I am using a GTX470 with an HDMI output, this card is able to handle the video and audio. I have no issues with the video but I get no sound. Is there a guide to enable sound on this card through hdmi that could be written out or I could be guided to. Thanks!
The only way for the moment to have HDMI Audio support in an Nvidia card is by first installing the proprietary drivers and then selecting the HDMI Audio as output.
This should be enough to have sound in any of the Nvidia Cards that support HDMI Sound.
I have tested this with:
I also recommend using the Nvidia PPA in this question: Newest Nvidia Card - what driver should I install? which I can say has improved my Nvidia card a bit.
Open the sound settings by clicking the volume applet and selecting "Sound Settings". From there, make sure that under the "Hardware" tab, the HDMI card is selected, as well as under the "Output" tab. That should do the trick