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Check my port length BPD 1803

Discussion in 'Archived Threads 2001-2004' started by Craig Woodhall, Aug 4, 2002.

  1. Craig Woodhall

    Craig Woodhall Supporting Actor

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    Hey, i finished my box for my BPD 1803.. After I subtract all the bracing/driver/etc i have a net enclosure of 11.302 ft3. I want to tune it to 17.5hz and the inside diameter of the sonotube port I will be using is 8.25". I come up with a port 35" long, does that look about right? How do you account for the volume the port itself takes up?
    Hopefully the airspeed won't be too high and the enclosure isn't under-ported, it would have been too difficult to fit a 10" port in.

    Craig
     
  2. Pete Mazz

    Pete Mazz Supporting Actor

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    The tuning is right.

    You have to deduct the volume of air that the port takes up, which would be Pi*R^2*Height. If it affects the overall volume by a lot, then re-do the tuning based on the new volume.

    Pete
     
  3. Craig Woodhall

    Craig Woodhall Supporting Actor

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    Pete,

    the sonotube im using for a port is only 1/8" thick, so you mean just subtract the material of the port inside the box, not all the air volume inside the port?

    Craig
     
  4. Chris Carswell

    Chris Carswell Supporting Actor

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    No, all the air. Treat it as a soild object.
     

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