How much can pollyfill get me away with.......

Discussion in 'Archived Threads 2001-2004' started by Chris Carswell, Aug 12, 2002.

  1. Chris Carswell

    Chris Carswell Supporting Actor

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    I read a great post about it here;
    http://integra.cyberglobe.net/caraud...ces/fiberfill/
    but still have 2 main questions about pollyfill.
    1.It is my understanding that you can make the box "seem" larger that it is by stuffing it. Lets say I have a PORTED box that is 5 cu ft. I need it to be 6.25 cu ft. for optium performance but don't I don't want to build a bigger box or have a bigger one in the corner of my house. I could fill it with 5lbs pollyfill (1 lb per cu ft) and will play / seem like a 6.25 cu ft. box correct?
    2.Do I port the box according to the 5 cu ft. size or the new 6.25 cu ft size? For example a 4" port would need to be 12" long to be tuned to 21hz in a 5 cu ft. box , where as in a 6.25 cu ft box it would only need to be 9" long. It would seem more logical to use the 6.25 size and go with the 9" port but I though I would run it by the higher powers to be here on the forum [​IMG]
    Thanks Guys!!!
     
  2. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Not one of the higher powers but my opinion on #2 is that you would calculate port length based on the larger effective box volume. For instance, I took some measurements on the SVS 25-31PC and I estimate its internal volume is about 80L. If I'm generous and use 85L, calculations say it would require a 15.1 inch straight port to hit 25Hz. But the port SVS uses is about 14 inches and flared, so figure 13 inches straight. The difference must be in the filling.
     
  3. Patrick Sun

    Patrick Sun Moderator
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    Yup. This happened to me when I stuffed the hell out of my Sunosub III, and dropped the tuning down to around 13Hz (when I was shooting for 16Hz with the existing port length and didn't factor in the extra polyfill).
     
  4. Chris Carswell

    Chris Carswell Supporting Actor

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    Cool, Thanks guys[​IMG]
     

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