Can't get 5.1 audio, only stereo from HTPC

  • 27 November 2016
  • 8 replies

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I have a Playbar, Sub, and 2 Play1's setup as a 5.1 system. However when connected to my Windows 7 HTPC I only get stereo (PCM) audio.

I have tried connecting the Playbar directly to the PC's optical out port (Realtek) and also tried using the audio channel over HDMI from the TV (My TV absolutely passes 5.1 over the optical output). In both cases I get just stereo.

I updated to the latest Realtek drivers and made sure that DTS was disabled and just Dolby Digital was enabled. When I do the sound check in the Windows sound applet I hear audio correctly in the left, center, right, and the 2 rear channels. But when I play a movie that is Dolby Digital 5.1 (AC3) either through VLC or KODI all I get is stereo. I've confirmed this via the Sonos app "about" section.

In addition, when I had the audio going out via HDMI to the TV and then the TV's optical out port to the Playbar, the PC only shows "stereo" as the speaker setup in the Windows sound app. It should show an option for 5.1

Plus, if I switch my TV over to my Comcast cable box and go to a channel that is in 5.1 I hear audio in all 6 channels.

So, the problem appears to be that the Windows PC doesn't see the Sonos system as a 5.1 system.
I know it's an issue with Sonos because before I had Sonos I had a Sony HT-NT5 5.1 system and the Windows computer recognized it as a 5.1 system. But this darn Sonos only shows up as stereo.

Anyone had any luck with their HTPC?

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8 replies

I know this is an old thread, but I'm in the same situation you're in. My Nvidia 1080 ti supports surround via HDMI, but my PC only detects the TV as stereo. As "ratty" said, the PC can't see the Sonos system as anything. How can it recognize it now?
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Just an update - installing the nVidia GTX-1050 solved the issue. It supports DD 5.1 over HDMI (and out the TV's optical port to the Playbar).My Sonos 5.1 setup is now finally working with my HTPC.
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I've changed my plan of using an optical switcher to combine audio from the HTPC and TV to the Playbar.

I contacted the manufacturer (MSI) who makes the nVidia GT-710 video card I have and they confirmed that this cards only supports stereo over HDMI.
So, I checked with nVidia and got a list of cards that do support DD 5.1. I just ordered a Zotac nVidia GTX-1050. I figured, what the heck as this card also supports HDMI 2.0b and 4K and it's only $99. If this works I can go back to audio over HDMI to the TV and won't have to deal with the switcher.
I've ordered a SPDIF/TOSLINK switcher from Amazon.

Sensible move. That's what a lot of us have done.
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Thanks for your help ratty.

But, I've finally got it sort of figured out. At least with getting surround from the PC over the optical port.

With the PC's optical port connected to the Playbar I decided to throw in a blu-ray disc and see if that worked or not. It did! The Playbar was decoding Dolby Digital 5.1 when the "PowerDVD" software was playing a blu-ray. Ah-ha! I was using VLC and KODI to play the movie files. So, the problem must be with the software player application, not the Playbar. Since KODI is all I really use on the HTPC I spent even more time fiddling around with the audio settings. I finally got it to work!

Though this does cause a slight problem. Since I can't get the surround to work over HDMI and the Playbar has only 1 input I now have 2 optical sources, the HTPC and the optical port from the TV that's still getting a DD 5.1 source from the Comcast Box. So, I've ordered a SPDIF/TOSLINK switcher from Amazon.
Could there be an HDMI which is reacting to the HTPC and only accepting stereo?
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Yeah, now that I think about it, you're right about it being unidirectional.
However, that just makes this problem more mysterious.

If I connect my old Yamaha AVR to my HTPC using the optical out port I get Dolby Digital 5.1 surround. But when I plug the optical cable into the Playbar and then bring up the Sonos app and go to "about my sonos" I see stereo as the audio in.
I've confirmed that the movie is encoded in AC3 at 48KHz. This should play in 5.1 on the Playbar, but it doesn't.

I really can't figure this out?
So, the problem appears to be that the Windows PC doesn't see the Sonos system as a 5.1 system.
The PC can't see the Sonos system as anything. S/PDIF is unidirectional.