Background:
Gigabyte G31M-S2L
ALC662
(has SPDIF header - 3 pins)
NVIDIA 9600GT
(HDMI + DVI - has header for SPDIF to pass-through to HDMI)
I connected the patch cable that came with the graphics card to attach the SPDIF header on the motherboard to the SPDIF plug on the 9600GT.

I have tried various kexts available for ALC662 and audio output through line-out works great on all of them. Currently I am running the "Legacy HDA" version (seems to be the cleanest). There is a "Digital-Out" option, but I am getting no output via the graphics card. I am using an EFI string for the graphics.
In Vista, I am able to output audio through the graphics card, through HDMI to my TV but no such luck under OS X. So I know that everything is physically hooked up properly at least...
My goal is to have an HTPC that has basically two connections on the back (Power + HDMI ... no clutter). Almost there... Anyone have ideas/advice? Thanks in advance.

Hi,
I have a similar issue. My MB is a G31m-ES2l which has an ALC883, had hoped that with my 9400GT card I could get both video and audio down the HDMI port. Unfortunately every kext I've tried doesn't work with this and I am not knowledgeable enough to modify things myself. just have to wait until someone smart enough and needy wnough does it!

best of luck
Gary

Hello,

My MB is a G31m-ES2c which has an ALC883 and i want to know if there is HDMI audio solution too.

I've got Asus 9400 with hdmi and manage to have audio but not true hdmi

Any new solution?

Best regards,
Chopy