Need help designing a box for 2 soundqubed 12's

[TheLeeStrikes]

So im starting a new budget build for my cavalier that consist of 2 soubdqubed HDS312 im trying to stay on a budget and not have to upgrade my alternator, i already have the big 3 upgrade did it with 0 gauge welding cable (that one that is really hard to flex) i have stock alt and stock battery but i will upgrade the batteries for some agm in the future more than likely one under the hood and another one in the back, right now i have only 1 hds312 on a hifonics glz1400.1d and voltage drops to like 12.5 or so but thats because i have a really shitty battery its like a tiny small one lol not even agm. now i saw a box that i liked the design of the box and i would like to make the same box design for my set up but i cant figure out how would the port go in the inside of the box or how to actually tuned the, ive made boxes before but most of the times only single subwoofer boxes was wondering if anyone knows how this design is from the inside and how would i know how to tune it to like 30 hertz for the lowz. heres the design im talking about. http://s348.photobucket.com/user/solis_pablo/media/box.jpg.html

[Joe X]

That box is good for a hatchback but not a trunk car.

[dharris2488]

You need something like this? These are exactly what you have tuned to 33hz. I wouldn't go much lower with the HDS3's... I can give you dim's if you want them?

Pardon the shitty video, it was the first video i ever made and I didn't know how to speak into a camera. You can skip through a lot of it, cuz I'm just blabbering and couldn't get words out of my mouth!

But, you'll get an idea of what this style of enclosure will sound like...

https://www.youtube.com/watch?v=5CyvstaKbYw