box builders, can someone please help me asap

[t-money 10+ year member]

my friend built a box for my 15 mag but i want to make sure its built properly. The box is 3.7cf tuned to 27hz. When i confirmed with my friend that the box is tuned to 27hz he told me the the box has 25sq inches of port. I know theres more to determine tuning like the length of the port. So my question is how long would the port need to be so my box is tuned to 27hz. Any and all help is appreciated.

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[jalverson 10+ year member]

i wanna say somewhere arroun 28-30 inches but thats off the top of my busy head

 

[lilmaniac2 5,000+ posts]

sounds about right maybe a lil shorter

 

[jalverson 10+ year member]

like i said a guys off the top of my head while doing some accounting work //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[_PuNiShEr_ 10+ year member]

20.85 is what i got

 

[jalverson 10+ year member]

way to short mang //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[_PuNiShEr_ 10+ year member]

you serious? that could **** cause thats the formula i used to get my box to 28hz so mine might be way off

EDIT: I used another calculator and got the same number again *SHRUGS*

 

[SubbinNCali 10+ year member]

I get 21.65 ish.

 

[t-money 10+ year member]

so does around 26 inches sound about correct for my box to be tuned to 27hz, or should it be smaller? What is the formula i would use to find out exactly. thanks for all the help so far guys

 

[jalverson 10+ year member]

sounds alot closer

 

[t-money 10+ year member]

i've been told around 22 inches.Now the box is 3.7cf after port and driver displacement. Does this sound about right?

 

[jalverson 10+ year member]

here is one at 3.8 cubes tuned to 29 pretty close to what u r asking about should give you a good idea of what you should be looking for plans are by moe lester http://img10.imageshack.us/my.php?image=38cubes29hz5075sqin5af.png

 

[CBFryman2 5,000+ posts]

this isnt complicated...

:pens WinISD::

:icks random speaker::

::enters 3.7cf @ 27Hz::

:uts a 5x5 slot port::

::Gets 21.41::

that is without end corrections (if its flared or if it has a wall close to it it doesnt have to be as long)

FYI 25sqin is NOT enough for that enclosure with that driver.

 

[t-money 10+ year member]

this isnt complicated...
:pens WinISD::

:icks random speaker::

::enters 3.7cf @ 27Hz::

:uts a 5x5 slot port::

::Gets 21.41::

that is without end corrections (if its flared or if it has a wall close to it it doesnt have to be as long)

FYI 25sqin is NOT enough for that enclosure with that driver.

well i've been told atleast 25sq inches of port , how much port should i use?

 

[CBFryman2 5,000+ posts]

40sqin+ //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif