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[Paul Drenth]

After looking under a few rocks here and there to no avail, I am now asking for a bit of input on a question about EASE 4. Note: I have emailed the guys at RH and EASE and haven't received any answers on this. I'm tired of waiting on them, so now I'm waiting on you 

DISCLAIMER: I know that without EARS and AURA (and especially in the JR version), EASE isn't really "dead nuts on" for legit acoustics work. But it's close enough for what I do, and I don't want to spend 10k+ on Odeon.

After recently installing EASE JR 4.3 and running some calculations, I grew scpetical of the data EASE was giving me. In digging around, I noticed that the "scattering" values for all materials in the the base were "0". This doesn't seem right too me, and definitely effects STI, ALCONS and other (if not all) calculations. Is this a JR thing? Does EASE not render the scattering factor of materials important enough to include in their base? Is this an error? I can (and have) placed scattering values for some materials that I use often, but I'm annoyed that this factor is not included in my material base.

Any insight fellow EASE users can give me would be appreciated.

Thanks!!!

-Paul

[Brad Weber]

I'm fairly sure that EASE and EASE JR use the same material database.  The underlying issue is that people have been testing absorption coefficients of materials, as well as predicting and measuring spaces based on that data, for many years, resulting in a more extensive and better supported database for absorption coefficients.  In comparison, measurement of scattering coefficients is much less common and actual test data is available for a limited number of materials.  In addition, scattering may highly affected by the specific application of a material, for example carpet on a flat floor and the same carpet on steps could behave differently at some frequencies.  In many cases the scattering coefficients have to be predicted, estimated or 'guesstimated' and entered manually.

[Paul Drenth]

I'm fairly sure that EASE and EASE JR use the same material database.  The underlying issue is that people have been testing absorption coefficients of materials, as well as predicting and measuring spaces based on that data, for many years, resulting in a more extensive and better supported database for absorption coefficients.  In comparison, measurement of scattering coefficients is much less common and actual test data is available for a limited number of materials.  In addition, scattering may highly affected by the specific application of a material, for example carpet on a flat floor and the same carpet on steps could behave differently at some frequencies.  In many cases the scattering coefficients have to be predicted, estimated or 'guesstimated' and entered manually.

Brad,

Very true. However, RPG publishes both absorption and scattering data for their products. While "rockwool 3" panels don't requre scattering data (since it's virtually nil anyways), other common materials such as chairs, acoustic concrete blocks, and even open steel ceilings have high scattering values which are essential to accurate calculations. (and of course, I can manually add these values to the materials, so all is not lost...)

I assumed that both full EASE and JR use the same bases, but I wanted to be sure.

So what you are saying is that EASE doesn't include scattering for any of their materials in the bases? If so, then I guess "it is what it is" and we all just have to work around it.

Thanks again.

[Brad Weber]

So what you are saying is that EASE doesn't include scattering for any of their materials in the bases? If so, then I guess "it is what it is" and we all just have to work around it.

It may be a function of my running EASE with AURA but if the data provided to AFMG for manufacturer specific products includes scattering coefficients then those are included in the material data, for example many of the individual RPG products have scattering coefficients.  If scattering coefficients were not part of the data provided or were not included in the information upon which the data included was based, then they are left as 0.  I think that is partially intentional as nothing really has a 0 coefficient so it makes it rather obvious.
 
I know that one of the features of AURA is a Scattering Coefficient Wizard, you give some basic information about the surface shape and it calculates the Scattering Coefficients.
 
However, that Wizard also shows some of the issues with applying scattering coefficients to more generic materials as the scattering coefficient is a function of the actual implementation and not just the material.  A sheetrock surface could be flat or sawtooth or have raised rectangles or circles or whatever with the perturbations having different dimensions.  The specifics of each individual implementation could potentially result in different scattering coefficients.  Therefore, for materials such as chairs or audience areas, concrete blocks, steel ceilings, etc., one would either have to create an individual material for each specific use or modify the data for each use.

[Bruce Olson]

After looking under a few rocks here and there to no avail, I am now asking for a bit of input on a question about EASE 4. Note: I have emailed the guys at RH and EASE and haven't received any answers on this. I'm tired of waiting on them, so now I'm waiting on you 

We also have a support forum at http://afmg-network.com that you may find useful.

DISCLAIMER: I know that without EARS and AURA (and especially in the JR version), EASE isn't really "dead nuts on" for legit acoustics work. But it's close enough for what I do, and I don't want to spend 10k+ on Odeon.

Two comments: EASE is not that expensive for AURA, and there are significant differences between EASE Jr. and EASE/AURA, especially with regard to scattering. More below...

After recently installing EASE JR 4.3 and running some calculations, I grew scpetical of the data EASE was giving me. In digging around, I noticed that the "scattering" values for all materials in the the base were "0". This doesn't seem right too me, and definitely effects STI, ALCONS and other (if not all) calculations. Is this a JR thing?

It is a JR thing in that all of it's calculations are based on Hopkins-Stryker statistical calculations.  EASE also does those calculations but with the AURA module, it also does sophisticated hybrid ray-tracing calculations. In the first case, there is no place that scattering coefficients are used in statistical calculations. The AURA module ray-tracing calculations do include and consider the scattering coefficients.   Still more later...

