New guy from Chile, need help with port :(

[Joe X]

Are you sure you want to build something that complex ?

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thanks for responding

yeah sure, I know when you are short in dimensions things get tricky, but I find myself very attracted to detail of things, so this won't be a challenge for me (I think)

let me upload the 3D model so you can take a look by yourself (if you want to)

will give the link as soon as I find where to upload

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here's the link for anyone who wants to see it

https://www.dropbox.com/s/lemp15kcmg689gi/vvx.skp

[Joe X]

Just by looking at your numbers above, 2.8 cubes net is kind of low, it starts at 3 cubes net but I would probably give more, depending on what you want, for SQ I would keep it 3-3.3 for deeper low end and higher efficiency and output 3.5-4 cubes net. Just saying though one can never exactly know what the next guy will like.

Take away 5-10% of the length you calculated following the center line and use that and it may be more like what you will be getting. If you didn't figure the end correction for slot ports add half of the width of the port to the length.

[Joe X]

I would also suggest to take away the top of the port chamber and grow it to the top of the box if possible.

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mmmhhh.... this is driving me nutz lol

what do you mean when you say sound quality and output?

I'm gonna re-measure again my trunk to see if I can make a bigger box.

my real goal is to have the box move lot of air between 20-35 hz, that means bigger box or smaller? (I think is bigger right?)

[Joe X]

A small box ported box has better transient response and plays flatter which is what you want on SQ setups, a larger ported box will be peaky and have lesser transient response but it gets louder on the same power, a good daily box seeks to find a good balance. So yes bigger in your case but keep within 4 net and not too much above rated power to prevent damage to the sub.

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ok Joe, if you approve this box, I'll build it

if you think there's something wrong just tell me, I rather redesign the box 100 times than build one that isn't going to go towards my goals.

as you said to have a balance between output and SQ, this is what I got

net volume is 3.55 cuft after port volume and sub displacement

port is a perfect square, 18cms on every side and it's 104 cms long, this gives me a 28.5 hz tune

port area is 14.15 square inches per cubic feet. (port area on the enclousure skar audio recommends is 12 sq/cuft, so I think with the one I got I won't have port noise)

Tell me what you think

[Joe X]

It looks definitely better, increased port area and a single turn port is nice I would keep the inner end of the port at least 10" from the side wall, 29Hz or so is plenty low, maybe too low considering cabin gain, I have done spectral analysis in many low tuned songs and is extremely difficult to find something below 25Hz other than slowed music.

One other thing, boxes firing back need a return path for sound waves to easily go into the cabin so is not good that a box goes full width full height. not really sure if it's the case with yours but bear that in mind.

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hey again,

ok, I fixed a few things, port is 10" away from inner wall, so new port lenght is 89 cms, also new net volume is 3.82 cuft (due to less port lenght)

port area is 13,15 sqin/cuft so I'll use a round bit to flare both ends.

with all this, box gets a 29hz tune (I think is perfect for me cause I listen mostly decaf songs)

about the dimensions, height is the same as the last box I built for the IVX sub, so there's enough room above to go into cabin, other thing to consider is as I removed the slanted part of the box, there's a lot of space back there so waves can go through there too

this is the final design

I really want to thank you Joe because you've helped me so much in this design. I would like to shake hands but you know, I'm very far away from you lol