DVI to HDMI with Audio adaptors

[fromaron]

I can find few of such adapters on a net sold for ~$260.
I don't have much knowledge on the digital audio conversion suitable for HDMI, but it seems strange that such devices are sold for the price.
What I need is just a DVI to HDMI cable which is not a problem and to have SPDIF audio coupled to the same cable so it appears at the HDMI plug.
What is so different between digital audio signal in the HDMI compared to SPDIF one?
Maybe someone can suggest a source for such devices in Australia?

[fandtm666]

if you are using the hdmi for the picture and try SPDIF for the sound at the same time there is a big sync problem between pictures and sound as the hdmi carries both the video and audio sound to the tv /amp etc

you can always look at these cables and have a look at their forums they are a huge help

[Padre]

just know that youll be restricted to 640kbps streams and u wont be able to get DDplus or DDTrueHD without HDMI connected to the amp

[eastlake]

Padre refers to the HDCP, if you don't have a "legitimate" HDMI HDCP compliant monitor or amp on the other end of the cable, then your HD content will be limited to 720 lines, ie not the full 1080.

[fromaron]

Thank you guys for the info, I'll check them out.
And I do have 1080p lcd screen with HDMI connector, as ell as I would like to have DD functionality.