When pavucontrol is not running, it depends on sample rate of playback, whether or not the sound is audible:
$ speaker-test -r 48000 not audible $ speaker-test -r 47999 audible -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1829364 Title: Will not play sound via HDMI unless you run pavucontrol first To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1829364/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs