View Full Version : port help please........

09-04-2009, 06:35 PM
i have a enclosure that has 3.22 cubft after sub displacement. i wanted to do a kerfed port tuned to 47hz with about 96 square inches of port . can someone help me out on the length. i was thinking about doing the port 18" long by 5.25" wide.

i got the 18" because that is the size of the box from one side to the other ( inside walls ). the 5.25" is what it takes to make it 94.5 sq inches.

i figured it out but then when i add the port displacement the box volume goes down and the port length gets longer. then if i make the port longer it adds more to the port displacement. what do i have to do ?

am i missing something here. i have done it before but i just cant figure this out .... i think i am getting stupid.

i appriciate all your help. THANKS

09-04-2009, 09:46 PM
Make your box 4.88 before port displacement. The port will displace 1.66 cubic feet. Make the port 26.59" long. There it is, 3.22 @ 47 with 94.5 sq. inches of port.

09-04-2009, 10:35 PM
Can't build a box and then throw a port in it. Would be easier to just add an external port to your existing box.

09-05-2009, 04:00 AM
i started with 3.45 cubic feet and after sub displacement i had 3.22.

i was told that 3.5 before sub and port displacement was the best way to go for my set up. it is strictly for a spl burp and that is it. i kind of don't want to go from 3.45 to 4.88.

i already have the box built just not the side that the port will be on untill i can figure it out.

jake760 : any chance u can help me with the port with the volume that i have already with out changing it ?

someguydude : i don't have room for a external port with this box.... i already have one with a external that i built i wanted to try one with a kerfed port to see how this works compared to my external aeroport box.