Building sub box

[ZX9RCAM]

Who here can help an idiot out.

 

I dont want to pay for a program,

& I want to be able to do it by myself.

 

How does one go about figuring the size of box needed for

different size subs??

 

TIA,

 

- Cam

[maroonsilverado]

you get the recommended size for your particular sub. then you draw up a diagram on paper. you mulitiply length x width x height then divide by 1728, that gives you cubic feet. just dont forget to subtract the thickness of the wood too, usually 3/4 MDF is what you use to build a box. you're wanting INSIDE measurements, if you use the outside ones you're numbers wont be right

[Wingnut]

Why would you divide by 1728?

[maroonsilverado]

1728 is how many square inches there are in 1 cu. ft. take 12 (height) x 12 (width) x 12 (depth) and you get 1728, and that is exactly 1 cu. ft. so in order to convert from square inches to cu. ft. you need to divide by that number

[ian]

for the formula!

Now what if the height is uneven?

One side is higher than the other?

What's the formula for that?

Thanks.

[maroonsilverado]

why would one side be higher than the other?

[ian]

Thinking about making a box to fit under the rear seat of my Suburban.

The space gets taller towards the front.

It should have more volume if I make one side taller than the other.

I'm sure somebody has done it already.

[01Burb]

I assume that you are making a tapered box. Think of it as being made up of a two parts - a cube and a triangular section. The volume of the cube is as stated above - h x b1 x d. The volume of the triangular section is 1/2 x base (b2) x height x depth.

 

Add them together - make allowances for the depth of the mdf.

 

 

            ------------------------         /                             /\       /                             /    \   d/                             /        \   /                             /            \ /                             /                \           /          b1                /                    \------------------------                       \|                            |\                       \|                            |  \                       \|                            |    \                     /|                            |      \                  /|                         h |        \              /|                            |          \          /d|                            |            \       /|                            |              \   /|                            |                \/|----------------------------------------                            |         b2     |

 

My asci art sucks

[rhilton]

Now what if the height is uneven?

One side is higher than the other?

What's the formula for that?

the tapered box is an easier design than I think what you're asking for. If it's your first box, I'd go with this design

 

 

But if you want I can figure out a formula for this box you've described.

 

Give me a little bit of time and I'll get back to you

[rhilton]

actually, give me some measurements and I can give you the specs for your "sealed" box. I can't design you a wedge-type ported box. Too complicated.

[ian]

maximum measurements:

 

height(rear)= 5"

height(front)= 7.5"

length(side to side)= 16"

width(front to rear)= 14.5

 

[maroonsilverado]

that is going to be a tiny, tiny box. it's going to have an internal volume of .52 cu.ft. (actually it came out to .5181568 cu.ft., but for the sake of argument we rounded up to .52)

 

and that's not even counting the volume you're speaker is going to take up. so you're going to need to find a speaker that will be happy with less than .52 cu.ft. probably going to be a 10 at the biggest, more than likely an 8".

 

oh yeah, that number is assuming you're using 3/4" material (MDF or HDF is the best all around)

[rhilton]

you can get a little bit more volume if you can find 5/8" MDF board, but don't be confused, it's NOT particle board

 

Go with maroon's calculation, and put an 8", or maybe 2-8" back there, or find a low volume 10" sub

 

search around crutchfield.com for the volumes of certain subs.

[maroonsilverado]

yeah, you could probably get by using 5/8" since it's going to be a smaller sub and you probably wont have more than about 300 watts rms to it. i always use 3/4" because i have a tad bit more power and bigger subs than that

[ian]

Great info!

Thanks!