New box, few port questions...

Discussion in 'Home Theater Projects' started by BryanDO, Oct 21, 2004.

  1. BryanDO

    BryanDO Stunt Coordinator

    Mar 22, 2004
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    Hey guys, I'm looking at building a new box for my Shiva, it's the 142.5L ported design. The sub is down firing along with the port. The question I have is the box is 20" high, my flared 4" port will sit 17 1/4" inches inside the box leaving only 2 3/4" between the port and the box wall. Is this enough room? I plan on using polyfill and heavy bracing as well. Thanks guys...
  2. Dennis Gardner

    Dennis Gardner Stunt Coordinator

    Dec 12, 2002
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    That clearance is a little tight for that size of port. I like to keep the clearance at least the diameter of the port away from back walls, this is more important if the port if cornered in the box or if the internal opening is close to bracing. Just helps with good airflow, otherwise the tuning of your box is changed.

    You could always put a 45 or 90 angle in your flare to turn back into your box. Just measure the average distance added by the turn and remove that much of your port.

    I wouldn't add too much polyfill to the ported box, since loose fill sometimes plugs ports when air gets to really moving around. I used open cell foam glued to the inside of my box to damp a bit, and liked how it seemed to tighten the bass a tad without affecting the awesome extension of the 17hz. tuning.

    Good luck with your EBS!!!

    You'll love the huge bump in bass!



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