Playing below tuned Freq

[Dangerous10k 0]

I just wanted to know, Is there a way to calculate how much power handling drops below tuned freq in a ported box. And how much power handling drops in larger ported enclosures, Other than win isd.

I mean is their an actual mathmatical formula or no? Like for example I have 2 Fi Q 15s with BP power in a box that is 9.5 cubes gross 8 after the port @ 33 hz. How do i figure out how much power handling I have in this size of enclosure and how much it drops below 33 hz? Or does everybody pretty much play by ear and listen for bottoming out?

[Adrian_D 520]

There are formulas for calculating the excursion, that's what the software is based on.

Why do you want to play the subwoofers below tuning ?