2 Unrelated 2-speaker sets for 4.1?

[Alphanos]

This might be a really stupid question, but here goes. I have a pair of speakers with a subwoofer. If I buy another pair of speakers of a different type/brand, can I combine them with my existing speakers to get 4.1 sound? This just occurred to me as a possibility since sound cards have separate front & back speaker outputs. It seems that whether its possible or not I'm stupid.

 

[LED]

Yes you can...On one of my setups I run 3 pairs of 2.1's which give me 6.3 sound

 

[Alphanos]

Thanks.