LG OLED C9: PC audio via ARC (not eARC) Stereo Only?

VincentHanna

VincentHanna

VincentHanna

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So for years I've been using my Denon AVR to do video pass-through to the TV from my PC GPU. This allowed me to listen to high quality audio, such as movies supporting True HD/DTS-HD Master and more recently, Dolby Atmos.

The OLED C9 has now been updated to support Nvidia G-SYNC over HDMI, so I've now plugged the HDMI output from my 2080ti - directly in to the TV, bypassing the receiver completely.

G-SYNC is working fine, but now to get sound I am forced to use the audio return channel (arc) and the only option under Windows sound is 'Stereo'

Is that the best I can hope for? I assumed it would do 5.1 surround sound at least.

I know I can hook up an optical cable, but that will still only give me lossy 5.1

AVR is a DENON X3200W so it only supports HDMI 2.0 and came out before eARC was a thing. Upgrading the AVR isn't currently an option as I am waiting for 2020, when Denon will likely support HDMI 2.1
 
Radox-0 said:
Yes but problem is he will not get 5.1 etc or higher format's if going from GPU to TV then TV to AV receiver via ARC.
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Exactly this

Yes, ARC works - Sound comes out through my speakers. But Windows only lets me select Stereo sound and though I'm sure I can use some trickery to make a 5.1 surround sound from a stereo signal, it's not the same as proper surround sound.
 
Radox-0 said:
Sound does indeed work over DP, but not sure how an adaptor would play out. Could be worth a try with a DP to HDMI cable as if it does work, would be a solution and one that I use (One cable to TV / Monitor and another to AV receiver)
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I wonder if this might work - bit pricey though:
https://www.belkin.com/uk/p/P-F2CU038bt/

sHo0sH said:
Have you got the latest sound drivers for your motherboard? https://appuals.com/channel-surround-sound-not-working-in-windows-10/
Seems that there is an issue in general with this by the looks of it.
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I'm not using the soundcard for this, this is pure audio from the GPU
 
soulstoner said:
Made an account just to reply with my findings on this.

The LG C9 has a bug where it will not process LPCM signals directly through eARC or ARC. The reason you're seeing those 5.1/7.1 options is because the receiver is capable of processing that signal, as it is bypassing the LG C9 entirely and just passing video.

LG has announced that it will be issuing a firmware update in the second quarter of 2020 to resolve this issue. It feels like a long distance away, but I guess it's better than nothing.
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Thanks for registering, I really appreciate it and the feedback.

Yes Q2 2020 does seem miles away, but at least they are addressing it.

I'm down to my last throw of the dice now - I've ordered a 'Displayport to HDMI' active adaptor, hoping I can send that signal from the GPU to the AVR and get decent audio again, whilst still having the HDMI connection direct to the C9 with G-SYNC.

Kind Regards
Gary Ambrose
 
soulstoner said:
I also tried that, along with a USB-C > HDMI adapter > AVR. For whatever reason, I was still unable to pick 5.1/7.1 when outputting via that connection, which I verified in sound options that the AVR was the default sound device. I am not sure why, but I'm curious if you have better luck.
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Same as you.

I'm going to hazard a guess that Nvidia will only output the full range of audio options via HDMI.

I notice ASUS do a Strix 2080Ti with 2x HDMI ports - Obviously i'm not going to go to those sorts of lengths to get decent audio back, but maybe somebody who has one can confirm that both HDMI outputs offer the full range of audio options?
 
What AVR do you have @MassiveJim

I should mention that I still had to set my Windows 10 to 'Dolby Atmos' (I already had the app) and that's when the receiver picked it up and showed the 'Dolby Digital' logo and then also D+

Either setting the TV HDMI sound to auto or enabling eARC seemed to make the bitstream work better.
 
Last edited:
james.miller said:
The solution appears to be a passive adaptor. More here:

https://www.avsforum.com/forum/26-h...o-receiver-through-dp-hdmi-adapter-cable.html
Click to expand...

UPDATE

It only flippin' worked!

Bought a basic 'Display port to HDMI' cable, plugged it in to the spare Display Port output and voila - All the multi-channel surround options:

DPtoHDMI_01.jpg
DPtoHDMI_02.jpg


And thanks to a certain generous rain-forest return policy, I can get back the the money I spent on a MSI NVIDIA GEFORCE GTX 1030 and my 2080Ti is back to 3.0x16 mode :)
 
Correct. I've been using it for 6 weeks and it works great.

The minor downside is that the AVR is detected as another display/monitor (I 'Extend' my displays) so occasionally things will launch on that 'monitor' and I have to faff around slightly.
 
Hello again. Obviously I solved my issue previously

But I was just wondering if I had an eARC AV receiver, Would the TV actually passthrough the full audio signal to the AVR so I could free up a connection?

Or would it still be detected as Stereo 2.0?
 
It's been a while since I did this and I since have a modern AVR with eARC.

Are you extending the display in Windows? I'm sure that has something to do with getting the surround options.
 
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