slot port tuning

[suprefly 0]

I looked at a couple of websites but am still confused as to how to tune the port to the frequency you want. And how does the length, width, height of the port affect the tuning?

[ABXX49 20]

I looked at a couple of websites but am still confused as to how to tune the port to the frequency you want. And how does the length, width, height of the port affect the tuning?

Have you checked out JL's website?

[suprefly 0]

yep, but i don't quite get the formula. Just for kicks, lets say i want it tuned to 38hz and the box net to be 2cuft.....but how do i know how long to make the port, or what area i need to get the 38hz tuning?

[john denver 1]

For your port area most usally go for somewhere between 12 and 16 square inches per cuft. So somewhere between 24sq" and 36sq" for 2 cuft.

[suprefly 0]

Whats the difference between 12" and 16" in^2 per cuft?

[KU40 173]

You need as much port area as necessary to not stifle the sub or cause port noise. That's it. It may not be between 12 and 16 sq. inches per cubic foot.

As for the port, only the square inches of the opening matter. It doesn't matter if the port is 4" x 5" or 10" x 2", it's 20 sq. inches either way. The length, then, depends on the net size of the box, the size of the port opening, and the desired tuning.

Go to the port calculator on SSA's site or download winISD or some other box building program. Then you can see how these things interact.

[suprefly 0]

Ok will do that! yeah right now i have pretty bad port noise

[ABXX49 20]

Ok will do that! yeah right now i have pretty bad port noise

If you download winISD and get familiar with it, you'll find that there is a port velocity section. This will allow you to see if you're going to have port noise with your desired port.

[KU40 173]

Ok will do that! yeah right now i have pretty bad port noise

What box size, port, and sub do you have now?

[BigDaddy13440 3]

Ok will do that! yeah right now i have pretty bad port noise

What box size, port, and sub do you have now?

Try this:

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

It bases the cross-sectional area of the port on the amount of air the sub displaces. Input the diameter of the sub(s), the Xmax, and the desired tuning frequency - it'll tell you the size of a square port. From there, figure out the dimensions of the slotted port you need.

[suprefly 0]

here's a link to all that....be sure to at least read the last half of the thread. I believe i changed dimensions

http://www.soundsolutionsaudio.com/forum/i...showtopic=26746

and here is my build thread....it shows the steps i talked about and the finished box

http://www.soundsolutionsaudio.com/forum/i...showtopic=26820

edit: oh and what is the xmax of an AQ SDC2.5? Is it on the website and im just missing it?

Edited April 10, 2009 by FF5