The hell? DVI-HDMI cable carrying audio...

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Bit of a weird one this... (Or not -- I don't claim to be a cable expert :p).

Basically, I have this 5ft DVI-HDMI cable I use to connect my PC to my TV for when I want to watch stuff on BBC iPlayer (or other VoD services) or if I want to play games with my girlfriend.

Now, I used to just swap over a couple of speakers that are connected to my subwoofer (I basically had a four-speaker setup: two sit on my desk and are used when I'm at my PC; while the other two speakers sit beside my TV for when I've got my TV set up as my PC display). However, since getting some good headphones, I've opted to use those instead of my speakers, which I've actually removed from my desk. The speakers beside my TV I kept there because it's still useful to have them for those occasions I mentioned previously.

Tonight is when my mind boggled, though, as when I went to start the video I wanted to watch on iPlayer, I noticed audio coming through my TV despite my headphones being plugged in and not having connected the two speakers I was going to use. I checked the playback devices list and lo and behold my TV is listed. Unplugging the cable also revealed as much.

DVI-DVI doesn't transmit audio, and I always thought a DVI-HDMI cable also would not transmit audio because one end of the cable is DVI. But it seems I am wrong, unless there are specific circumstances or conditions that enable the DVI end of a DVI-HDMI cable to transmit audio.

Oh, and this isn't so much of a 'help' thread as it is an educational experience, as I am actually quite interested to know why my cable is suddenly capable of doing what I always thought it incapable of. :D :p
 
DVI to HDMI carrying sround has been around for a while now. It basically uses the unused pins on the DVI port for the sound signals.

If you look at your sound devices you can see AMD/Nvidia High Definition audio, which is the sound chip on the GPU.
 
Cheers guys. :)

I knew graphics cards have an audio component, I just didn't realise they could utilise DVI in such a way that transmitting audio was possible.

But now that I know this, I may as well just pack away my speakers completely -- they're quite old and I don't use them enough to bother getting new ones.
 
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