ok so i have a power acoustik 15inch fubr that has a recommeded sealed box airspace of 2 cubic feet. the speaker itself needs 15 1/2 inches to mount. so i was thinking a box that was 16x16x18 would be about 2.0088 cubic feet but i was just wondering if anyone else had anymore options or what the dimensions and shape of their box was. thanks.

 

dont forget displacement. i dont have any idea how to calculate box air space but wouldnt a 12x12x12 be 1cuft? so wouldnt 12x24x12 be 2 cuft?

 

Sure, but it wouldn't give a mounting surface large enough. two of the boxes dimensions need to be at least 15.5 inches. I prefer to work with cubic inches when calculating box volume.. you need 3456 cubic inches (same as 2 cubic feet). the 16x16x18 size is too large, that would be 2.667 cubic feet. (4608 cubic inches total, 1728 cubic inches per cubic foot)

First, find the total required box volume including any displacement for the sub. Let's pretend that your woofer requires .15 cubic feet. the box volume in cubic inches is 3456, required for the sub is an additional 259.2 for a grand total of 3715.2. next, take a look at your required internal dimensions. First off is the mounting surface. You need at least 15.5 - that would put the edge of the speaker quite close to the edge of the box. We can add to that a bit for some more room. If your internal dimensions are 17"x17" for the mounting surface, you'll have a little room to spare. to find the final dimension, you can divide the required volume by the two known dimensions. 3715.2 / 17 / 17 = 12.86". a box 17x17x12.86 should be about perfect, if it fits in your car well. to make the measurement easier, you could go 17x17x12.875 and you would only gain 5 cubic inches, or less than three thousandths of a cubic foot... not much to worry about.

 

First determine if you want the box to be deep or wide. Then take the mounting depth of the sub and add atleast 2" to it. Now, determine what thickness material you are going to use. Got that? Now, play with the dimensions you want. Remember, the interior volume needs to be calculated by subtracting the thickness of the material you are going to use, if its 3/4" MDF, subtract 1.5". If it's 1" MDF, subtract 2". Got that? Now, take your interior dimensions and multiply them all together and then divide by 1728. That should give you the interior cubic feet you need. I hope that helped.

 

Check out this thread for calculating sub enclosure demensions.

http://forums.maxima.org/showthread.php?t=274335

 

Hey SEmy2k2go, what you forgot to mention in your post is that you have to subtract the thickness of the wood you are using to get INTERIOR dimensions. The way you have it, assuming you are measuring outside dimensions, the calculations are going to be wrong. Remember to subtract the thickness of the materials you are using for interior dimensions.

 

comon, its a sealed box! There is nothing complicated about it. Just apply common sense and use the sites posted & you'll do find.

 

hitmanse- the reason i posted is becuase i was unsure the largest dimensions that would FIT in the trunk opening. the box it was originally in was too big and so i wondered what other people had to make mine

liquid nine- by using the volume calculator on the12volt.com for a rectangular enclosure. the dimensions 16x16x18 using 3/4 mdf board would put me at 2.0088 cubic feet, not 2.667 cubic feet.

i made the box 16x16x18 and it came out great. fits just barely through the opening but still allows me to move it around if need be.

 

Understood, the 4th gen doesnt really have the largest opening as far as the trunk goes. You'll be able to fit a larger box by sliding it in through the back (behind the rear seats )