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Natural Science Forum / Physics / Acoustics / January 2004Harmonoise: how it'll end up?
That question concerns at first Europeans but that would probably concern other people that use ISO's calculation methods for environmental noise. I'm wondering about how the Harmonoise project will end up and I'd like to have your meaning colleages about that. The way I see it, Harmonoise is a big exciting project where very clever people spend a lot a energy and money on trying to elaborate a better calculation method for environmental noise than everything existing by today. The main goals og getting more representative and more accurate results is just fine. If one looks at the Harmonoise website, it's so far so god. However, I've heard here and there that in trying to cover so many situations with so many factors Harmonoise will lead to a greater incertainty then existing methods, the sum of the incertainty of each factor being responsible for that. So, how Harmonoise will end up? Would it be: a) a big waste: no conclusive results, no new method, everything is just as it was b) another big waste: a bad method, worse then the existing, but adopted in EU because of political reasons c) not new method, but improved existing methods based on the enorme work done to get reliable data through quantities of well executed measurements. d) a new method that doesn't give more accurate results than existing methods but has the advantage og harmonising the results such as everybody talk about the same thing when they talk about noise levels. e) a success: a new more accurate method harmonising the results Alain Bradette Alain, Whatever the outcome will be, it is a great initiative. It starts by putting people (experts) of lots of countries together. Studying the methods used in all those countries. Choosing the best to start from. Checking what's missing or can be improved. One can only hope that chauvinism and politics have very little influence. But: it's great!!! After that: expanding acoustics worldwide: Not a dream? Imagine just simple ISO Sabines meaning the same as ASTM Sabines (or vice versa) . Tempting not? A dreamer Eric > That question concerns at first Europeans but that would probably > concern other people that use ISO's calculation methods for [quoted text clipped - 26 lines] > > Alain Bradette > Alain, > [quoted text clipped - 3 lines] > Choosing the best to start from. > Checking what's missing or can be improved. I totally agree with you Eric and therefore hope that Harmonoise will be a success. > One can only hope that chauvinism and politics have very little influence. That's one big fear I have. Even little Norway is pushing hard to get its point of view influence Harmonoise. It even exists at the moment a revised version of the Nordic method actually in use in Norway, Nord2000, which is a bit strange since Norway is also involved in the Harmonoise project. Dobbel work in parallel? That leads to Karis comments where software developers always come with small changes presented as improvements: Nord2000 is already sold by a software company even though that method hasn't been adopted anywhere! > But: it's great!!! > > After that: expanding acoustics worldwide: Not a dream? > > Imagine just simple ISO Sabines meaning the same as ASTM Sabines (or vice > versa) . Tempting not? If I was you, I would forget about it. USA is about the only place in the world (besides countries with an economy directly linked to USA's one) where they still use imperial units even though the metric system is almost as old as their country. I think that rule will apply also for harmonising in acoustics, unfortunatly. > A dreamer > Eric A more realistic dreamer Alain Bradette > > That question concerns at first Europeans but that would probably > > concern other people that use ISO's calculation methods for [quoted text clipped - 26 lines] > > > > Alain Bradette > > Alain, > > [quoted text clipped - 14 lines] > Nord2000, which is a bit strange since Norway is also involved in the > Harmonoise project. Dobbel work in parallel? Not strange. The Nord2000 project delivered a method at the closing seminar: Presentation at NGS seminar , Copenhagen, September 27, 2001. Most of the people involved in the Nord2000 project are working within the Harmonoise project also, simply because Nord2000 is one of the most advanced existing methods. Much more physics involved. Anyone can compare e.g. ISO 9613 (basis of many national methods) and Nord2000 http://www.sintef.no/units/informatics/projects/dn2000/ or http://www.delta.dk/nord2000/ - Gunnar Hello Gunnar, This was the type of chauvinisme I'm squared of . For the train trafic models, the Dutch were used as basis, for road traffic the French, and I'm neither of both. That's what made ISO 717-1 