calculating port displacement

[Bass head 4-15s]

Guys need help using torres box calculator and when I put my port dimension in it says that,

t​he displacement is 1.36 cube feet but when I add it up it's 1.09 cube feet am I wrong or torres.

port size is 47.5-4.25-6.5 port wall is 1.5 thick. that's inside measurement.

w h L

[Joe X]

Torres miscalculates port displacement but maybe you did a mistake too, best way to calculate volume is by using sketchup.

[Bass head 4-15s]

Ok what is that and were do i find it and thanks joe.

[Bass head 4-15s]

Ok i look it up got it bro.

[Joe X]

Here's a link:

http://www.sketchup.com/download/all