15 inch DD

[Pop da Hatch 10+ year member]

Was just trying to figure out some specs to a box for a 15 - was at the digital designs website and at 5 cubes for a 15 inch driver it recommends 75 sq" of port that is 16" long would come out to 40hz tuning. Well i figured id do some calculations box would be 30"x12"x28" (width by height by depth) which comes out to 5.13 cubes - port would have to be 12" tall by 6.25" wide to stick with the 16" length to hit the 40hz tuning, i was just wondering if i could make it 12" tall by 4" wide which would come out to 25" long - was just wondering if this different port size - since it isnt 16" long would still be at 40hz - help me! how do i figure out my tuning?

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[Pop da Hatch 10+ year member]

NEED HELP - where da answers at?

 

[radiohead76 10+ year member]

make the port @ least 16" long and 15^2 inch per cubic foot to get a kickass output @42-50hz ....... i usually make the port 20"+ for extra low end output @ 35hz and lower

 

[audioholic 5,000+ posts]

Was just trying to figure out some specs to a box for a 15 - was at the digital designs website and at 5 cubes for a 15 inch driver it recommends 75 sq" of port that is 16" long would come out to 40hz tuning. Well i figured id do some calculations box would be 30"x12"x28" (width by height by depth) which comes out to 5.13 cubes - port would have to be 12" tall by 6.25" wide to stick with the 16" length to hit the 40hz tuning, i was just wondering if i could make it 12" tall by 4" wide which would come out to 25" long - was just wondering if this different port size - since it isnt 16" long would still be at 40hz - help me! how do i figure out my tuning?

Why would you think the tuning would remain the same if/when you changed the port size? Port length is not the only determining factor in a port's tuning, its cross-sectional area (LxW) also determines this. Change any of those three variables and the tuning changes as well.

There are many port calculators floating around out there. Do a search for one, should be easy.

 

[Pop da Hatch 10+ year member]

i was confused that day basically i wanted to keep that same 75 cubic inches of port area but i didnt want my port to be ****in 6.25" wide - i got it now

 

[audioholic 5,000+ posts]

i was confused that day basically i wanted to keep that same 75 cubic inches of port area but i didnt want my port to be ****in 6.25" wide - i got it now

You can adjust the length and width of the port, so long as the port area remains the same (75 inches in this case), and the required port length should not be affect. In other words, with 75 square inches of port area, no matter what your port dimensions are to get that 75 inches, port length will remain the same for a given tuning frequency.

Glad you got it figured out. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif