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Thread: Vas Derivation

  1. #1
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    Vas Derivation

    Hi All
    Originally posted by Giskard
    Given a value for Fs of 35 Hz, Mms of 0.055 kilograms, and Sd of 0.090 square meters, Vas SHOULD be ~427.7 liters instead of 274.7.

    This is given by:
    Vas = (2 * pi * Fs)^2*Mms)^-1 * p0 * c^2 * Sd^2 * 10^3
    Where Vas is in liters
    Mms is in kilograms
    p0 is 1.18 kilogram/cubic meter (mean density of air)
    c is 345 meters/second (speed of sound)
    Sd is in square meters
    - I now have quite a few le14a & le10a with refurbished LansaLoy surrounds. The range of Fs is fairly broad ( 20 to 30 hz ) . I should derive new Vas figures for them. If I can avoid building a dedicated Vas test enclosure - then that's a route I'd like to examine.

    - Does anyone know the origin/author of the above quoted Vas formula ?
    - & How does it compare or correlate to deriving Vas from a test box ?



    best regards <> Earl K

  2. #2
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    Re: Vas Derivation

    "- Does anyone know the origin/author of the above quoted Vas formula ?"

    From Thiele, Small, Keele, etc.

    "- & How does it compare or correlate to deriving Vas from a test box ?"

    Well it isn't "fuzzy" math...

    You could always go with added mass instead of the test box. Not quite as easy as plug and chug but easier than sawdust, bailing wire and bubble gum.

  3. #3
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    Thanks !!

    Hi

    Thanks for the insight. I'm always attracted to formulas that keep my error inducing fingers, off the proverbial scale ( so to speak ) .

    <. Earl K

  4. #4
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    Corrected and reposted below...
    Last edited by 4313B; 08-16-2003 at 12:03 PM.

  5. #5
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    Thumbs up Thank-You !

    Excellent

    Thanks for the clarity of the formula in "Word" - helps my ADD / math-symbol challenged brain .

    regards <> Earl K

  6. #6
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    Re: Thank-You !

    Sure Earl, sorry for the error in the first place.
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