need box advice from the pros

I am about to build a 4 12" ported box for my dakota. I have sketched up a design and figured the old school way for air space and port.

I would like one of the pros to run the numbers for me so I don't waste time and material buildingthis box.

The box will be to sperate boxes just to get them through the doors of the truck so I will explain all measurments.

Overall 52w x 26h x 16d     VB 4.85 per box

2 sperate boxes at 26w x 26h x 16d

there is a 14.5 x 2.75 x 21 port in each box a opposite ends (see picture)

any help would be greatly appreciated....

It looks like your just building a generic box just to make it fit into your truck. With no account for what the specs for the specs of the speakers your using. If that is the case if, measure 2x then check your space again then measure more times then cut one time. And then hope for the best as far as to how it sounds. You really should take into account to what the speaker wants for air space and where to tune your ports too. Someone should be able to point you in the right direction as to where to find a program for what your doing.

I agree with the other post. you seem to be building a box for some speakers just to put in your vehicle. to build a proper size box you need to know the thiele-small parameters (specs) of the speakers. with this info you will be able to determine inner box volume and proper port size. i assume all of the speakers are the same model with the same specs, if not, don't expect optimum performance. your stated box volume seems entirely too large. I would build a whole box with separate chambers for each speaker with its own tuned port. If you don't have the specs of the speakers, you may want to build each chamber at 1.5 cubic feet with a 3" diameter port at 5.25" long. If I take your 26x26x16 dimensions per separate box, you would have a 6.25 cubic foot box which is way too large, even if each speaker was in its own chamber; even a 3 cubic foot box is too large for a 12" woofer. I would build a box with inner dimensions being 28" tall by 28" wide by 14" deep with wood dividers in the middle giving each speaker its own 1.5 cubic inch area. Its a simple square box, but I bet it would sound nice with a proper size amp pushing all 4 woofers.jpeterman15

Alright here is the specs and the box recommendations for the speakers. All 4 speakers are the same and are brand new and same kind.

Amp is a monoblock running at 1ohm 2400 watts rms with 4000 watts peak

Box 1.5 to 2.0 Cubic ft ported

so any recommendations will be helpful since the above box is to big.

Looks like you got yourself some high end speakers. After taking the thiele-small specs from your speakers it calculates to having a 1.738 cubic foot box for each speaker. I would round up to a 1.75 cubic foot box for each speaker, your ear won't be able to tell the difference. Guess I was not that far off on box volume from my earlier estimate. Design your box however you want, but make sure the internal volume of each compartment measures 1.75 cubic feet, and use a port with a 3" diameter opening at approx. 6.5" long. I would use nothing less than 3/4" inch particle board for your box. Make sure you use plenty of glue and wood screws, otherwise, with the amount of power you are using that box could flex, so make it sturdy. I would also use poly-fil in each speaker compartment. Lightly fill each compartment, don't pack it in there. You can get Poly-fil at any craft/fabric store. I just noticed you are putting this box in a Dodge Dakota. To make it simple I would build a square box with the speakers directed at the back of the seat, but then again with 4 woofers pushing out hundreds of watts it won't matter where the speakers are. Just a side note and from past experience; this box is going to sound good and the more people notice it the chances are higher it could be stolen. I would secure this box down with metal plates and lag bolts so nobody can steal it. Maybe even some chains with locks. And finally.....protect your ears.jpeterman15

According to the manufacturer specs you gave, it shows a box with internal volume can be anywhere between 1.5 to 2.0 cubic feet. So with a 1.75 cubic foot box you are safe. Also with your specs your box is going to have a 25Hz frequency with it being 1.75 cubic feet, which is low. The "E" string on a bass guitar is around 79HZ and that is a low sound. I assume your mono amp also has a variable low pass crossover adjustment that you can set for lower frequencies. If your amp has that adjustment the only sound that go to your speakers are going to be low frequencies, everything else will be sent to your mid-range and tweeters if you have them. I would be very surprised if you built a sturdy box with thick wood and it did not sound good. Also, don't be fooled by the speakers stated power handling capacity of 1200 watts. That is a manufacturers selling point for people to buy their speakers, and the same goes with the amp. If you try to blast the speakers it is just going to sound like crap. Set the gain and crossover adjustment on the amp within reason and you will have a very nice sounding system for others to be envious of. Just to give you an example of a system I built years ago for a ford escort I had. I had a 10" dual voice coil sub-woofer, two 8" woofers and two 3/4" tweeters all in one box with separate chambers for each woofer. This system was powered by a 30 watt "crutchfield" made amp, and it was loud and the bass was awesome and shook the whole car. Unfortunately Crutchfield don't make amps anymore. So you see to have an awesome system you don't need massive power. I would like to have the manufacturer and model number of the speakers if you don't mind. Thanks.jpeterman15