Need some help with sub woofer enclosure design port displacement

[boxman75]

I am new here and may be posting this in the wrong place but I was wonder if someone could point me in the direction `of reading material web or other wise on the formulas and such for figuring out slot port displacements on various designs. For example a box that the port does not reach the back wall of the enclosure is easy but boxes where the port must turn inside the box or where the ports must make 3 or 4 walls is what I am looking for.

Thank you

Mat

below are some of the port configs i am talking about

[mikee12345]

www.jlaudio.com 'tutorials'

http://www.bcae1.com/ scroll down to 116.