95 probe, calculations for box w/ 12's

Hey guys. Ryan here. Umm i have a 95 probe gt.. i have 2 rockford 12s.. and i have them in a box for tens.. obviously cut the holes bigger but i only have one of the subs plugged in (dont want to risk blowing anything ya know). Well..im designing plans to build a new box..custom like nothing else.. thats what im good at.. the only thing im not good at is.. well.. calculations. this site is SWEET but not the info i need. Im gonna make two different boxes.. so i need calculations for the box tho. im building two wedge shapes. i need some help guys..im a designer kinda guy.. not the mathematics. can yall help me,... im not as dumb as most people.. but im trying to learn as much as i can ya know?! so, i know 12 boxes need 1 sqft right?!?! but ive decided to port them (if thats whats best for a hatch). help me out if anyone can please.

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-Ryan Strobel

What modle of Rockford subs are they? Your box should be bigger if its ported. Not all boxes for 12s are just autiomatically 1 square foot big. The manual for your subs should give you proper box and port sizes.

punch hz's and i think they are 4 ohm. and i have to find my manual.. but i think it was 1 for 1 tho.

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-Ryan Strobel

Ryan,
If you really want to build a good ported box your going to need to learn about T/S (Theil Small) parameters. These are a list of values and properties that are different for each model of sub. This site has a page where you can learn what each one means and then you need to find a good book on how to use them. The "Car Stereo Cookbook" by Mark Rumreich is one that I have found most usefull.

Your manual or another paper that came with your subs might have some suggested configurations already calculated with volumes, port diameters, and lengths.

I guarantee you that if you build a acousticly correct ported box you will end up closer to 2 cu. ft. per sub than 1. This could end up taking most of your trunk. IMO you should stick with a good sealed box especially if this is your first box project, then later you could mess with a ported system. You might not get a much spl out a sealed box as a ported one, but it will sound very clear (I'm more of an sq guy so that is my main concern).\

my 2c

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If quiters never win, and winners never quit, who the heck came up with the idea that you should quit while your ahead?

Ryan, i agree that you definately need more space.  My G-friend has a 94 Probe GT, she previously had 2 Audiobahn 10's in a bandpass box that was WAY too small.  The subs distorted and sounded like total ass cuz they needed much more room.  I built a ported box according to the factory tech/spec info and now they POUND!!!   12's push a lot of air so you need to give them some room to "breathe".   Most 12's need at least 1.75 cuft. and 2.0 seems to be somewhat standard.  Chech the RF homepage for info on box sizes.  B.T.W., a duel-chambered ported box sounds loudest in a hatch.  Good luck!