Port question

[Better-Action]

I plugged my numbers into two different port calculators and am getting a difference of an inch from the 2.

Not really understanding what's going on here.

The box volume is 3.589 going of the external dimensions minus the mdf thickness, driver displacement and bracing. 16h x 18w x 28d .75" mdf

Tuning is 31hz. 14.5" high by 2.5" wide slot port.

When I punch these numbers into the two calculators, I get a port length of 23.35" from one and 22.1" from the other.

So something isn't right. I would assume over an inch different would really affect the tune, correct? I'm just wondering if I'm going about it wrong in some way and could possibly get some opinions on my course of action.

Hopefully I can get some input on it. In the end If its to much of a hassle, may just switch to Aero ports.

[schrummy]

i get 23.35 using my calculator.... as for one extra inch.... i have you at a swing of 30 hz to 32 hz within 3.75 inches..... also, was there an end correction on the other port calculator? that would allow a shorter port.

[Better-Action]

It could be. So.... basically with the margin of error I'm still going to fall in the 30-32hz range?

Also, the enclosure before the port is 3.589. So I take the port volume and subtract from the overall volume?

So subtract .49 to get 3.099. So the final product would be 3.1 cubes at 31hz correct?

Sorry for the stupid questions. I have built a few boxes but somebody else has always designed them for me. Trying to learn to do it on my own correctly.

[Better-Action]

Nevermind. Read the sticky on this subject. Guess that's what its there for haha