box rise

So i have an re sx 18 d2. The i built is 9.2 cu. Feet. So when i get my amp i heard there is a thing called box rise which changes the ohms when the music starts playing. So is the more so an amp problem or box design. I justt want to get all the power i paid for

I have an unmodded ma audio hk4k with a 2ohm ratin from manufacturer. I have been told several time they will run at 1ohm with the right electical. Ok, I have 2 200amp alts bout charging at 14.4 on 3 batteries 2 yellow tops opti and one yellow walmart special. Is this not suffencient? My prob...