SC-04-08 Richard Cabot posted an update in the group SC-04-08 3 weeks ago No folders found. Please create and select folder. Documents Folder Title Following special characters are not supported: \ / ? % * : | " < > Privacy Public All Members My Connections Only Me Cancel Create 000030.html 3 KB HTML - Click to view Options Copy Download Link [SC-04-08] Nonsense pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Nonsense John Woodgate jmw at jmwa.demon.co.uk Wed May 15 04:49:28 MDT 2013 Previous message: [SC-04-08] Nonsense Next message: [SC-04-08] Let's Not Get Sidetracked Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] In message <001401ce5146$7df71b30$79e55190$@goehme.de>, dated Wed, 15 May 2013, Gunter Oehme <post at goehme.de> writes: >Hi all, > >I seems that the X curve is something like a red rag to a bull thing. >Perhaps we better should sort out what the problem is and how to >improve it: the current measurement method, the target curve or the >human factors. I recommend converting your very useful message to a Word or PDF document and uploading it to the SC-04-08 documents on the web site. -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk They took me to a specialist burns unit - and made me learn 'To a haggis'. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Previous message: [SC-04-08] Nonsense Next message: [SC-04-08] Let's Not Get Sidetracked Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000031.html 12 KB HTML - Click to view Options Copy Download Link [SC-04-08] Background literature pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Background literature Brian Long blong at skysound.com Wed May 15 12:45:22 MDT 2013 Previous message: [SC-04-08] Let's Not Get Sidetracked Next message: [SC-04-08] Background literature Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Hello Colleagues, Given the recent traffic I feel it may prove useful to provide a list of reference documents in order for folks to familiarize themselves with the legacy of the X-Curve. Myself and a group of colleagues have presented two papers in the last two years at SMPTE on topics that have also been brought up in this thread: B. Long, R. Schwenke, P. Soper, G. Leembruggen," Further investigations into the interactions between cinema loudspeakers and screens," SMPTE Mot. Imag. J; November-December 2012; 121:(8) 46-62; doi:10.5594/j18247 B. Long, R. Schwenke, "Physiological and Psycho-Acoustic basis for Multi-Resolution Frequency Response Analysis," presented at the SMPTE 2011 Technical Conference, Hollywood, California, Oct 2011. Additionally the following may prove useful and I am sure there are many more out there: I. Allen, " The X-Curve: Its Origins and History: Electro-Acoustic Characteristics in the Cinema and the Mix-Room, the Large Room and the Small" SMPTE Mot. Imag. J; July 2006; 115:(7-8) 264-275; doi:10.5594/J16175 J. Allen, J. Hunter, K. Geist, and R. Delgado, "Employing Specific Loudspeaker Designs Which Can Substantially Reduce Motion Picture Screen Interference and Losses," presented at the 132nd SMPTE Technical Conference, New York, Oct. 1990. M. Barron, Auditorium Acoustics, Spon Press, 2003. J. Eargle, J. Bonner, and D. Ross, "The Academy's New State-of-the-Art Loudspeaker System," SMPTE J 94: 667-675, 1985. J. Eargle, M. Mayfield, and David Gray, "Improvements in motion Picture Sound: The Academy's New Three-Way Loudspeaker System," SMPTE J 106: 464-476, 1997. T. Holman, " Cinema Electro-Acoustic Quality Redux," SMPTE Mot. Imag. J: 116:(5-6) 220-233; doi:10.5594/J11446, May 2007. J. Meyer, P. Meyer, J. Baird, "Far-Field Loudspeaker Interaction: Accuracy in Theory and Practice", presented in 110th Audio Engineering Society Convention (Amsterdam), PrePrint 5309, May 2001. M. Rettinger, "Sound Transmission through Perforated Screens," SMPTE J 91: 1171-1174, 1982. T. Schultz, "Acoustical Uses For Perforated Materials: Principles and Applications," Industrial Perforators Association, 1986 W. Szabo, " Guidelines for the Design of Effective Cine Theaters (Part I of a Proposed SMPTE Engineering Guideline)," SMPTE J 1986, 95:30-36. Regards, Brian Long Skywalker Sound -----Original Message----- From: sc-04-08-bounces at standards.aes.org [mailto:sc-04-08-bounces at standards.aes.org] On Behalf Of Gunter Oehme Sent: Wednesday, May 15, 2013 1:31 AM To: 'Working group on Measurement and equalization of sound systems in rooms' Subject: Re: [SC-04-08] Nonsense Hi all, I seems that the X curve is something like a red rag to a bull thing. Perhaps we better should sort out what the problem is and how to improve it: the current measurement method, the target curve or the human factors. First observation: The idea of cinema standardization always was and currently is to translate between mixing room and cinema which not necessarily means that is has to sound identical which might not happen e.g. due to different speaker quality. It is not really important whether the achieved response is linear or not, it only should translates. The timbre of the