port question when stuffing encl

Discussion in 'Archived Threads 2001-2004' started by ross ish, Mar 10, 2003.

  1. ross ish

    ross ish Stunt Coordinator

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    The box I am using physical vb is 101.5 L. By using heavy fill, the box apparent vb changes to 123 L. When calculating port lenghth, do I use the physical vb or apparent vb in the formula?
     
  2. Owen Bartley

    Owen Bartley Second Unit

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    I just learned that apparently you're not supposed to stuff a ported enclosure, just line the walls. It made for a bit of a job, but I opened up my 210L Tempest and fixed this up, but I'm in the process of painting now so I can't tell you how much of a difference it makes... but it is my understanding that you use the net volume for your calculations. So the 123L (if you're going to keep it that way).
     
  3. ThomasW

    ThomasW Cinematographer

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    Use the actual (physical) Vb not the 'virtual' Vb when calculating the port. That way you can adjust the amount of 'fill' and not have it adversely impact the port tuning

    BTW, with ported designs there's about a 10% fudge factor with the calculations.
     

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