Help with port tuning

[BoxdGM 10+ year member]

i recently bought a box from someone who had it built for a 15" L7. i was wondering if you gurus wouldnt mind helping me out with what the port is tuned to and the internal size of the box.

Box: 18" tall by 32" wide by 24" deep made of 3/4" Mdf

Port: 3.5" wide x 16.25" tall x 13.75" deep

Thanks for the help, if im missing any important info let me know

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[GearGuy2001 10+ year member]

Alright Im sure someone will double check me but

After you subtract .75 around the demensions I come up with 16.5 X 30.5 X 22.5=11323 The Port takes up space as well so subtract 16.25x13.75x0.75=167

11323-167=11156/1728=6.45 Cubes

Also for the Port does it make an L turn of is it really only 13.75" deep?

edit: Im new at WinISD but I think the box is tuned to 34hz

 

[BoxdGM 10+ year member]

ok cool thanks alot. the port made with a wall that is 13.75" on the shorter side, the longer side (the box wall) goes all the way to the back of the box, but theres no "L" shape to it just one shorter wall

 

[GearGuy2001 10+ year member]

Yeah thats what I typed into WinISD, I think like I said Im just learning WinISD and it said 34hz

 

[BoxdGM 10+ year member]

seems kinda high for a 15, but it made it alot louder

 

[schrummy 10+ year member]

not to second guess gearguy but i always understood that the port is not part of the box and u have to add the port on to the air space. like if u wanted a 6 cubic foot box u would design that then find how long of a port and add it to the box plan.

i did the math and got 6.025 cubic ft net. will be less once u add the sub. i got 36 hz.

 

[adam212 10+ year member]

yes the port will take up the volume so once you find the standing volume thats when you see waht the port is tuned to

also if those were the outter dimensions of your box it will be tuned higher too

 

[GearGuy2001 10+ year member]

yes the port will take up the volume so once you find the standing volume thats when you see waht the port is tuned toalso if those were the outter dimensions of your box it will be tuned higher too

Yeah Im still learning this stuff so I knew I was close but the cubes I figured include the port area, so you subtract the port area? or in this case Port: 3.5" wide x 16.25" tall x 13.75" deep ?

Let me know

 

[schrummy 10+ year member]

then the wood thickness so the 3.5 wide port would take up 4.25X16.5X13

 

[adam212 10+ year member]

you add up the dimensions of the port or multiply and then divide by 1728 just as for cubic footage and you'll get a number probably a decimal and just subtract it from your box volume