Box design Questions

[ryls 10+ year member]

Okay let me start off by saying this is my first ported box as all my other setups have been off sealed enclosures and i wanted to play with a ported box. With that said i have been reading alot lately to try and comprehend how to build a good ported box and had a few questions regarding a box i made and am wondering if what i am seeing is right.

First off i used Re's L shape box calculator and came up with this

Now here is something i did quickly in mspaint to try and explain what i am seeing.

Now the green area i have in actual area 18.25x15.75x12.5 for 3592.97. The red area is 12.5x6.12.5 for 937.5. Add the two together for 4530.47 then devide by 1728 for cubic feet and i get 2.622 which is close to the 2.682 but not quite the same.

My real question/concern is the fact that the port says its 24.5 inches and i come up with 23.25 when i add the two lengths together. Am i right or is the calculator?

Now that i have built this box and am getting more familiar with the how to's will probably just use it as a guildline when i build my next one. I was aiming for tuned to 35 and when you take out the .2 dispacement for my sub ( 05 xxx 12") im pretty close but not sure if im close as in my number in port lenght or close as in the calculators.

Im thinking the next one i do will be a bit bigger not sure if i want to go a full 2.5 or 3 (after sub displacement) cubic feet tuned to 33.

So yeah basically i would just like some confirmation on my numbers and what is the actual port lenght for the box i built.

Thanks in advance

Oh and as a side note any input on box size/tuning freq is appreciated aswell, i plan on building as many boxes as it takes to get the sound i want.(time is free and wood is cheap) Which isnt easy considering the wife listens to rap/dance and i listen to all kinds of metal.

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[dappa5 10+ year member]

to measure port length you measure down the center of port not @ inner or outer wall

so re measure down the middle and see what you get

 

[dappa5 10+ year member]

and sounds like you need a diff set up a XXX12 for dance/metal/rap??

G/L with....um...that

 

[ryls 10+ year member]

and sounds like you need a diff set up a XXX12 for dance/metal/rap?? G/L with....um...that

Actually in the sealed box it sounded pretty good was just missin a bit of punch for my type of music ( metal). That being said it definatly dosnt now but it is a bit on the real lows but i can live with that, mostly cause thats the wifes type of music.But mid 30's+ it sounds pretty good if not a bit overpowering at times.

As for the port measurement if i measure down the centre i get my 23.25 and not the 24.5 that is showing on the calc. So am i right or am i missing something ?