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Old 08-10-2009, 08:38 PM   #1
tomgiboney
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Need volumes checked on Bandpass Box please!

Here is my bandpass box design to fit my '02 Eclipse GT trunk.
It should come VERY CLOSE to:

2.7 cu ft - front ported chamber
1.3 cu ft (each)- sealed rear-fire chamber

I need someone who is really good with math to check my work here, please... Thanks!!
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Old 08-11-2009, 01:13 AM   #2
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Re: Need volumes checked on Bandpass Box please!

honestly I have NO idea how this would fit together. Did you remember to subtract the volume of the driver from each of the diver enclosures ? and subtract the volume of the ports from the ported chamber ?
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Old 08-11-2009, 12:52 PM   #3
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Re: Need volumes checked on Bandpass Box please!

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Originally Posted by PaulD View Post
honestly I have NO idea how this would fit together. Did you remember to subtract the volume of the driver from each of the diver enclosures ? and subtract the volume of the ports from the ported chamber ?
The volumes I got from Kicker Technical and they already take the volume displacement of the drivers & ports out of the equation. So, I just need simple volumes from these chambers. But thanks for a great question.

Now, can anyone solve this? The hardest part is in the corners. Where it makes an angle (I think a 49 degree) then goes 11 inches, then angles again (41 degree I believe) so it equals out to 90 degrees. But during that 11 inches, the other two sides of the invisible 'triangle' it makes inside the box must be 8 1/4 & 7 1/4. But will the thickness of the wood take any of this away?

once we divide the internals up into triangles and cubes, then it becomes easier to reach a final volume.
if I am correct in thinking the inside of the 'triangles' will be 8 1/4 & 7 1/4 then this is how I'd come to the final volume:

A right triangle is merely half of a cube, but since we have two of them, no need to divide by two.
8.25 x 7.25 x 12.25 (height) = 732.703125 (triangle parts volume)
3.75 x 35 x 12.25 = 1607.8125 (rectangular cube underneath triangles)
8.25 x 20.5 x 12.25 = 2071.78125 (rectangular cube between triangles)
1.5 x 8.75 x 20.5 = 269.0625 (add-on box in the front)
total = 4681.359375 (cubic inches)/ 1728 = 2.70912 cubic feet

the sealed chambers are the easiest and are also identical.
17.125 x 10.75 x 12.25 = 2255.1484375 / 1728 = 1.305

If I did this right, and used the right numbers (you should be able to check the angles and make sure I did it right) then my box would be green lighted for building.

Thanks for all your help in advance!

Last edited by tomgiboney; 08-22-2009 at 10:52 AM.
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Old 08-11-2009, 05:43 PM   #4
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Re: Need volumes checked on Bandpass Box please!

I am still having a hard time seeing the box as a finished product, so the angles and everything just don't seem to make much sense to me. Bandpass boxes are very picky about volumes, I think you made a poor choice for a box that has to meet such odd angles and sizes. Even worse, the "perfect" box size will NOT take into account it's interaction with the cars interior. All I can say is, good luck getting it just right on the first try.

P.S. don't forget about subtacting the driver volumes and port volumes.
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Old 08-11-2009, 06:57 PM   #5
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Re: Need volumes checked on Bandpass Box please!

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Originally Posted by PaulD View Post
I am still having a hard time seeing the box as a finished product, so the angles and everything just don't seem to make much sense to me. Bandpass boxes are very picky about volumes, I think you made a poor choice for a box that has to meet such odd angles and sizes. Even worse, the "perfect" box size will NOT take into account it's interaction with the cars interior. All I can say is, good luck getting it just right on the first try.

P.S. don't forget about subtacting the driver volumes and port volumes.
Made a 'difficult' choice, maybe, 'poor' ... no, I don't think so. It doesn't matter how many knooks and crannies there are, as long as it comes to the right volumes. The only hard part is the port placement. And the cars interior is a hurdle that will have to be overcame by any box, of any type. I believe I will have a good system, if I can make sure I have the correct volumes. My trunk doesn't leave much room for creativity, and as such, it is very oddly shaped. But I do believe it will work and will be quite a step above my sealed box (which wasn't truly as 'sealed' as it should have been).
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Old 08-22-2009, 10:49 AM   #6
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Re: Need volumes checked on Bandpass Box please!

I thought this place was to help people out with their dilemmas. I guess we don't have any scholarly types here, or even anyone smart enough to give it a try. This is a challenge, yes. Are you ALL going to pass it up because the math is too scary?

This box will work out just fine as a finished product, and excuse me, but did I ask for critiques or opinions? No, I did not! I asked for help on finding the VOLUMES, that's it! I'm sorry if you 'can't see it as a finished product' but that's entirely on you and your lack of intelligence, NOT ME. So either PUT UP or SHUT UP.
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Old 08-22-2009, 11:42 AM   #7
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Re: Need volumes checked on Bandpass Box please!

whoa ... what's ip with all the hostility ?

What I am not seeing is the other like 10-12 panels of wood you will be using. It's easy for you to see because you sketched it out. Looks like the bottom 2 panels in the diagram are the same piece, I have no idea what the top figure is. Perhaps you could sketch 3 or 4 3D type diagrams so I could "see" what you are trying to do.
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