Hey @the_jsg, welcome to the community.

Yeah, this should be possible. As long as your PCs sound card can pass a 5.1 signal to your TV over HDMI your TV should have no issue sending that on to Sonos. I don’t have the equipment you listed myself, but from what you’ve mentioned here I don’t see why it wouldn’t work. I have, however, used my gaming PC with my Sony TV + Playbase with surrounds and that worked great. I’ll leave this open for anyone who may have first-hand experience with this setup who can provide more detailed feedback 

Hi @the_jsg 

You’ll find that you’ll need the device supplying the game audio to encode to Dolby Digital in real-time.

Although some Sound Cards allow this (Creative have a feature called Dolby Digital Live), it’s likely that your graphics card is in fact supplying audio via HDMI. I don’t know of any graphics cards that support live encoding of Dolby Digital, but there is a hack that can achieve it. It’s not overly user-friendly. This post has some more information:

If you use only the PC (and don’t watch TV), you could connect the Arc via optical directly to a sound card delivering Dolby Digital Live without the need to hack drivers. If you do anything on the TV other than use it as a PC monitor, however, this would get annoying quickly.

Im sort of on the same boat, but Im not using a TV. Im using my UltraWide monitor.

I had a Sonos 5.1 (still have) system with a PlayBar  (worked fine with the OpticalCable) but I just set up a new Sonos system with an Arc but I cant seem to get the audio from my PC to the new system with the Arc.

Theres an HDMI/OpticalAdapter included but from a thread I read somewhere Im still not sure if this adapter is for this sort of situation or if its for something else. Can anyone clarify if this HDMI/OpticalAdapter should work? Right now I dont get any audio with this setup.

If this adapter doesn't work in this scenario what can I do to get this to work? Do I have to purchase something else from Sonos or another third party?

@Corry P thanks for your reply!

I’m still learning a lot about audio formats, what passes what and when, etc.

Is DD/DDL a prerequisite for LPCM? Most games use LPCM as the source. So, if that’s the case, then the issue with DD/DDL wouldn’t be an issue, right? And things should work pretty normally whether using HDMI or Optical?

Appreciate your guidance and education!

Hi @Manuel Gonzalez 

You cannot connect a source device directly to the Arc via HDMI as the source, by definition, does not use HDMI-ARC, which is on a different physically wire in the cable from source audio.

You will need to use the optical converter, and the computer’s output must be in either stereo PCM or Dolby Digital 5.1 (or 2.0) - the optical link cannot handle LPCM or Atmos and the Arc cannot decode DTS.

Hi @the_jsg 

DD/DDL is compressed audio - after it’s decompressed, it’s handled internally as LPCM (this is standard for all digital audio equipment). The problem is in transporting it. So, games work in LPCM, because that’s how digital audio works. You then need the computer’s sound device to compress the LPCM to DD for transporting to the Arc, which will then decompress the DD back into LPCM prior to mixing and processing. With optical, all you need to worry about is encoding to DD in real-time. As I mentioned just above, HDMI will not work without a TV to put the source audio onto the ARC line. 

@Manuel Gonzalez & @the_jsg 

If you want to connect an Arc directly to the PC with HDMI, you will need an “HDMI to optical audio extractor” adaptor. Conversion to Dolby Digital on the computer will still be required.

Note: Surround sound movies on a PC will work without issue as the audio comes pre-compressed and is typically taken from the file and handed straight to the sound card device for (untouched) passthrough. It’s just Games that need the audio to be encoded to DD in real-time.

The above information is totally wrong by the way. Corey and James don't appear to have any experience with a PC connected to the ARC because the above information only applies to the Playbar not the ARC

just run Hdmi from your PC to TV and set the TV audio to pcm pass through. You don't need a soundcard

My statement above was meant for Manuel Gonzalez, who reported having a Monitor and not a TV. Monitors do not have HDMI-ARC.

ah ok. For a non eARC device like a monitor yeah he’d need a way to split and video and audio as you mentioned. I was more getting to the first coupe posts replying to jsg about needing to use a soundcard to convert audio into dd live and an optical cable etc - which won't be needed since his TV supports hdmi 2.1 and eARC so he can simply run one cable from pc to tv and one cable from TV to the Sonos ARC. The post also contained a link to a post from another user where they quoted me however that information is 10 months old and is no longer valid after Sonos released the LPCM update for the ARC, audio pass through became much more simple since that update, it made my life a lot easier 

Hi @Naekyr 

As the OP mentioned a surround-sound system, I presumed they were after surround-sound output - I know of no video card that supports this via HDMI, compressed as DD or uncompressed as LPCM, without the drivers being hacked - though I admit that my own research was a while ago and specifically for nVidia. Here’s a related post from nVidia forums: https://www.nvidia.com/en-us/geforce/forums/geforce-graphics-cards/5/122325/forcing-51-audio-to-tv-via-hdmi/

Wanted to leave this here in case anyone has or hasn’t tried it but seems this might be the easiest route to go:

https://www.tenforums.com/sound-audio/148247-force-hdmi-carry-5-1-dolby-whatever-5.html

We will see if I am able to get it to handle 5.2 as this fix is for 5.1. Hoping the way Sonos handles dual subs will make it easy-peasy but will try and test myself once my full system arrives.

Thanks for everyone weighing-in.

Reading this thread has left me confused; I’ve had very different experience. Enabling LPCM 5.1 was actually the easiest part of my struggles, as my ultimate goal was Dolby Atmos.

Getting LPCM 5.1 to the Sonos Arc with just a PC and TV, you’ll need the TV to be configured for eARC enabled, Passthrough and for HDMI Audio Input to be set to PCM. At this point, speaker setup for NVIDIA Audio will show you only Stereo as an option. That’s because the EDID info communicated from the TV is saying it only supports that, but LG announced it is able to do LPCM passthrough (so, not sure what’s going on there). You need “Custom Resolution Utility” (CRU) to edit the “Extension Block → Audio Formats → LPCM” channels (currently, you’ll see it’s set to 2). Up it to 6 (5.1), restart the PC and you’ll see 5.1 now available as a speaker setup option. That’s it.

Now Atmos is the real problem. For that, you need to purchase Dolby Access, and change the TV’s HDMI Audio Input back to Bitstream. Change the speaker setup to the “Dolby Atmos for home theater” option, and you should be good to go, according to some CX owners I’ve spoken with.

However, I have a B9 and have had audio drops constantly when Atmos speaker setup is enabled, even with non Atmos content coming across as Dolby Multichannel PCM. I tried everything, and determined dropping refresh rate helps in certain instances, but ultimately, there’s either a problem with B9 passthrough or my specific unit.

I ended up getting the HD Fury Arcana, and having two HDMI out from the NVIDIA GPU; one for 120Hz, G-SYNC enabled display experience straight to the TV, and the other going to the Fury, which has its audio out to the Sonos Arc. I have no audio drops now with any Dolby format.

Really sad Sonos decided to make Arc incompatible with standard HDMI output devices (leaving the Fury as the only option, which is eARC capable), though I have a sneaking suspicion it could be fixed with firmware (have a “PC” mode or something).