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EF950V - No 5.1 Channel Audio Via HDMI From PC

F1aw1ess

Standard Member
I have a 980Ti graphics card with an HDMI 2.0 cable coming directly from the back of the card into the HDMI socket 1 on the TV.

It recognises the resolution correctly @ 3840x2160 @ 60hz however when I change the sound output in Windows 10 to the LG TV, I only have the option of 2 channel stereo sound.

I know the card works okay because if I use my AV AMP's 4k passthrough I can select multi-channel PCM etc, the downside is the passthrough is 4k @ 30hz which is a deal breaker.

Anyone know why it wont give me the option to select 5.1 out (using optical) in Windows when I connect the HDMI directly to the TV bypassing the AMP?

Cheers
 

Thug

Moderator
I had a similar problem with my blu Ray, try to set your tv to 'internal speakers + Audio out' then 'digital sound out' set to auto.
Also I might be totally wrong as I am new to this.
 
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F1aw1ess

Standard Member
No luck. I didnt have it set as you suggested, I had the internal speaker off completely but either way I still dont get the option to select 5.1 in Windows so therefore the TV only outputs 2 channel.

Here's a screeny of my sound settings on the PC

2channelsound.jpg


When I go through the AMP, I get max number of channels supported is 5 or 7.

I'm guessing but it looks like the problem is to do with how the NVidia card is handshaking with the TV, not getting the correct number of channel info back and in turn they just arent selectable?

Any ideas would be much appreciated :)
 

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spyshagg

Novice Member
Dear op,
I think you are mistaking raw output channels with encoded channels.

Dobly Digital and DTS use those two PCM channels to carry their 5.1\7.1 encoded sound.

So, you do have 5.1 sound in your computer. BUT only if the application (some games, vlc, mpc, kodi, etc) supports the aforementioned encoded sound (DD DTS and lossless variants).
 

F1aw1ess

Standard Member
Thank you, I didn't know that DTS and DD were 2 channel raw however it still doesnt appear to output in 5.1 which ever way I try it.

I have tested it with TED 2 using VLC player which comes through my AMP as 3/2/.1 EX Off when I use the HDMI to the AMP in, yet if I go via the HDMI from the GPU to the TV and then optical from the TV to the AMP, I only get 2/0/0?
 

Ian_S

Distinguished Member
Dear op,
I think you are mistaking raw output channels with encoded channels.

Dobly Digital and DTS use those two PCM channels to carry their 5.1\7.1 encoded sound.
Sorry that's just plain wrong unless you're talking about Dolby Pro-Logic/Surround.

For the OP....

Where is the optical out? On your computer or on your TV?

If it is on the TV then your PC knows nothing about it, and I'm not sure any TV's support passthrough of a multi-channel audio stream to their optical out via HDMI input.

The screen you show for the LG TV properties is correct, in that it only has two speakers, and supports 2 channel audio inputs only from there. When you connect to your amp, it will report that it supports more formats and channels, but like you say you have a restriction on frame rate.

What is the Realtek HD audio device there? And Likewise, does the soundblaster have optical out?
 

spyshagg

Novice Member
Sorry that's just plain wrong unless you're talking about Dolby Pro-Logic/Surround.

Hello Ian
Could you elaborate?

It is my understanding that if your goal is to pass DD&DTS to the TV/receiver, it doesn't matter how many hdmi sound channels appears on windows. Those are just how many channels windows can use to pass normal sound (stereo).
But the DD&DTS aware applications (kodi, for instance) will send 5.1/7.1 DD&DTS encoded sound to his TV despite windows only recognizing 2 channels for his own use. Now its up to his TV to enable passthrough to the receiver.
 

deltafx

Active Member
turn amp on first and select pc channel on amp before tv dont know why but its works for me ..this is on a sammy plasma tv .if i select tv channel first no sound a tall wouth a try
 

Ian_S

Distinguished Member
Hello Ian
Could you elaborate?
DD/DTS are not transmitted in stereo PCM channels, they're a different bitstream if enabled. So having a stereo PCM connection will not get you DD/DTS, it will only get you old fashioned Dolby Surround if processed by prologic and the player down-mixes to that format. (You'll see this option on many BD players)

TV's tend to be quite hit & miss over what they will spit out over their optical outs, or via HDMI ARC.

I think the simplest solution for the OP is likely to be finding a way of getting a different digital output connected directly between the PC and Amp. This may though introduce lipsync delays on the picture.
 

F1aw1ess

Standard Member
Thanks for all of your help.

As you said, it looks like the easiest way to get round this issue is to run a 10m optical cable from the Sound Blaster X-FI which does have an optical out from the PC straight to the AMP. Its just a shame cause I don't have a huge amount of space round the edge of the room and I would have liked to do it with the HDMI cable that I have already run round.
 

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