Subs don't cause rise boxes cause rise it's actually a trade off of having good efficiency. Thus why so many competitors wire into the dirt. They take the efficiency of the rise and use lower impedances to rise to a lower ohm load to get more power. A box that has little rise at your peak frequency isn't very efficient.
Amps like the Rockford power bdcp, Taramps smart series, JL slash and hd line, sundown Sia all do better to fight rise because they make the same power at various ohm loads so if you are wired to 1 and rise to 2 they output the same power or near the same power.