sound created in the mixing room is an artistic decision and the content is equalized according to this decision. In fact the intended sound timbre seems to be different in Europe (e.g. France, Italy and Germany) compared to the US - voices are expected to sound more bright and direct. Second observation: At least in Europe the equalization found in many theatres sucks due to many reasons of bad alignment causing that the translation to the theatres often does not work out as intended. Third observation: To my experience the translation between mixing rooms within the same facility and between different facilities works pretty well. Again this does not necessarily means that is has to sound identical e.g. due to different speaker quality. The reasons for better translation are that mixing rooms usually are within the recommendations for RT60 resulting in more similar direct sound level to total sound level ratios. More advanced people doing the eq for studios and finally the Dolby consultants ensured that the response complies to the SMPTE 202 standard. Listening the different mixing rooms of the technical tours in Rome to 3 facilities showed pretty much the same timbre of the 2 way JBL 4570 and JBL 4575 installations found there. Historically the X-curve was created the same response of the screen speaker compared to a flat monitor in a room of that time. The curve was explained as result of a level build-up of the reverberant field. The X-curve was suggested to compensate RTA measurement with steady state pink noise resulting in flat response. I am not sure if this ever was the case as only measured that kind of level build-up in very reverent rooms. In modern mixing room in the RT60 ranges recommend by SMPTE EG18, Dolby ad THX (they agrees on same RT60 at 500 Hz) I never measured a level build-up of the reverberant field similar in the X-curve. Fourth observation: By the current standards we have a roll-of direct sound response in the mixing rooms which causes some sort of pre- and de-emphasis in cinema mixes. Again it is an artistic decision how much the sound elements are equalized by listing to the mix in the mixing room. The RTA measurement was state of the art in the 70s. Today it is outdated and needs to be replaced as we have better measurement tools and reasonable eq in the cinema Actually I am using time windowed FFT measurement for doing cinema equalization for about 15 years verifying that the special averaged RTA pink noise response is reasonable within the X curve tolerance range. The issue is to improve alignment quality in the field. We should sort out the aspects and issues involved and work through the issues as a work program: Aspect 1: Proper measurement To my understanding SC 04-08 is about alignment of sound system for different kind of venues not only bound to cinema application. For this purpose standardization of practical far distance response measurement in the auditorium is required. E.g.: What are proper time windows to measure direct sound for different frequency ranges that correlates to human direct sound perception? What is the impact of diffuse sound for timbre perception? Is there weighting factor between direct sound and diffuse sound response for timbre perception? In modern multiplex cinemas at least in Europe the RT60 is typically much lesser than the value recommended by SMPTE EG18, Dolby and THX over 125 Hz. However the RT60 below 125 Hz is much higher than recommended by Dolby and THX. Due to lacking bass treatment these auditoriums have high bass ratio values. Therefore diffuse sound may have less impact on perceived timbre for higher frequencies in modern movie theatres compared to other venue types. However the high bass ratio is an issue for low frequency reproduction and measurement because there is a build-up in low frequencies. Aspect 2: Linear curve How should linear response be defined? The difference to music listening at home and music mixing room is a much higher listening distance. To which extend is the "roll-off" due to air attenuation at typical humidity expected/compensated? What are the linear target curves for given distances? Aspect 3: Cinema target curve The current multi mic measurement standard should be compared to the new measurement standard. This should be done for typical mixing room measured to current standard with several mic positions to determine the typical current target curve measured with the new measurement process. That is the target curve which is currently used for content production. A curve similar to the X curve with some less roll off is expected. Either this curve is used as target curve for all cinemas. This in fact does not create any real problem to continue with the current roll off as it is compensated in the mix as artistic decision... Expand This file was truncated for preview. Please download to view the full file. 000032.html 7 KB HTML - Click to view Options Copy Download Link [SC-04-08] B-chain definition pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] B-chain