If you have a media centre PC, chances are you want to connect it to a home cinema system or HDTV, most of which can take an audio signal over HDMI. This has the advantage of not requiring an optical or coaxial cable and less chance for the audio signal to become desynchronised from the video, as is sometimes the case when outputting them separately. With most ATI cards the sound chipset is built in, and most new motherboards have 2-Pin SPDIF headers designed specifically for adding an audio stream to nVidia cards, however many high-performance sound cards such as those made by Creative and Auzentech do not make it clear how you should connect an internal SPDIF cable.
NOTE - SOME CARDS DO NOT HAVE THIS FACILITY. THEY ARE LISTED BELOW
Audigy Value Models
Audigy SE Models
X-Fi Xtreme Audio (Except MSI OEM Card)
X-Fi Xtreme Gamer
This tutorial assumes you already have a supported nV card, Creative Audigy/X-Fi or Auzen X-Fi card and a 2-Pin SPDIF cable as shown below:
1. Insert the 2-Pin SPDIF cable into your graphics card.
This should not require you to remove your graphics card. The connector is normally located near the PCI Express power connectors, as shown here:
2. Insert the other end of the SPDIF cable into your sound card.
This may require you to remove your sound card, as most Audigy and X-Fi cards contain the SPDIF out pins as part of the two long strips of pins on the card. I will provide diagrams for as many cards as I can, please post in the thread if you have a card I haven't explicitly mentioned and I will check it out.
Firstly, check the labels on the connector that you will plug into your sound card. It should be labelled SPDIF and GND, or similar. If it is not labelled it is usually safe to assume that the black wire is GND and the other one is SPDIF.
Creative Sound Blaster Live!
This is a pretty old card and unless you're using XP it's probably best to upgrade or just use your onboard audio.
COMING SOON - HAVE DETAILS BUT NEED TO CREATE IMAGE
Creative Sound Blaster Audigy (Most Models)
These cards are great for home cinema use as they support 24bit/96khz playback and a majority of them also support SPDIF passthrough to allow you to bitstream Dolby and DTS to your home cinema system.
You'll want to connect your GND connector to Pin 7 on the diagram and your SPDIF connector to Pin 9. (These pins are contained with in the smaller SPDIF_IO pin bank)
Creative Sound Blaster X-Fi (PCI Models)
These cards are great all round cards, despite being plagued by bugs when used with certain motherboards. They support 24/192 audio output and Dolby/DTS bitstreaming.
This has exactly the same pin layout as the Audigy cards, so follow the instructions above.
Creative Sound Blaster X-Fi (PCI Express Models)
Small improvements and bug fixes over the PCI models, but lower audio quality than the high end PCI cards (Especially Elite Pro).
I do not currently know the pinout for these cards but I will fill in this area as soon as I obtain one.
Creative Sound Blaster X-Fi (MSI OEM)
These cards offer a small improvement over onboard sound, but are not as good as a standalone card. However, they do have the advantage of creating a cooler northbridge chipset by removing the sound hardware from the board itself.
Your card will most likely have a cover on, but it is easy enough to work out which pin is which:
Connect GND to Pin 1 and SPDIF to Pin 2.
Auzentech X-Fi Prelude
Regarded by most as the best sound card for gamers and very highly rated for home entertainment, this is a great choice for a HTPC.
This card uses a slightly different pinout than the Creative cards, and as such you must follow this diagram:
Connect GND to Pin 17 and SPDIF to Pin 15.
Auzentech X-Fi Forte
Containing the new PCI Express chipset, this card has slightly lower audio quality than its big brother but its small form factor design makes it ideal for a shuttle PC or similar.
Again, this card has a different layout from the Creative equivalent. However, I also do not have the pinout for this card but will be enquiring about it and will post it here as soon as I get it.
3. Configure Your Sound Settings
In Windows XP, simply enter the advanced play options in the volume control and tick the checkbox that enables Digital IO.
In Windows Vista, set the "Digital Out" or "SPDIF Out" as the default audio device.
You should now be able to send a digital audio stream through HDMI with your card.