double check ported box.

[bvr_j_0969]

i dont know anything about building ported boxes so i had a guy design one for me and he seems to know what he is doing but since i dont i cant double check his stuff (i like to double and sometime triple check everything to cut down on wasted mdf and money) besides im broke so i dont have the extra money to be wasting on wood. so can anyone check to make sure everything is right.

http://img.photobucket.com/albums/v653/bvr_j_0969/BOXPLANS.jpg

[bvr_j_0969]

using this site
http://www.carstereo.com/help2/Articles.cfm?id=31
and the outside deminsions of the box,
then subtract the sub displacement put it at 2 cft
then putting in his port opening i got 16.26" long would this tune the box more towards 30 hz?

[bvr_j_0969]

so im guessing i answered my own question?