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View Full Version : taking consideration for mdf width in box volume calc



brandonloserkid
10-21-2003, 11:29 AM
when i type in my calculation for box volume, in ft^3

its H x W x D \ 1728

do i anything further to get the internal volume like subtract .75 for each side or something to that nature..

and also how do i get the volume of a wedge box, since it has 2 depths, and a slope.

sorry for like 3 questions in one post... any help would be great.. in new to actually building enclosures

LoneRanger
10-21-2003, 12:53 PM
when i type in my calculation for box volume, in ft^3

its H x W x D \ 1728

do i anything further to get the internal volume like subtract .75 for each side or something to that nature..

and also how do i get the volume of a wedge box, since it has 2 depths, and a slope.

sorry for like 3 questions in one post... any help would be great.. in new to actually building enclosures

http://www.eatel.net/~amptech/elecdisc/spboxnew2.htm

everything you need is right there.....and you don't even have to break out the pen and paper!

infrabass
10-21-2003, 02:12 PM
Why are you supposed divide it 1728 anyways? Whats the reason?

TheVanMan
10-21-2003, 04:17 PM
Why are you supposed divide it 1728 anyways? Whats the reason?

To convert from cubic inches to cubic feet.
(12inches/foot)*(12inches/foot)*(12inches/foot) = 1728cuin/cuft
Most people prefer to see the box volume in cubic feet.



its H x W x D \ 1728

do i anything further to get the internal volume like subtract .75 for each side or something to that nature..

and also how do i get the volume of a wedge box, since it has 2 depths, and a slope.

sorry for like 3 questions in one post... any help would be great.. in new to actually building enclosures

If it is a single sub enclosure (no divider), then subtract 1.5" from every dimension (assuming your using 3/4" mdf). So you would get [(H-1.5")*(W-1.5")*(D-1.5")]/1728
If it is a double do the above but also subtract the volume of the divider and then divide by the number of chambers (in the case of the double 2). That would get you cubic feet per chamber.

Wedge boxes are tricky to get the volume of . First you get the internal volume of the box not including the wedges. This volume is [(H-1.5")*(W-1.5")*(TopD)]/1728.

Then find the volume of the wedge (right triangle) parts of the box. The internal volume of a wedge is 0.5*(W-0.75")*(H-1.5")*(wedgeD-1.5")/1728 (again assuming 0.75" mdf).

infrabass
10-21-2003, 04:24 PM
why dont you just convert your H W and D to ft and decimal feet, and then multiply them by each other (assuming its a rectangular type cube)

TheVanMan
10-21-2003, 04:36 PM
why dont you just convert your H W and D to ft and decimal feet, and then multiply them by each other (assuming its a rectangular type cube)

You could, it doesn't make a difference. It is just less calculations this way. Three conversions with your and one conversion with mine. :p