Is this box design right?

[orphe 10+ year member]

this box is for 2 12 L7's

Just wondering is all the calculations right or what?

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it is supposed to be tuned around 37 hz

Click to read more...

 

[orphe 10+ year member]

bump....

 

[slc72005 10+ year member]

its tuned to about 40hz. with the port being 10 inches long

which is pretty good if you are going for a spl set up, you will lose a bit on the low end but will get loud.

but for a daily driver that you want loud i would make the port 12.1 long that would tune it to 38

for 37hz make it 13.25

for 36hz make it 14.4

for 35hz make it 15.75

 

[slc72005 10+ year member]

heres a good tool for you to use

http://www.carstereo.com/help2/Articles.cfm?id=31

 

[Trixter 10+ year member]

using those dimensions i get that the port should be 18.19" long to get a tuning freq. of 37Hz...and that's not including sub displacement...which would make the port a even longer.

 

[slc72005 10+ year member]

using those dimensions i get that the port should be 18.19" long to get a tuning freq. of 37Hz...and that's not including sub displacement...which would make the port a even longer.

his box is about 5.33cf total. and a port area of 58sq inches

the port being 18+ inches would tune it around 33hz, but also as you stated you have to subtract from sub and port displacement.

what is the sub displacement? that would get you a more accurate answer

if assuming each sub is .25cf for a total of .5cf

for 38hz make the port 14.13 long

for 37hz make the port 15.35 long

for 36hz make the port 16.68 long

use the calculator i posted up earlier for you

 

[Trixter 10+ year member]

the calculator your using does not account for port displacement....in a way

example: for a 3cu' box tuned at 30hz with 30sq" of port i will need a port that is 25.41" long....the calculator says this.

but the displacement of the port must now be added making the total box volume 3cu' + the port displacement

now if i have a box that is 3cu' and put the port in it that brings the box size down to 2.36cu'. this number includes the port's displacement.

that calculator is good...if the box has not been built yet. if the box is built then you need to account for the displacement yourself.

(i just tested that calculator with the above example.)

 

[orphe 10+ year member]

what is the sub displacement? that would get you a more accurate answer

use the calculator i posted up earlier for you

the sub is a kicker l7 . the displacement is 151 cubic inches wich is about .087 cubic feet

so should the port length be about 13.5?

 

[Trixter 10+ year member]

37Hz the port should be 20.1" long. since it will be longer than you box is deep, i would suggest putting the port on a side and L'ing it around the back side. if you do this, since the port will share a common wall with the box, you will need to add an additional 2" to the length for the correction factor...giving you a total port length of 22.1".

 

[orphe 10+ year member]

The internal volume with driver displacement

5.516

2 40 18

2 16.5 15.5

2 11.25 15.5

2 18.25 15.5

1 40 15.5

tuned at 37.22???????

so do I got it this time??

 

[Trixter 10+ year member]

ummmm.....no.

a box with the volume of 5.516, a port that is 3.5 x 15.5 (is this correct?) and a tuning of 37Hz.....

the total port length should be 15.13.

get rid of your 10 9/16 and replace it with a 14 3/8. you will need at least 3.5" from the end of the port and the back of the box so shorten up the sides of the box a little and bring out the back. keep the same volume in doing so.

 

[orphe 10+ year member]

ummmm.....no.
a box with the volume of 5.516, a port that is 3.5 x 15.5 (is this correct?) and a tuning of 37Hz.....

the total port length should be 15.13.

get rid of your 10 9/16 and replace it with a 14 3/8. you will need at least 3.5" from the end of the port and the back of the box so shorten up the sides of the box a little and bring out the back. keep the same volume in doing so.

what vent calculator did you use?

 

[Trixter 10+ year member]

what vent calculator did you use?

a TI30