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Thread: I need some port length help for the "widgets"

  1. #1
    Administrator Wardsweb's Avatar
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    I need some port length help for the "widgets"

    I don't have any modeling software and need to now how long to make the ports on these speakers. I'm hoping someone here will find this task easy.

    Cabinet internal volume: 5.75 cu ft
    Driver is an Altec 416-8C. The specs I found here: http://www.lansingheritage.org/image...6-8c/page1.jpg
    Re:6.5 ohms
    Fs:24.1 Hz
    Qts:0.26
    Qm:6.73
    Qes:0.28
    Vas:22.9 ft3
    Vd:0.20 ft3

    So with two 4" ports, how long should they be?
    Thanks

  2. #2
    Senior Member duaneage's Avatar
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    5.25" each tuned to 37.75 hz in 5.75 cu ft. This assumes no inductor , you going to be a little off if you have a inductor in the mix, maybe tuning them a little higher at 39 hz at 4.75 inches each might work better.

  3. #3
    Senior Member duaneage's Avatar
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    graph here
    Attached Images Attached Images  

  4. #4
    Administrator Mr. Widget's Avatar
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    I am only casually familiar with that woofer, but I'd guess at around 38Hz too for a good tuning. Using BB 6 Pro I get a port legnth of ~3.5" for the pair of 4" ports.

    I sent you (4) 11" ports so I guess you could make up a pair at 5" and a pair at 3.5" and compare them.


    Widget

  5. #5
    Steve Gonzales
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    GPA?

    Hey Wardsweb,

    You gettin' those 416-8C's from GPA?. Best kept secret this side of epay don't ya think? $400 bucks a pair for BRAND NEW, CORRECT woofers!

  6. #6
    Administrator Wardsweb's Avatar
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    Quote Originally Posted by Steve Gonzales
    Hey Wardsweb,

    You gettin' those 416-8C's from GPA?. Best kept secret this side of epay don't ya think? $400 bucks a pair for BRAND NEW, CORRECT woofers!
    Actually, these came out of my A7's along with the 802-8G drivers and 511B horns. These mounted in the new cabinets will be my main 2 channel rig in the living room. AHHH vinyl, tubes and horns...gotta love it.

  7. #7
    Administrator Wardsweb's Avatar
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    Duaneage and Widget - thank you very much for the help. I will make up a couple pair and see how they sound to me. Thanks again.

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