I was just going to ask this same type of question .
I was going to Buy Logitech Z5500, with dolby digital 5.1...
But does that mean your sound card has to have that? or since it has it's own amp/reciever, it will take a audio output from an integrated audio source and turn it into something good?
I only have a PCI x1 slot left, would it be necesary to upgrade a sound card?
I just checked, the computer I have has "AC '97 Audio, Dolby 5.1 (6-Channel)"
I did that by checking the website that I bought it off though.
When i check my "sound" by running dxdiag, it only says
"Realtek AC '97 Audio" though.
I could take out my 56kmodem i suppose to add a sound card.