How to calculate weird shaped box?

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=40516
Printed Date: May 11, 2024 at 4:37 AM

Topic: How to calculate weird shaped box?

Posted By: BrettG
Subject: How to calculate weird shaped box?
Date Posted: October 08, 2004 at 10:11 AM

I am building a new enclosure for my 92 Camaro and the trunk sucks as many know!! How so you calculate the CuFt for the weird shaped box!!! I have added a picture that isn't too good but u get the idea.....
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Thanks a lot!
Brett

Replies:

Posted By: BrettG
Date Posted: October 08, 2004 at 10:13 AM

Posted By: stevdart
Date Posted: October 08, 2004 at 11:27 AM

Use the face of the box as your reference, draw it on paper with all dimensions. Break it up in chunks, some will be rectangles, some will be triangles. Add them all up for the total.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Posted By: heavilymedicate
Date Posted: October 08, 2004 at 12:41 PM

Fill it with water! Then get a HUGE measuring cup and dump out all the water (get a few friends with strong backs to help, it will be heavy). Read the measurement! Your done. If you dont have a giant measuring cup and a water proof box or if your friends think your stoopid and refusue to help; do what stevdart said.

Posted By: heavilymedicate
Date Posted: October 08, 2004 at 12:42 PM

BTW, i would brace that badboy, looks like a long span. Remember to count your bracing in your numbers.

Posted By: boxmaker85
Date Posted: October 08, 2004 at 12:50 PM

Well... If you use the formula for integrating multiple variable functions that you should remember from calculus 3 then calculating the volume of the box will not be that difficult (except for finding the equations of the curves and such). But if you're not a math/science dumb @$$ like me then try water. Or even styrofoam peanuts. Both work well. Both have benifits and disadvantages (water = free, water = heavy; peanuts = light, peanuts = some money unless you have a ton of peanuts laying around just for that). Good point heavilymedicate. Brace that biatch up. or it will flex.

Posted By: forbidden
Date Posted: October 08, 2004 at 1:02 PM

Here is another thing to consider. If you know the volume requirement of the sub, build the box as a rectangle (simple math) if it will fit. Make the top to fit the contours of the panelling. Make sure you have enough depth to the box for that port to fit. Another thing to consider on these cars is the back hatch comes down on such an angle that it gets hella close to the sub in some cases, make sure you have enough clearance between the sub and the hatch when it is closed.

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Top Secret, I can tell you but then my wife will kill me.

Posted By: flynntech
Date Posted: October 08, 2004 at 10:59 PM

Hi Bret,

I owned an '84 TA once, I actually stuck with a regular sealed box with two 12"s in the rear seat area for better wieght distribution. The rear pit is an excellent place for the subs though...the rear hatch provides incredible relflection.

https://www.thirdgen.org/techbb2/forumdisplay.php?s=&forumid=9

This is a great site for anyone who owns a thirdgen. It's possible you will find some more box ideas too. As for cubic feet, you should have payed more attention in math geometry! Really, I second the peanuts.....but do you have a sub picked out yet?

Posted By: Asmodeus
Date Posted: October 08, 2004 at 11:25 PM

Make a box that is like 3cuFt without a top on it....Get some sand and fill the little box...Then start filling the large box and count how many cuft of sand you put in it...I did this once for S*&%s and giggles just to see what the box had...It was a weird design also....

It works but takes a long time and a lot of sand...Have fun

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Making the World A Louder Place

Posted By: jeffchilcott
Date Posted: October 08, 2004 at 11:56 PM

asmodeus it really sounds like you have had a little to much time one your hands to make a "sand Box" haha had to say it

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

Posted By: Asmodeus
Date Posted: October 09, 2004 at 4:19 AM

Saturday night...case of coors....Lotsa sand on hand and nothing better to do...

That and I really wanted to know the exact cuft of that dang box...it was driving me nuts....When I was done I made a kick ass castle....

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Making the World A Louder Place

Posted By: King_Midas
Date Posted: October 09, 2004 at 7:56 AM

water's good too. helps you find any leaks at the same time posted_image

Posted By: Asmodeus
Date Posted: October 09, 2004 at 10:52 AM

Yeah as long as its a water proof box and not made from MDF.....

Sand is the best way..No danger to the box....And you can make castles later

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Making the World A Louder Place

Posted By: forbidden
Date Posted: October 09, 2004 at 1:17 PM

Use a weird shaped ruler to measure a weird shaped box posted_image

OK I'm bored and my install has not shown up.

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Top Secret, I can tell you but then my wife will kill me.