I want to get an 8" sub, mainly because I don't want a box sticking out from under the seat, or want to lift my seats. How much can you cheat the box volume (sealed) and still be okay?? I'm looking at a JBL 8" which needs .3 cu ft, or a Rockford Fosgate with a .25 cu ft. min? I've figured that I'll have about .2 - .25 cu ft, so the Rockford Fosgate is closer....

 

just put 1/2 pound of polly-fil in the box and you can use the JL sub.

 

Remember to subtract driver volume also. With an 8 is it probably only around .05 cu. ft.

Are those on the low end of a reccomended airspace (ex. .25-.75 cu.ft.) or just a single recommended number. If its a single number you should be fine and have a little more fudging you can do compared to going under the smalles reccomended box, if you understand what Im saying.

In reality, you shouldnt have a problem with either one in .25 cu ft.

 

I'm going to go with the Rockford Fosgate 8". It's going to be a minimal box, with the volume under the drivers side of the back. I am going to have some sort of storage over the hump.

 

Check out the dual 8" plans in my gallery.

 

how much space does poly-fill give you? and how do you find that?

 

Poly-fill lets you build the box 10% under spec. That's what I did. Use 1 lb per cubic foot.

 

Interesting dual 8". I'm sticking with the single 8". Just need a little fill in the cab. after the sub goes in, it will be time to amp the door speakers.