definition Brian Long blong at skysound.com Wed May 15 12:57:44 MDT 2013 Previous message: [SC-04-08] B-chain definition Next message: [SC-04-08] Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Hello SC-04-08, It is also important to read SMPTE RP 200 regarding setting reference level which is a companion to ST-202. Regards, Brian Long -----Original Message----- From: sc-04-08-bounces at standards.aes.org [mailto:sc-04-08-bounces at standards.aes.org] On Behalf Of Mark Yonge Sent: Wednesday, May 15, 2013 3:11 AM To: Working group on Measurement and equalization of sound systems in rooms Subject: [SC-04-08] B-chain definition Dear John, and SC-04-08, I have posted, courtesy of SMPTE, a copy of the current ST202 standard that is the basis of our AES-X215 project, "Liaison with SMPTE project to codify current procedures to calibrate the Cinema B-Chain" The document is on the SC-04-08 document site and has the filename: x215-smpte-st0202-130403.pdf This document, like all the documents posted to the document site, is for AES standards committee use only and may not be distributed further. A direct login is available at: https://secure.aes.org/standards/documents/?ID=91 In ST202, a reference cinema audio chain is is defined in two parts in clauses 4.4, 4.5, and figure 2. The A-chain comprises the various playback devices. The B-chain comprises source selection, fader (level control), room equalization, crossovers, power amplifiers, speakers, and auditorium acoustics. The fader (level control) exists primarily to handle program transitions and is expected to be set to a calibrated position giving a standard sound-pressure level during film playback. Fader calibration is not included in ST202. The term "X-curve" is defined in clause 4.9 and subsequently - it is the main focus of ST202. Calibration of the electroacoustic response to produce the X-curve, as I discussed during the Rome meeting, is made using fairly conventional tone controls for overall shape, and third-octave equalizers for more detailed trim. These are not intended to be adjusted arbitrarily like the tone controls on a hifi system. So far as I am aware, there is no prescription for the type of equaliser to be used in this application: modern implementations may have evolved smarter equalization techniques than simple cut or boost in third-octave bands. Regards, Mark On 2013-05-15, at 08:49, John Woodgate wrote: > In message <DC98EF6CF2F08F40AA5AA23B3509EDA971160E0F8D at KRIX-DC.Krix.local>, dated Wed, 15 May 2013, david murphy <dmurphy at krix.com.au> writes: > >> Anyway, if the attached jpeg gets through the AESSC upload system, it will repay a bit of study. > > No attachments do that. You must upload your graphics to the Documents > page for SC-04-08 on the AESSC web site.The typical cinema audio path > is defined > > Thank you for the information. Having 'tone controls' in a system makes a nonsense of having a 'standard gain control setting' and expecting that to set 'loudness'. > > I would like to see: > > - Why is it called 'B-chain'? > > - What is an 'X-curve', and why? > > - explanations of probably a number of other terms peculiar to cinema sound. > > -- > OOO - Own Opinions Only. See www.jmwa.demon.co.uk They took me to a > specialist burns unit - and made me learn 'To a haggis'. > > John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK > _______________________________________________ > SC-04-08 mailing list > SC-04-08 at standards.aes.org > <http://standards.aes.org/sc.cfm?ID=91> _______________________________________________ SC-04-08 mailing list SC-04-08 at standards.aes.org <http://standards.aes.org/sc.cfm?ID=91> Previous message: [SC-04-08] B-chain definition Next message: [SC-04-08] Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000033.html 5 KB HTML - Click to view Options Copy Download Link [SC-04-08] Project scope, was Re: Nonsense pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Project scope, was Re: Nonsense David Josephson dlj at josephson.com Wed May 15 14:02:00 MDT 2013 Previous message: [SC-04-08] Background literature Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Dear SC-04-08 colleagues, I would suggest that we all take a step back, and carefully review the scope of the relevant projects before jumping in to the fray. This is not the only effort within AESSC that has attracted this kind of response, and it's rather disturbing, particularly when it involves liaison with other professional associations who have more experience than we do in the field. The scenario looks like this: Someone proposes a project with a clearly defined need and a clear scope, and it's duly assigned to a working group. Members in the working group who are expert in their own fields see things they don't understand, and immediately try to be helpful by re-arranging the existing world to fit their concept. This does not have a positive result. AESSC has had some significant successes in recent years connected with providing our expertise in audio engineering to