After almost two years of dealing with this issue, I think that I finally found out what is causing the random loud static noise coming from my soundcard Xonar STX.
The issue is regarding the Xonar STX soundcard when using chromium-based browsers, such as Google Chrome, Microsoft Edge or Brave, on both Windows 10 and Windows 11.
Randomly, what seems to be out of nowhere, an extremely loud static noise occurs. It could be when I just open one of these browsers, or simply press play on a video/music, the loud static noise might randomly appear. It is shockingly loud.
Once the static noise appears it doesn't go away by itself, I have to change the audio output within the Xonar driver, for example, from headphone out to speaker out. I noticed that the static noise only appears when starting a video or opening the browser, so never in the middle of a video or in the middle of a song etc. (maybe a chrome-media suspend feature issue?)
Anyway, since the past few weeks im using Firefox and I noticed that this issue does not occur anymore. This leads me to believe that it is very likely that there is actually a problem specific to chromium-based browsers in combination with the Xonar STX driver. It's quite a sporadic problem, but it can be very disruptive.
For now I will keep using Firefox and report back if the static noise will appear using Firefox.
Meanwhile, how likely is it that someone @asus will look into this potential Xonar driver issue?