Real Quick question about sealed boxes..

[yne721 10+ year member]

I was wondering if the shape of the box mattered at all? Seeing as how I have a very small trunk on my 79 Beetle, i was looking to save a little bit of space by making the box C shaped to go around all sides of the trunk, instead of just taking up the middle of it...

2 8 inch subs, the holes represent where the sub would go. and my cubic footage was just to show you that they'd both be the same internal volume....

Click to read more...

 

[Pyro_By_Nature 5,000+ posts]

Do a search for something called "the golden rule" //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[yne721 10+ year member]

thank you

 

[yne721 10+ year member]

the only "golden rule" i found was measure twice cut once?

 

[tRiGgEr 5,000+ posts]

Golden Ratio
Once you have determined the proper volume for your enclosure, the “Golden Ratio” is a simple way to calculate enclosure dimensions that minimize panel resonances.

Begin by finding the volume of the enclosure in cubic inches. If your volume is in cubic feet, simply multiply that number by 1728. Next, find the cube root of this number (you will need a scientific calculator for this). This is your first panel dimension. Then take the first dimension divided by 1.62, This is your second dimension. For the third dimension, multiply the first panel dimension by 1.62.

Example

Volume = 1.75 Ft^3

1.75 X 1728 = 3024 in^3

cube root of 3024 = 14.46” (1st Dimension)

14.46 / 1.62 = 8.93” (2nd Dimension)

14.46 X 1.62 = 23.43” (3rd Dimension)

Remember that these are internal dimensions, so you will need to add for the thickness of the wood. Assuming 3/4” wood, this enclosure would be 15.96 X 10.43 X 24.93 .

Here you go.

 

[yne721 10+ year member]

Here you go.

oh i'm sorry i saw that. i understood that whole thing, so i if i do need a rectangular box i'll take that into account, but what i'm asking is does it have to be a rectangle, or rather does it have to take a 'box' shape?

would "Box 2" sound the same as box one if they were both built to spec?

jl audio.com says "In short, don't worry too much about shape. Make the box to fit the space you can allot to the enclosure and forget about it--there are more important things to worry about... like bracing."

am i taking that too literally?

 

[tiger777 10+ year member]

well thats what the golden rule is saying that its better to have a box with those dimensions then the one you wanna build. Now is it gonna matter that much? no. so go ahead and build it the way you want. better yet why not fiberglass you a box and save even more space. Really easy to do if you read all the tutorials here.

 

[yne721 10+ year member]

well thats what the golden rule is saying that its better to have a box with those dimensions then the one you wanna build. Now is it gonna matter that much? no. so go ahead and build it the way you want. better yet why not fiberglass you a box and save even more space. Really easy to do if you read all the tutorials here.

i was actually really thinking about that, but there's a lot of stuff in my trunk that i wouldn't want to block off. seeing as how my trunk is in the front, i have my windshield washer fluid up there, my spare tire, my cruise control controls, and a couple things that i haven't even figured out what they are yet.

but thank you for giving me a solid answer. and if i do decide to fiberglass, i'll definately post pics.(well i'll even post pics of my oddly shaped box)

 

[tiger777 10+ year member]

well you can fiberglass the box on the side and it shouldn't block anything. like one sub on each side in the space along side the wheel well.

 

[yne721 10+ year member]

the problem with that is that all the shit in my trunk IS on the sides in the wheel wells...

not to mention that i don't even know what half of it is yet...

 

[Volenti 10+ year member]

jl audio.com says "In short, don't worry too much about shape. Make the box to fit the space you can allot to the enclosure and forget about it--there are more important things to worry about... like bracing."

am i taking that too literally?

No you can take it quite literally, for subwoofers in general enclosure shape makes little difference (it's full range/midrange drivers that are sensitive to enclosure shape), correct enclosure volume and structural integrity are far more important.