stupid box building

Hey guys, I am getting ready to build a box and I am using the sites calculator, I have built many sealed boxes but never a vented enclosure. I am confused... So I enter my dimensions i.e (26"x14"x14) which is 2.2ft3 Then i took that 2.2 and plugged that into the vent calculator building my vent 2"x12.5" tuned at 35hz and it tells me the vent needs to be 20.87 inches long. Here is my question, do I now need to add that space to the outside dimensions of the box or is the calculator factoring everything in taking up internal space of the box? Thanks Keith

The calculator assumes you have already factored in the space consumed by the vent.  The volume you enter should be net, with vent, woofers, bracing, etc. subtracted.  With your 2.2 cuft calculation I suspect the real net volume you will end up is closer to 1.8 cuft.  If you want to have 2.2, you need to make the enclosure larger by at least the size of the vent.Support the12volt.com