Newb question about 4 inputs - Digital and Analog

[ST1NG3R]

My Altec Lansing sub-woofer speaker set has two sets of two inputs. One that says "Digital Input" and has the Front labeled in yellow and the Rear in black. The other input says "Analog Input" with Rear in black and Front in green. (obvious info for anyone who knows speakers)

For years I have just plugged in a green speaker cable into the Front Analog input and into the back of my computer. The sound has never been amazing, but it's always been good and comes out of all four speakers. When I test the speakers, the sound only comes out of the Front Left speaker. Do I need another cable for the rear speakers? If so, what type of cable? I've tried switching the green cable just to test the Rear Analog and nothing plays. Does the second cable go into the black input in the back of my computer?

Also what is the difference between the Analog and Digital cables? I've only seen the basic green analog cable when dealing with computers. How can I tell if my sound card supports the digital inputs?

-Thanks

 

[PunterCam]

A photo would be handy mate, I can't really see how this works from that description...

As for the difference between analogue and digital cables, there are none. Obviously a light-pipe can only send digital, but a coax (for example) will transmit anything. Wire is wire.

 

[ST1NG3R]

Here ya go. Pics of the sub inputs and computer inputs attached.

 

[PunterCam]

I wish I knew!

A regular 5.1, industry standard surround sound setup would output (usually) on three, 3.5mm mini-jack (1/8th inch) cables. The 1st cable carries FRONT LEFT and FRONT RIGHT, the 2nd cable carries REAR LEFT and REAR RIGHT, and the 3rd carries FRONT CENTRE and SUBWOOFER. Presumably if you plugged the 1st output into the 'analogue input front', and the 2nd into the 'analogue input rear', you'd get all 4 channels working fine. But I don't know if the lower frequencies are filtered out at the sound card stage (probably not). In fact no, they definately won't be. So ignore that last sentence.

If I could decipher your soundcard I'd know more, but I still don't have a clue after years of staring blankly at them. Someone'll know. If it supports 5.1 then you can absolutely do what I said above. You'd need a 3.5mm mini-jack cable.

I would assume the digital inputs are s/pdif, since they only carry 2 signals on each. I don't know of any soundcards that output s/pdif surround signals though...