Cant find the post where he went back and said .6 is the biggest recommended on any power level...but I know for a fact that came from Jacob himself after a few people were destroying them in higher power applications with larger boxes.Perhaps you should go to the Sundown site and read...Jacob recommends 0.6 to 1.1 ported per driver.
With that said, 1.5 should be perfect for a pair of them.
