"Send along your shriveled balls and I'll pay to have those tested as well."
I tested mine while at Riverbank. I think at 50hz it was something like 5000 sabins. The problem was it was only 2 balls (16 squ foot) so the numbers really are not correct. I will check our 10 page report and get back to you.
LMAOooo... glad to get you all back in a good mode.
did the "shriveled-ness" diffuse the sound waves any... and would and unequal amount of "shriveled-ness" create an unequal amount of diffusion on one side of the ball area in question??
I'd have to use the same criteria for shriveled balls as I would for diffusion; I don't want it closer than about 10-12 feet from my head (Maybe that's even a bit close; but don't hold yer breath for a review in THIS lifetime )
Come to think of it, I should have specified that to mean someone ELSE's shriveled apparati - whew, that coulda been painful
Last edited by knightfly on Wed Jul 12, 2006 8:48 pm, edited 1 time in total.
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
"Converting a garage into living space requires a city permit . . . homeowners insurance won't cover a structure that's been changed without a building permit . . ." --Sacramento Bee, May 27, 2006
Tipically the newly added LENRD measurement, couldn't find a place in that "absorption coefficient" table. Put in in there and it becomes obvious why.
Ethan's said in the locked thread he left that out on purpose because there is no fair way to get absorption coefficients. You're saying there IS a fair way to do that? I had LENRDs and now I have MiniTraps and I'm surprised ANYONE says their comparable!
Can you show the data showing that RAL systematically measures higher, and IBM systematically lower
I remember when you and studiotips measured minitraps and fiberglass and lenrds and I remember minitraps were a LOT higher at RAL than what Ethan shows at realtraps. I'm surprised Ethan didn't put those numbers on his site!
Typically the newly added LENRD measurement, couldn't find a place in that "absorption coefficient" table. Put in there and it becomes obvious why.
Ethan's said in the locked thread he left that out on purpose because there is no fair way to get absorption coefficients. You're saying there IS a fair way to do that? I had LENRDs and now I have MiniTraps and I'm surprised ANYONE says their comparable!
It should be believable if Ethan applied the same method for all.
For years I tried Ethan to follow the standard. The first and only measurement which shows annoyingly high, and Ethan now tells he does it for this one and single measurement because of my complaints, to please me.
http://www.realtraps.com/data.htm Ethan Winer when useful wrote:What's most important here is the huge disparity in the first table (highlighted in white) between the data published by Foam By Mail versus what we actually measured in a real acoustics lab. To convert Sabins as measured to absorption coefficients we again used the standard formula that divides Sabins by the corner foam's front surface area of 5.67 square feet. (The 17-inch front width times four feet of length equals 5.67 square feet of front surface.) As with MiniTraps, the triangle shaped ends of each four-foot length of corner foam were exposed during testing, but not included in the calculation to convert Sabins to absorption coefficients.
This are exactly the same objects but with inferior foam (you must almost be an expert to see the difference). They stand and stood always in that table.
WTF?! Are you joking, or smoking crack again? First, I purposely did not calculate absorption coefficients for the LENRD data we measured at IBM for the very reason you criticize me repeatedly! It is impossible to fairly portray a triangle shaped absorber, where only one face will be exposed in use, using the standard calculations. .........
Put this all in a much broader context. Both above quotes are used simultaniously depending on its purpose.
You must compare sabins, and I doubt anyone will say LENRDs equal MiniTraps (not even Auralex), because they simply are acoustically much smaller devices.
Can you show the data showing that RAL systematically measures higher, and IBM systematically lower
I remember when you and Studiotips measured MiniTraps and fiberglass and lenrds and I remember MiniTraps were a LOT higher at RAL than what Ethan shows at RealTraps. I'm surprised Ethan didn't put those numbers on his site!
There have been different sets of measurements. The ones published at Studiotips made part of a designated comparison. They mainly showed a difference at this peak area, not at the overal level
But those measurements looked a lot more like the back then MiniTraps measurements at the RealTraps site as well.
Last edited by Eric_Desart on Thu Jul 13, 2006 4:07 pm, edited 5 times in total.
Best regards - Eric Desart My posts are never meant to sell whatever incl. myself, neither direct, nor indirect.
Eric_Desart wrote:It should be believable if Ethan applied the same method for all.
Unless Ethan is lying he shows sabins he measured for lenrds and minitraps and foam by mail. That's not good enough?
You must compare sabins
Ethan DOES compare sabins!
I doubt anyone will say LENRDs equal MiniTraps (not even Auralex), because they simply are acoustically much smaller devices.
YOU just said that!
There have been different sets of measurements.
Whats different? You asked if RAL measured more than IBM and I showed that.
They mainly showed a difference at this peak area, not at the overal level
I saved those graphs. I told you I lurk for a long time. RAL is higher everywhere.
Your intent is clear here. You think you can trick me on words.
I'll answer that more in-depth later.
BTW I NOWHERE said that LENRDs equal MiniTraps. They do partly if compared by a not allowed method. If your intent was pure you should as well know my numerous descriptions about that. Hence if you say YOU just said that!, be at least honest and mature enough to leave exactly what I said in the context it belongs.
And since you like to play with me, you'll also get the description of those measurements back.
But at my time, not at the time of somebody who likes to trick me, not having any real question at all, just wanting to score some cheap points rather than to know and/or learn anything.
And if you want to know or understand something you can ask with some respect as well. If however you choose to play "cowboy and indian" choose a more suitable partner.
