could someone help me with cubic measurement please

[jsayre914]

i am trying to figure out the cubic foot of a box. the box is a wedge shape with 2 chambers.

measurements:

height 19inch
width 32inch
bottom 14 inch
top 11 inch

if you need to know they are seperated inside with 11/16 mdf

i am not so good with formulas

thank you very much

thanks.

[ttocs]

is that external dimensions or internal? If exernal what thicknes wood are you using?

[jsayre914]

external

11/16ths

[ttocs]

what/where is the wedge?

[jsayre914]

if the bottom is 14 and the top is 11, isnt that a wedge

[Bfowler]

i got 3.475, but i didnt put the middle brace in

heres a calculator for future reference:

http://www.bcae1.com/spboxnew2.htm

[smgreen20]

Brian is right, but take into account the divider then your total box volume is:
3.467 cf
5991.35 ci

or

1.7335 cf
2995.488 ci
per chamber

[smgreen20]

what/where is the wedge?

I don't thank you mean wedge, but divider/brace.

[jsayre914]

I am going to put this box to the test with a rsd122 in each chamber. Each chamber after displacment comes out to 1.53 cubic foot. I have a XS2500 to drive each side. We shall see

Thanks for the link its awesome, i learned a lot of stuff.

[gridracer]

fill the box with packing peanuts then dump the amount used into a sguare box and measure that to find out your cubic feet.

[smgreen20]

Whenever you have a box that has one side w/a 2 different dimensions, like the top and bottom, just add them together and divide by 2.

[stipud]

Whenever you have a box that has one side w/a 2 different dimensions, like the top and bottom, just add them together and divide by 2.

This!


Also I assume you are using the RSD competition woofers? Since there are no D2 regular RSD's. In that case I recommend taking up a bit of airspace with styrofoam or 2x4's. The competition 12's really like 1-1.25cuft for best results in my experience.

[jsayre914]

Also I assume you are using the RSD competition woofers? Since there are no D2 regular RSD's. In that case I recommend taking up a bit of airspace with styrofoam or 2x4's. The competition 12's really like 1-1.25cuft for best results in my experience.

yes rsdc 122 , i have heard sooo many opinions and they are all so different. i also read every thread on rsdc12 since this sight started

seems like the box really depends on the application, and i understand that factory spec is the best smallest reccomendation. i figure i would start with the 1.5 and if it sounds sloppy or boomy i would take up some space. Its better to start too big right?

i appreciate all the opinions.

also keep in mind, these woofers will be in the front trunk just a few feet from where you are sitting. i am going to have them firing upward and the box will probably take up 3/4 of the trunk space. there will not be a whole lot of room between the woofer and the lid to the trunk. This could pose as a problem, trial and error I also have to 4inch round holes from the trunk airspace to the drivers and passengers footwell, so i dont blow the lid of the trunk

who here is running a larger box for the rsdc 12 2 and are you happy with it??

thanks
Joseph

[jsayre914]

O.K.

seems my box has too much space. What is the easiest/ lightest way to take up .28 cubic feet in each chamber??

...that will bring me to the magic 1.25 after displacement

[stipud]

Strofoam, 2x4's, dildos... basically anything solid you can get your hands on

[jsayre914]

Strofoam, 2x4's, dildos... basically anything solid you can get your hands on

Styraphome Dildos OMG!!!

[Bfowler]

the canned expanding foam works pretty good.

[jsayre914]

the canned expanding foam works pretty good.

you mean this stuff?? what a great idea. How in the hell would you figure out cubic foot from an expanding foam

[ttocs]

I would be afraid that after time it would break down into dust and get sucked into the voice coil if it is a vented sub.

[Bfowler]

you have to do a trial and error with it. you know that .25f^3 is roughly 7x7x8 inches.

so take up about that much area. you can cut away or add the great stuff as needed.

paint it in latex paint or use cascade spray sound deadener to cover it if you are worried about the dust aspect mentioned above.

generally the foam hardens with a smooth coating that doesnt breakdown very easy. but if you cut some away, the "inside" of the faom could potentially make dust like ttocs mentioned.

i would do the same thing if you used Styrofoam though

[ttocs]

you can also use wood to take up space if you should happen to have any extra.

If I were to use the foam I think I would go over it with a couple layers of duct tape to seal it into one area and hopefully prevent it from breaking down.

[stipud]

you can also use wood to take up space if you should happen to have any extra.

Yeah you can always add a shitload of bracing to the box. That will even help improve how it sounds

[jsayre914]

I just got Ground Shaker to build me a box. Custom. It was easier for me since i dont have so much time and when i get time i am working on putting the car back togeather so i can drive it again

My box is 32 X 17 X 11 X 9.5 using the calculator with 11/16th it comes to a net of 2.458 total. Perfect

[jsayre914]

so now i need weatherstripping to go around the openings? and should i cut the carpet back 1/4 inch so the strip makes contact with the wood? Anything eles to prep the box before install??

thanks

[bretti_kivi]

I'd want to damp the inside... with a "milkshake" of polyester and some sand or bitumen for home use.

Oh, and some stuffing.

Bret