18 ported box

I would like to apologize for having to ask about this topic. I personally wouldn't use a sub that doesn't have info on optimal box size and what not. The sub I'm building a vented box for is a Pyle PL1890BL. I've entered in the specks from Pyle's web site to Winisd. It says I need a 299 ft^3 Box. What is wrong with that picture? I changed the box size to 29"x19"x14" MDF of .75" thick = internal volume of 3.48126. I have no idea about woofer displacement. Tuning the box to 45hz using a 4" port Winisd says I need a port length of 1.82" (doesn't seem long enough)gives me an 8+DB gain from 45hz to about 60hz. Can anyone help I'm looking for port length for a 4" port and does that length include .75" wood thickness? And woofer displacement I'm sure that will be needed to get the port length right.I'm also using a .5" shelf brace with holes in it.Christian

Well I went with a 10.25" long port. I don't know if this is the optimal length but it hits pretty hard. Just finished sealing up the top baffle. So I wont get to hear it in the car till tomorrow. I still would like to know why winisd was telling me to build a 299 cubic foot box.Christian