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View Full Version : Help me fig. the volume on this box, i need help!

Afboy143
06-09-2003, 02:12 PM
Here is a rough pic of the box i made. Sorry its not too good, im not that good with photoshop. This was built using 3/4's mdf btw. THanks guys i really need help

slipknot87420
06-09-2003, 02:19 PM
2.58

ShaunMac
06-09-2003, 02:53 PM
If the measurements you listed are external.
With 3/4" MDF the box has 1.63cu ft. of air space.

Gauntlet
06-09-2003, 02:57 PM
Originally posted by slipknot87420
2.58

Not quite sure how you came to that number....

Assuming the dimensions given are external, break the box into a triangle and a rectangle, and factor out the width of the MDF. Using the pythagorean theorem, the internal dimensions of the triangle are 3.75 x 15.04 x 15.5, and it's 48.5 long. The rectangle is 2.25 x 15.04 and 48.5 long. The squre inches of the triangle are 1367.7, and the rectangle is 1641.24, for a total of 3008.94. Divided by 1728 equals 1.74 cuft.

slipknot87420
06-09-2003, 03:01 PM
Originally posted by Gauntlet
Not quite sure how you came to that number....

Assuming the dimensions given are external, break the box into a triangle and a rectangle, and factor out the width of the MDF. Using the pythagorean theorem, the internal dimensions of the triangle are 3.75 x 15.04 x 15.5, and it's 48.5 long. The rectangle is 2.25 x 15.04 and 48.5 long. The squre inches of the triangle are 1367.7, and the rectangle is 1641.24, for a total of 3008.94. Divided by 1728 equals 1.74 cuft.

ok 7.5+3 divided by 2 = 5.25 ok now 5.25x50x17=4462.5 ok now you divide that by 1728 and that = 2.582

fantomas
06-09-2003, 03:01 PM
i got 1.63 cuft

Gauntlet
06-09-2003, 03:06 PM
Originally posted by slipknot87420
ok 7.5+3 divided by 2 = 5.25 ok now 5.25x50x17=4462.5 ok now you divide that by 1728 and that = 2.582

Why did you add 7.5 and 3 and divide it by 2? And you forgot to factor out the MDF.

slipknot87420
06-09-2003, 03:09 PM
Originally posted by Gauntlet
Why did you add 7.5 and 3 and divide it by 2? And you forgot to factor out the MDF.

because how the box is shaped you just take the average from the wall that is slanted adn yeah i know i didnt take out mdf oh well....

Gauntlet
06-09-2003, 03:14 PM
Originally posted by slipknot87420
because how the box is shaped you just take the average from the wall that is slanted adn yeah i know i didnt take out mdf oh well....

The average from the wall that is slanted??? You have to break the box up into separate shapes and figure out the volume of each individually

Afboy143
06-09-2003, 03:22 PM
Thanks guys for the help, u all are the best, i really **** at this stuff, so id say around 1.70?

fantomas
06-09-2003, 03:28 PM
Originally posted by Afboy143
Thanks guys for the help, u all are the best, i really **** at this stuff, so id say around 1.70?

about that....and thats BEFORE driver displacement.

slipknot87420
06-09-2003, 03:32 PM
ok you guys were right after wood displacment 1.631
and i was right before wood displacment and yeah that is how how you find the volume of an enclosure like he has:)

ShaunMac
06-09-2003, 03:34 PM
Originally posted by Gauntlet
The average from the wall that is slanted??? You have to break the box up into separate shapes and figure out the volume of each individually
Or you can take the average of the top(1.5") and the bottom(6") which is 3.75" internal
Then you can figure up the air space as if it was a rectangle.
3.75" x 15.5" x 48.5" = 2819.06sqin./1728 = 1.631cuft.

Afboy143
06-10-2003, 01:27 AM
**** i swear u all are the best, thanks fo everything, this is why i love this forum! so much help. Hmmm How much polyfil should i add to this box cuz its a lil too small?

Gauntlet
06-10-2003, 04:25 PM
Originally posted by Afboy143
**** i swear u all are the best, thanks fo everything, this is why i love this forum! so much help. Hmmm How much polyfil should i add to this box cuz its a lil too small?

16-20 oz per 1 cuft.....so probably around 2 pounds or so...