Hello

I am building a sub box but i know nothing about sound equipment. First of all im using two 12" subs. Do i need to put a separator in between them? Second off all do i need to make a hole for each speaker so they dont blow up?

Thanks

Speed

 

unless you want it to sound like crap, or you are the most talented box builder i've run across, you want to build a sealed box. theres no need to have seperate chambers, or to have the box be symetrical, but you may want to add some bracing if you're using serious woofers. make sure you figure up how much airspace it will have before you start building it.

 

They need 1 and a half cubic feet each but when i got them they were in a box, separated, and there were holes out the back he air would constantly push and pull through. If i dont put holes wont they push themselves out?

Speed

 

Building a ported box doesn't require much more talent than a sealed one. All you do is cut one more hole and slide a port in.

Designing one takes slightly more skill, but these days every manufacturer provides recommended enclosures, so anybody who can read has that part covered.

As for separating the chambers, no, it's not necessary, but I usually do it anyway because it makes the box much more sturdy. In thirdgens, due to the non-symetrical shape, my "divider" bar is usually full of holes so that it serves only as a brace and not a true divider.

 

The holes you are referring to are port holes. They are not there to keep the subs from pushing themselfs out, they are there to tune the feq. output of the enclosure.

Do a search on ports to learn how they work and when to use them.

 

I wouldn't bother with the divider wall - there’s no need for one. Also, if you don't understand how a ported enclosure works I would suggest steering away from it. If you don't know what you're doing odds are it could turn out sounding like poop. Stick with sealed for now.

 

ported box, not hard, i've built a few. ported box for 2 12's in the well of a third gen, good luck. i'll pay someone to design me one if they can.

 

I charged $450 for my last one. Give me a call.

 

I would agree if we could be like the majority of the car audio community and build square boxes. A properly tuned ported box requires an exact box volume so that you can install the right sized ports. Aside from that there are quite a few things to worry about with the ports themselves (port area, port area counting against volume, port noise, etc). It will turn into a headache quickly.

For any other car I would be more than willing to help design a ported box. In this case I think you’re best off just going sealed.

 

i can build a box, i just need the plans, or a rough idea of where to position and how to fire the ports.

 

There's a lot more to just slapping a piece or two of pvc in a box to have a properly tuned ported enclosure. You must know exact box volume, etc. I guess if someone were to sit down and make detailed hatch box plans that won't have to get modified to work so that you can calculate the exact box volume you could in theory port it. The other problem becomes the smaller the box the larger the port has to be. This really becomes a problem under 3 cubes of space because the ports become too long to fit in the box so you have to start running slot ports that have a kink in them to get some more area.

Build the bottom/sides of your box and measure the volume then get back to us and we will direct you from there.

 

i realize that, i've built ported boxes before. i also paid attention in high school so i know how to figure volume with angles. i can say there is 2.6 ft^3 in my sealed box, taking the displacement of the woofers into account, within .1 ft. i was planning on building the same box, just extending it up to the back of my back seats. i worked it out once but lost the paper, i came out with something like 5.5 net ft^3, should be enough for my 12's, if i could figure out the port i'd be good to go.

 

I always found having a divider worked better for enclosures.

 

You don't need a 5 cube box for a ported enclosure. Big ported enclosures usually mean peaky output. If anything I suggest building a smaller box. Maybe like 1.2 cubes total tuned to 34 Hz.

Download WinISD, enter the t/s from soundsplinter's website, and play around. Just keep in mind that port area doesn't count toward box volume.

If you're planning on building a new box anyway you could try cutting a 4" round hole anywhere in the top of the box and inserting a 12" long piece of 4" round pvc to tune what you have currently to 30 Hz. Not ideal but it will give you a feel for ported. Please note that I’m assuming you’re running a box with no dividing wall in the middle.

 

na i dont want to molest my sealed box, i'm either going to want to keep it to switch out for potential long road trips, or sell it. it's a pretty nice box and a LOT of planning and effort went into it, i wouldn't feel right violating it like that.

as for the box size, i'll go with what everyone who's played around with RL-p's in different boxes, and the owner of soundsplinter say will work rather than what some computer program says.

i have no divider, just some bracing.

 

Ported boxes that are too small don't sound much different than sealed boxes, plus you can run into power handling problems if you tune the port frequency too high.

A properly sized ported enclosure will be considerably larger than a sealed box for the same sub... say 50 to 70% larger on average.

But, you are correct that if you make the ported box too big, you'll get a bump in output at the tuning frequency.

 

go to your local audio store, as long as you don't live in the sticks, and buy one for 100 bucks. save the other 350 for amps, mids, highs, etc...

 

You're going to get a prefab box for that $100 and odds are it won't match your subs or sound very good at all. It's also probably going to be tuned fairly high to give the impression of more output while killing low end. Jim knows his stuff and will design a box around what you own to give the best sound possible.