I will be getting a Atlas 15" for my ford ranger extended cab. I have a box designed but I don't know how to build the port. I want to tune the box to 28Hz. Can you help me with the port? A link to the box is below.
First I don't know the displacement for your sub. The displacement for the port will be so small I don't even worry about that.
From your photo I got 3.61 cu ft if you made it out of 3/4 wood. For the port you can take round PCV pipe and put in the box. To get 28 Hz you can use one 4 inch pipe and have it 9 inches long one 3 inch pipe and have it 4 and 1/2 inches long. I tune my boxe at 36 hz
ok if your cubic feet of box is 3.61 internal after displacements for sub and port then you want two 4 inch inner diameter ports 21 inches deep a piece for a 28 hz tune even if that box size was before the sub and port youd still be tuned around 29 hz port volocity is accounted for even up to 1200 rms( im not sure of that subs power handling)