HDMI/optical sound output

By St1ckM4n
Dec 10, 2012
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  1. I have a mobo that supports optical out, along with a GTX295 that has HDMI. The problem is, I broke the S/PDIF connector pins on the GPU, so I can't connect it to the mobo pins. I need this cable for sound-over-HDMI to work, correct?

    The second question - I am connecting to TV and home theatre, by the way - is what's the go with the optical? I did try for about half an hour, but no dice. The Yamaha receiver simply didn't get any sound out of it (TV optical out works). I did change audio output in windows, tried 'HDMI - no audio' mode in Nvidia settings, etc.

    Is there some sort of option that is overriding my mobo optical out with the (faulty) HDMI out on GPU? :( I'd love to get this working..


    Edit: Third question.. I am of the belief that the optical will only give me 5.1 in games if the receiver and game are both in a supported format, e.g. Dolby something-something. Is HDMI bound by these same rules?
  2. St1ckM4n

    St1ckM4n TechSpot Evangelist Topic Starter Posts: 3,384   +607

    Bumpity bump. :(
  3. nismo91

    nismo91 TechSpot Maniac Posts: 999   +11

    yes, if you're using optical or coaxial connection (SPDIF) you can transmit either of these data:
    - Uncompressed Stereo (2.0) PCM
    - Compressed 5.1 Dolby Digital (AC-3)
    - Compressed 5.1 DTS

    im pretty sure most of the games in the market doesn't specifically output Dolby Digital sound. hence you'll be limited to stereo sound. if your motherboard supports Dolby Digital Live or DTS: Connect, you can turn it on so it will turn every sound in your PC into 5.1 Dolby Digital format, effectively allowing you to enjoy 5.1 sound from your music, games, etc.

    HDMI on the other hand can transmit either of these:
    - 8ch (7.1) Uncompressed PCM
    - 8ch (7.1) Uncompressed Dolby TrueHD
    - 8ch (7.1) Uncompressed DTS Master Audio

    and is of course backwards compatible with older format such as 5.1 dolby or dts. the problem is that only newer receiver supports it.

    a piece of advice: have you tried changing the default format used in the optical audio? it is possible that your receiver uses different format than your TV.
    [​IMG]

    and to check if your motherboard support DDL:
    [​IMG]
    St1ckM4n likes this.
  4. St1ckM4n

    St1ckM4n TechSpot Evangelist Topic Starter Posts: 3,384   +607

    Thanks for the info. I somehow got this working yesterday. Very helpful info.

    I spent two hours or so getting the TV working via HDMI with no overscan, and gave up on the sound after half an hr. On this second try, I got my sound working but the video now doesn't work. :(

    Might make another thread, I lost some sleep over it I think..
  5. nismo91

    nismo91 TechSpot Maniac Posts: 999   +11

    No worries.. also did "nvidia spdif" come up in the list of sound devices in control panel? I remember my 8800GT card has it and it came up on the control panel. not the case with the newer 560Ti where audio is through HDMI by itself.

    it also appears that the dongle maybe the uurl=http://www.tomshardware.com/forum/305784-33-audio-hdmi]culprit[/url]. I think it really sucks when you have pretty good equipments that wont work together.
  6. St1ckM4n

    St1ckM4n TechSpot Evangelist Topic Starter Posts: 3,384   +607

    I had three sound outputs show up: speakers, digital audio S/PDIF, and Digital HDMI. I also didn't use a converter - just HDMI to HDMI.

    But yeah, sound seems to be working now, and after fiddling with the TV some more I have what I believe to be close to 1:1 pixel mapping.

    Good enough, heh.


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