Help Audigy LS +MX5021

[aa1128]

Hi I have a Audigy LS and Mx5021. I just want to know, how am I to use the Digital output only? Want I need to buy so that I can use digital sound? DIGITAL輸出真比AUDIO音感好嗎,我該如何將此兩元件發揮最大的功效呢(小弟電腦以聽音樂為主,遊戲為輔).........請各位前輩能指導指導...謝謝