I also do have the IBM measurements from the MiniTraps of RealTraps themselves dating from the time THOSE measurements were made.
Don't play cheap games with me. I don't feel like it.
If you quote me than quote me in context.
BTW: welcome to the group as well and nice to see you here too with your first message. Becomes really busy here.
Best regards - Eric Desart My posts are never meant to sell whatever incl. myself, neither direct, nor indirect.
Now that I'm completely finished moving out of my old place (though still not entirely unpacked in the new one), I have a little more time to get into this a bit more in depth. So . . . as promised, I would like to continue the discussion about variations between results from testing identical specimens in different labs.
First, I'll start off by clarifying some things, including some misstatments I made. Initially, I stated that it was common knowledge that RAL's test results tended to come out on the high side of the mean, and that IBM's test results tended to come out on the low side of the mean -- and that I was certain I had seen the data that demonstrated this.
Indeed, I did NOT have the ASTM data for their round robin tests, which I believed I had seen . . . but I have now acquired the ASTM E33-1005 research report for these tests.
I do have other ASTM papers (and indeed I have the paper on the ASTM 423 standard, which references this round robin test and the inconsistencies between labs), I just did not have this one. So, between that mention, a statement that Ethan made to me as to his initial source for the information, various discussions on different forums about this subject, and also the fact that various tests of MiniTraps in other labs (such as RAL) reported higher numbers than the IBM data, I formed my opinion.
Ethan's initial source for the idea that certain labs are known to report higher figures in their testing, and that some companies
intentionally seek out certain labs, was from a conversation with Dr. Matt Nobile, the head guy at IBM. So this was not something Ethan just made up to serve his own purposes . . . however, it should be clearly noted that Dr. Nobile did not mention any specific labs in connection with this statement. This was something that Ethan told me a long time ago, when I was trying to do some behind the scenes moderating of this whole feud as a moderator for Sound on Sound. I have not mentioned this item before, as I have only recently asked him if I could state this publicly, so I could include it in stating the basis for my conclusions.
As to the ASTM round robin tests, IBM was not part of that particular round robin, but RAL was. So . . . a little about what those test results say and also what they do not say:
They do NOT say that RAL reports on the high side of the mean across the board, throughout the frequency response, in every type of ASTM certified test that was part of this round robin. So in this regard my statement was certainly overbroad at best.
But in certain tests, in certain frequencies bands, they DO report on the high side of the mean -- and this is the case in some of the tests that would be closest in relevance to comparison between MiniTraps and Ready Acoustics products, GIK products, etc., and IMHO certainly give rise to significant doubts as to using test result figures for different products taken in different labs -- and, therefore, Scott Foster's graph made up of data from two different labs to compare Ready Acoustics products to RealTraps products (as well as a number of other figures and similar graphs put out by Eric and some others from the Studiotips group from time to time in the past) is not a legitimate comparison, ESPECIALLY considering that this is for non-ASTM certified "J" mounting tests. If the test results between labs for ASTM standard "A" mounting and "E400" mounting vary as much as this paper demonstrates, I think it's fair to say it's more than a little bit certain that test results for non-ASTM certified tests (and indeed for figures below the ASTM certified range of 125 Hz and above) are going to be even more inconsistent!
So, please accept my apologies and retractions for any misstatements I have made. But, unless I am misunderstanding the data, there are definitely substantive inconsistencies in test results from lab to lab, and this is the main point I'm trying to make.
I will also point out that, as I believe Scott Foster(?) alluded to earlier in the thread, the round robin results indicate that the variances for 95% confidence tests for proper ASTM certified tests WITHIN a given lab are generally within about 3%, give or take. However, as you will see, they are NOT always so close with test results from lab to lab, and there is NO data to show what variances there may be below the ASTM certified range of 125 Hz -- either within a given lab or from lab to lab.
Below is a list of the participating labs (with their accompanying numbers used to indicate each lab in the graphs), a description of the testing for specimen 1, and two graphs showing the test results for specimen 1 in each lab for both A mounting and E400 mounting tests. Since this is from a copyrighted document for which ASTM charges a fee for copies, I certainly did not want to post a copy of the entire document, so I have taken a couple of excerpts here for the purposes of education and discussion. If anyone wishes to see the entire document for themselves, for purposes of disputing or clarifying my conclusions or whatever, I would invite you to get a copy for yourself from ASTM -- It is available for download for ~US$35. I mention this because, among other things, I don't want to be accused of intentionally taking something out of context to prove a point (since these kinds of accusations seem to be running rampant in these threads from time to time). If I'm somehow misunderstanding something, I am as always happy to be corrected. Further, I'll be happy to answer any additional questions about the data, descriptions of test methods, etc. in the report if there is further information needed for a clear understanding of the excerpted data I've posted here.
The ASTM E33-1005 committee's round robin test was done using three different methods for three different specimens. The first specimen was a rigid fiberglass panel (as described below), the second was a free standing office divider, and the third was a specimen of Owens-Corning Fiberglas Structo-Fab 120 Teflon coated woven glass cloth fabric.
I have only included the information and lab-to-lab comparisons for Specimen 1, as the data for the other specimens is somewhat less complete, and is not as directly relevant to the arguments here about acoustic devices made with OC 703/705 and/or similar absorption materials.
so the numbers really are not correct. I will check our 10 page report and get back to you. 
(Maybe that's even a bit close; but don't hold yer breath for a review in THIS lifetime 
:)