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TheVanMan
09-18-2003, 09:56 AM
Ok, I decided to scrap the plan for 2 15 SE and decided to go with a 15 XXX (since they cost the same anyway). Here is my box. Tell me what you think. I would try for 5 cubes but there are these stupid floor rails for by back seat to move on so it's can be bigger then 34.5" wide.

Here it is:
H = Height (external, in inches) = 18"
W = Width (external, in inches) = 34.5"
D = Depth (external, in inches) = 17.75"
T = Thickness of material used (Most common = 0.75" MDF)
Hv = Height of the port (in inches) = 16.5"
Wv = Width of the port (in inches) = 2.75"
Ap = Area of Port (in square inches) = 45.375in^2
De = Effective diameter (in centimeters) = 19.306cm
Lv = Length of the port (in inches) = 26"
Vg = Gross volume (in cubic feet) = 5.120ft^3
Vb = Net volume (in liters) = 4.07ft^3
Vd = Port displacement (in cubic feet) = 0.8439ft^2
Dd = Driver displacement (in cubic feet) = 0.21ft^2
Bd = Brace displacement (in cubic feet) = (have decided yet)
Fb = Tuning frequency (in Hz) = 31.29hz

TheVanMan
09-18-2003, 05:53 PM
:rolleyes: Wow, thanks for catching that. I did have my calculations correct I just was supposed to put 8.25" instead of 9" (it only messed up my port displacment by like 0.002). However I did luck out since the port is now 8" away from the wall. I fixed everything now. Your too good at this stuff, it scary. The formulas I found was from a post you had a few months ago.

Here it is:
H = Height (external, in inches) = 18"
W = Width (external, in inches) = 34.5"
D = Depth (external, in inches) = 17.75"
T = Thickness of material used (Most common = 0.75" MDF)
Hv = Height of the port (in inches) = 16.5"
Wv = Width of the port (in inches) = 2.75"
Ap = Area of Port (in square inches) = 45.375in^2
De = Effective diameter (in centimeters) = 19.306cm
Lv = Length of the port (in inches) = 26"
Vg = Gross volume (in cubic feet) = 5.120ft^3
Vb = Net volume (in liters) = 4.071ft^3 = 115.300 liters
Vd = Port displacement (in cubic feet) = 0.8385ft^2
Dd = Driver displacement (in cubic feet) = 0.21ft^2
Bd = Brace displacement (in cubic feet) = (have decided yet)
Fb = Tuning frequency (in Hz) = 31.27hz

TheVanMan
09-18-2003, 10:24 PM
Ok, thanks for the double checking of my box. That was the first ported box I designed so I think I did well for the first time. I didn't use you formula for displacement since I knew that was wrong. I realized that I double counted a piece of the wall so thats why my displacement was a little bigger. The way you did it elimated the possibility of error. I calculated the volume of the inside of the port and then added the volume of the 2 walls afterward. You added them together so you way is easier. Next I do it your way. :) Again thanks for all the help. :thumbs_up