i have 2 JBL135SAT speaker,1 philips MC165 amplifier and 1 JBLSUB135 subwoofer.point is, do i need a sound card for this,i don't want to buy an expensive sound card,my choice would probably be asus sonar DG or DS.my onboard sound card is supremeFX.i want great audio but if supremefx is not enough,what sound card would be suitable for me?with low price?