So I just recently built my own box for a Sundown Audio sa 12 D2. It's 2.3 cubic feet port tuned to 35hz. I also recently went from using to sa 12s to just one because I didn't have the amp powerful enough to push two of them so while I'm waiting for my amp to come I am just running the one in the Box I built and I have it powered by a Phoenix Gold SX 1200.1. Its rated at 1200 watts at 1 ohm 800 watts RMS. Anyway every time I turn my sub up for a while I could smell it burning first it was a voice coils now it just smells like something's burning and it seems like after I play it for a little bit it doesn't hit as hard as it used to until cools down again. I probably already caused irreparable damage. The only thing that I could think of which from what I hear is almost impossible to do is overpower it. So I clamped my Phoenix Gold amp and it said it was putting out 1293 watts. I checked it 3 times and it came up the same way every time. I know the subs can handle a lot of power but it's only rated for 750 can it take almost 1300 Watts constantly?