what it was/is. That's why Finland wants to sell there approach to the USA deviating from the rest of Europe. And I don't like neither ISO 717 not the Finnish/Nordic alternative. Please leave me my dream, that there are still lots that like acoustics for the science of it, even with all its uncertainties and limitations. I like dreaming but still can count too. Eric > > "Eric Desart" <afbox-@belgacom.net> wrote in message > news:<40057723$0$6088$ba620e4c@news.skynet.be>... [quoted text clipped - 32 lines] > > - Gunnar Hello There seem to be some confusion. > "Eric Desart" <afbox-@belgacom.net> wrote in message news:40088573$0$321$ba620e4c@news.skynet.be... > Hello Gunnar, > > This was the type of chauvinisme I'm squared of . > > For the train trafic models, the Dutch were used as basis, for road traffic > the French, and I'm neither of both. Well, chauvinism ? In the end You can compare Dutch/French versus Harmonoise versus Nord2000 and see for yourself. It is possible that you will see some similarities between Harmonoise and Nord2000, but who knows? > That's what made ISO 717-1 what it was/is. > That's why Finland wants to sell there approach to the USA deviating from > the rest of Europe. > And I don't like neither ISO 717 not the Finnish/Nordic alternative. Finland? I do not know what You are talking about. Below I referred to ISO 9613, which is used in the Dutch and French methods. > Please leave me my dream, that there are still lots that like acoustics for > the science of it, even with all its uncertainties and limitations. Nice, so You should really consider the WEB references below to the Nord2000 documentation. It is an attempt in a more scientific direction than the earlier much more primitive ISO 9613. > I like dreaming but still can count too. But, it is of course easier to dream than to read. Dream on. - Gunnar > Eric > [quoted text clipped - 35 lines] > > > > - Gunnar > > That's what made ISO 717-1 what it was/is. > > That's why Finland wants to sell there approach to the USA deviating from [quoted text clipped - 3 lines] > Finland? > I do not know what You are talking about. Most probably about these http://www.nordtest.org/register/techn/tlibrary/tec471.pdf http://www.nordtest.org/register/techn/tlibrary/tec471m.pdf Reading those papers mentioned in the list of reference may help to understand the details and derivation of equations (I guarantee that understanding is not easy, but is this enough to trow the baby out with the wash). Some backgrounds, not mentioned in the list of references Ratings of sound insulation proposed by the ISO and CEN working groups, J. Sound Vibr. 169(1994)5, 709 - 715. + 286(1995)5, 866 - 873 + 213(1998)4, 763 -773 (from my files :)) As far as I know the intitiative was taken from US side of the Atlantic. To say shortly: It is question about the ability or accuracy to rank partitions/building parts in proper order or about how much mistakes alternative methods make -or can make is somebody will make use the gab(s) - in ranking. Kari Pesonen > There seem to be some confusion. >>"Eric Desart" <afbox-@belgacom.net> wrote in message [quoted text clipped - 7 lines] > Please leave me my dream, that there are still lots that like acoustics > for the science of it, even with all its uncertainties and limitations. It seems now that we talk about sound isolation (insulation), via reference to ISO 717. In the US, we have had ASTM E413 for some decades for the same purpose, and we know that neither is very good for transportation noise. So it also seems now that there is great difficulty in choosing a "better" rating scheme for harmonization. Over a decade ago, ASTM undertook to define a method that they believed to be very good for transportation noise insulation rating. This method was developed by Keith walker, a USG industrial scientist (also a past UK émigré) that spent some years contemplating this very problem. His method was to select a transportation noise spectrum, reasonably representative of train, aircraft and truck/car traffic, then to apply the laboratory measured noise insulation values for a specimen of the material at each test frequency. The frequency range chosen was (is) the 80Hz through 4,000Hz 1/3 octave bands. The reduction in A-weighted noise level before and after transmission are calculated. The difference is reported. It is a single number, and so could be a reasonable statement of the noise isolating capability of a specimen. This method is embodied as ASTM E1332 (reapproved 1998). It is essentially to be used in lieu of ISO717 or ASTME413. I think it is very realistic. I recently measured aircraft fly over noise reduction by lightweight construction houses, and there seems to be reasonable agreement of those noise reduction values with the OITL values derived by E1332 for the materials used in