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 000251.html 3 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] X215 Point of order </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] X215 Point of order</H1> <B>John Woodgate</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20X215%20Point%20of%20order&In-Reply-To=%3CFpPQ3bSa0SWUFw4X%40jmwa.demon.co.uk%3E" TITLE="[SC-04-08] X215 Point of order">jmw at jmwa.demon.co.uk </A><BR> <I>Tue Nov 4 12:46:34 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000247.html">[SC-04-08] X215 Point of order </A></li> <LI>Next message: <A HREF="000250.html">[SC-04-08] X215 Point of order </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#251">[ date ]</a> <a href="thread.html#251">[ thread ]</a> <a href="subject.html#251">[ subject ]</a> <a href="author.html#251">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">5459278E.6060307 at josephson.com</A>>, dated Tue, 4 Nov 2014, David Josephson <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dlj at josephson.com</A>> writes: ><i>'d like to confirm that we are all shooting at the same target. </I> I've just posted a message suggesting that we are shooting at two different targets. Maybe I've misread the situation, but... Stabilizing the old methods is one target. Bringing the methods into the 21st century is a completely different target, and one which SMPTE seems not to want to address at present (because it can't address both at once). But I think AES CAN address both. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Quid faciamus nisi sit? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000247.html">[SC-04-08] X215 Point of order </A></li> <LI>Next message: <A HREF="000250.html">[SC-04-08] X215 Point of order </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#251">[ date ]</a> <a href="thread.html#251">[ thread ]</a> <a href="subject.html#251">[ subject ]</a> <a href="author.html#251">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000252.html 3 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>John Woodgate</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3CNJESPxS02SWUFw7Q%40jmwa.demon.co.uk%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">jmw at jmwa.demon.co.uk </A><BR> <I>Tue Nov 4 12:49:08 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000246.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000253.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#252">[ date ]</a> <a href="thread.html#252">[ thread ]</a> <a href="subject.html#252">[ subject ]</a> <a href="author.html#252">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>In message <CAEEhACmrn7W_bsWZE0_bKq_rw5U0Oj=FAya=<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">cASp7bU6KZPqnA at mail.gmail.com</A>>, dated Tue, 4 Nov 2014, philip newell <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">philiprnewell at gmail.com</A>> writes: ><i>Attached here is the Cardiff paper (if the attachment works). </I> You can't attach anything. I'm surprised no-one told you before. You must upload it to the SC-04-08 web page. If you don't know how, Mark will tell you, or If he's not around, send it to me by private email and I'll upload it. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Quid faciamus nisi sit? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000246.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000253.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#252">[ date ]</a> <a href="thread.html#252">[ thread ]</a> <a href="subject.html#252">[ subject ]</a> <a href="author.html#252">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000253.html 18 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>philip newell</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3CCAEEhACnmpwKpBUZ9zSEefyCmfxyasv9EsBsmfhE5B0ZL8tOBjw%40mail.gmail.com%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">philiprnewell at gmail.com </A><BR> <I>Tue Nov 4 12:57:13 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000252.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000255.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#253">[ date ]</a> <a href="thread.html#253">[ thread ]</a> <a href="subject.html#253">[ subject ]</a> <a href="author.html#253">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Dear Brian, As I suspected, attachments cannot be made, so perhaps you could deal with this. Best wishes, Philip On 4 November 2014 20:01, Brian McCarty <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">bmccarty at coralseastudios.com</A>> wrote: ><i> I believe that document can be attached. If not let me know and I'll add </I>><i> the TC reference. </I>><i> </I>><i> Brian </I>><i> </I>><i> </I>><i> > On 5 Nov 2014, at 4:59 am, philip newell <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">philiprnewell at gmail.com</A>> </I>><i> wrote: </I>><i> > </I>><i> > Dear Brian, </I>><i> > </I>><i> > You refer to the Cardiff IOA conference paper (as did </I>><i> > the SMPTE report). Will this reflector accept attachments? If so I will </I>><i> > send the paper for all to see (only 521 KB). </I>><i> > </I>><i> > I agree with Pete Soper that the X-curve is not really </I>><i> > a subject for X215. However, if some people still think that it is a </I>><i> > measurement artifact the situation needs to be dealt with. Otherwise, we </I>><i> > will continue having to deal with such measurement myths and get nowhere. </I>><i> > </I>><i> > </I>><i> > Best wishes, </I>><i> > </I>><i> > </I>><i> > </I>><i> > Philip </I>><i> > </I>><i> > </I>><i> > </I>><i> > On 4 November 2014 19:18, Brian McCarty <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">bmccarty at coralseastudios.com</A>> </I>><i> > wrote: </I>><i> > </I>><i> >> I agree with Mr. Soper that the objective of the Modern Calibration </I>><i> >> document is to provide improved calibration methods. </I>><i> >> </I>><i> >> However I continue to believe that this is putting lipstick on a pig. </I>><i> >> </I>><i> >> As the B-Chain Report has so aptly demonstrated, along with the work of </I>><i> >> Philip Newell et. al. in 2010, the dubbing rooms are not following the </I>><i> >> X-curve or any other Standard to reference their rooms. In fact we’re </I>><i> all </I>><i> >> aware that there are dubbing rooms in Hollywood that are run off two </I>><i> sets </I>><i> >> of equalizers - the “X-curve alignment” equalizers and the “daily </I>><i> mixing” </I>><i> >> equalizers. </I>><i> >> </I>><i> >> As the audio coming out of the dubbing rooms no longer meets the </I>><i> Standard, </I>><i> >> it’s ludicrous to think that updating the calibration methodology in </I>><i> S202 </I>><i> >> will accomplish anything positive. It in fact will serve to re-cement a </I>><i> >> theater system that’s broken. </I>><i> >> </I>><i> >> It is again my recommendation that this document not move forward, as </I>><i> the </I>><i> >> fundamentals it is built on are gone. S202 is no longer operative, it’s </I>><i> >> broken. Proper aiming of the calibration microphones and looking at the </I>><i> >> room on an FTA instead of an RTA won’t do one whit of good if the </I>><i> product </I>><i> >> they’re getting is coming out of studios who are making ad hoc </I>><i> calibrations </I>><i> >> of their dubbing rooms. </I>><i> >> </I>><i> >> The system of half-baked bandaids on problems as we find them doesn’t </I>><i> >> work. What needs to happen is a logical analysis and implementation of </I>><i> >> solutions, starting with SC-04-08 - calibration of sound systems in </I>><i> rooms. </I>><i> >> This is the first work that should be completed, which then the SMPTE </I>><i> would </I>><i> >> reference for the specifics necessary to meet a performance Standard for </I>><i> >> cinema. </I>><i> >> </I>><i> >> Brian McCarty </I>><i> >> </I>><i> >> </I>><i> >> </I>><i> >>> On Nov 5, 2014, at 4:03 AM, Pete Soper <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A>> wrote: </I>><i> >>> </I>><i> >>> Regardless of any individuals perceived/believed/rumored rationale </I>><i> >> behind the X-curve, the fact remains that it is still the prescribed </I>><i> >> response plot for audio frequency response in ST-202M and RP-200 which </I>><i> are </I>><i> >> still the current SMPTE standard documents and practices for cinema </I>><i> B-chain </I>><i> >> alignment and calibration. </I>><i> >>> </I>><i> >>> The objective of the modern calibration AHG is not to re-write these </I>><i> >> standards, but rather to provide guidelines for using more commonly </I>><i> >> available modern measurement tools and techniques such as dual channel </I>><i> FFT </I>><i> >> transfer function analysis in performing the setup and verification of </I>><i> >> systems in accordance with SMPTE 202M and RP-200. As such, any arguments </I>><i> >> for or against the X-curve are completely outside the scope of that </I>><i> group- </I>><i> >> and correspondingly, AES X215. </I>><i> >>> </I>><i> >>> </I>><i> >>> However, with that said- I think it is important to point out that </I>><i> >> several recent studies have illustrated that the matter of needing </I>><i> sound to </I>><i> >> project through a perforated screen results in a nominally "flat" </I>><i> speaker </I>><i> >> behind the screen results in very close to an "X-curve" response in </I>><i> front </I>><i> >> of the screen, this net effect on system response is repeatable and </I>><i> >> verifiable with either 1/3 octave RTA or dual channel transfer function </I>><i> >> analysis and despite claims by many to the contrary- is NOT just a </I>><i> >> measurement artifact, it is simply what happens when sound is </I>><i> transmitted </I>><i> >> through a perforated barrier. </I>><i> >>> </I>><i> >>> The recently published B-chain theater test group report shows that </I>><i> only </I>><i> >> one of the dubbing stages having a woven fabric screen (as opposed to </I>><i> >> perforated solid material) required a low-order HF roll off be imposed </I>><i> to </I>><i> >> meet the X-curve target, all of the perforated screen systems in the </I>><i> study </I>><i> >> had either no significant HF equalization or actually required boosting </I>><i> of </I>><i> >> some high frequencies in order to comply with the X-curve target window. </I>><i> >>> </I>><i> >>> -Pete Soper </I>><i> >>> Meyer Sound Laboratories Inc. </I>><i> >>> </I>><i> >>> </I>><i> >>> </I>><i> >>> </I>><i> >>> </I>><i> >>> </I>><i> >>> </I>><i> >>> -----Original Message----- </I>><i> >>> From: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A> [mailto: </I>><i> >> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] On Behalf Of markyonge </I>><i> >>> Sent: Tuesday, November 04, 2014 6:32 AM </I>><i> >>> To: Working group on Measurement and equalization of sound systems in </I>><i> >> rooms </I>><i> >>> Cc: markyonge </I>><i> >>> Subject: Re: [SC-04-08] Comments on "SMPTE-Modern-Calibr... Expand This file was truncated for preview. Please download to view the full file. 000254.html 3 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Guides to standards development </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Guides to standards development</H1> <B>Bruce C. Olson</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Guides%20to%20standards%20development&In-Reply-To=%3C005501cff86d%246d3cd260%2447b67720%24%40aes.org%3E" TITLE="[SC-04-08] Guides to standards development">bco at aes.org </A><BR> <I>Tue Nov 4 13:25:07 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000250.html">[SC-04-08] X215 Point of order </A></li> <LI>Next message: <A HREF="000273.html">[SC-04-08] AES-X219 Clarifications </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#254">[ date ]</a> <a href="thread.html#254">[ thread ]</a> <a href="subject.html#254">[ subject ]</a> <a href="author.html#254">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Far too many people in this working group have not taken the time to read the simple guidelines that are published and waste a lot of their own time as well as others wondering about arcane matters such as how to communicate. If you have not already done so, please read the guides located here: <A HREF="http://www.aes.org/standards/development/guides.cfm">http://www.aes.org/standards/development/guides.cfm</A> , in particular the first document listed. Thank you, Bruce -- Bruce C. Olson Audio Engineering Society Standards Committee Chair phone: +1 (763) 493-5835 email: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">bco at aes.org</A> web: <A HREF="http://www.aes.org/standards/">http://www.aes.org/standards/</A> </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000250.html">[SC-04-08] X215 Point of order </A></li> <LI>Next message: <A HREF="000273.html">[SC-04-08] AES-X219 Clarifications </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#254">[ date ]</a> <a href="thread.html#254">[ thread ]</a> <a href="subject.html#254">[ subject ]</a> <a href="author.html#254">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000255.html 20 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>philip newell</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3CCAEEhAC%3DZcCy4o9HxwFt0n7aodTw8TWLccygbnBGh6tVWPy4Wmg%40mail.gmail.com%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">philiprnewell at gmail.com </A><BR> <I>Tue Nov 4 14:12:57 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000253.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000248.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#255">[ date ]</a> <a href="thread.html#255">[ thread ]</a> <a href="subject.html#255">[ subject ]</a> <a href="author.html#255">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>The aforementioned Cardiff document is now uploaded as - x215-PNewell141104-IOA2010.pdf Philip On 4 November 2014 20:57, philip newell <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">philiprnewell at gmail.com</A>> wrote: ><i> Dear Brian, </I>><i> </I>><i> As I suspected, attachments cannot be made, so </I>><i> perhaps you could deal with this. </I>><i> </I>><i> </I>><i> Best wishes, </I>><i> </I>><i> </I>><i> </I>><i> Philip </I>><i> </I>><i> </I>><i> </I>><i> </I>><i> On 4 November 2014 20:01, Brian McCarty <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">bmccarty at coralseastudios.com</A>> </I>><i> wrote: </I>><i> </I>>><i> I believe that document can be attached. If not let me know and I'll add </I>>><i> the TC reference. </I>>><i> </I>>><i> Brian </I>>><i> </I>>><i> </I>>><i> > On 5 Nov 2014, at 4:59 am, philip newell <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">philiprnewell at gmail.com</A>> </I>>><i> wrote: </I>>><i> > </I>>><i> > Dear Brian, </I>>><i> > </I>>><i> > You refer to the Cardiff IOA conference paper (as did </I>>><i> > the SMPTE report). Will this reflector accept attachments? If so I will </I>>><i> > send the paper for all to see (only 521 KB). </I>>><i> > </I>>><i> > I agree with Pete Soper that the X-curve is not </I>>><i> really </I>>><i> > a subject for X215. However, if some people still think that it is a </I>>><i> > measurement artifact the situation needs to be dealt with. Otherwise, we </I>>><i> > will continue having to deal with such measurement myths and get </I>>><i> nowhere. </I>>><i> > </I>>><i> > </I>>><i> > Best wishes, </I>>><i> > </I>>><i> > </I>>><i> > </I>>><i> > Philip </I>>><i> > </I>>><i> > </I>>><i> > </I>>><i> > On 4 November 2014 19:18, Brian McCarty <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">bmccarty at coralseastudios.com</A>> </I>>><i> > wrote: </I>>><i> > </I>>><i> >> I agree with Mr. Soper that the objective of the Modern Calibration </I>>><i> >> document is to provide improved calibration methods. </I>>><i> >> </I>>><i> >> However I continue to believe that this is putting lipstick on a pig. </I>>><i> >> </I>>><i> >> As the B-Chain Report has so aptly demonstrated, along with the work of </I>>><i> >> Philip Newell et. al. in 2010, the dubbing rooms are not following the </I>>><i> >> X-curve or any other Standard to reference their rooms. In fact we’re </I>>><i> all </I>>><i> >> aware that there are dubbing rooms in Hollywood that are run off two </I>>><i> sets </I>>><i> >> of equalizers - the “X-curve alignment” equalizers and the “daily </I>>><i> mixing” </I>>><i> >> equalizers. </I>>><i> >> </I>>><i> >> As the audio coming out of the dubbing rooms no longer meets the </I>>><i> Standard, </I>>><i> >> it’s ludicrous to think that updating the calibration methodology in </I>>><i> S202 </I>>><i> >> will accomplish anything positive. It in fact will serve to re-cement </I>>><i> a </I>>><i> >> theater system that’s broken. </I>>><i> >> </I>>><i> >> It is again my recommendation that this document not move forward, as </I>>><i> the </I>>><i> >> fundamentals it is built on are gone. S202 is no longer operative, </I>>><i> it’s </I>>><i> >> broken. Proper aiming of the calibration microphones and looking at </I>>><i> the </I>>><i> >> room on an FTA instead of an RTA won’t do one whit of good if the </I>>><i> product </I>>><i> >> they’re getting is coming out of studios who are making ad hoc </I>>><i> calibrations </I>>><i> >> of their dubbing rooms. </I>>><i> >> </I>>><i> >> The system of half-baked bandaids on problems as we find them doesn’t </I>>><i> >> work. What needs to happen is a logical analysis and implementation of </I>>><i> >> solutions, starting with SC-04-08 - calibration of sound systems in </I>>><i> rooms. </I>>><i> >> This is the first work that should be completed, which then the SMPTE </I>>><i> would </I>>><i> >> reference for the specifics necessary to meet a performance Standard </I>>><i> for </I>>><i> >> cinema. </I>>><i> >> </I>>><i> >> Brian McCarty </I>>><i> >> </I>>><i> >> </I>>><i> >> </I>>><i> >>> On Nov 5, 2014, at 4:03 AM, Pete Soper <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A>> wrote: </I>>><i> >>> </I>>><i> >>> Regardless of any individuals perceived/believed/rumored rationale </I>>><i> >> behind the X-curve, the fact remains that it is still the prescribed </I>>><i> >> response plot for audio frequency response in ST-202M and RP-200 which </I>>><i> are </I>>><i> >> still the current SMPTE standard documents and practices for cinema </I>>><i> B-chain </I>>><i> >> alignment and calibration. </I>>><i> >>> </I>>><i> >>> The objective of the modern calibration AHG is not to re-write these </I>>><i> >> standards, but rather to provide guidelines for using more commonly </I>>><i> >> available modern measurement tools and techniques such as dual </I>>><i> channel FFT </I>>><i> >> transfer function analysis in performing the setup and verification of </I>>><i> >> systems in accordance with SMPTE 202M and RP-200. As such, any </I>>><i> arguments </I>>><i> >> for or against the X-curve are completely outside the scope of that </I>>><i> group- </I>>><i> >> and correspondingly, AES X215. </I>>><i> >>> </I>>><i> >>> </I>>><i> >>> However, with that said- I think it is important to point out that </I>>><i> >> several recent studies have illustrated that the matter of needing </I>>><i> sound to </I>>><i> >> project through a perforated screen results in a nominally "flat" </I>>><i> speaker </I>>><i> >> behind the screen results in very close to an "X-curve" response in </I>>><i> front </I>>><i> >> of the screen, this net effect on system response is repeatable and </I>>><i> >> verifiable with either 1/3 octave RTA or dual channel transfer function </I>>><i> >> analysis and despite claims by many to the contrary- is NOT just a </I>>><i> >> measurement artifact, it is simply what happens when sound is </I>>><i> transmitted </I>>><i> >> through a perforated barrier. </I>>><i> >>> </I>>><i> >>> The recently published B-chain theater test group report shows that </I>>><i> only </I>>><i> >> one of the dubbing stages having a woven fabric screen (as opposed to </I>>><i> >> perforated solid material) required a low-order HF roll off be imposed </I>>><i> to </I>>><i> >> meet the X-curve target, all of the perforated screen systems in the </I>>><i> study </I>>><i> >> had either no significant HF equalization or actually required </I>>><i>... Expand This file was truncated for preview. Please download to view the full file. 000256.html 7 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>Vessa, Brian</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3C02BE568F-CB45-4500-AE36-E979D1EF4807%40spe.sony.com%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">Brian_Vessa at spe.sony.com </A><BR> <I>Tue Nov 4 14:53:13 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000248.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000257.