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coolest user
12-10-2007, 08:19 PM
I used the calc at subwoofertools and came up with a port area of 50 square inches x 27" long.

What if my port area would be 65.25 square inches, what length would the port be?

I'm trying to put 3 JL 12W1-V2 subs in 1 chamber 5.25 cubic feet with 1 port tuned to 28hz.


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BuckyBoy
12-10-2007, 09:33 PM
What do you want the height and width of the port to be?

coolest user
12-10-2007, 10:33 PM
The box I have drawn up for the 3 12's with 1 port is... 5.25 cubic feet net internal volume with a port 3.25" x 20" x 34.5" long.

subwoofertools says use a port 2.5" x 20" x 27" long. http://subwoofertools.com/forum/ported-box.asp?Ew=41&Eh=21.5&Dia=6&Xmax=9.5&Vd=.035&NumW=3&Vb=5.25&Fb=28&Qts=&Vas=&Fs=&CE=0

If the larger port size I have already designed will work the same, then I'll use my current plans. If not, I'll try something different. I don't have a clue about the effects of changing port sizes...


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BuckyBoy
12-10-2007, 10:53 PM
Try to get your port area between 73-84
Not sure of the area of 3.25x20x34.5 but that one is accurate with the tuning.
For 2.5x20 it would be more around 24 according to WinISD.

mlstrass
12-10-2007, 11:32 PM
Change the xmax figure to change the port size when using subwoofertools...

coolest user
12-11-2007, 12:15 AM
Thanks for the tip, mlstrass.



I changed the xmax to 14 and it says the port size should be 3.25 x 20 x 36 long, which is close to what I have drawn.

So, if both the larger port and smaller port are tuned to the same frequency, how do I know which to use? Does it matter?

Will it still sound the same using the larger port? Will it damage my subs?



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BuckyBoy
12-11-2007, 12:16 AM
Thanks for the tip, mlstrass.



I changed the xmax to 14 and it says the port size should be 3.25 x 20 x 36 long, which is close to what I have drawn.

So, if both the larger port and smaller port are tuned to the same frequency, how do I know which to use? Does it matter?

Will it still sound the same using the larger port? Will it damage my subs?



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When I ran it through WinISD it said between 36-37. I doubt that minimal difference will make a noticeable effect.