How do you "Tune" a box?

[Joysad24 10+ year member]

Hello all. I'm sure that this is a noobie question, but I searched for it, and could not find out...This pertains to ported boxes.

I know that when I look at subwoofer T/S parameters and specs, I notice most have a recommended box size. I understand that portion of it.

What I don't understand is how do you know what frequency your box is tuned to, and how big to make the port? Does it deal with how much polyfill or any other material you actually put in the box?

I'm interested in getting an IDMAX12 or JL 13W7, and I want to make the best possible box for which ever one I choose.

I'm thinking that a good tuning frequency is @30-32hz...being that I am looking for SQL.

All help is appreciated for my understanding of car audio. THANKS

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[ANeonRider 10+ year member]

the tuned frequency depends on the displacement of the port.

 

[Joysad24 10+ year member]

Sorry for the lack of understanding...

But, what does that mean?

Isn't displacement the amount of space something will take up to take up airspace?

If I added polyfill, would the frequency of the the box change?

 

[carguy83 10+ year member]

http://www.caraudio.com/vb/showthread.php?t=63426 //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Lots of good information on that thread.