those houses. I observe that OITL values often are about 5 points less than STC results (maybe 4 less than ISO717 results?), but can be greater for materials poor in low frequency isolation capability. OITL reasonably represents, in my opinion, what we hear inside such a house "when trucks drive by".. Sincerely, Angelo Campanella > After that: expanding acoustics worldwide: Not a dream? > > Imagine just simple ISO Sabines meaning the same as ASTM Sabines (or vice > versa) . Tempting not? Success means no sabins (note spelling and capitalization). Square feet don't cut the mustard. Gene Nygaard At the present time, however, the metrical system is the only system known that has the ghost of a chance of being adopted universally by the world. -- Alexander Graham Bell,1906 Hello Gene, > Success means no sabins (note spelling and capitalization). I stand corrected thanks. Square > feet don't cut the mustard. I didn't want to discuss culture, politics, geography etc. Leads to endless discussions as in the physics group (thousands of them). So leave that up to others. Kind regards Eric Correction, I don't stand corrected. I wondered why I made that mistake if it was..... a) So checked the official Vocabulary in my language Dutch b) Also checked the German: "Schalltechnisches Taschenbuch" by Helmut Schgmidt Also checked ISO 31-7: Quantities and units of acoustics. 1) Sabines (check spelling and capitalisation) as notion for units are not used in our Countries. We use as defined in ISO the abbreviation A which stands for Equivalent Absorption expressed in m2. 2) Both a) and b) + my old courses confirm the way I spelled it including capitalisation as correct and only spelling for the units. 3) The only reason I speak about Sabines rather than A is that Sabines are more commonly know in an Intercontinental group. Americans therefore distinguish between Sabines and metric Sabines. 4) Basically I don't mind at all how it is written, als long people can comunicate and understand one another. If tomorrow somewhere, someone publishes an official world-wide list I will gladly comply with this list. I find it complicated enough that those differences in notions and units burden things. But I know I make lots of spelling errors, because, being Dutch, I don't feel the need to study linguistics for every message + I'm no good at languages (but can comunicate in 4, even when bad). As kind regards Eric > Hello Gene, > [quoted text clipped - 11 lines] > Kind regards > Eric Eric, I do not know the practices in Europe regarding sabins. In North America, we do use sabins without the e that was present in the name Sabine. Why the e was dropped, I do not know. Regarding capitalization of units, normal practice here is to capitalize an abbreviation or symbol such as Hz, dB, or W, but not to capitalize the unit when written out such as hertz, decibel, or watt. Thus, we do not capitalize sabin. Without checking, I am not sure that we have a shorter way of writing sabin that would be capitalized. Noral Stewart > Correction, > [quoted text clipped - 43 lines] > > Kind regards > > Eric Noral, Roughly I think we work the same. I only have the impression that you more speak about absorption coefficient (which we use too) while we easier express it as alpha S, but the content is the same. And I think we express it as alpha S in order to distinguish it from alpha. alpha S clearly refers to the absorption coeficient obtained as per the Sabine method And for whatever historic reason I'm not aware off, we express Sabines as A (equivalent absorption). I enjoye to learn about those differences via the net. For info: to give the exact definition as stated in ISO 31-7 Quantity: equivalent absorption area of a surface or object Symbol: A Definition: The equivalent absorption area of a surface or object in a diffuse sound field is that area of a surface having the acoustic absorption coefficient equal to 1, which, if diffraction effects are neglected, would, in the same diffuse sound field, absorp the same power. That is literally text copied (never read it so exact before). Thanks for the other additional info. Best regards Eric > Eric, > [quoted text clipped - 57 lines] > > > Kind regards > > > Eric > Noral, > [quoted text clipped - 6 lines] > alpha S clearly refers to the absorption coeficient obtained as per the > Sabine method ... snip.. May I drop some words: s in alpha (sub) s also refers to statistical absorption coefficient or a coefficient measured/calculated (from results) when assuming (those simplified) theories of statistical room acoustics being valid. As we know: For example: alpha(sub)s * S = A = 0,16V/T (Sabin's formula in metric units) results in another statistical absorption coefficient than many other known "reverse" equations of reverberation time. Kari Pesonen > May I drop some words: > s in alpha (sub) s also refers to statistical absorption coefficient [quoted text clipped - 5 lines] > than many other known "reverse" equations of reverberation time. > Kari Pesonen And there are more "words to drop": 1- Of course we distinguish between the normal absorption coefficient obtained by impedance tubes, a.n for now, and a.s for Sabine. Sabine absorption, also(?) known as random incidence absorption, is obtained in a 3D room that contains what we think is fully diffused sound (all directions everywhere). 