Box tuning help for a noob

[Beavis]

Hi and thanks for looking, I'm trying to design a box for 2 fi bl 12s in my 1986 el camino. I've got about 5.85 ft^3 before the port and I'm a little hung up on trying to tune the box. I'd like to tune it to somewhere in the low 30s and tried using a couple of different calculators like this one

http://www.carstereo.com/help/Articles.cfm?id=31

I'm just a little confused because when i increase the height and width, the depth of the port also increases? Am I doing something wrong? Sorry if I'm overlooking something simple here and any help would be appreciated.

[jk13]

Yep, larger the port the longer it needs to be to keep the same tune in the same air space. Make sure you're also subtracting the greater port displacement as well.

[Triticum Agricolam]

If you post the dimensions of your box we can probably help you double check your numbers. Like jk13 said, as you give the port more area it has to get longer to keep the same tuning.

For a pair of 12" BL you are probably going to want to be somewhere around 60 sq in of port area.

[juan777]

Post dimensions

Or Torres Calculator

If as previously stated you are a noob, I would post max dimensions/desired tuning and let someone more knowledgeable design for you