sierra full size question

[gmsierra2000]

so I have been doing research on building a sub box for optimum performance out of my two Rockford T1 15", thanks to guys on here I am building a sub up port up design box that will be taking the place of my rear bench seat in my 2000 GMC Sierra Ex. cab, I will be tuning to 33 Hz as well.

My question is that I will be installing a full rag top on my trucks roof like the pics below:

when the top is closed its a really tight close but it still like a canopy type fabric. My question is how bad will it hurt my SPL with this mod with my sub up port up design?

should I point the subs and port in a different direction?

any suggestions from the big dawgs whose been successful?????????

[Neckbeard]

It probably will affect numbers, not sure how much, but i'm pretty sure it will hurt you. And 2 15s are gonna make that thing do the wave lol. My dad has a 12 in his samurai and it moves the fabric (although his is the whole back)

[gmsierra2000]

It probably will affect numbers, not sure how much, but i'm pretty sure it will hurt you. And 2 15s are going to make that thing do the wave lol. My dad has a 12 in his samurai and it moves the fabric (although his is the whole back)

but is it still going to be loud as hell??? its 15's tuned to 33Hz port up sub up about 850 watts rms each speaker rated at 1000 rms

I know it will effect numbers but buy how much db's with the rag open and close? that what im trying to figure out. and would anyone have any suggestions on the position of the subs and port???

im looking for as much steering wheel to body flex as possible lol