That's not how digital DSP technology works although it sounds good. Besides the .1 stands for a sub so you'll never have such a thing as a .2 Otherwise you'd have two subs and that would be pointless.
i have a 7.1 sound card in my new pc. could i get a 2.1 speaker system and plug it into the front channels and another and plug it into the rear channels and place them behind me and have 4.2 surround sound?

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