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Box building question... Noob sorry

362 views 7 replies 4 participants last post by  SPL Addict  
#1 ·
So im on the 12volt.com using their box calculator.
The box is 18x18x30 which gives 4.49cf using 3/4 mdf.
The port i put in is 16.5 wide figured by taking 1.5 from 18 and making it 4" tall. Tuning it to 34 hz calls for the port to be 27.4" long.
My question is if the box is 18x18x30 to get the 4.49cf do i need to add the extra 4" to that for the port to the height or is the port part of the 18" height?
Im thinking i need to add the 4" to the height. Just not sure tho.
 
#2 ·
if im reading this right the port will be 4" Wide and 27.4" long 16.5 Tall .. if ur port is going to be just a regular slot port then subtract 4" from watever part u deside to put port ... if subs are up and port is on right side of box then the fron panel will be 4" shorter becuz of port... hope that made sense
 
#3 ·
No 4" tall 16.5 wide 27.4 deep. The numbers i came up with for the box 18x18x30 gave me the 4.49cf my question was more is the port part of that 4.49cf or is the port just part of the port lol. Meaning i would do the box 22x18x30 so i would have the 4.49cf for the sub and then the port displacement. Am i right?
 
#8 ·
That is to much port area for your sub.

you take you box volume 4.49x16=71.84 sq inches/2= 0.3592 cu ft

You have 0.96 cu ft of port area. that's for a 6 cu ft box

21w x 18h x 30d

port 3w x 16.5h x 18L

you get 4.5 cu ft after port and sub displacement, tuned to 34.4hz with 17 square in of port area per cubic feet.