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Absorption data conversions
PostPosted: Thu Mar 17, 2016 7:14 pm Reply with quote
andrzejhd
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Joined: 21 Jul 2015
Posts: 18
Location: Szczecinek/Birmingham




Hi again everyone! In my latest model, I need to simulate large audience area consisting of upholster seating. I found the right material in the EASE database, but it's american and all the coefficients are in sabins/sq ft. Any idea how do I convert it into metric? Or is it somehow done automatically by the program?

Thanks for help,
A. Rolling Eyes
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PostPosted: Mon Mar 21, 2016 11:26 am Reply with quote
Waldemar
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Joined: 05 Dec 2005
Posts: 112




Hi,
to obtain the absorption coefficient (alpha) of the material (which is used in the EASE material database) you have to know the total surface (S) of the measured object.
alpha = Sabine / S
If the Sabine-value is in imperial units (sq ft) then the surface S must be in sq ft also.
If there are no different data for the used octaves, use the same value for all octaves.

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SDA, Waldemar Richert
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Practical solution
PostPosted: Mon Mar 21, 2016 11:46 am Reply with quote
andrzejhd
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Joined: 21 Jul 2015
Posts: 18
Location: Szczecinek/Birmingham




My question was rather how to reverse-engineer the absorption coefficients from imperial to metric. Is it even possible?

I don't get what you mean here:
"If there are no different data for the used octaves, use the same value for all octaves."
EASE database coefficients are usually 1/3 octave values ^^

Have a great day,
A.
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PostPosted: Mon Mar 21, 2016 1:43 pm Reply with quote
thomas
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Joined: 16 Mar 2011
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Quote:
I found the right material in the EASE database, but it's american and all the coefficients are in sabins/sq ft. Any idea how do I convert it into metric?


The absorption value in EASE is the absorption coefficient (alfa) - no dimension - no conversion. You can use all the materials in the EASE-database without any conversion.

Kind regards
Thomas
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Alfa
PostPosted: Mon Mar 21, 2016 2:10 pm Reply with quote
andrzejhd
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Joined: 21 Jul 2015
Posts: 18
Location: Szczecinek/Birmingham




Thank you Thomas... That's what I thought from the very beginning! Now I understand my mistake - as you correctly pointed out - alfa is unit-less.

Thanks again,
A.
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