2- We know that a.s is always greater than a.n. 3- Sabine's formula assumes always perfect diffusion. 4- But we also know that a.s for the same material in a room that is not fully diffuse is not the same as the a.s obtained in a lab. We will say that the material has not changed, only the way it is used. 5- My way of mitigating this problem in the field (practical architectural acoustics) is to assume that ALL rooms are non diffuse, by applying the Fitzroy modification to Sabine's formula (the decay rate for X-, Y- and Z waves are independently computed and then averaged) when predicting the RT60 of a practical room. Thus, only installing an acoustical tile ceiling in a room will reduce the RT60 only so far and no more. Some side wall treatment is also needed. 6- Life is never ideal, and most room are neither only Fitzroy, nor only Sabine in their RT60 behavior. The truth is somewhere in-between. 7- There remains the problem of small openings (vents and HVAC diffusers) that can also absorb sound. 8- The only reliable way to "tune" your software (Sabine paradigms) is to revisit old jobs, make field RT60 measurements, and refine said software. I've been doing that since about 1980. Angelo Campanella Hello Kari, First 1000 times Sorry. I wrongly hit the "Reply" button rather than the "Reply group" button. Sorry for the private one. Just noticed it by not seeing my message in group. So copied it here. ----- Original Message ----- From: "Kari Pesonen" <Kari.Pesonen@no_spam.welho.com> Newsgroups: alt.sci.physics.acoustics Sent: Monday, January 19, 2004 11:40 Subject: Re: dreamerRe: Harmonoise: how it'll end up? I didn't know that, in this sense that I always used S (sub) when the alpha refered to, or was calculated from, but always based on the Sabine formulas/approach. Do you distinguish between alpha S and alpha s? As far as I think/learned and can see in ISO 354 when refering to Sabine it is the capital S in subscript. Best regards Eric > > Noral, > > [quoted text clipped - 19 lines] > > Kari Pesonen > Hello Kari, > [quoted text clipped - 15 lines] > > Do you distinguish between alpha S and alpha s? Yes, but depends on the case (on the equations/theories I am using in my room acoustical predictions, as well as on availability of different alpha-data). I even may try to use angle dependent alphas when expected by the equations I am using (in this case one have to trust predicted alphas, because angle dependent values are usually not available from material vendors). Have a look, for example, on Hirata Y, Geometrical acoustics for rectangular rooms. Acustica 43(1979), 247-252. Hirata Y, Dependence of the curvature of sound decay curves and absorption distribution on room shapes, J. Sound Vibr. 84(1982)4, 509 - 517 Jacobsen F, Decay rates and wall absorption at low frequencies, J. Sound Vibr. 81(1982)3, 405 - 412. + two more general papers Polac J-D, Modifying chambers to play billiard: the foundations of reverberation theory, Acustica 76(1992), 257 - 272 Mehta M L, Mulholland K A, Effect of non-uniform distribution of absorption on reververation time, J. Sound Vibr., 46(1976)2, 209-224. kind regards Kari Pesonen > As far as I think/learned and can see in ISO 354 when refering to Sabine it > is the capital S in subscript. [quoted text clipped - 30 lines] > > > > Kari Pesonen Kari Thanks for the info Eric > > Hello Kari, > > [quoted text clipped - 73 lines] > > > > > > Kari Pesonen >I do not know the practices in Europe regarding sabins. In North America, >we do use sabins without the e that was present in the name Sabine. Why the [quoted text clipped - 3 lines] >or watt. Thus, we do not capitalize sabin. Without checking, I am not sure >that we have a shorter way of writing sabin that would be capitalized. I thought the practice was to capitalize unit names that were people's actual names. Names are munged slightly to allow lower case. Thus, Hertz and Mach are still capitalized, but bel and sabin are not because the final letter of each original name was dropped. Ken Plotkin > I thought the practice was to capitalize unit names that > were people's actual names. Names are munged slightly > to allow lower case. Thus, Hertz and Mach are still > capitalized, but bel and sabin are not because the > final letter of each original name was