Unable to use 5.1 surround sound in game

[Pure1]

Hi,

My PC has 5.1 surround sound using optical cable, but when I play games I am unable to enable the surround sound. Does anyone know how I can fix this?

[codesplice]

@Pure1 Do you have a Stadia Pro subscription? 5.1 support is only available with Pro.

[Pure1]

Yes, I signed up today and am on the one month trial

[codesplice]

@Pure1 Hmm, 5.1 should be automatically enabled when playing on a system which supports 5.1 sound. Does the Stadia menu indicate that 5.1 is activated?
https://support.google.com/stadia/answer/9595943

[Pure1]

It said it was disabled by hardware. 5.1 works when I play games like World of Warcraft on my pc though 

[codesplice]

@Pure1 I checked with someone else and found out that Stadia uses an uncompressed PCM audio stream which unfortunately won't work with an optical connection, which requires a Dolby bitstream to support surround sound. It just doesn't have the necessary bandwidth for the uncompressed audio.

It sounds like you'd need to use an HDMI connection to get 5.1 surround sound to work with Stadia.

[Pure1]

OK, thanks. Do you know if there is anyway I could get my PC to convert it? Or if I used 6 wires from my motherboard? Or does it have to be HDMI? 

[codesplice]

@Pure1 To be honest I genuinely don't know. Speaker setups aren't really my strong suit. From a bit of Googling though it does sound like HDMI is probably your best bet for outputting an uncompressed PCM signal - optical and standard typically won't be able to keep up.

[Xeperu]

Are you talking about using the 1/8" (headphone-style) ports built into the motherboard on the back of your PC tower?  I am an audio engineer, always trying to learn more about surround sound, and frankly I have no idea what that protocol is officially called or if it utilizes PCM, Dolby, DTS, let's you pick, or what.  I would be so curious to know; if anyone who does sees this I hope they reply.

To my knowledge, optical actually is capable of carrying up to 7.1 PCM.  I'm using a Sound Blaster X3 and trying to figure out how to get it to output PCM like it says it can in the ads.  Once I hooked up optical to my AVR from the X3 it took me a few minutes of random button pressing and/or holding to make it produce sound, so I probably just have to keep digging through X3 manuals, forums, the sound card's proprietary software app, etc.

I don't know, maybe you figured it out by now or tried something different.  I just wanted to put my surround sound question out there and offer my knowledge that there shouldn't be a problem with optical cables running PCM (I'm pretty sure I accomplished this on a friend's home theater setup) - the problem would probably be somewhere in the audio hardware's software settings.  Or maybe the option isn't there.  Or maybe it's supposed to be automatic but isn't smart enough to sync with Stadia.  Just gotta keep digging...

[RXShorty · Accepted solution]

Hi @Xeperu,

Thanks for jumping in! I had some issues with the 5.1 setup on multiple systems but as it turned out: 

PCM can carry surround sound, but it cannot do so over an optical cable—the optical cable can only carry stereo PCM (using TOSLINK, the home stereo standard). To send surround PCM, you'd need to use an HDMI cable (or alternatively displayport on a PC), which carries both the video and audio signal. [Source]

So to get Stadia 5.1 surround on your PC there is no way to achieve this with a optical cable I am afraid.