firing direction for subs

i have a 1997 mazda protege and im trying to figure out how im going to shove 4 12 inch subs into the trunk.

the space i have to work with is...

37 inches wide,16 inches tall,32 inches deep....

im thinking of maybe firing them all up im the trunk, theyde fit perfectly. but how would it sound?or how about all firing down?

or maybe curving the front inalmost like a U shape then they all could fit and fire forward.

do you guys have any suggestions? im so stuck on this and i need to get it done lol

any help would be appreciated, thanks guys

dump 2 of the subs....make a bigger box and give your subs more power.

Ill bet if ya put all 4 in the trunk, you won't be able to make the enclosures the optimum size.

If U used every sq. inch of the trunk space ....youd get 2.74 ft per sub. But thats not possible.

What kind of subs...and are ya lookin for sealed or vented ?

New and improved...

You've got plenty of cu. ft. to put in 4 subs, just limited on width to put 4 across.  But plenty of depth to work with at 32".  Here's a thought on splitting the subs into two enclosures, 2 in each box, a back row and a front row.  All are firing same direction, the subs in the back row are inverted, and you take advantage of the 32" depth you have to work with.  These subs can use 1.75 ft^3 or quite a bit less air volume.

The boxes can be of different shapes as long as the volume in each is the same (volume for inverted subs is less by the displacement of the driver plus some for the concave cone). 

Wiring would be separate from each box so you can reverse the phase of one of them.  4 ohms per pair and paralleled at the amp hookup for 2 ohm total.

It looks like a tight fit and not enough volume in the rough pic I made, but you have 37" of width to use so there's plenty of room for air volume.

 

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

im only going to be running one amp though,a rockford fosgate 1000a2, so how would i phase only two of them?

i love that design though, it looks awsome, thanks man.

p.s. i know the subs only require a 1 cubic foot box each sealed. but i could go bigger and sound better right?

also with 2 rear inverted subs in the back, how would the SQ/SPL be affected?

1.  You just reverse + and - wires at the amp terminals.  You'll have a wire coming from each box, so when you connect the back box wire, switch polarity at the amp.  (You can put double wires on the amp terminals.)

2.  Glad you do, I would like to try this out myself.  It should look real cool when you see it with the trunk opened.  It will be calculations like mad to get the boxes designed, but it's a lot of fun IMO.  Should be very do-able.

3.  Yes, work on the math using your full working width and see how close to the max. 1.75 ft^3 you can get.  The larger enclosure space will give you more SPL per watt.  Smaller spaces take more power.  You'll be along the lines of 1 to 1.5ft^3 for each driver with this setup, though, in my estimation.

4.  There should be no decline in either when all is done properly.

I can link you to some help files on calculating angles and stuff.  There are good wedge enclosure calculators on this site, here.  For figuring interior space put a "0" in the thickness category.  And a lot of other good links:  copy and paste my sig.

...and here I was anticipating a question on Step 2: Figuring Volume and Measurements.......lol...but you are already setting up the saw for the build!  No, I know you wouldn't start cutting wood before its time...

For visual appeal, the design wants the face of each box to be the same angle.  Their bases also are the same height.  Now, since you (I hope) have already figured out volumes for each box, you know how much room (depth) to give the front one and how much for the back one.  To have figured angles for the back box, you will already know what the depth and height is, and the angle of the face.

Copy the same angle for the front box.  The highest point should be the same as the highest point of the rear box.  The depth is determined by the available space overall (still 32"?) minus the depth of the rear box.  That leaves one angle, the backside of the front box.  It is formed by drawing a line from the center top to the top of the base.  During a build, I would measure and fit angled baffles after the base and any other known baffles are cut and assembled.

This project takes careful consideration of driver fit.  I hope you have the subs so you can work up a virtual mockup before cutting MDF.  The inverted subs have to clear the front box while allowing the boxes to fit snug together.  And the front subs have to easily clear the floor of the box.

The pic I made is true to scale as far as depth and height.  The subs were drawn freehand, but I tried to approximate scale as close as my eye let me.  You can copy the pic to a picture program and print it "to fit page".  You'll then have a working paper model for figuring volumes.

Front box will have two right angle wedges and a rectangle.  Back box will have one right angle wedge and two rectangles.  Those rectangular air spaces will most likely be about 1" but that's valuable air volume.  For wedge calculation, use the formula 1/2 base X H X W, or use the wedge 1 calculator in this site using "0" for thickness.  You are just figuring interior volume.

But, then, you may have really gotten past all this already.  What is the volume for each chamber, and what is the displacement of the driver?  How much did you add for cone area for the inverted subs?  Do you have a divider baffle figured in to separate the subs and provide bracing support?  What thickness of MDF are you using?

im using 3/4 inch MDF....here are the subs im using.

http://www.shopping.com/xPF-Rockford_Fosgate_HE2_RFP4212

i came up with 2.532 cubic feet for the rear box on the rockford fosgate website