Usually 2 subs hit harder than one, but it is hard to say... Compare the wattage, if the 12 is way higher, than stick with the 1 12... I did have 1 12" Orion HCCA 2000 watts rms, and downgraded to 2 10" RE Audio SE 600 watts rms each... And I am very satisfied... I mean the bass is a lot cleaner and travels through the car better, but I do have to turn the sub on the deck to about -10, instead of the -22 I had with the 12 to get about the same bass...
