getting cubic feet of a box by dimensions

[jonnybusa 10+ year member]

can someone please tell me some kinda formula to get cubic feet going by the measurements of a box?

Thanks......then I can just subtract the sub's space take up.

Click to read more...

 

[Raven 10+ year member]

The search button would serve you well, as would basic geometry.

X = length - width of lumber * 2

Y = height - width of lumber * 2

Z = depth - width of lumber * 2

X * Y * Z / 1728 = CF

Say the box is 12 * 12 * 24 on the outside and made of 3/4" MDF.

3/4 MDF * 2 = 1.5

X = 24 - 1.5 = 22.5

Y = 12 - 1.5 = 10.5

Y = 12 - 1.5 = 10.5

22.5 * 10.5 * 10.5 = 2480.625 / 1728 = 1.435546875 CF

Round it out and you've got a little less than a cube and a half.

 

[jonnybusa 10+ year member]

The search button would serve you well, as would basic geometry.
X = length - width of lumber * 2

Y = height - width of lumber * 2

Z = depth - width of lumber * 2

X * Y * Z / 1728 = CF

Say the box is 12 * 12 * 24 on the outside and made of 3/4" MDF.

3/4 MDF * 2 = 1.5

X = 24 - 1.5 = 22.5

Y = 12 - 1.5 = 10.5

Y = 12 - 1.5 = 10.5

22.5 * 10.5 * 10.5 = 2480.625 / 1728 = 1.435546875 CF

Round it out and you've got a little less than a cube and a half.

1st...search didnt serve me well, and i didnt do too well in geomeotry.

 

[jonnybusa 10+ year member]

ok..........next question..........by measuring and doing math on port size, length, etc, how can I figure out the tuning freq/htz??

Thanks alot for any help!!!

 

[mannyb18b]

box programs.

seriously these don't deserve to have a new thread made. Search...doesn't mean you have to search JUST on CA.com

 

[Wide Back 10+ year member]

This might help, hope your other math skills are better.

http://mobile.jlaudio.com/support_pages.php?page_id=165

Also, you can find tons of info on this using the search button.

 

[jonnybusa 10+ year member]

box programs.

seriously these don't deserve to have a new thread made. Search...doesn't mean you have to search JUST on CA.com

I have a box already. I have all the measurements on my box. I am looking to find the actual freq. of MY box.

all the searches that came up are for people asking how to get certain frequencies made and port length, etc. None show how to get the frequency of a box done already.

Dude, you dont have to help if you dont want.....doesnt mean you have to reply w/ just a dumb comment either.

I have a snailshell box, and the only thing I'm trying to figure out is exactly what I have to measure for the port. Meaning if I had to measure the height of the port by the width and then the length of it. It goes back the depth of the box, and then turns, and goes the lenget of the box.....so I was just getting confused on do I measure the COMPLETE port or just part of it, etc.

I'll figure it out......

sorry to piss you guys off by asking for help, when the search doesnt answer my question

 

[mannyb18b]

I answered your question man...or so I thought was your question.

You measure the length of the port, width and height. throw those numbers in a box program where it determines port length for a desired frequency. sheesh

 

[Wide Back 10+ year member]

If you know all the necessary dimensions/areas/volumes all you have to do is plug them into the equation in the link I supplied above. Otherwise you can download Winisd pro and figure it out using that.