Port breathing space

[Fique]

I was thinking this today while designing another box. I have a 9"x25" port. Its a dual sub enclosure with port in the middle. I always hear the diameter of the port is what you need between the facing wall. Does this apply to only round ports?

My understanding would be at least 4.5" would suffice since there are two chambers going into one port, 1/2 of the 9 is 4.5. If i were to divide the single port with a board I would only have a 4.5 inch port, 4.5" away from facing wall ( X 2)? So the 9" port is just removing the dividing baffle. Still only 4.5" away. I went with 5 1/2" for safe measure anyhow. Does this make any sense?

[mmouse57]

9in x 25in? god damm thats huge what kinda subs 4 15's

[Fique]

Yeah, f-n huge man, not sure how Im gonna lift it into truck, lol. Twin 18's. 9x25x27" port. Got great pics of the build, hope I calculated everthing correctly.......oh yeah box is 17 cubes dead on, so does anyone know on the clearance?