someone help please

[pmpdoutaltima 10+ year member]

If I built a box 37x15x20 out of 3/4 mdf, the internal space would be like 5.13 cu.ft. before displacement, could someone tell me what it would be after sub and port displacement with 2 Memphis PR 12's with a round port 4x12. I am needing atleast 4 cu.ft. and I cant go much bigger, so would that be atleast 4. thanx.//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

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[Randy Savage 5,000+ posts]

Originally posted by pmpdoutaltima If I built a box 37x15x20 out of 3/4 mdf, the internal space would be like 5.13 cu.ft. before displacement, could someone tell me what it would be after sub and port displacement with 2 Memphis PR 12's with a round port 4x12. I am needing atleast 4 cu.ft. and I cant go much bigger, so would that be atleast 4. thanx.//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Should be well over 4...

 

[Gauntlet 5,000+ posts]

5.13 before displacement:

Port volume: Pi*R^2*H = 3.1416*(2^2)*12 = 150.7968"

150.7968 / 12^3 = .09 cuft

Displacement for both subs is probably around .25 - at the most, you'd be losing .5cuft after port and sub displacement.

So to answer the question, yes it will be bigger than 4.

 

[pmpdoutaltima 10+ year member]

Originally posted by snova031 Should be well over 4...

well, I need it as close to 4 as possible, would 37x15x15 be better with everything else the same, because 37x15x20 takes up a hell of alot of my trunk, but if thats what it needs, thats what it gets.

 

[Gauntlet 5,000+ posts]

If you need as close to 4cuft as possible

4 + .09 + .3 or so = 4.4 cuft. That's roughly how big your box needs to be internally.

For the 37x15x15, are those internal, or external dimensions?

 

[pmpdoutaltima 10+ year member]

ok I fugured it out, If I loose .5 after sub and port displacement and I built it 37x15x18 using 3/4 mdf, the internal size would come out to 4.57617, that would make it 4.07617 cu.ft. after port and sub displacement, which would be perfect. But anyone, fell free to check me if you think I might be wrong. I used the volume calculator on the12volt.com website.//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif