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View Full Version : Dual slot port.

grimreper912003
04-18-2008, 06:12 PM
Hey, I was woundering how do you determin the tunning on a dual slot port box with only one sub? Is there a calculator online or equation to use to find the tunning?

hoxie08
04-18-2008, 06:14 PM
i would imagine its just like a normal port just port area /2??? idk.

grimreper912003
04-18-2008, 06:18 PM
i would imagine its just like a normal port just port area /2??? idk.

I got that. I.e if you needed 80 sq in of port area you would do 2 40sq in ports, but I mean how do you find what your port length needs to be?

SPY
04-18-2008, 08:43 PM
When using mutiple port you end up with longer ports.

example

5 ft^3 @35 with one 4x16 port is 22.5" long

5 ft^3 @35 with two 2x16 ports is 24.12" long

basshedz06
04-18-2008, 11:13 PM
well what about those ports that has one opening on front of box but T's off inside the box with two openings i have seen some boxes built like that jblcamry did a design like that once for someone but i could never get a hold of him to ask him how he done it

BuckyBoy
04-19-2008, 12:30 AM
well what about those ports that has one opening on front of box but T's off inside the box with two openings i have seen some boxes built like that jblcamry did a design like that once for someone but i could never get a hold of him to ask him how he done it
You mean a port in the center of the box right? That's two separate ports, and the divider is to divide the ports and keep the port width consistent. For example, if the main opening is 5.75" wide, then that is two 2.5" wide ports.

basshedz06
04-19-2008, 03:41 PM
well the one i was tallking about was without a divider umm i was checking out brianchia's box design pics he has on his image host page and he has one of the boxes i was talking about i suppose i should holla at him to find out how he figured out his port area and length

IDSkoT
04-20-2008, 03:49 AM
The formula for Aeroports [tubezz] is...

LV = (8466 x R^2 / Vb x Fb^2) - (1.463 x R)

Where:
LV = Length of Port
Vb = Volume of the Box
Fb = Frequency

For multiple ports, you divide the volume of the box by how many ports you want.

Enjoi.

[and double, triple, or even quadruple check your work. Rather do extra work than have a sh!tty tuned box :fyi:]

EDIT:: I'm an idiot... I can't read :crap:

Formula for slotted ports:

LV (Length of Port) = [(1.463 x 10^7 x {SqRt(A/Pi)}) / (Fb^2 (Desire tuning frequency in Hertz) x Vb (Internal Volume of Enclosure in Inch^3)] - 1.463 x {SqRt(A/Pi)} (<-- Square vent's A x Pi )

With the same rule that applies to the aeroport being divide the Vb by the amount of ports wanted.