Want to build my first box

[KickersintheTrunk]

So I have 2 Kicker compvr 12's and was wondering how do you figure out what is the best shape and size of the box. I do want the box to be ported. My car is an 06 Pontiac g6 GT coupe. Don't have trunk measurements and couldn't find them so will have to measure it tomorrow unless someone can find it.

Anyways what I want from this box is simply more SPL. To be honest I have no clue what people are talking about when they talk about the tuning of ports or what it's even for. Anyways if anyone can provide some feedback that would be greatly appreciated. Thanks.

[KickersintheTrunk]

Anyone?

[Rail]

Easiest to measure your vehicle for yourself and determine what you have to work with. Shape of the box doesn't matter, size does. Since you have two 12" you will need about 4 cubic feet of internal volume (after displacement). You can think of the tuning frequency of an enclosure as a glass bottle, when you blow over the top of the bottle it makes sound at its resonant frequency. A ported sub box just resonates at a much lower frequency. This is why ported is louder, because the port helps you out. Tuning higher will be louder, but you wont be able to play the lower notes as loudly, and if you play notes below the tuning frequency the subwoofer will reach its mechanical limits very fast. If you tune lower you will not be as loud, but the benefit of course is being much louder on the low notes (and actually being able to play low notes). Most people find 32 or 33 hertz to be a good middleground for tuning.

As port area increases, tuning goes up

As box volume increases, tuning goes down

As port length increases, tuning goes down

However there is a minimum amount of port area for each setup

[KickersintheTrunk]

Easiest to measure your vehicle for yourself and determine what you have to work with. Shape of the box doesn't matter, size does. Since you have two 12" you will need about 4 cubic feet of internal volume (after displacement). You can think of the tuning frequency of an enclosure as a glass bottle, when you blow over the top of the bottle it makes sound at its resonant frequency. A ported sub box just resonates at a much lower frequency. This is why ported is louder, because the port helps you out. Tuning higher will be louder, but you wont be able to play the lower notes as loudly, and if you play notes below the tuning frequency the subwoofer will reach its mechanical limits very fast. If you tune lower you will not be as loud, but the benefit of course is being much louder on the low notes (and actually being able to play low notes). Most people find 32 or 33 hertz to be a good middleground for tuning.

As port area increases, tuning goes up

As box volume increases, tuning goes down

As port length increases, tuning goes down

However there is a minimum amount of port area for each setup

Cool, thanks. I have a ported box from a previous setup I bought from a friend. Doesn't handle lows well at all. The port is vertical right down the middle between the two subs. Is there a way to find the tuning of that box? Because I would definitely would like to be able to play a little of the lows.

[Triticum Agricolam]

Cool, thanks. I have a ported box from a previous setup I bought from a friend. Doesn't handle lows well at all. The port is vertical right down the middle between the two subs. Is there a way to find the tuning of that box? Because I would definitely would like to be able to play a little of the lows.

Its possible to find the tuning but you would have to get accurate measurements of the box and port to do it. From what you said I'd guess that the old box was tuned fairly high (>40) which would explain why it wouldn't do the lows well.

[Rail]

Its possible to find the tuning but you would have to get accurate measurements of the box and port to do it. From what you said I'd guess that the old box was tuned fairly high (>40) which would explain why it wouldn't do the lows well.

Two ways to find your tuning frequency. As you said, find the port area, port length, and internal volume and calculate the tuning. Or an easier way would be to play test tones and sweeps to see at which frequency your sub moves the least. It should have more excursion as you get lower, then at the tuning frequency there will be a lot less excursion because the port is doing all of the work, then if you go lower than tuning you will notice that there will be a lot of excursion and the sub will bottom out if the subsonic filter is not set correctly. Upwards of 40Hz is a safe bet for guessing the tuning of that box.