i'm thinking of buying a pair of 12" alpine 1242d type r's,dvc, but pretty new and don't really understand the whole dual voice coil. i like the alpine mrd-650 amp and the specs on that say 400wx1 @ 4ohm, 600wx1 @ 2ohm, and 1000wx1 4ohm bridged. what does that exactly mean? running one of the subs with one of these amps, does that mean i'll be putting in 400, 600, or 1000 watts into each sub (one amp for each sub). also, my box is a sealed with 1.25ft. each side, subs say .75 to 1ft. each, does it really matter that much? please help!!