Do you always do that kind of measuring for percieved length when the distance from the end of the port to the wall is the same distance as the width of your port.
So your width is 3 inches and teh length from teh end of your port to the wall of the enclosure is 3 inches.
Because is that what you did for this...
(off of the third page)
You are commenting on my diagram that i originally posted.
about your T port. my drawing is a true T port "no baffle separating each port". your drawing is not a T port, but two L shaped ports back to back, so you would calculate your T port length and width of the port at the end of the port, just like you would for a regular L shaped port. and 12+7+1.5 is incorrect. assuming that the port end is 3" from the nearest wall and 3" wide. it would be: 12" + 7" + 1.5" + 1.5" + .75 + 1.5"= 24.25" of perceived port length
when you draw your port you don't draw the port with port end correction, because port end correction is a perceived length. its not the physical length of the port. you draw the physical length of the port. the same way it would be built.