Passing digital optical xbox audio in and out through USB 5.1 sound card to x540.

[ChickenNuggets]

Here's the deal:

I have a set of logitech X540 5.1 surround speakers with only analog input, 3.5mm plugs (red, orange and black).

I have an xbox that outputs dolby digital surround through a toslink optical cable.

I have a mac mini running OS 10.64 with Xcode installed.

I have the CM6206 soundcard:

I want to convert the digital optical audio from my xbox into 5.1 analog audio that my logitech x540 speakers can use to give me full surround sound.

Here's what I've done.


I plugged my xbox optical audio cable into the input of my mac. I used AU LABS to pass the audio through to my USB soundcard and to my X540s.

It is not 5.1 surround that is getting through. I have to switch my xbox's output to "Dolby pro logic II" (2.1) output in order for it to work. In regular Dolby digital I hear only a loud chatter blasting out my speakers.

I need a way to decode the AC3 encoded audio from my xbox before I pass it through to my speakers...

I may need the griffin firewave in order to get surround sound...

Is there a way to do this? How can I get full surround sound?