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#256">[ date ]</a> <a href="thread.html#256">[ thread ]</a> <a href="subject.html#256">[ subject ]</a> <a href="author.html#256">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Hi John- SMPTE is already planning exactly this. Once we have the Pink Noise standard and Modern Calibration recommended practice finished, which will bring things to the best practices using current standards, we plan to move forward with new standards. We are purposely taking this path rather than launching directly into new standards in order to provide a stable launching pad and also because it is more likely the industry will adopt the new standards using this approach. If we just created new standards and handed them to the industry, it is unlikely they would receive wide adoption, so we are taking a step-wise approach. Therefore, I don't think it is time to create a new group to tackle new standards yet. Let's get thru this first phase of work, which I think is on track to go to publication early next year. Cheers, Brian Brian Vessa Executive Director, Digital Audio Mastering Sony Pictures Entertainment 310-244-3306 office 310-779-9938 cell On Nov 4, 2014, at 11:41 AM, John Woodgate <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A><mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jmw at jmwa.demon.co.uk</A>>> wrote: In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">2BE563BCBE473946A8E72AE261D4F64B0177FD82D8 at XCHG1.ms.msli.com</A><<A HREF="http://XCHG1.ms.msli.com">http://XCHG1.ms.msli.com</A>>>, dated Tue, 4 Nov 2014, Pete Soper <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A><mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">psoper at meyersound.com</A>>> writes: Regardless of any individuals perceived/believed/rumored rationale behind the X-curve, the fact remains that it is still the prescribed response plot for audio frequency response in ST-202M and RP-200 which are still the current SMPTE standard documents and practices for cinema B-chain alignment and calibration. Yes, but when you let slip the dogs of war... The objective of the modern calibration AHG is not to re-write these standards, but rather to provide guidelines for using more commonly available modern measurement tools and techniques such as dual channel FFT transfer function analysis in performing the setup and verification of systems in accordance with SMPTE 202M and RP-200. As such, any arguments for or against the X-curve are completely outside the scope of that group- and correspondingly, AES X215. ... you can't really expect AES members to feel bound by the terms of reference of the SMPTE ad hoc group. Well, you can expect it, but it won't happen. Equally, AES can't necessarily expect SMPTE to withdraw some standards now, leaving a hiatus while newer and better are developed. I suspect all the argy-bargy here is simply due to that; AES wants to move the whole room measurements scenario into the 21st century, but SMPTE has some standards that need maintaining and that's their immediate priority. So, I suggest a compromise, which by definition isn't perfect. - AES members work on X-215, strictly under SMPTE terms of reference, i.e. nothing out of scope, however imperfect the result is in actual fact; - SC-04-08 starts a new project (no, I won't sponsor it, I don't know enough about the subject to lead the project; what I know about is how to get the standards we want, with least grief) on assessing or evaluating rooms according to best current knowledge. This work may be shared with SMPTE at some stage, with the object of helping SMPTE update or replace those standards that are no longer optimum. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk<<A HREF="http://www.jmwa.demon.co.uk">http://www.jmwa.demon.co.uk</A>> Quid faciamus nisi sit? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK _______________________________________________ SC-04-08 mailing list <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A><mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A>> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000248.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000257.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#256">[ date ]</a> <a href="thread.html#256">[ thread ]</a> <a href="subject.html#256">[ subject ]</a> <a href="author.html#256">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000257.html 4 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>John Woodgate</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3CLetjaPWR%24UWUFw7Y%40jmwa.demon.co.uk%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">jmw at jmwa.demon.co.uk </A><BR> <I>Tue Nov 4 15:14:41 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000256.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000258.