I use Debian with the notion (ion3) window manager and manage audio with a bunch of different tools.
Sometimes I forget how to configure something so this is a reference for myself:
Add user to audio group:
usermod -G audio
pactl exit (run as user, stops pulseaudio)
pulseaudio (run as user, starts pulseaudio)
To send output through HDMI, choose Audio | Audio Device and select an HDMI channel.
Alternatively use pulseaudion / pavucontrol to send VLC output through HDMI.