those xsession and container and what not is still a bit confusing to me. However, when I exit Kodi with Alt-F4 and get into my root account in my xubuntu session (how do I get into my htpc account with no password?), I could open the Sound Panel Configuration, switch the device to HDMI and got the sound working. But this setting is only applied to the xubuntu session with my root user, not to kodi and kodi-openbox. In Kodi itself I can’t select HDMI, only PulseAudio default etc.

I guess this is really simple and doable with a single command, but I’m don’t know what I’m doing yet. Can you guys help me?