To figure out the needed information for a transmission line:
1: The subwoofer needs to have a Qts of .40 or lower
2: Get the subwoofer’s Fs
3: (1130/Fs)/4 will give you the length of the 1/4 wave length needed in feet. This needs to be the length of the port. Don’t worry, it will be long.
4: Next you need to figure out the port area needed, which should be the same as the subwoofer’s Sd. If you don’t have the Sd, here’s how to figure it out: Measure the subwoofer from center of surround to center of surround and divide that by 2. Then take that measurement and apply it like this: (measurement/2) x (measurement/2) x 3.14, that will give you the Sd. This is also your port area. If you are using multiple woofers, just multiply that by the number of woofers you have.
Confused yet?
5: Now you know how much port area and port length you need, and there is no chamber, it’s all one port, so now all you have to do is figure out how to get that length in the area that you have to work with.
You can thank stratusrt01 on the realm fourms, that's who I got this info from, I have not tried it yet.