port tuning question

[brokeitagain 10+ year member]

ok i borrowed this pic from fischer customs.

how do u figure the tuning on a box that uses a shared port in between the drivers. I am hoping for a detailed explanation. thanks

I hope fischer customs does not mind me using their pic.

That guy builds some nice stuff

Click to read more...

 

[dan5505 10+ year member]

You could throw all of the specs into here http://www.subwoofertools.com/forum/ported-box.asp

or winisd. Then just adjust the tuning frequency until everything matches up right.

 

[brokeitagain 10+ year member]

i would much rather get a technical explanation of how properly figure it. i dont want to trust some online calculator that may be way off.

i want to know how to figure the volume and tuning of an enclosure like the one that is pictured above. i know how to do it if the subs are in the same chamber but is it different when the enclosure is built as the one above?

 

[dan5505 10+ year member]

As far as I know, most people use the online calculator or Winisd. I may be wrong though. I have no clue how you would calculate the tuning out by hand. I would kinda like to know that myself. Even though the two chambers in your picture are separated, they share the same port. Again, I may be wrong, but i think you can calculate it just as if the two chambers were connected. Use the combined volume of the two.

 

[brokeitagain 10+ year member]

thats what i was thinking originally. Now i think that it is supposed to be two separate chambers then figure the port in somehow

thats where i am lost at.

i am trying to figure out the tuning on the box i might buy to use with the new subs i bought. The audio shop says it is built for these but( i know that they did build it)i want to know what it is tuned to before i spend 60 bucks on it. If its not what i want i will build my own to suit my desires

 

[RAM_Designs 5,000+ posts]

Just plug in the internal volume of your box(minus port/subs), port area, and port length into a calc and it'll tell you the tuning frequency. There's nothing special or tricky to having two subs and one port.

 

[dan5505 10+ year member]

If you were to calculate them separately maybe you would divide the port area in half? 1/2 for each driver? hmmm.... im lost. You could try calculating both ways and see how much they differ.

 

[brokeitagain 10+ year member]

and where do i find this calc?

 

[dan5505 10+ year member]

I think i know what your saying now though, the left driver wont be using the port area on the right side of the box and vice versa.

 

[brokeitagain 10+ year member]

thats what i meant i know it is kinda difficult to understand what i mean until u think of how the port is arranged in the box

 

[RAM_Designs 5,000+ posts]

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

 

[brokeitagain 10+ year member]

that isnt what i need to know, I WANT TO MEASURE THE BOX I AM LOOKING AT THAT I AM CONSIDERING BUYING, SO I KNOW THE TUNING FREQUENCY OF THIS BOX WILL BE WHAT I OR NOT

 

[dan5505 10+ year member]

do you know the dimensions of the box?

 

[brokeitagain 10+ year member]

out side dimensions are 13.5 high, 17.5 deep, 34 inches wide, its build from 3/4 MDF

The port in side dimentions are 3" wide 12" tall 14" deep

EDIT: driver displacement is .068

 

[twisztdauthorit 10+ year member]

this thread is a failure.....

just use a **** calculator... theres nothing more accurate then one.