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View Full Version : Port location on the RE calc



JStar22
08-21-2007, 11:17 PM
So Im making plans on my box, and working with the RE Enclosure calculator for the tuning etc.

To get to the point, they have the port location to the left of the box and when I make the box I would like the port to be in the center of the box, I was thinking of putting angled pieces to help airflow and perhaps and single wall down the middle to divide the two chambers... Would the location change my frequency the calculator came up with? and how much difference would changing the port to the center of the box have on air flow?

JStar22
08-21-2007, 11:22 PM
please?

bigbang
08-22-2007, 09:08 AM
The port should be as far away from the woofer as possible so the airflow from the woofer basket reaches the port more equaly. Also if the port is too close, when it unloads below tuning frequency the presure areas generated outside the port will effect the side of the woofer cone closest to it in a non-symetric way especially outside the box, causing cone stress. If possible have the port openings on the same side as the woofers so the sound outputs are in phase and will bleed together after a certain distance. If you do a divider because you have two woofers, you dont just make two ports each half the length, calculate a box for each woofer with its own individual air space. I made up most of that stuff but it sounds good to me.

JStar22
08-22-2007, 09:19 AM
Well info from the heart is always best I assume...:crap:

JStar22
08-22-2007, 09:22 AM
wow i totally forgot to put that the box was for a pair of 10's that would help a bit i think... dumb me

bigbang
08-22-2007, 09:49 AM
Do two slot ports in the middle of the box beween the two tens. Just design two boxes. I cheched out the RE calculator, pretty simple. Try WinISD beta. It gives you a graph, and by tugging at it the frequency response you shape it just how you want it, while simultaneously the box volume, tuning frequency, and port lengths change alowing you to test virtualy every combination by click and drag. You do need to know some woofer specs though, at least qts, vas, fs. What kind of 10's? Im doing a dual slot design for 10's right now in my "tuning for fixed volume thread" in this enclusure forum.