5.1 surround only after restarting pulseaudio

I added/uncommented in /etc/client.conf and /etc/daemon.conf the setting default-sample-channels = 6
pulseaudio is not deamonized.
I use pavucontrol. The profile is set in the Gui to Analog Surround 5.1 Output (which is what I want)

I only have stereo sound unless I restart PA using pulseaudio -k (after I started some music), which is pretty annoying. Why is that, and what do I have to change that it works out of the box?

I’m on arch btw