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#257">[ date ]</a> <a href="thread.html#257">[ thread ]</a> <a href="subject.html#257">[ subject ]</a> <a href="author.html#257">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">02BE568F-CB45-4500-AE36-E979D1EF4807 at spe.sony.com</A>>, dated Tue, 4 Nov 2014, "Vessa, Brian" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">Brian_Vessa at spe.sony.com</A>> writes: ><i>MPTE is already planning exactly this. Once we have the Pink Noise </I>><i>standard and Modern Calibration recommended practice finished, which </I>><i>will bring things to the best practices using current standards, we </I>><i>plan to move forward with new standards. We are purposely taking this </I>><i>path rather than launching directly into new standards in order to </I>><i>provide a stable launching pad and also because it is more likely the </I>><i>industry will adopt the new standards using this approach. If we just </I>><i>created new standards and handed them to the industry, it is unlikely </I>><i>they would receive wide adoption, so we are taking a step-wise approach. </I> OK, that's your decision. Maintenance first, innovation later. Reasonable. ><i> </I>><i>Therefore, I don't think it is time to create a new group to tackle new </I>><i>standards yet. </I> Not in SMPTE, for sure, because you've decided not to do that. But that doesn't mean that AES SC-04-08 is also barred from starting a new project, if that's what the members want to do, and it seems like they do want to do that. There is no need to disagree: it's not an 'either/or' situation. ><i> Let's get thru this first phase of work, which I think is on track to </I>><i>go to publication early next year. </I> Sure. Full speed ahead! -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Quid faciamus nisi sit? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000256.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000258.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#257">[ date ]</a> <a href="thread.html#257">[ thread ]</a> <a href="subject.html#257">[ subject ]</a> <a href="author.html#257">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000258.html 4 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>David Josephson</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3C54595499.3030501%40josephson.com%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">dlj at josephson.com </A><BR> <I>Tue Nov 4 15:35:05 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000257.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000247.html">[SC-04-08] X215 Point of order </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#258">[ date ]</a> <a href="thread.html#258">[ thread ]</a> <a href="subject.html#258">[ subject ]</a> <a href="author.html#258">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>On 11/4/14 1:53 PM, Vessa, Brian wrote: ><i> Once we have the Pink Noise </I>><i> standard and Modern Calibration recommended practice finished, which </I>><i> will bring things to the best practices using current standards, we </I>><i> plan to move forward with new standards. We are purposely taking </I>><i> this path rather than launching directly into new standards in order </I>><i> to provide a stable launching pad and also because it is more likely </I>><i> the industry will adopt the new standards using this approach. If we </I>><i> just created new standards and handed them to the industry, it is </I>><i> unlikely they would receive wide adoption, so we are taking a </I>><i> step-wise approach. </I>><i> </I>><i> Therefore, I don't think it is time to create a new group to tackle </I>><i> new standards yet. Let's get thru this first phase of work, which I </I>><i> think is on track to go to publication early next year. </I> The group is already formed, this is it (within the AES Standards Committee, anyway.) We very much need to get a consensus on current practice before we go off blazing new trails. We are working on at least one proposal for a new project, and there will need to be many more, with the work broken into manageable sub-tasks if we are to develop an approach that will be useful to the industry. Measurement standards need to be separate from performance standards, and it's a dead end to try to mandate behavior with a voluntary standard. SC-04-08's scope is wider than just cinema. We're happy to support SMPTE's work, but we would like to proceed deliberately so that these same issues that apply to program content in other venues besides cinema can be addressed too. My closing comment on the X215 document is that the language about reaching a desired response curve should be limited, and the discussion focused on reaching consensus about the measurement methods. David Josephson Chair, SC-04 </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000257.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000247.html">[SC-04-08] X215 Point of order </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#258">[ date ]</a> <a href="thread.html#258">[ thread ]</a> <a href="subject.html#258">[ subject ]</a> <a href="author.html#258">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000259.html 8 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>Brian Long</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3C8DBDC6D514F3F44B99EA56F331381FE1C32EA9F5%40mailbox10.lucas.alllucas.com%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">blong at skysound.com </A><BR> <I>Tue Nov 4 19:00:56 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000249.