Port area WTF!!?? Please help me!

[explosivesound 1]

So Im building my box but am confused as hell. Ive read I need 12-14sq. in. of port per ^3 but the manufacturer insists on 40sq. in. x10" long @32hz. for a 6^3 net box for my 18. Its an Atomic APX. When I spoke with them they said dont listen to anybody build this exact. WTF?! Any idea why? Its rated at 5000rms. Would the larger port make it unload at low freq. with that much power and thats why they say what they say? Shouldnt it have massive port noise?! Im so confused. Someone please straighten me out on why they want it EXACTLY as they say and yet the port area doesnt make sense?

[KU40 173]

I'm very surprised they say that as well. I'd use at least twice their recommended size for that 18.

[shizzzon 461]

this reminds me of the Orion H2s...

No matter how much power u planned on runnin to those subs, they wanted very small boxes and small ports for the best spl output.

It's something like for a single 12... 1.0cuft ported at 2.500wrms with 35sqin of port.

[explosivesound 1]

This is only 5sq.in of port more than that but for 6 cubes and an 18?!