Flared Port

Discussion in 'Archived Threads 2001-2004' started by Rick Thomas, Mar 28, 2002.

  1. Rick Thomas

    Rick Thomas Agent

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    I'm going to be putting a 4" port in my sono sub.What should I use for the port and where do i get something flared for the ends thanks.
     
  2. jeff lam

    jeff lam Screenwriter

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    If you want flared ends you will need the kit. Partsexpress, madisound, adire audio all have them.

    Or you can just use a straight 4" PVC pipe. But the flared ends would be required if you had a Shiva, Tempest, or similar driver.
     
  3. Rick Thomas

    Rick Thomas Agent

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    Do i need the port flared on both ends or just the end inside the sono?thanks
     
  4. Dan M~

    Dan M~ Second Unit

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    Poor Mans flare...

    Cut your PVC to length, glue/insert into a laminated scrap of MDF (1.5" thick)that has a hole cut to the right size, use router roundover bit with guide bearing to roundover ID of tube/MDF, cut OD of MDF round and use roundover bit around the outside of MDF. Experiment to find out what size of OD works best. Roundover bits can be found up to 3" radius (to much for handheld router, works with large router/shaper table though, also big bucks$$$$!!!) but a 1/2" radius looks good and gives a full 1" diameter lip to your port. Install tube in cabinet and rout mouth there...

    Hope that makes some sense... experiment and see what you can do.

    Good luck
     
  5. Jack Gilvey

    Jack Gilvey Producer

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  6. Dan M~

    Dan M~ Second Unit

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    Keeping with the poor mans ideas...

    If your air flow is sub sonic (
     
  7. Jack Gilvey

    Jack Gilvey Producer

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  8. Dan M~

    Dan M~ Second Unit

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    Jack,
    Good point. A/c air movement would consist of air moving in one direction, stopping and then accelerating in the other direction, repeat until the music stops. The average airspeed will be zero! [​IMG]
    The actual peak speed is the point of concern. Do the design programs that report port speed give an acurate number? I wonder what accounting do they take for "drag" within the port? The hard answer is to have as large a port as possible (length being the usual limiting factor) and ad some flare. The simple answer is "closed box". [​IMG]
    Have fun.
     
  9. Jack Gilvey

    Jack Gilvey Producer

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  10. Dan M~

    Dan M~ Second Unit

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  11. Brian Bunge

    Brian Bunge Producer

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  12. Rudy H

    Rudy H Stunt Coordinator

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    Dont forget that the air inside the ports has weight as well..... that's how longer ports tune to lower frequencies.

    An "ideal" PR would probably be one that has a very very soft suspension, SQ wise that is.
     
  13. Dan M~

    Dan M~ Second Unit

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    Jack,

    Thanks for the link. I printed it out and will sit down and study it.

    With respect to PR's and moving mass... The PR's move a mass of air too. How much compared to a ported system, I do not know. When the driver moves, it displaces air. On a sealed system, the air compresses and acts like a spring to help the cone recover. In a ported system the air is compressed and pushed out the port, the driver must "suck" the air back through the port to return to it's starting position (There is some residual "spring" pressure within the box to help). In a PR system the air compresses and moves the PR's out (displacing air outside the box). The PR's provide some help in recovery, as they want to return to the starting position too.

    I need to study this somemore.

    P.S. Rick Thomas, sorry for hi-jacking your thread.

    Happy Easter/Passover.
     
  14. Jack Gilvey

    Jack Gilvey Producer

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  15. Dan M~

    Dan M~ Second Unit

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    Hi Jack,
    Yes my discription was VERY simplified, but you do have moving air. Push in on your driver and the air moves out of the port or your PR's move out, pushing air.
     
  16. Jack Gilvey

    Jack Gilvey Producer

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  17. Bryan Michael

    Bryan Michael Supporting Actor

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    if you use a bigger port do you need it flaried to be used with a tempest? like a 6 or 8 in port
     
  18. Bryan Michael

    Bryan Michael Supporting Actor

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    if you use a bigger port do you need it flaried to be used with a tempest? like a 6 or 8 in port
     
  19. Dan M~

    Dan M~ Second Unit

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    Jack said-
     

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