Recycle a box?

So I have the box that I just pulled out of my car about a week ago. The box is 5.0 cubic feet after displacement with 67 square inches of port tuned to 34Hz. It was for 4 12's. My question is how could I find out how much wood to add to the inside to decrease the volume of the box to closer to 3.5 cubes? And how would this effect my tuning? I'm hoping to lower the tuning closer 30hz. This would be for a pair of 12's instead of 4.

Is this all possible or should I scratch the whole thought? I have them in a sealed box at the moment and i'd rather have it in a ported box. This is all temperary until I can get a box made that is the correct volume and tuning.

you want my prefab? lol im planning on pulling my system, just a thought thatway you dont have to worry about cutting down a box lol

EDIT: i forgot you live in idaho lol that would be a fardrive for a box lol

you could use 2x4's and just do the math, length x width x height /1728. Add enough 2x4's to take up 1.5 cubes. If you leave the port the same though, your tuning will go up. I looked at a box calc and it showed the same port on 3.5 cubes being at about 41hz.
If you shrink the box, you will need to shrink the port some too. I don't know where you get your #'s but I like to use the calcs on the12volt, it's easy and all the calcs are on one page.

stephen_og wrote:you want my prefab? lol im planning on pulling my system, just a thought thatway you dont have to worry about cutting down a box lol

EDIT: i forgot you live in idaho lol that would be a fardrive for a box lol

Thanks for the offer! But yes i'm in Idaho. I looked around CL for a ported box that fits my needs but haven't found one that's tuned low enough.

RRR37 wrote:you could use 2x4's and just do the math, length x width x height /1728. Add enough 2x4's to take up 1.5 cubes. If you leave the port the same though, your tuning will go up. I looked at a box calc and it showed the same port on 3.5 cubes being at about 41hz.
If you shrink the box, you will need to shrink the port some too. I don't know where you get your #'s but I like to use the calcs on the12volt, it's easy and all the calcs are on one page.

I figured doing 2x4's would be the easiest way to do it. I didn't think the tuning would go that high, but kinda hoped it would have gone down instead of up. Oh well, I guess I'll run a sealed for the time being. Thanks for running the numbers for me!

So I can never remember... The bigger the box, the less power you wanna give the subs? Or do I have that backwards?

Topdawg wrote:So I can never remember... The bigger the box, the less power you wanna give the subs? Or do I have that backwards?

You got it right, smaller box and you can feed more power.

RRR37 wrote:

Topdawg wrote:So I can never remember... The bigger the box, the less power you wanna give the subs? Or do I have that backwards?

You got it right, smaller box and you can feed more power.

Hmmm maybe I'll just keep the box as is....