Question about ohms and such

i am currently looking for the best setup that i would be able to upgrade when i get the cash, i may be stupid but the resistance between the amp and the sub is kinda confusing me.  if i were to get a 2 channel amp that is 400 watts bridged at 4 ohms and 1-4 ohm subwoofer would that setup work? and would it be easy to add a second 4 ohm woofer to that setup?  leave your input thanks

if your interested i was thinkin about getting a infinity kappa perfect 12.1, but im not sure if i would want the DVC or not? help me out please!

if you bridge your sub on the amp it will recieve the 400 watts at the 4 ohms but when you add the second sub you need to get another amp or set the subs up so that they run in parallel with the amp, or you can unbridge the first sub and use the channels seperatly. one for each sub, the subs would then be seperated to left and right so be sure to hook that up correctly.

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