For Grant:
Calculating the sub box volume for the X-star:
1. Determine the desired box volume
a. JL specs a NET interior volume of 1.25 cuft.
b. JL specs the volume of the JLW6v2 at 0.068 cuft
c. So each sub should have 1.318 cuft or 1.318 x 1728 = 2,277.5 cu.in. interior volume or 4,555 cu. In. per box of a pair of subs
2. Box volume: W x L x H = 4,555 cu.in.
a. Z – 1.5” = H, 22-1.5” = 20.5 fixed
b. X – 1.5” = W, max dimension of 23”
c. Y – 1.5” = L, max dimension of 16” (for each box section housing a pair of subs)
d. (X – 1.5) x (Z – 1.5) x (Y – 1.5) = 4,555
e. Since Z is fixed then (X-1.5) x 20.5 x (Y – 1.5) = 4,555 but there is that little triangle cut out of the top so we need to remove that space from the volume calculation. The best way is to figure the area of a square less the area of the triangle then multiply the result times the length to determine the volume.
f. The sides of the triangle adjacent to the right angle are 9.625 and 8.5”
g. {[(X – 1.5) x (Z – 1.5)] – (9.625 – 8.5)/2} x (Y – 1.5) = 4,555
h. Or (((X – 1.5) x 20.5) -40.9) x (Y – 1.5) = 4,555
i. Solving for X = (((4555/(Y – 1.5))+40.9)/20.5)+1.5
j. Or solving for Y = (4,555/((X – 1.5) x 20.5) – 40.9) + 1.5
3. Pick an X or Y value and calculate the remaining variable
a. X = 14: Y = 22.65”
b. Want a longer but narrower box? OK Y = 25: X = 11.8”
c. Using the equations you can play with each dimension
4. So is there enough room to run a ported box?
a. ((23 – 1.5) x (22 – 1.5) – 40.9) x (16 – 1.5) = 5798 cu in or 2899 per sub or 1.68 cubic feet each, once you deduct the volume of a slot port it gets a little tight but you could easily run 2 big 3” ports and be within the spec…
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