how do u calculate cf for fiberglass box?

Printed From: the12volt.com
Forum Name: Fiberglass, Fabrication, and Interiors
Forum Discription: Fiberglass Kick Panels, Subwoofer Enclosures, Plexiglas, Fabrics, Materials, Finishes, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=115452
Printed Date: April 19, 2024 at 7:29 PM

Topic: how do u calculate cf for fiberglass box?

Posted By: diverdown269
Subject: how do u calculate cf for fiberglass box?
Date Posted: August 04, 2009 at 1:57 AM

With all the curves, How do you calculate the area of the enclosure on a fiberglass box ?

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Some fear the Abyss... Other, chase it into the DEPTHS !!!

Replies:

Posted By: ianarian
Date Posted: August 04, 2009 at 2:30 AM

I know a guy who will take a large garbage bag, set it in the speaker hole as if it was a trash can. He fills it with water then vacuum's out the water in a shop-vac. Then dumps it in containers to get the volume by liter. Professionals use the ol' "eye ball" method-experience. I rebuild until Im satisfied. Another guy I know uses beach sand then shop-vac, which always was weird to me....the enclosure is done, whats it matter now?

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This is what I do for FUN!

Posted By: i am an idiot
Date Posted: August 04, 2009 at 7:28 AM

Build a box without a top on it. Make the inside dimensions 12 X 12 X 12. Find a worn out bean bag chair or some shipping peanuts. Cut the bean bag chair open and dump the pellets into the sub enclosure.. Or the shipping peanuts into the sub enclosure. Fill the enclosure with whatever material you can. Scoop it out and place into the 1 Cu. Ft enclosure you built. When it is full write a line on the side of the little box and empty it. Repeat until the sub enclosure has no more material in it.

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Posted By: vibrationcustum
Date Posted: August 05, 2009 at 11:14 AM

i am an idiot wrote:

Build a box without a top on it. Make the inside dimensions 12 X 12 X 12. Find a worn out bean bag chair or some shipping peanuts. Cut the bean bag chair open and dump the pellets into the sub enclosure.. Or the shipping peanuts into the sub enclosure. Fill the enclosure with whatever material you can. Scoop it out and place into the 1 Cu. Ft enclosure you built. When it is full write a line on the side of the little box and empty it. Repeat until the sub enclosure has no more material in it.

Great way I am a idiot, Done this many times. Great job

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Can't be loud then don't have it.

(power acoustik system)
Head unit- TID-896 7" TOUCHSCREEN
ovn1-5500d 09 and another one coming soon
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Posted By: torquehead
Date Posted: August 12, 2009 at 7:38 PM

Diverdown, in SO many cases there are way too many curves in an enclosure to actually calculate. So filling a 12 x 12 x 12 square box with some time of lightweight media is the first and easiest thing to do. I havent read this thread in a few years so here it is.... https://www.the12volt.com/installbay/forum_posts.asp~TID~41102~PN~1

You ask about calculating though. Lets say you need to make an enclosure that contains 1.25 cu. ft of volume.

We know 12 in. x 12 in. x 12 in. = 1728 cubic inches (aka...1 cubic foot). Also 1728 divided by 0.25 is 432 cubic inches...add your 1728 and you have a total of 2160 cubic inches to be 1.25 cu.ft. Make a mark 3 inches up from the bottom of the box. When you fill the box full of media you know that you have 1 cu.ft. volume of measuring media...you then empty it into a "semi-fabricated" enclosure...but you need that extra 432 cu.in. of media...so fill your the 12x12x12 box up to the 3 inch mark, thats the additional amount (432 cu.in.) of media you would have to add to total 1.25 cubic ft. (Make a mark 6 inches high would of coarse be 0.5 cu.ft. A mark 9 inches from the bottom would be 0.75 cu.ft.....and so on.)

....sorry if you knew all of that, but you asked. :)