First box, (the first time it broke) 1 ft^3 sealed. Second box, 1.1 ft^3 tuned to 30.
I've also tried it in 1.6 at 35, and .8 at 40 but those were just test boxes.
Its been powered with an Infinity 1211a. Now I realize the sub could take more power than a claimed 1300 watts, but I always...