Recently I did a clean install of Kubuntu 24.04 from 22.04, and have encountered several strange issues with my sound only partially working - but what fails depends on the context. If I am playing a mp4 from my local drive the center channel does not work at all so no dialog can be heard but all the music and sound effects are there unless I change the device from (Digital Surround HDMI) to (Digital Stereo HDMI).
Running the speaker test in System Settings/Hardware/Audio only the Left Front channel works correctly, the Right Front channel can be heard but is muffled and barely audible, and nothing from Front Center/Rear Right/Rear Left/Subwoofer
However, if I am streaming something on Hulu/Netflix the surround sound appears to be functioning perfectly. Yet, if I'm streaming something on YouTube Front Left works, while Front Right plays through the Front Center, but none of the other speakers have sound.
Other devices connected to the Surround Sound continue working correctly through all 6 speakers, and 24 hours ago all of the above contexts worked perfectly using 22.04. I'm used to having to manually retask the jacks on the onboard sound during a clean install because it's a unique Bang&Olufsen setup with 4 internal speakers and a powered subwoofer, but those settings do not affect the audio through HDMI which uses a different sound profile.
The strangest part is a local mp4 (in VLC) plays perfect 5.1 surround only when PulseAudio is set to a 2.0 HDMI device profile, but everything else only plays the Front Left on that profile until it's changed to the 5.1 HDMI profile where everything works except the Front Right, and no matter what profile is selected only Front Left works in the Sound Test.
HP Envy m7 - Kubuntu 24.04 - 6.8.0-45-generic (64-bit)