Optical audio to PC speaker surround sound

[Steven2k7]

I have a set of Logitech x530. Its a 5.1 surround sound system thats made for a PC with the three 3.5mm green/black/orange connectors for the input. I use it on my computer and xbox 360 a lot and just manually switch inputs. The only problem is I am only capable of getting stereo sound through the speakers when I use the xbox 360.

How can I get my xbox to output to the speakers as true surround sound? I cant seem to find any optical audio adapters that will output to the three 3.5mm jacks that my speakers use. Sound from the computer will be fine as stereo, I mostly just want the xbox to be 5.1 surround sound. Manually switching some wires

I'd rather not buy a new set of speakers or a big audio receiver as there isnt anything wrong with the current speakers and I have no room for a big audio receiver.

I'd like to go cheap as possible, under $50 would be great, but I have a feeling its going to cost a bit more...

I would rather have an external device if possible. I switch between windows 7 and OS X Snow Leopard (I have a hackintosh going) so if its a sound card it would have to work with windows 7 and snow leopard.

Thanks.

 

[MEgamer]

...

by the way receivers arent big.

 

[Steven2k7]

They're big when all I want is something around the size of 2 hard drives stacked on top of each other. A home theater receiver is big for my room and the only place I can put it is standing on its side under my desk.

 

[MEgamer]

40 cm length wise is big????

 

[rexter]

Creative and other company use to make a preamplifier decoder but I haven't seen any of those in awhile.

http://www.head-fi.org/forum/thread/94870/creative-ddts-100-decoder

Like MEgamer suggested; a receiver would be your best bet unless you want to spend more... But try ebay.

 

[Steven2k7]

I just realized a receiver wouldnt even work for me.. I have no way of hooking up my sub or my front right speaker to it.

I looked around for the ddts-100 decoder but I couldnt find it for sale anywhere.

 

[astrallite]

Let me google that for you...

http://compare.ebay.com/like/230373818421?ltyp=AllFixedPriceItemTypes&rvr_id=&crlp=1_263602_263632&UA=%3F*F%3F&GUID=e3119b151290a0aad2448764ff9aefd1&itemid=230373818421&ff4=263602_263632

 

[astrallite]

Or if you have a pre-hdmi 360...

http://www.ecrater.com/p/5735488/dts-ac3-51-decoder-aluminium-casing

 

[Steven2k7]

Well thats not the DDTS-100 like I was looking for. That could work, except I dont want to spend 143 for that.