other standards bodies that might need a bit of help. Hopefully the recent revision of IEC audio interface and microphone standards will be thought of in that way. We have embarked on a similar project with SMPTE standards, which have evolved over the years and are more or less accepted in the field. If you are unfamiliar with the concept of "A" and "B" chains, and the reasoning behind the X-curve, I would humbly suggest that you learn a bit more before contributing to the discussion. It certainly does not help our credibility to attack something we don't even understand the need for. In this case, the SMPTE standards require a bit of adjustment, apparently (my own experience in cinema playback systems is decades old so I'll be watching from the sidelines for now). I would invite those with experience applying these standards to suggest areas where the existing approach can be improved. The prerequisite is complete familiarity with the existing standard, please. I can gently remind the group that when I organized SC-04-04 more than 15 years ago, a number of industry professionals were alarmed that I intended to rip apart the existing standard (IEC 60268-4). I believe the work of that WG is considered in a different light today, and I would hope the same for SC-04-08 with the SMPTE standard. -- David Josephson Chair, SC-04 Previous message: [SC-04-08] Background literature Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000034.html 3 KB HTML - Click to view Options Copy Download Link [SC-04-08] Project scope, was Re: Nonsense pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Project scope, was Re: Nonsense John Woodgate jmw at jmwa.demon.co.uk Wed May 15 15:22:23 MDT 2013 Previous message: [SC-04-08] Project scope, was Re: Nonsense Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] In message <5193E9B8.904 at josephson.com>, dated Wed, 15 May 2013, David Josephson <dlj at josephson.com> writes: >If you are unfamiliar with the concept of "A" and "B" chains, and the >reasoning behind the X-curve, I would humbly suggest that you learn a >bit more before contributing to the discussion. It certainly does not >help our credibility to attack something we don't even understand the >need for. That's precisely what I asked for. I suggest that you make more clear whose contribution you are censuring. -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk They took me to a specialist burns unit - and made me learn 'To a haggis'. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Previous message: [SC-04-08] Project scope, was Re: Nonsense Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000035.html 4 KB HTML - Click to view Options Copy Download Link [SC-04-08] Project scope, was Re: Nonsense pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Project scope, was Re: Nonsense David Josephson dlj at josephson.com Wed May 15 15:41:22 MDT 2013 Previous message: [SC-04-08] Project scope, was Re: Nonsense Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] On 5/15/13 2:22 PM, John Woodgate wrote: > In message <5193E9B8.904 at josephson.com>, dated Wed, 15 May 2013, David > Josephson <dlj at josephson.com> writes: > >> If you are unfamiliar with the concept of "A" and "B" chains, and the >> reasoning behind the X-curve, I would humbly suggest that you learn a >> bit more before contributing to the discussion. It certainly does not >> help our credibility to attack something we don't even understand the >> need for. > > That's precisely what I asked for. I suggest that you make more clear > whose contribution you are censuring. John, I am not censuring anyone. I respectfully encourage people, particularly in the case of projects that envision liaison with another group about their standard, to read and understand the existing standard first. Indeed your request was for elucidation on this topic and is not the subject of my concern. Hopefully we can all educate each other in the process. The other case I was mentioning is in another subcommittee, and involves codification of an existing frequency response format which is widely used if imprecisely defined (by happenstance, the existing implementations interoperate properly.) The WG's opinion was that the existing text format should be replaced wholesale with something in XML, which would break all of the legacy applications that use it. Growl. -- David Josephson Chair, SC-04 Previous message: [SC-04-08] Project scope, was Re: Nonsense Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000036.html 3 KB HTML - Click to view Options Copy Download Link [SC-04-08] Project scope, was Re: Nonsense pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Project scope, was Re: Nonsense John Woodgate jmw at jmwa.demon.co.uk Wed May 15 15:46:51 MDT 2013 Previous message: [SC-04-08] Project scope, was Re: Nonsense Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] In message <51940102.8050507 at josephson.com>, dated Wed, 15 May 2013, David Josephson <dlj at josephson.com> writes: >John, I am not censuring anyone. I respectfully encourage people, >particularly in the case of projects that envision liaison with another >group about their standard, to read and understand the existing >standard first. Thanks for your clarification. -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk They took me to a specialist burns unit - and made me learn 'To a haggis'. