ok, so ive had this huge sub box sitting on my back seats since august. I got sick of watching the ox rock back and forth as i accelerated and braked, it got rediculous. Well i went to college and put my car on stands in the garage. Ive been back for a couple weeks and ive wanted a project to work on for my car. So i ordered a hood and decided to move that box. So heres where questions come in. Ive got 3 ten inch Polks in a factory, ported box. I really like the sound so i want to keep em ported. Im not looking for dimensions. I just want to know what all is in building a box. Do i just build a box to fit the well and put a faceplate on with holes for the subs, and a few ports. or is there more to it. ( Im guessing theres a whole lot more to it.) Hope my questions arent to dumb. hopefully you guys can tell me what the hel im suposed to do. thanks for any help

mitch

 

making a ported box yourself will be hard to do, you need to have the right volume first off, ported boxes are bigger than sealed, and you need the right length and diameter for your ports

 

I agree, to get it right, you really need to know what you're doing. I had two 12' subs on my back seat for a long time...luckily, someone helped me fix the problem.....they broke into the car and took the speakers. Problem solved. Our cars are one of the easiest to get into so I'd recommend getting a custom box for the rear tub or make one of your own.

 

you need to find the internal airspace of your box

so a box 12X20X18 using 3/4" wood would be

(12)x(20)X(18)=432000cubic inches divided by 1728=2.50cubic feet

then you can go to a port calculator like this one:
http://www.carstereo.com/help/Articles.cfm?id=31

and figure out your port dimensions. You will have to play around a bit with the length and width of the ports to get the length you are looking for. I suggest using rectangular ports because generally you will see better results with more port area.

The higher you tune your box the more SQ you will lose generally. For all out SQ many people will tune to 20hz or so which is quite low for streat beating, i recommend a 35-45 hz tune for a good SPL/SQ mix...but you can make different ports and figure out what you prefer. I had lots of fun with a box tuned to 22 hz, it peaked at 27hz and it was just brutal inside the car. Hit 142.2 @ the 27hz note which is a fairly good accomplishment, probably was capable of 147ish in an SPL box tuned higher

 

Ya. I would get something thats not easily taken out. I hope your good at making custom boxes...
anyway good luck let us know how it goes.

Nate

 

yah man look into makeing a fiberglass if you really want 3 10s in there to get the most space out of your car. Look at my site or at thirdgen.org tech articals. If i were you id do a sealed box but thats just my opinion.