Does EASE not render the scattering factor of materials important enough to include in their base? Is this an error? I can (and have) placed scattering values for some materials that I use often, but I'm annoyed that this factor is not included in my material base.

In AURA, a default value is used when scattering is not included for that material. For common materials like Gypsum Board or window glass that is usually sufficient. Sometimes however, there is additional scattering that should be used based on the actual construction of the wall. For instance you may have repeated features that add additional scattering. Here you would start with the basic Gypsum Board and then use either the Scattering Wizard included in EASE to predict the scattering coefficients and add them to the material, or you would use our new AFMG Reflex tool (see links below) to update the EASE material for scattering.

http://www.afmg.eu/index.php/read-news/items/new-ease-tools-go-beta.html
http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/548479-qrd-skyline-well-dividers.html

But there are also manufacturers like RPG that have included their scattering data in the materials supplied with EASE.  Here is one example:
 

Any insight fellow EASE users can give me would be appreciated.

Thanks!!!

-Paul

I hope this helps.

[Paul Drenth]

It may be a function of my running EASE with AURA but if the data provided to AFMG for manufacturer specific products includes scattering coefficients then those are included in the material data, for example many of the individual RPG products have scattering coefficients. 

I have gone through 20+ materials in the RPG base and all have "0" values for scattering. I can't say, absolutely, that ALL RPG materials have "0" values for scattering. However, I can say with quite a bit of certainty that scattering data is not included in my database.
 

I know that one of the features of AURA is a Scattering Coefficient Wizard, you give some basic information about the surface shape and it calculates the Scattering Coefficients.

Now I want to get AURA... AND the full version of EASE.
 

However, that Wizard also shows some of the issues with applying scattering coefficients to more generic materials as the scattering coefficient is a function of the actual implementation and not just the material.  A sheetrock surface could be flat or sawtooth or have raised rectangles or circles or whatever with the perturbations having different dimensions.  The specifics of each individual implementation could potentially result in different scattering coefficients.  Therefore, for materials such as chairs or audience areas, concrete blocks, steel ceilings, etc., one would either have to create an individual material for each specific use or modify the data for each use.

Granted. However, were not always designing Carnegie hall with 1,000's of faces. At some point, its nice to know that if I just make a long flat wall with acoustic blocks, it's going to render the data accurately. But, I guess thats where self-entry of data comes in.

[Paul Drenth]

Great! Thanks Bruce. I'll check out the links and forums you posted. And yes... you did help.

[Bruce Olson]

I have gone through 20+ materials in the RPG base and all have "0" values for scattering. I can't say, absolutely, that ALL RPG materials have "0" values for scattering. However, I can say with quite a bit of certainty that scattering data is not included in my database.

Be sure to look under Manufacturers in the American Base.  Why two locations you ask? The materials under Full are retained for compatibility purposes. The ones under Manufacturer are from a major update to the database circa 2003 done by Ron Sauro. These are now organized by Manufacturer with a few Generic and Standard materials that come from a variety of sources other than manufacturers.  Ron added a lot of data related to how the measurements were made, interpolated, etc. He also included references to any test data that was published.
 

Now I want to get AURA... AND the full version of EASE.

 
 

Granted. However, were not always designing Carnegie hall with 1,000's of faces. At some point, its nice to know that if I just make a long flat wall with acoustic blocks, it's going to render the data accurately. But, I guess thats where self-entry of data comes in.

Yes, or the default value presented by AURA for the simple cases.

HTH,
Bruce

[Paul Drenth]

Be sure to look under Manufacturers in the American Base.  Why two locations you ask? The materials under Full are retained for compatibility purposes. The ones under Manufacturer are from a major update to the database circa 2003 done by Ron Sauro. These are now organized by Manufacturer with a few Generic and Standard materials that come from a variety of sources other than manufacturers.  Ron added a lot of data related to how the measurements were made, interpolated, etc. He also included references to any test data that was published.

Interesting. Yep, now some RPG materials have scattering values included. But not all. For instance "diffractal" does, but "flutter" and "pyrmidiff" do not. Hmmmmm

Are there any resources in EASE or elsewhere which list the EASE material names with descriptors, such as Mfr model #'s or materials? Most are self-explanatory, but others are a bit cryptic.

Thanks again for your help!

[Bruce Olson]

Interesting. Yep, now some RPG materials have scattering values included. But not all. For instance "diffractal" does, but "flutter" and "pyrmidiff" do not. Hmmmmm

Yea, that's probably because the data was not yet available when the database was updated by Ron.

Are there any resources in EASE or elsewhere which list the EASE material names with descriptors, such as Mfr model #'s or materials? Most are self-explanatory, but others are a bit cryptic. 

Ignore the ones in Full, they have been given full descriptions and moved to an appropriate place under Manufacturers.

Thanks again for your help!

You're welcome. 

[Paul Drenth]

You're pretty helpful for a "newbie"  ...thanks to the new forum, that is.

[Bruce Olson]

You're pretty helpful for a "newbie"  ...thanks to the new forum, that is.

SMIRK

You did see this though, right? "Member since 1984, if you count CS & live-audio"

[ProSoundWeb Community]