Issues with audio over HDMI

I’m trying to run my TV off my desktop via an HDMI cord to the other side of the room, and while the video side is working great, I can’t get audio to go through the HDMI connection to the speakers that are attached to the TV. Everything seems to be correct, I just… don’t get sound. Here’s the general state of the situation:

  • The HDMI cable is 25 feet, so it’s long but not overwhelmingly so; the HDMI source is my two-month-old RTX3060
  • There is an HDMI device available in the audio settings; it just doesn’t result in any audio output when it’s selected
  • I get audio out of the TV-attached speakers if I use the smart TV functionality to go to Youtube or wherever
  • I get audio out of my desktop speakers just fine if those are selected
  • It’s not just the program I’m using to test, as the settings panel’s test option also produces no audio

Interestingly, sometimes when I switch to or from the HDMI output in the audio panel, it causes the displays to all refresh. If I run speaker-test on that device, it causes the TV specifically to continuously refresh.

I did briefly get audio out of the TV speakers initially; I checked the box to create an ‘all audio outputs simultaneously’ device and that got output out of both the desktop speakers and the TV speakers. I decided not to use it because the audio wasn’t quite synchronised, but when I switched off of it the TV audio just ceased to output at all through the HDMI connection and hasn’t come back, even after a reboot.

Any idea what’s going on here? Again, as far as I can tell all of the various devices are all set up and available correctly; I just don’t actually get sound through the HDMI connection.

(this is the KDE version of Manjaro; kernel version 6.1.26-1.)