Surround 5.1 audio not working for games (only stereo output), setting doesn't survive reboot.

[DNKROZ]

Your system information

• Steam client version: 1726256783
• SteamOS version: 3.6.13
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: Yes
• Have you checked for updates in Settings > System?: Yes

Please describe your issue in as much detail as possible:

Hardware tested is a Steamdeck OLED 512 GB version using the official dock (sw updated) and a direct HDMI connection to a Marantz SR7011 receiver (no ARC being used), 5.1 audio has been tested and used multiple times, daily, with several other elements (Apple TV, nVidia Shield, PS4, PS3, Nintendo Switch... and so on...) and it's working fine so I rule out the receiver and cable completely.
With SteamOS current stable version audio is 2.0 by default, I can get to Desktop Mode and change the audio properties of the current device being used (HDMI connection) and change those properties from Stereo to 5.1 mode, I can also test the individual output speakers and they work perfectly fine, when I get to Game Mode I see that the AV receiver is currently getting a LPCM 5.1 signal and all speakers are active (and also LFE channel), when I launch a game (I've tested with Alan Wake 2 (Epic), RDR2 (Steam), Cyberpunk 2077 (GOG) I get a 5.1 sound (RDR2 and Cyberpunk 2077 need to configure the audio in their settings but Alan Wake does this automatically), if I reboot the Steam Deck I'm still getting a LPCM 5.1 signal and games still function the same with the expected 5.1 audio.

Using SteamOS current Beta (and second RC, this is the thing that worries me most) I get the same 2.0 audio by default but redoing the same steps never end in a 5.1 working audio for games and it does not survive a reboot (2.0 signal after reboot).
I can get to Desktop Mode and change the audio properties to 5.1 and the speaker test works perfectly fine but no 5.1 audio in any game (only stereo and even if the audio signal is still being identified as 5.1), there is no difference if the game is launched from Game Mode or Desktop Mode.

Steps for reproducing this issue:

1. From Game Mode get to Desktop Mode (since we don't have a way to change this from the Game Mode UI).
2. Select the correct audio device at audio settings and change several times from Stereo to 5.1 (for good measure) and leave 5.1 selected.
3. Go to extended properties (top middle icon if I remember correctly) and click the "Test" button, verify that every speaker works as expected (this works for me)
4. Launch any game from Desktop Mode or go to Game Mode (check the signal at the AV receiver and you should see a LPCM 5.1 audio signal) and launch any game and you 'll get Stereo output even if the output signal is still 5.1, doesn't matter if you configure the game with 5.1 audio (RDR2 or Cyberpunk 2077)
5. Downgrade to Stable version and retrace these steps and you should get a 5.1 signal AND 5.1 audio in game everytime.

[Gausak]

I have exactly the same problem, in stable it works correctly and even holds up after a reboot, but if I update to beta or preview, the surround sound is lost and it only outputs in PCM 2.0.

[DNKROZ]

Thanks for the input @Gausak , can you check if your receiver still gets a 5.1 LPCM signal? (I get a visual feeback in mine using the "info" button, with signal, active speakers for that signal and current active speakers), I think this is important, because the output signal seems fine, but I only get Stereo output from the two front speakers.

[Gausak]

On the receiver it shows PCM 2.0, it is the only difference with respect to your error, I suppose it is a question of how the Steam Deck is connected to the AV (in my case I use a jsaux and fiber optic dock, not via HDMI)

[DNKROZ]

I see, thanks for the input, what signal do you get when you are in stable?, as far as I remember, 5.1 LPCM signals are only available via HDMI connections and I can't get AC3 or Dolby or anything aside that, maybe it uses compressed formats when only fiber optic is available, I'm just curious.

[Gausak]

I think it outputs LPCM 5.1, nothing from Dolby or similar, right now I couldn't tell you 100%

[DNKROZ]

Thank you, lets see if anyone has any more info or workaround for this issue. Regards.

EDIT: Confirmed broken also on 3.7 update track

[ahydronous]

@DNKROZ not only that, many TVs and receivers <2022 only support ARC which doesn’t do 5.1+ PCM passthrough, because there isn’t enough bandwidth. You need eARC for surround PCM passthrough.

It would be nice if Valve added a “Dolby” purchase to the Steam store that unlocked Dolby Digital Plus, maybe even Dolby Atmos compression. Although honestly that should have been folded into the purchase price of the Deck. It’s only a few dollars of licensing fees, and now instead most Deck owners with gear from <2022 are boned.

[DNKROZ]

I've just updated to 3.6.19 stable (you know... for science) and the bug is still present, no way to recover 5.1 audio now (since you can't roll back from stable) :(

[JorgeRamirezDEV]

SteamDeck Oled 512
Steam OS 3.6.19
JSAUX Dock
LG C1
LG SC9S connected through EARC

I’m facing the same problem. In desktop mode, it correctly detects the eARC soundbar, and with the built-in testing sounds, I can confirm that everything is working fine. However, when switching back to game mode, games that worked perfectly on the previous stable build (3.5.X) are no longer working.

[aemiliu5]

Can confirm as well. This should be easier to configure with a dedicated audio channel option in Game Mode, without needing to go into Desktop Mode.

[cbodenst]

Can also confirm this. As I use the Steam Deck as my main rig (+geforce now) this is a big deal breaker :-(
On 3.5.x everything was fine.

[remoteman213]

Same issue here... looks like they've updated how the audio sinking works with the latest update.
#1671 (comment)