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000260.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#259">[ date ]</a> <a href="thread.html#259">[ thread ]</a> <a href="subject.html#259">[ subject ]</a> <a href="author.html#259">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>1. The results of the report contradict Mr. McCarty's statement: "As the B-Chain Report has so aptly demonstrated, along with the work of Philip Newell et. al. in 2010, the dubbing rooms are not following the X-curve or any other Standard to reference their rooms." The report clearly shows the high end roll off which can be compared to the curve. The report is also done in a higher resolution than third octave smoothing to better allow a compare and contrast of the room responses. 2. ".... we're all aware that there are dubbing rooms in Hollywood that are run off two sets of equalizers - the "X-curve alignment" equalizers and the "daily mixing" equalizers. " This is a dangerous statement at best. I have not seen the data that shows this. If there are indeed these places then how do we know that the daily mixing EQ is not within the X curve tolerances but with slightly different filters applied for any number of reasons? I can certainly say that this statement of rumor is NOT the case at the majors or a number of the major independents. If there is data to the contrary rather than rumor I am open to seeing it. 3. Laboratory tests, the survey of technicians, and the in room tests by SMPTE as part of this work indicate the ramifications that nuisance variables have in the equation. Limiting these and providing advice on how to avoid them is key regardless of any target curve in the room. We could write a standard at this point that says set the room response to flat, the ABZ curve, etc, it would not matter unless recommendations are in place to limit the nuisance variables. 4. SMPTE purposefully set forth a path of discovery to assess the situation to discover what was going on in the field, the condition of venues in the field, and the knowledge level in the field before deciding to tackle any additional standards work. It was decided that in recognition of how long new work would take any clarification or limiting of the nuisance variables and variation as found in the field at this time would be helpful and key to preparing new standards. I would encourage the members of this committee to take the time to read the report and form their own analysis and opinions. Regards, Brian Long -----Original Message----- From: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A> [mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] On Behalf Of John Woodgate Sent: Tuesday, November 04, 2014 11:44 AM To: Working group on Measurement and equalization of sound systems in rooms Subject: Re: [SC-04-08] Comments on "SMPTE-Modern-Calibration" In message <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">8DBDC6D514F3F44B99EA56F331381FE1C32E84F0 at mailbox10.lucas.alllucas.com</A>>, dated Tue, 4 Nov 2014, Brian Long <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">blong at skysound.com</A>> writes: ><i>I disagree with a number of statements made in the post included below </I>><i>and would encourage the members of this group to review the report and </I>><i>data in it, along with the Newell et al. research (and supporting </I>><i>sources), rather than relying the summary statements presented. </I> With respect, I don't think that is helpful. WHAT don't you agree with? If we don't know that, we are really chasing a wild goose through all the posts, wondering which statements you accept and which you do not. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Quid faciamus nisi sit? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK _______________________________________________ SC-04-08 mailing list <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>> I agree with Mr. Soper that the objective of the Modern Calibration document is to provide improved calibration methods. However I continue to believe that this is putting lipstick on a pig. As the B-Chain Report has so aptly demonstrated, along with the work of Philip Newell et. al. in 2010, the dubbing rooms are not following the X-curve or any other Standard to reference their rooms. In fact we're all aware that there are dubbing rooms in Hollywood that are run off two sets of equalizers - the "X-curve alignment" equalizers and the "daily mixing" equalizers. As the audio coming out of the dubbing rooms no longer meets the Standard, it's ludicrous to think that updating the calibration methodology in S202 will accomplish anything positive. It in fact will serve to re-cement a theater system that's broken. It is again my recommendation that this document not move forward, as the fundamentals it is built on are gone. S202 is no longer operative, it's broken. Proper aiming of the calibration microphones and looking at the room on an FTA instead of an RTA won't do one whit of good if the product they're getting is coming out of studios who are making ad hoc calibrations of their dubbing rooms. The system of half-baked bandaids on problems as we find them doesn't work. What needs to happen is a logical analysis and implementation of solutions, starting with SC-04-08 - calibration of sound systems in rooms. This is the first work that should be completed, which then the SMPTE would reference for the specifics necessary to meet a performance Standard for cinema. Brian McCarty </PRE> <!