dropped. Hallo Ken, interesting to hear of not capitalizing only the shorted names. We write Farad even if it was Faraday and the capacitance is 10 F with a capital letter F. Is there an institution in the US to make those rules or is it the folk. Is the same happening in the UK? Cheers Eberhard Sengpiel German forum of microphone recording and studio techniques http://www.sengpielaudio.com You got me to wondering so I went to the NIST website http://physics.nist.gov/Pubs/SP811/ If we trust this by example throughout the document, hertz, kelvin, watt etc are not capitalized though of course Hz, K, and W are. I did learn something new. The kelvin K according to this is the unit of absolute temperature, not degrees Kelvin. On the other hand, if you are expressing the temperature in degrees Celsius, the units is degrees, and Celsius is an adjective modifier. In that case, they capitalize Celsius. Noral Stewart > >I do not know the practices in Europe regarding sabins. In North America, > >we do use sabins without the e that was present in the name Sabine. Why the [quoted text clipped - 10 lines] > > Ken Plotkin [snip] >temperature, not degrees Kelvin. On the other hand, if you are expressing >the temperature in degrees Celsius, the units is degrees, and Celsius is an >adjective modifier. In that case, they capitalize Celsius. So capitalization is now based on grammatical usage, not whether it's a proper name? I'll believe that. At one time capitalization of units was based on the way I described it, but standards committees do thrive on changing things. The world has been a confusing, inconsistent place ever since they did away with cps in favor of Hz (or is it hz?). Ken Plotkin One last point I didn't refer to the Sabines originally in function of the units (that's just a sometimes confusing conversion if used to think in one or the other system) but to the physical content and methods of the standards, which cause deviating end results. Eric > Hello Gene, > [quoted text clipped - 11 lines] > Kind regards > Eric >> Success means no sabins (note spelling and capitalization). >> Square feet don't cut the mustard. Oh, heck, I'll jump in, too. The problem is that Sabine was a too-successful American. If he had been European, we would not be having this problem. If he were not successful, we also would not have the problem. He had the fortune to have discovered, if not invented, the concept of "sound absorbing capability". This discovery has brought merit to him in the form of the likelihood of the unit of sound absorbing capability being named after him. He aptly realized that it can be thought of having the physical units of area (dimension squared). [NB: There are those that think that the unit of sound absorbing capability also has a decibel component. I believe that it is not there, but rather it is an artifact brought on by Sabine's early approximations.] I believe that Europeans have no basic problem with naming the unit after the person that first promulgated it, but OH!, the problem of its quantitative units!. It is traditional in the US to use our beloved "feet" as that unit. Practitioners in the rest of the world use meters for that value. And never the twain shall meet. For some years, I heard the term "metric sabins" applied with good correlation and comfort. Recent European sentiments have been to only use square meters. I personally like the term metric sabins because it "says it all" without ambiguity. Some time in this new millennium, the modifier, "metric" will atrophy. Angelo Campanella Hello Angelo, In facts it's as long as I know. We do not avoid Sabine's name or so. We do speak about alpha S (in subscript then) and call it alpha S or alpha Sabine. We speak about the Sabine formulas and approach etc.... We only distinguish in a different way between alpha S and A, which then are your Sabines. But as I said, I think most here didn't use the notion Sabines, just because it is, without wondering. I only learned this via the net the last years. And as you could notice yourself, I automatically used Sabines, to make sure it was commonly understood. Your assumption of being jealous of a successfull American, I find that a personal idea :):) If I use A for Sabines, for me it's just a Unit, nothing more, just as using m for meter and N for Newton. And it's relative recent (certainly for me) that the net made this distance between us less important, and I enjoy that. Warm regards from a non-jealous European :):) Eric > >> Success means no sabins (note spelling and capitalization). > >> Square feet don't cut the mustard. [quoted text clipped - 29 lines] > > Angelo Campanella > In facts it's as long as I know. This is a good time to discuss this mattr of "conventional" units, and especially absorption which can be confusing. > We do not avoid Sabine's name or