View Full Version : would this box design be bandpass or just a wierd sealed box

04-25-2007, 11:38 AM
What i am trying to do is completely isolate my trunk from the rest of the car. My box will be 2 separate hatchback boxes 14.5" deep at the top and 19" deep at the bottom. Width is 17" and height is 14".
The two boxes will face each other with the bigger opening of 9 inches between the top edges of the boxes pointing to where the factory 8 " sub used to be in the deck panel. I am going to plate the boxes together with more mdf to create a front chamber sort of on the front rear and bottom. like putting the smaller boxes in a bigger mounting box. The fourth side will be open to the top facing the deck lid.
Here is where it gets strange. I was going to make a plate/port to fit up through the 8" opening in the deck lid to try to direct all the sound through. But the virtual front chamber volume would only be around .78 cu ft. That is way too small for a bandpass to work right so i am considering cutting the 8 inch hole to around a 10" square hole. Because i am concerned about attaching the plate to the deck lid i was thinking i could stop the top plate/port about 2 inches from the new opening and screw a frame made from angle iron to it and attach a boot from that to the new opening. Would i still just have a wierd sealed enclosure system or did i cross over into a useless bandpass setup?
I am probably either crazy or just desperate but either way i just wanted some input about it before i broke out the plasma torch and went ape S**t
The car is a 2007 dodge charger
The speakers are 12" Kicker comp cvr's i have 4 but i think there is now way to get them all in there and get any output so i am just using two of them wired paralled (dual 4 ohm subs). I have tried everything i could think of .
I am running them with an exile 1200.1 and wiring it to a 1 ohm load for the full 1200 watts

04-25-2007, 11:44 AM

pictures would REALLY help! lol

04-25-2007, 12:23 PM
i am stuck in africa right now and my car is in oklahoma so i am just brainstorming for ideas for when i get home. really all i want to know is would connecting the two sealed boxes and leaving a 10 inch opening on the top have a bandpass effect or would it still be able to work as a sealed enclosure

04-25-2007, 12:26 PM
Worry about your life right now, beware of the Rebel Troops.

**** car audio buddy, you're in Africa!

04-25-2007, 12:29 PM
Maybe this would help explain it. I don't know if you remember the old Qlogic bandpass boxes that had a plexiglass front removable panel. It was one enclosure with the dividers angled backward and some space left in the middle around 10x10 inches to install or service the speakers. What i am wondering is if you were to take a box like that and pull off the plexiglass front and instead put a tunnel the same size on it through the decklid would that work.

04-25-2007, 12:41 PM
i'm not in the military and i am bored out of my mind and am going home in a week but thanks for the concern

04-25-2007, 02:15 PM
if your actually willing to start hacking into the rear deck of that car, then why not just cut 2 holes in the rear deck and mount the subs there. make a box on the under side....

04-25-2007, 02:28 PM
i think it would just be plain sealed.

04-25-2007, 03:39 PM
believe me i thought about hacking the thing to pieces but if this works alright i still have two 12's left and i don't have the room to put all four on the rear deck. i am hoping that if this works then i can add the other 2 12's behind these 2 boxes and go through the same opening and make another opening into the cab through where the fold down armrest is. That would give me another 6X9 inch hole to feed the sound through. So i would have around 308 sq inches of cone area and 154 sq in of opening to let it out into the world using all 4 and 154 to 100 with 2. I wish that the numbers were a little closer to even using all 4 but we will see how it works. I know that that is all fuzzy logic but it kinda makes sense.

04-25-2007, 03:41 PM
Is this what you're wanting to do?


04-25-2007, 04:45 PM
that is pretty much the idea except the speakers will be angled back away from each other and the opening at the top won't be across the whole depth of the box. just the middle 10 inches but that is a pretty cool program you got there

04-26-2007, 02:42 AM
It's free and easy to use; google sketchup.

If the panel doesn't cover the entire width, then yes, it will work like a 4th order bandpass.

04-26-2007, 03:55 AM
i guess that i can go my buddies stereo shop and hop on their box building program and plug in this box and see what the output would be using the open space between the sealed boxes as a front chamber with a 10 by 10 by 3 in port. i am still kinda thinking that it is just closed enough to put some back pressure on the subs but not like a bandpass completely because of the port opening. I think i will just build it and see what happens. hell it's only one more sheet of mdf. i have spent more time analyzing it than it would take to build it.

04-26-2007, 04:07 AM
Its a compression bandpass. what your doing is basically trying to have 2 sealed boxes with the woofers face each other but with a openening in the middle of the two correct?

04-26-2007, 06:19 AM
Yeah that is the idea. Is a compression bandpass a bad design or just not all that common. I am going to be gone for a while to work but keep leaving input about it and thank everyone for their thoughts on it. Check out my gallery. I was in the construction phase of putting all this stuff in my old pickup and this is all the stuff i am putting in my new charger if i can make it all fit.

04-26-2007, 06:35 AM
never mind about my gallery i am having problems with the upload

04-26-2007, 07:17 AM
ok i can't figure out how to fill up my gallery but i did change the avatar.

04-26-2007, 07:42 AM