i dont no which speaker is best..advice?

BLAST kING! Never heard of it. the only way it makes a difference is by what amplifier you have or one you will be getting. 2 4ohm speakers wired in parallel give you a 2ohm mono load. 2 8ohm speakers wired in parallel give you a 4ohm mono load. if you are using a mono channel amp you would need to find out whether or not it is 2ohm mono stable. which most amps are. but if you would be using a 2 channel amp and using both channels you would need the 4 ohm subs. this is all considering we are talking about a car audio system. if you are buying these for an in home system you would need to check your amps ratings.

parallel wiring is positive to positive negative to negative

M.E.C.P. Certified Installer since 1997

I agree with Cornell, it depends on you aplication.

If the impedance is the only issue will depend on how much amps and speakers you are going to drive.

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