No sound from tv with hdmi

OK, totally frustrating problem. I've been using an old server box with an ATI Radeon 9700 pro video card (dvi to hdmi adapter) and an Audigy 2 soundcard to my Philips LCD for video content. Runs OK, but slow as hell.

I built two different boxes to replace this one (it's 2 feet tall and purple, don't ask...) but run into the same problem with both of them. I have sound coming off of the audio out on my new soundcard, but the TV won't accept it. If I flip the audio to a different input on the tv, it comes through fine. Just doesn't want to have both at the same time. One box has Intel integrated audio and sound, the other has integrated sound and a Geforce video card.

Any thoughts on why the tv fails to allow sound on the hdmi channel with the new setups?

Note: I've tried these systems with XP Pro and Vista both with no success.

As far as I know DVI does not have audio and hence DVI to HDMI adapters may not work well or may not work at all. So probably the fault is with your video card itself. There are various Video cards which do not have the audio output to HDMI.

You are absolutely correct Amosz, DVI don’t have any audio lines. I can say this because one of my PCs is also running with Radeaon 9800 PRO (AGP) and it does not support any audio function on that video card. So in case your system as well using an AGP slot then probably you will not be able to get Video and Video using HDMI.

Actually, it's the agp-based ati 9700 card that connects and the tv accepts the sound. (via the audigy 2's analog output (miniplug to rca)) The Geforce card and the integrated Intel audio on the other ones seem to do something to prevent the tv from accepting the audio, as I can hear it just fine when I plug the same rca's directly into my stereo's aux inputs. I use a fairly ancient JVC receiver for my audio (tv headphone jack to aux input, as the receiver has no optical or digital inputs). Seems ghetto, but sounds great with some Infinity bookshelves and Polk woofer. I'm not worried about surround sound atm, but I will in the future when I upgrade the audio.

Could there be some drm function or something built into the tv or later video cards that blocks the sound? Or some setting on the geforce and intel vid that I'm missing? Or does the Audigy 2 automatically flip to digital out through the rca's? It's set for analog, and I've been using the analog out so I wouldn't think so. Just can't figure out why my $%& tv won't let the sound through with any except my old setup.