box design help

[Zilla the Hun]

I'm trying to figure out the right box to shove in my challenger. i'm a build by trade so i have the ability to create it

the opening behind my seats is 31.5x14.5 inches

i have 2 crossfire c3v3 12d4

i've tried using winisd but it wont allow me to use these speakers for some reason i keep getting errors when entering the info
i've tried sub box pro but i don't know if i'm to double the port size and so on due to having the 2 speakers

sorry i'm noobish please help

 

[Buck]

You have to start by figuring your 3 way dimensions and how big of a box you can fit. Your subs need a certain amount of airspace, so first you need to do math to see how much airspace inside of a box you can fit that will also fit inside of your trunk.

 

[Zilla the Hun]

You have to start by figuring your 3 way dimensions and how big of a box you can fit. Your subs need a certain amount of airspace, so first you need to do math to see how much airspace inside of a box you can fit that will also fit inside of your trunk.

my trunk is 16 cu ft

 

[SlugButter]

That is going to be tight to fit 2 12s and a port on a 30.5 inch baffle panel. Make sure you design around that. Depending on outside diameter of your subs, 2 12s and a 3 inch wide port will take up every inch of 30.5.

 

[SlugButter]

Also, if you’re facing the box forward, you’ll want to seal off that trunk from the cabin, even the rear deck should be sealed up. Most of the time firing to the rear and letting the air flow out of the trunk is louder, unless you seal the trunk off from the cabin.

 

[SlugButter]

If you haven’t bought the subs yet, you could switch to 10s, or do a sealed box for the 12s.

 

[Zilla the Hun]

Also, if you’re facing the box forward, you’ll want to seal off that trunk from the cabin, even the rear deck should be sealed up. Most of the time firing to the rear and letting the air flow out of the trunk is louder, unless you seal the trunk off from the cabin.

so you're saying i should face the subs towards the back of the car? i was always under the impression to face them forward and put the seats down if possible but i don't know much about car audio other than i need it in my life.

i do have the subs already and i do regret not getting 10s

my trunk grows in size the further it gets away from the seat. once i get past the wheel wells which is about 16 inches away from the seat it's roughly 48 inches the height grows as well so i could certainly make a bigger box that isn't just a rectangle. i just have no idea based off the t/s specs how much internal volume i need or how big to make a slotted port or how long
does having 2 subs in 1 ported box make the suggested port size double?

i also found this.
would everything double in size for 2 speakers?
internal net volume 1.75cu ft to 3.5?
port area 18"sq to 36"sq?
port length 19" to 38"?
and the displacements?

sorry for my noobaliciousness

 

[SlugButter]

so you're saying i should face the subs towards the back of the car? i was always under the impression to face them forward and put the seats down if possible but i don't know much about car audio other than i need it in my life.

i do have the subs already and i do regret not getting 10s

my trunk grows in size the further it gets away from the seat. once i get past the wheel wells which is about 16 inches away from the seat it's roughly 48 inches the height grows as well so i could certainly make a bigger box that isn't just a rectangle. i just have no idea based off the t/s specs how much internal volume i need or how big to make a slotted port or how long
does having 2 subs in 1 ported box make the suggested port size double?

i also found this.
would everything double in size for 2 speakers?
internal net volume 1.75cu ft to 3.5?
port area 18"sq to 36"sq?
port length 19" to 38"?
and the displacements?


View attachment 41615

sorry for my noobaliciousness

You can try facing forward, it’s just typically not the best result because it leaves a standing wave behind the box. In simple terms, the trunk turns into a void that svcks up your bass and robs it from hitting the drivers seat. Facing to the rear almost always works best.

 

[SlugButter]

Go with your 12s. Get a box that is 3.5-4 cubic feet tuned between 32-37 HZ. port area 42-60 inches. That will work with your 12s and also work with a ton of other popular 12s on the market. Fire to the rear and sound deaden your trunk lid if possible

 

[Zilla the Hun]

Go with your 12s. Get a box that is 3.5-4 cubic feet tuned between 32-37 HZ. port area 42-60 inches. That will work with your 12s and also work with a ton of other popular 12s on the market. Fire to the rear and sound deaden your trunk lid if possible

i appreciate the help dude.
right now they're in a box that is 31.5x14.5x19 outside dimensions but the port hole is only 1.5 inches wide and like 16 inches long by 13 tall. to me that is way too narrow but that's what sub box pro said to build.

 

[SlugButter]

i appreciate the help dude.
right now they're in a box that is 31.5x14.5x19 outside dimensions but the port hole is only 1.5 inches wide and like 16 inches long by 13 tall. to me that is way too narrow but that's what sub box pro said to build.

yeah. That probably is 3.5 cubes or so, but the port is super small. It would be tuned in the low 30s being that small, but I’m surprised you aren’t hearing really bad port chuffing and it’s not going to let even close to enough flow come out of the port. Probably 6-7 inches of port per foot of box space. That’s not going to give much bass. It needs to be at least 12 probably

 

[Zilla the Hun]

yeah. That probably is 3.5 cubes or so, but the port is super small. It would be tuned in the low 30s being that small, but I’m surprised you aren’t hearing really bad port chuffing and it’s not going to let even close to enough flow come out of the port. Probably 6-7 inches of port per foot of box space. That’s not going to give much bass. It needs to be at least 12 probably

That's what brings me here. They don't sound like they should. I had the old version, like 15 years ago old, of these subs. They were in a box sealed box from a car audio shop and that sound compared to my current sound is like a prius vs a hellcat in a drag race.
So, I figured the box built is all sorts of wrong and I imagine it is due to the port.

Well round 2 tomorrow after work. Now knowing they should be facing back I'll be able to make the baffle much bigger so that i can make a wider port

 

[SlugButter]

That's what brings me here. They don't sound like they should. I had the old version, like 15 years ago old, of these subs. They were in a box sealed box from a car audio shop and that sound compared to my current sound is like a prius vs a hellcat in a drag race.
So, I figured the box built is all sorts of wrong and I imagine it is due to the port.

Well round 2 tomorrow after work. Now knowing they should be facing back I'll be able to make the baffle much bigger so that i can make a wider port

In the meantime you could stuff that port hole with a blanket or some pillows and it would probably sound better, if you want to listen to some bass while you get a box. Shove it in tight.