Steam deck docked surround sound works great--in tests only

[deedaleet]

I have a sonos arc 7.1 system that works great. No problems with setup.

Docked deck in desktop mode, selecting the HDMI audio out, profile 5.1 or 7.1, I can "test" the audio right in the OS and I get all channels, including surround, no problem. Sonos reports Multichannel PCM 7.1. Great!

Start game that has surround in desktop mode? No surround. All channels downmixed to stereo, though sonos still reports Multichannel PCM 7.1.

Start game that has surround in gaming mode? No surround. All channels downmixed to stereo, though sonos still reports Multichannel PCM 7.1.

Play any Youtube surround sound test (or confirmed surround audio/video file)? No surround. All channels downmixed to stereo, though sonos still reports Multichannel PCM 7.1.

Interestingly, while playing a surround test file (or Youtube vid) I can go to the OS audio options again and test the surround channels successfully! The downmixed audio will continue to play stereo only, while I clearly hear OS test tone/voice out of the surround speaker(s) I select.

I have tried:

Different HDMI cables, different inputs, different docks (1st and 3rd party), messing with the OS audio settings (5.1 vs. 7.1, "pro audio", etc). Steam deck and dock are latest software/firmware. Restarting deck, TV, dock, etc.

Conclusion:

Surround sound is obviously working. Sonos reports expected input, OS-level multichannel tests function perfectly. There is SOMETHING software going on here, like SteamOS force-downmixing all audio regardless of channel count.

Anyone actually has this working, please let me know.

TLDR:

Surround sound output on steam deck certainly works on OS level, but not for any games or media.

[gachnar]

I'm having this exact same issue. Different receiver, getting surround in tests in desktop mode, but games won't do more than stereo.

[deaddoof]

Desktop mode and Game mode are separate desktop

I would recommend you check your game mode

Add konsole as a non steam game.

Change back to game mode

Open konsole

Enter

wpctl status

In sinks, it should list 7.1 or 5.1 HDMI surround if it's selected. The classic two channel should show up as just HDMI.

You can run the command in desktop mode as a comparison. Just open up the konsole.

[HappySpaceInvader]

There was a SteamOS release some time in September 2024 that completely borked surround in games when docked.

There’s not really anything you can do about it unfortunately, but there is this GitHub thread discussing the issue: https://github.com/ValveSoftware/SteamOS/issues/1639#issuecomment-2660987283

Seems like something that was picked up in beta and not fixed for the main release.

Unfortunately, the supposed fix in that thread did not resolve the issue for me. My Sony surround system reports 7.1 surround, but all games launch in 2.0 stereo.