@freashseason im sorry to burst ur bubble m8
but 7.1 means 7 plus subwoofer
and 5.1 means 5 plus subwoofer
think abt it ... according to what u said then 2.1 would mean 1 speaker and a subwoofer

the ".1" indicated the subwoofer .. the precedin number indiacates the number of channels aoart from the sub
@danny onboard cannot compare to creative audigy series
if u got the money and are an audiophile get creative
otherwise the onboard is good enuff
and NO u cannot just add speakers and make ikt a 7.1 setup
u have to buy 7.1 speakers separately