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Earl K
08-14-2003, 08:02 AM
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

4313B
08-14-2003, 08:16 AM
"- 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.

Earl K
08-16-2003, 08:06 AM
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 :)

4313B
08-16-2003, 11:14 AM
Corrected and reposted below...

Earl K
08-16-2003, 12:10 PM
Excellent :bouncy:

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

regards <> Earl K :)

4313B
08-16-2003, 01:08 PM
Sure Earl, sorry for the error in the first place.