I've been reading up on 7.1 sound systems, and they're far out of my price range. So I started at looking around and seeing if I could make my own. I just wanted to know if it's a viable option to make one? With a 5.1 speaker setup paired with a 2.1 setup? If so how much would it cost?
rmark, if you're speaking of making a 7.1 computer speaker set then it is possible to use a 2.1 and 5.1 speaker set to make a 7.2. not ideal perhaps but it should work with a 7.1 soundcard. there really isnt any good reason for 7.1 though as there is not much content so its not worth the added price so i'd suggest a half decent 5.1 set instead such as the logitech z506.
to do this for home audio however is going to be a bit more of a pain and the extra adapters needed to do so might cost you $100+. to do the same thing with HT speakers means you're likely looking at htib sets which might not have inputs necessary to worth in this way.
if you are going to be using this for home theater use one of the cheaper yet GOOD sets i would recommend is the energy classic 5.1 take set which often goes for about $350. you could then pair this with an AVR (receiver) that you can buy for $150-200. if that is a bit high on budget then the monoprice 9774 is a budget clone of the set available for $230 but it may not be quite as good (i've heard they are comparable but i'm not sure if completely equal). that means $380-600 for a full featured 5.1 system which really isnt bad considering the junk you will find in HTIB (home theater in a box) sets for the same price.
for pc use only i'd say the logitech z506 should be fine.
for home theater i'd suggest the energy 5.1 (or clone) + receiver. its also possible to use the z906 pc speakers via optical connection if you have one available but it would be worthwhile to spend a little extra and go for full home theater instead of pc speakers.
the 2.1 set doesnt have a seperate sub connection like the 5.1 does. it just triggers on the 2.0 speakers low notes.
you could sync up the subs on two 5.1 sets since they have seperate c/sub connections but then you'd have two speakers doing fronts each side, two centers and two rears with just one set doing surrounds. kind of excessive just to fix a little problem with it acting like a 7.1 not 7.2
if you have both subs sitting in the same area you likely wont notice which is firing so i say having the 5.1+2.1 in that way wont be a big deal really... your two subs would just act like 1 sub.
basically it would act like a 7.1 not 7.2 non issue in my book since you wanted 7.1 anyways.