# Nice Site to calculate Absorbers



## Guest (Apr 25, 2007)

http://www.mhsoft.nl/Helmholtzabsorber.asp

br Gerd


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## bpape (Sep 14, 2006)

Just be careful. The formulas for the Helmholz absorbers are incorrect on that page - as they are on many web sites. There was an error in a book that's been propogated. The rest of the calculators work OK.

Bryan


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## Guest (Apr 25, 2007)

Its allways risky with Helmholz Resonators. We had a lot of disskusiones and research and some works to, and we descoverd, that this formula is close.
http://mb.abovenet.de/allabout-hifi/index.php/topic,112.0.html
This Formula should work
f = 172,71 * Wurzel(A/(V * (l + (0,732 * d))))

mit
f = Frequenz [Hz]
V = Volumen des Resonators [in liter]
l = Länge des Kanals in [in cm]
A = Fläche des Kanals ( = pi * r*r)
d = DURCHMESSER der Fläche des Kanals [in cm]
pi = 3.1416

Thanks to Joachim from kea audio for this:clap: 
Gerd


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