HDMI audio from S/PDIF output on Asus M5A97 R2.0 motherboard

AdamMil

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Dec 12, 2013
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I just bought an Asus M5A97 R2.0 motherboard. This motherboard has a Realtek 887 8-channel high-definition (Azalia) audio device. It has two "SPDIF" outputs, one in the form of an optical S/PDIF port, labeled "SPDIF_O2", and one in the form of a header, labeled "SPDIF_OUT". (The SPDIF_OUT header has these pins: +5V, [blank], SPDIFOUT, and GND.) The BIOS has a configuration option that allows you to set the "SPDIF Out Type" to either "SPDIF" or "HDMI". The S/PDIF standard does not support 8-channel high-definition audio. S/PDIF only supports 2-channel high-definition (uncompressed) audio. However, HDMI supports 8-channel high-definition audio. Therefore, I would like to set this option to "HDMI" and connect an HDMI cable to my computer in order to get 8-channel audio output.

How exactly can I connect an HDMI cable to my computer carrying 8-channel HDMI audio output from my motherboard, suitable for connecting to an audio receiver, for instance? I have an MSI Gaming N760 TF 2GD5/OC video card, if that matters. (I know some solutions pass the audio through the video card, though I don't prefer that if possible because I'm already using that for video and I want to send the audio elsewhere.)

This question is NOT about getting HDMI video.
 
Solution
the video can pass it automatically, when you insert an hdmi cable into your video card and your receiver, you can go to the sound properties in the control panel and select hdmi audio as the output device.

AdamMil

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Dec 12, 2013
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How do I get the audio from the motherboard to the video card? Is it automatic? I don't see any place where an audio cable can be attached to the video card.
 

AdamMil

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Dec 12, 2013
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I suppose that's not using the motherboard's audio device at all, but instead using some kind of audio device built into the video card? If so, I wonder how it would affect the ability to plug headphones into the minijack and hear the same audio stream. I'd still prefer a solution that uses the motherboard audio device, but thanks. I will try it when my video card arrives. :)
 

AdamMil

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Dec 12, 2013
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I believe a complete answer to my original question is:

The "SPDIF Output Type" option only controls the SPDIF_OUT header, not the SPDIF_O2 port. When set to "SPDIF", it outputs a standard S/PDIF signal. When set to "HDMI" it outputs a signal that is not actually HDMI but that supports HDMI-quality 8-channel sound and is intended to be multiplexed into an HDMI signal. In either case, the expected use is that the SPDIF_OUT header will be attached to a video card that supports HDMI audio pass-through. Whether the video card supports S/PDIF and/or the "HDMI" signal depends on the video card. If you don't have an HDMI multiplexer (like a video card) that supports HDMI audio pass-through from the motherboard, then you cannot get HDMI audio output using the motherboard sound device.

However, many video cards that don't support audio pass-through have an onboard audio device of their own, and if you configure the system to use this audio device, then the audio should be included in the HDMI signal from the video card. (This is the solution suggested by getochkn.) Naturally, you won't be using the motherboard's audio device in that case.
 

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