System sound keeps changing.

I have a really annoying issue with W11 sound settings. There are 3 audio output settings available on my PC:
Realtek Digital Audio - Realtek High Definition Audio
Speakers - Realtek High Definition Audio
VX3276-QHD - NVIDIA High Definition Audio
The speakers I use are on my monitor, and via PC audio output to an external amplifier and speakers.
I may have any one of these selected and the audio is working correctly. However, if I do not touch the PC for maybe 30 minutes or more, the next time I try to play audio, there is no sound and I have to change the setting to one of the other options and then it works depending on which option I choose. That sounds very confusing. As an example - the audio is set to SPEAKERS. I leave the PC for a while and when I return there is no audio. I then change to Realtek and I have audio again. I once again leave the PC for a while and then return to no audio again. I then change settings back to Realtek but still no audio, so instead I select VX3276 and I have audio. There appears to be no pattern as to which output to select - it appears to be random which output I should select after every time it changes itself.
That still sounds confusing but there it is. So there are really 2 questions:
1. Why do the settings change on their own after a delay?
2. Why does each option appear to work sometimes but not always.
I have tried to see a pattern as to which options work but it seems to be random which will work and which will not.

The same thing happens to me at times and I have only 2 outputs, Realtek audio (external speakers) and Intel Display audio (my monitor speakers)but I've mostly noticed it at boot or after restart but not every time. Waking from sleep seems OK. It's aggravating but only happens 2 or 3 times a week. I haven't tried disabling Intel Display audio in device manager. I'll do that to see if it will stick on Realtek.

The Nvidia and Realtek drivers may be conflicting each other. They both conflict with my Creative driver so on-board audio is disabled and I always deselect Nvidia HD Audio when I install the latest driver. Just a thought.

If the computer is connected via HDMI the default is to redirect audio to the HDMI output. What happens if you change it so it outputs audio from Realtek speakers anyway? If computer sleeps and you wake it, it will try to redirect audio to the HDMI output again, unless you have manually set it to Realtek speakers. Have you tried to manually download latest Realtek audio driver (not from Windows Update)?

I can't speak for OP but in my case Realtek driver is updated and set as default sound device. I've not spent a lot of time troubleshooting why the Realtek sound on 2 machines at times switches on its own to display audio since it doesn't happen often. I thought (and still think) it may have something to do with when I use remote desktop but I have a pretty weird setup so it may have something to do with that as well.

When I use RDP from either machine the sound output switches to "remote audio" on the accessed machine. When I disconnect the RDP connection it is supposed to switch back to the default Realtek. I'm usually not listening to audio when I do this so I'm not aware of it until later when I do play audio,.

My setup is outside the norm so there's a lot of room there that could cause the issue as well.. Windows 10 PC and Windows 11 PC each connect to its own set of powered external speakers. Windows 11 connects directly to the monitor using hdmi, Windows 10 connects to the monitor using DP. Sometimes instead of using remote desktop I will directly use my secondary computer . To do so I switch video input to the monitor using the monitor's controls and a switch (not a kvm) that switches the peripherals (one mouse, one keyboard, one wired printer and an external drive) between the 2 PCs.

I've now disabled Intel Display audio on Windows 11 and Nvidia display audio on Windows 10. I'll see if that doesn't solve the problem.

I use AnyDesk or TeamViewer to access my PC and the audio output remains Realtek speakers when I disconnect.

spapakons said:

If the computer is connected via HDMI the default is to redirect audio to the HDMI output. What happens if you change it so it outputs audio from Realtek speakers anyway? If computer sleeps and you wake it, it will try to redirect audio to the HDMI output again, unless you have manually set it to Realtek speakers. Have you tried to manually download latest Realtek audio driver (not from Windows Update)?

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The computer is not connected using HDMI. The monitor is connected by Display port, and the external speakers/amplifier just use the 3.5mm jack on the back of the PC. The driver is the Realtek driver.

Could audio being redirected to the DP? Have you tried to manually change it to Realtek speakers? Does it stay in Realtek speakers once you manually set it?

spapakons said:

Could audio being redirected to the DP? Have you tried to manually change it to Realtek speakers? Does it stay in Realtek speakers once you manually set it?

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Whatever manual change I make does not stay that way. Everything works fine when set manually, but if I leave my PC on and return to it after say 30 minutes, the outputs have changed on their own. For instance, the external speakers via the 3.5mm jack are working on SPEAKERS. When I return, the audio has stopped and I then have to change from SPEAKERS to REALTEK for audio to start again. If I then leave the PC again and return later, the REALTEK audio has stopped and I then manually change back to SPEAKERS again. The PC has remined on without entering sleep mode. It is as if the output changes because it is not being used for 30 minutes.

Check your Power Settings and remove any sleep or time out. Allow only the screensaver or just blank the screen after some minutes. Don't allow the computer to sleep or the hard drive to sleep or whatever else. See if that fixes your issue.

sydh said:

It is as if the output changes because it is not being used for 30 minutes.

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Could be the case. I've been using Sound Keeper since Win 10 to keep my soundbar awake.