Sound Cards are the sound-processing device of the computer. They can be built into the motherboard or be added to an existing PCI expansion slot.
If you're casually playing music & movies on your PC, a built-in
sound card would be enough. For applications such as PC games and
sound mixing, a dedicated sound card would make the game come alive.
Of course, the sound card is only good as the speakers you connect
it to. For example, a Soundblaster X-Fi wouldn't sound that great
connected to a pair of lower-end, paper-cone speakers.
Sound Card Selections
When searching for a good Sound Cards and speaker set, it's a good idea
to match the card & speaker set. For example, a Soundblaster 5.1
card would work well with a Logitech 5.1 speaker system.
The connections for this would be 2 front speakers, 2 rear speakers,
1 center speaker and 1 subwoofer. (hence 5.1 = 5 speakers & 1 subwoofer)