Box Builders Enter - Double Check And Cut Sheet

[Johnny Law.Lulz 5,000+ posts]

I want someone to double check all my measurements and write me out a cutsheet please. I will pay for the cutsheet but i need it tonight.

This is all 3/4", Measurements are of the outside ( gross )

I have

23" Tall

60" Wide

13" Deep

I have that all of these equal 8.37 cubic feet. Minus sub displacement gives me 8.12.

At 8.12 Cubic feet, 2 8" Aeros tuned to 36 Hz says that each port 20.8" Flared a piece.

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[97maxima 10+ year member]

No bracing?

 

[97maxima 10+ year member]

your off my friend 6.91 cu ft net and tuned to 38.3hz

 

[Johnny Law.Lulz 5,000+ posts]

Is fosgates site that far off, What are you using ?

 

[GearGuy2001 10+ year member]

If you do a double baffle front I came up with 7.82 Internal Cubes after wood displacement or 8.37 Internal Cubes with a single baffle front

20.8" is correct for 2 8" Flared Ports @ 36Hz

 

[Johnny Law.Lulz 5,000+ posts]

If you do a double baffle front I came up with 7.82 Internal Cubes after wood displacement or 8.37 Internal Cubes with a single baffle front
20.8" is correct for 2 8" Flared Ports @ 36Hz

Im counting the box as 1 layer all the way around. I will go back and double layer everything after its built but i plugged it in fosgate as 3/4" wood so single layer.

 

[Johnny Law.Lulz 5,000+ posts]

If you do a double baffle front I came up with 7.82 Internal Cubes after wood displacement or 8.37 Internal Cubes with a single baffle front
20.8" is correct for 2 8" Flared Ports @ 36Hz

Can you make me an accurate cut sheet. I dont care how it fits together as long as everything is right because when i do the second layer i am covering up all the seems ( staggering ), so either way, everything will be good.

 

[mbrooky 10+ year member]

I got

8.37cuft gross

100.48 sqin port

6.84cuft net (8.12 after sub minus 1.28cuft for the ports)

36.90Hz tuning

 

[GearGuy2001 10+ year member]

Can you make me an accurate cut sheet. I dont care how it fits together as long as everything is right because when i do the second layer i am covering up all the seems ( staggering ), so either way, everything will be good.

Yep can do, Ill shoot you a PM in a few

 

[Johnny Law.Lulz 5,000+ posts]

I got
8.37cuft gross

100.48 sqin port

6.84cuft net (8.12 after sub minus 1.28cuft for the ports)

36.90Hz tuning

Now i didnt do the displacement of ports because aeros dont displace anything do they. Considering they are not solid, the only area they are displacing is the thickness of the wall of the port because it isnt solid. Correct.

 

[Johnny Law.Lulz 5,000+ posts]

Also, how do i figure out how long an elbow is, do i measure the short side or long side of the inside of it ?

I found these elbows online and they seem to be what i would need.

8 90

 

[RAM_Designs 5,000+ posts]

Gotta account for the space the ports take up. Assuming the sub displacement is correct, you have about 1.25ft^3 displacement for the ports(depending on the flare and wall thickness...but very close to 1.25ft^3). So now you have 6.87ft^3. 21" long ports will give you a 39hz tuning(remember that with flares you have to add an inch to account for the flare, so when using a port calc, you're actually needing an extra inch than what it gives you).

 

[Johnny Law.Lulz 5,000+ posts]

Gotta account for the space the ports take up. Assuming the sub displacement is correct, you have about 1.25ft^3 displacement for the ports(depending on the flare and wall thickness...but very close to 1.25ft^3). So now you have 6.87ft^3. 21" long ports will give you a 39hz tuning(remember that with flares you have to add an inch to account for the flare, so when using a port calc, you're actually needing an extra inch than what it gives you).

The port calc already added the inch. So my box needs to be 9.37 to account for port and sub displacement. Then my 21" aeros would equal 36 hz right ?

Edit. The port calc says that for 8.12, i need 19.8" straight or 20.8" flared ports to get to 36 hz.

 

[Johnny Law.Lulz 5,000+ posts]

Bump

 

[RAM_Designs 5,000+ posts]

The port calc already added the inch. So my box needs to be 9.37 to account for port and sub displacement. Then my 21" aeros would equal 36 hz right ?
Edit. The port calc says that for 8.12, i need 19.8" straight or 20.8" flared ports to get to 36 hz.

But you only have 6.87ft^3 after ports, so that is what you put into the calc. It's an ass-backwards way of doing it, but it has to be done that way. It's a lot easier to do with a slot port, because you can make the port however wide to increase or decrease the port length in order to achieve a predetermined volume that you set aside for the port(that's how I do it anyways).