QuestionHi, im mark and i drive an 02 lincoln ls. im looking for some help on how to build a box to fit the sides of my trunk and aim the speakers forward an slightly up. i have two 12" pg subs that need to have an encloser of .9-1.2 cubic ft of airspace. can you help me with a design that could meet those dimensions an get the speakers facing the way id like them to be. thank you
AnswerSure, I can help. I would recomend that you build the box so that the back of the box is up against the backs of the rear seats and the speakers face the rear bumper.
Assuming this the next part is to determine weather your box should be at the .9 or 1.2 range. your amplifier will tell you this. if the amp is rated for LESS power than the subs are rated for go with the 1.2. if the amp is rated for HIGHER power than your subs are rated for go with the .9
Lets assume 1.2
Rember to build your box smaller than your trunk measurments since it will be nearly impossible to squeeze in if it's exact. leave at least 2 inches all around and take into account the fact that the openings and such will have to acomodate the box.
Usually there are 2 dimensions that you are kindof stuck with and the 3rd you need to calucate for. In other words you want the box to be as tall as the trunk and as wide but you dont know how deep.
take your measurements (with the 2 inches or more of space taken off). say it's 18" high and 48" wide. you need to subtract the thickness of your material (usually you use .75" MDF wood) so subtract 1.5 off each side or 2.25 off the length if using a divider in the middle which you should (.75 for each end and another .75 for the divider. so:
18" - 1.5" is 16.5" high
48" - 2.25" is 45.75" wide
and since you are using 2 subs you need to cut that width in half to get each side of the box as a separate number so:
45.75 divided by 2 is 22.875
so you can muliply these 2 together and get 377.5
Now to get the depth.
1 cubic foot is 1728 cubic inches so we need 1.2 cubic feet
1.2 times 1728 is about 2074
divide 2074 by the 377.5 square inches and you get 5.5 inches. This is the INTERNAL depth of the box. so if you add your wood thickness on this you get 7" deep
you can always check your math by muliplying the final numbers all together and dividing by 12 3 times.
(5.5 x 22.875 x 16.5) divided by 12 divided by 12 divided by 12 is 1.2013 pretty much exactly 1.2 If you have braces inside you should include them as taking up space and the size of the speaekr inside the box should be calculated into this as well. you do this when you take the 1.2 times 1728. if the sub takes up .1 you just need to figue a box that's really 1.3 not 1.2. so you can muliply 1.3 times 1728 and this will give you close to 6" deep for your internal depth instead of 5.5
Hope that wasnt theroughly confusing but that's how its' done. Any more questions please feel free to ask!
Good luck and please let me know how it comes out!
