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I have read that post before and just read it again now, it states nothing about what your saying of a 6:1 ratio or what basis youre using to say its inefficient. That post is about surface area. I adjusted the dimensions slightly and increased the port to 3in. Cant do any larger or it wont fit. Air velocity peaks at 20 now. Im not trying to fine tune or do aeroports or hexagons or any of that. I just wanted to know if Im in the right ballpark area. ill add some flares to the outside of the port and round the corners and paint the inside for a smooth finish whatever etc. Just want someone to confirm if the specs are in the right ballpark for a 32hzish port lol. And also a little on the confusion between people saying 17 peak air velocity vs others saying 30 or mid 20s

I would have to agree, I like the Stone Paint! Gives me an idea for my next update. This build is lookin really good, can't wait to see the finished system!

Yes of course the elbow has it's own center line length and the straight pipe length needs to be adjusted, it's pretty simple to do that, you want to pick an elbow that does not turn too abruptly to help with port efficiency. I will provide you with details if you end up going that route.

The elbow itself would be considered part of the length, and I don't know how to account for that

You can do them external or partially external if you want but not having a self contained enclosure is not something you see done, round ports are hard to work with, you can install elbows in the ports to change direction if you can't make the design work with the port straight. Round ports also need bracing sometimes. Hopefully you are not doing your box calculations by hand.

And if I run them externally out of the enclosure, would that hurt anything?

0.831 cubic feet for both, bear in mind that the external diameter of the port is what counts for displacement, not the internal which is 6". Small difference anyways.

Does 0.38 each sound right?

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What would the displacement of each port come out to?

Yes, exactly, you need two to reach the necessary port area for proper box operation.

Couple as in (2) 6” ports?

A couple of 6" ports 23.25" long each will tune you to 35Hz, the ports will ideally need 6" clearance on either size to work as expected. Driver displacement should be around 0.15 cubic feet each.

Currently trying to design a box for 2 SoundQubed HDC3.112’s on an Orion 2500.1Dz at 1ohm. I am aiming for 2.25ft3 per driver, 4.5ft3 net volume, with a 35hz tuning on the port. I would love to use an aero port, but I have absolutely no idea what I’m doing when it comes to ports, let alone aero’s lol. I’m looking for help choosing the size/length of the aero, and am able to make my own if necessary. Just don’t have the slightest clue on what I’m doing.

Does 54.86 sound ok for port area with flared ports for a 4.92 net cube box? Box is being ran with 2500 watts with a Fi Hc 15”

The area ratio issue is explained in the first post of the thread I told you about, bottom line is friction losses, you want to minimize the amount of contact surface for a given port area, in order of efficiency circular is best, 5 or more sided regular polygons, the square port and then the rectangular ports which get worse as the area ratio increases. This is one case in which you may want to increase port area as a countermeasure if you have to go with a high area ratio port. BTW further information regarding port area ratio and other slot port design guidelines can be found at JL Audio's support articles at jlaudio.com.

Your suggestion is to start with 15/30 give output from lc2i 5v to amplifier and set gain with -5db . Is this right ?

Already aware of all those points except 6:1 port ratio? First time Im seeing that anywhere. Everyone talks about the air velocity and chuffing whatever which I already mentioned the ranges I read and still confused on that. What exactly about the port I have makes it inefficient? I already have 2 hooked up in a crappy old prefab box my brother had laying around. Id prefer all 4 and the boxes are designed for sub up/port back. I just need to option of easily removing 2 or all for space when needed.

You have chosen a spec as follows on a per driver basis: 2 cubic feet net 32 Hz and 27 square inches of port area (per driver). 1) Port area will be good for the threatcon-2 (600w) drivers but not for the threatcon-4 variant which were 1200W or 1500W RMS. 2) your port is too thin making the port inefficient, best is to keep 6:1 heigh to width ratio or lower. 3) SUV boxes are subs up /port back. 4) generally 2 12s are lackluster in a SUV, probably that's what you will find out. That's about it.

if your radio is distorting at volume 15 with 40hz, than that should be your max volume regardless if volume 20 is clean with 1khz because anything after 15 will always be distorted on your lower frequencies. Not to mention most factory radio equalization starts to limit or lower the bass frequencies towards higher volumes to protect the crappy factory speakers, so you never want to set gains using a higher volume unless you're running some sort of DSP to fix the horrible factory eq curve, sum the channels together, etc.

You need to be below 30 m/s to avoid the worst from low port area, and you target a lower airspeed according to your needs, the ultimate way of checking how your port is doing is looking at your impedance curves (advanced topic), you may want to take a look at the following thread for some more infos on ports because raw port area is not the only thing that goes into an efficient port:

Total noob to box building never done one in my life. Saw some boxes from posts and websites but none really fit my space needs. I downloaded winisd watched some videos read a ton of posts and went to work. This is what I came up with, plan is to make 2 of them, 4x 12 c2 audio threatcons on around 2k right now possible upgrade to 3k if I can convince myself to buy 2nd battery which I dont want to. I wanted the option of only running 2 subs or being able to easily remove if need, so no massive single box. The only variation is that the subbox site has the port length a couple inches shorter. It will be 29in since thats what all of the calculators and winisd come up with. i have around 42-44in width, 33-34 depth, 15-16 height to work with. Am I in the right ballpark with this? And Im a little confused on port velocity. Ive seen some stuff saying it needs to be under 17, others saying it needs to be under 30 or mid 20. Seems like a pretty big range

It’s an old school Brahma

Hello guys , Stock HU not sony on ford with 6.5" front RSX165 gladen , audio control lc2i and 2channel amp. Active sub under seat us8 gladen . With oscilloscope play 40hz 0db dist 15/30 1KHZ 0db distortion 20/30 I know that is not right but I start it with 20/30 and set the hole setup. Continue with 1khz 0db and set the LC2i main output at 5v with DMM continue with 40hz 0db and give bass output 5v --->to underseat sub. After that -5 db 1khz to set gain to ampl with crossover to FULL. Is this the procedure almost correct guys ? (I know that I must change the HU but not know )