This is my first go at trying to design a ported box so just want to make sure I got the numbers right. This is for a coworker. The sub is a DD 9515. According to their site it should be 3 cu with 48"^2 of port.

Here's what I came up with:

24" x 22" x 15" and the port 3 9/16" x 13 1/2". If I follow the "rules" and make it 20" long it'll be 38ish tune.

I appreciate any input you can give. 15" height is to keep it under the window line and cannot be modified. Other than that any suggestions welcome!

You need to give more information. One can't recommend some amount of port area without making reference to the tuning (and to a somewhat lesser extent power).

 

Those dimensions alone are meaningless. Are they internal or external dimensions? If external, what wood thickness are you using? Don't forget to account for displacement of a double baffle if using one, the speakers themselves, bracing, etc. Until we know the volume we can't calculate the port.

They are external. 3/4 mdf. I did forget to add in for double baffle. I just went to the DD website and looked up the "DD box." They only say for 1 15" it should be 3 cuft with 48"^2 port 20" long. So I just tried to stick to that. The box should be 3.6 ish and then .5 subtracted for port displacement. And another .16 for sub. I had to guess sub displacement because I couldn't find an actual number. Figured that would be somewhat close.

So they're suggesting 40hz tuning--kinda shitty. Is this for daily? 0.16 ft^3 per sub for displacement is good.

Ya just a daily tune. I thought the same thing thing about tuning that high. He wants what they want so...