so. I realize that. I am being somewhat cynical that this confusion should have arisen. But I think we an help eliminate that. > We do speak about alpha S (in subscript then) and call it alpha S or alpha > Sabine. There are two autoritarian agencies in the US; ANSI and ASTM. They each have definned these terms in similar, but not entirely identical, terms. ASTM defines the absorption of a body or defined surface as A, and for US usage names its unit to be the "sabin", with the understanding that it is in square feet only. ANSI defines the absortion quantities as follows: " 11.10 Sabine absorption. Sound absorption defined by the Sabine reverberation-time equation. Unit, metric sabin. " " 11.11 metric sabin. Unit of Sabine absorption, equal to one decibel square meter (dB).m2. " " 11.12 room absorption. Sum of Sabine absorptions due to objects and surfaces in a room, and due to dissipation " of energy in the medium within the room. Unit, metric sabin. " " 11.13 Sabine absorption coefficient; sound absorption coefficient. Ratio of Sabine absorption of a surface " the area of the surface. Unit, metric sabin per square meter, often omitted. " NOTE With ai as the Sabine absorption coefficient of the ith surface whose area is Si, the Sabine absorption " attributed to the surface is Ai = Siai. Now that I read these anew, I find that confusion remains. The ASTM definition is simple and narrow in scope, allowing room for metric definitions in other ways. The ANSI defintion goes directly to the metric value, but maintains the noun to be "sabin", then uses Sabine only as an adjective to infer the method of measurement (in 3D space, a room). Finally, the extended term, "metric sabin" for A(=aS) and "metric sabin per square meter" for a, which of course produced the same value as "sabin per square feet". > We only distinguish in a different way between alpha S and A, which then are > your Sabines. I am not so sure we yet have adopted the term "Sabine" as the absorption cabability of a body or defined surface, especially in square meters, but it may eventually be practical to do so, in my opinion. > And as you could notice yourself, I automatically used Sabines, to make sure > it was commonly understood. If I talk with a person that is not from the United States, I fully understand "Sabine" to be referenced in square meters. > Your assumption of being jealous of a successfull American, I find that a > personal idea :):) I was being cynical about this terrible confusion that has arisen. > If I use A for Sabines, for me it's just a Unit, nothing more, just as using > m for meter and N for Newton. So that none of us now fall asleep too quickly, note that the ANSI defintion for today keeps the "unit" of decibels within the quantitative definition of A. This has been the object of great debate here for many years. I believe it to be an artifact of the very simple approximations used by W.C. Sabine in determining the phycial significance and character of the natural phenomenon of sound absorbing capability. It is introduced in the decay rate, "decibels per second", and it is not easy to discover the way that it should disappear from the final dimensions for A. > And it's relative recent (certainly for me) that the net made this distance > between us less important, and I enjoy that. > Warm regards. ditto. Sincerely, Angelo Campanella The development consortium has been rather silent. Silence very often means problems. http://www.harmonoise.nl/ Have a look at discussion forum and latest contributions Most probably we get at least something that result in revised prediction models/programs. (Too?) Many companies live on selling revised or new versions. This, selling revised versions to users of previous versions, is a must in software business. As we all know. Research institutes and consulting companies involved in Harmo- noise need work also in future. If we look at the history of environmental noise prediction methods we continuously have got smaller or bigger changes, that usually are called as improvements. This process will continue. No reasons to expect the opposite. This is: be ready to pay for new or revised software. all the best Kari Pesonen PS. What is more accurate? (e.g., the bigger the distance the more excess attenuation will vary in long term. We should know what is the right answer to say anything about accuracy. To increase accuracy, we need more and more details in models and input data. What is the accuracy of the input data available to users. Do all users use same data, or different data? How much they have to compose?). > That question concerns at first Europeans but that would probably > concern other people that use ISO's calculation methods for [quoted text clipped - 26 lines] > > Alain Bradette |
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