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Previous message: [SC-04-08] Project scope, was Re: Nonsense Next message: [SC-04-08] Project scope, was Re: Nonsense Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000037.html 4 KB HTML - Click to view Options Copy Download Link [SC-04-08] Let's Not Get Sidetracked pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Let's Not Get Sidetracked Brian McCarty bmccarty at coralseastudios.com Wed May 15 16:13:50 MDT 2013 Previous message: [SC-04-08] Nonsense Next message: [SC-04-08] Let's Not Get Sidetracked Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] I've been monitoring this discussion concerning ISO 2969, SMPTE S202, and S222. Please let's not get sidetracked into this issue as THESE DOCUMENTS ARE MOSTLY IRRELEVANT TO OUR WORK. We're working on calibration and testing of sound systems in rooms, which of course will include cinemas at some point. As a reference to what DOESN'T work, S202 is a data point, but no more. One of the last comments I made to the chair Ben Kok in Rome was: I envision the AES creating the above referenced Standard and stated direction of our work. At that point, the SMPTE will be free to use our work as a normative reference, with any possible modifications necessary by cinema-specific differences - notably the screen. The retention of the X-curve as a target for cinemas is largely now a business decision. The studios can continue to mix movies twice (or more); once for the X-curve and once for "nearfield playback" like DVD. Or they can decide to join the rest of the audio world and mix their product ONCE to a nominally flat system, and save time and money. There is no reason for the AES to be concerned with the X-curve as it doesn't have any relevance to our work. Cheers Brian McCarty AES Chair TC-SDCTV Previous message: [SC-04-08] Nonsense Next message: [SC-04-08] Let's Not Get Sidetracked Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000038.html 3 KB HTML - Click to view Options Copy Download Link [SC-04-08] Let's Not Get Sidetracked pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Let's Not Get Sidetracked David Josephson dlj at josephson.com Wed May 15 16:58:58 MDT 2013 Previous message: [SC-04-08] Let's Not Get Sidetracked Next message: [SC-04-08] Let's Not Get Sidetracked Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] On 5/15/13 3:13 PM, Brian McCarty wrote: > I've been monitoring this discussion concerning ISO 2969, SMPTE S202, and S222. > > Please let's not get sidetracked into this issue as THESE DOCUMENTS ARE MOSTLY IRRELEVANT TO OUR WORK. We're working on calibration and testing of sound systems in rooms, which of course will include cinemas at some point. As a reference to what DOESN'T work, S202 is a data point, but no more. > Are AES-X215 and X216 not specifically for liaison with SMPTE TC-25 in relation to their standards? -- David Josephson Chair, SC-04 Previous message: [SC-04-08] Let's Not Get Sidetracked Next message: [SC-04-08] Let's Not Get Sidetracked Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 000039.html 4 KB HTML - Click to view Options Copy Download Link [SC-04-08] Let's Not Get Sidetracked pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } [SC-04-08] Let's Not Get Sidetracked Brian McCarty bmccarty at coralseastudios.com Wed May 15 17:31:23 MDT 2013 Previous message: [SC-04-08] Let's Not Get Sidetracked Next message: [SC-04-08] Background literature Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Yes. But neither is the core issue for this group. Brian McCarty Sent from my iPhone On May 15, 2013, at 17:58, David Josephson <dlj at josephson.com> wrote: > On 5/15/13 3:13 PM, Brian McCarty wrote: >> I've been monitoring this discussion concerning ISO 2969, SMPTE S202, and S222. >> >> Please let's not get sidetracked into this issue as THESE DOCUMENTS ARE MOSTLY IRRELEVANT TO OUR WORK. We're working on calibration and testing of sound systems in rooms, which of course will include cinemas at some point. As a reference to what DOESN'T work, S202 is a data point, but no more. > Are AES-X215 and X216 not specifically for liaison with SMPTE TC-25 in relation to their standards? > > -- > David Josephson > Chair, SC-04 > _______________________________________________ > SC-04-08 mailing list > SC-04-08 at standards.aes.org > <http://standards.aes.org/sc.cfm?ID=91> Previous message: [SC-04-08] Let's Not Get Sidetracked Next message: [SC-04-08] Background literature Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the SC-04-08 mailing list Expand 0 Comments Public All Members My Connections Only Me PublicAll MembersMy ConnectionsOnly Me Public All Members My Connections Only Me