both dual 2ohm running at 1ohm. My question, which would be better for numbers. The 9512 in a 2.75cuft box tuned to 37hertz or a 9515 in a 3cuft tuned to 37hertz. My amp is a sundown 2000d. As of right now, my suv peaks at 50hertz with now deadening.

In theory, the 15, as it has more cone area.

The reason I say in theory, is that it really depends on install as well. But 3 cubes for a 9515 seems to be seriously choking it, the website even says recommended box is 4.25 cubes. If the max space you have is 3 cubes then use the 12.