Slotted port displacement question

[K5BEAST]

Where do you begin calculating the port displacement in a box design shown in the attached pic? Point A or point B or ??

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[1aespinoza Premium Member]

Point A

At the end of the tunnel. Point A.

 

[SlugButter]

Yep. Point A. The last 3/4 of an inch on the exit end of the port won’t count in the displacement though. Take 3/4 off your length. You also have to add the 3/4 wood thickness of the inside port wall. if your port is 4 inches w x 14 high x 30 long inside, your displacement math would be 4.75 x 14 X 29.25. For example.