--endarticle--> <HR> <P><UL> <!--threads--> <LI>Previous message: <A HREF="000249.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000260.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#259">[ date ]</a> <a href="thread.html#259">[ thread ]</a> <a href="subject.html#259">[ subject ]</a> <a href="author.html#259">[ author ]</a> </LI> </UL> <hr> <a href="https://secure.aes.org/mailman/listinfo/sc-04-08">More information about the SC-04-08 mailing list</a><br> Expand 000260.html 11 KB HTML - Click to view Options Copy Download Link <TITLE> [SC-04-08] Comments on "SMPTE-Modern-Calibration" </TITLE> pre { white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ } <H1>[SC-04-08] Comments on "SMPTE-Modern-Calibration"</H1> <B>markyonge</B> <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Comments%20on%20%22SMPTE-Modern-Calibration%22&In-Reply-To=%3CC9013EED-6984-4890-AA04-9116F4A0EBB3%40aes.org%3E" TITLE="[SC-04-08] Comments on "SMPTE-Modern-Calibration"">mark.yonge at aes.org </A><BR> <I>Fri Nov 7 09:29:46 MST 2014</I> <P><UL> <LI>Previous message: <A HREF="000259.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI>Next message: <A HREF="000261.html">[SC-04-08] Comments on "SMPTE-Modern-Calibration" </A></li> <LI> <B>Messages sorted by:</B> <a href="date.html#260">[ date ]</a> <a href="thread.html#260">[ thread ]</a> <a href="subject.html#260">[ subject ]</a> <a href="author.html#260">[ author ]</a> </LI> </UL> <HR> <!--beginarticle--> <PRE>Dear SC-04-08, In my note of 2014-11-04, I stated, "The X-curve is a measurement artifact and not an audio roll-off:. Philip Newell then asserted: "*It is an audio roll-off.*" Let me explore this statement a little more, if I may. I have been puzzled by this assertion - a roll-off is not specified in the standards (SMPTE ST 202 or ISO 2969) that define the X-curve, nor can I find any argument in favour of a non-flat frequency response for modern films in modern auditoria. Where has this idea come from? Then it occurred to me that a person calibrating an inappropriate room to ST 202 would be faced with a dilemma. He would be forced to conclude either: a) The measurement method is correct, but the room sounds dull, therefore the measurement method must be requiring a roll-off in the audio path. Or, b) The measurement method is incorrect in these circumstances because it can't achieve a flat frequency response for direct sound. The document, "Cinema sound: a new look at old concepts" seems to embrace conclusion 'a' as a starting point. It shows results for 20 rooms and implies that the room sizes varied significantly, but ignores the effect this would have on a classic X-curve calibration. It appears to consider the nominal X-curve as a rigid template that must be applied in the same way to all rooms regardless of size or acoustic absorbtion. While deprecating the X-curve in general, it fails to recognise the systematic flexibility in ST 202 (see * below). An engineering standard is not a law to be obeyed even if it makes no clear sense. If a standard no longer fits its purpose, then it is time to change it a better standard that does. Given that the range of cinema sizes and reverberation characteristics has expanded greatly since the late 1970s, applying the ST 202 X-curve now needs more care, skill, and experience, not less. A new RP requiring (in effect) semi-skilled technicians to apply the ST 202 X-curve in a doctrinaire way will tend to formalize dull-sounding small cinemas, which is the exact opposite of what we are seeking to achieve. The audiences that pay all our wages will not thank us for this. I would like to encourage this group to consider conclusion 'b', and that the X-curve in ST 202, used outside its originally-intended context, may simply not be useful for many modern cinemas and the modern cinema-equipment business. A new measurement method is required rather urgently, I think. * In "x215-PNewell141104-IOA2010.pdf", the only reference for the X-curve is to Ioan Allen's 2006 paper in the SMPTE Journal, and it avoids mentioning ST 202 entirely. This is a shame, because the important qualifications in ST 202 clause 6.2, figure 5, annex A.5e and annex A.5f make clear that the single curve shown as figure 1 in "x215-PNewell141104-IOA2010.pdf" is only valid for a medium sized theater (with between, say, 200 and 500 seats). Correction values are proposed for larger and smaller rooms that will change the shape of the X-curve that is approprate for them. The survey of room responses in "x215-PNewell141104-IOA2010.pdf", is interesting. The range of variation in the 2/3-distance RTA curves shown for these 20 rooms was, in my view, wide. If you take the nominal "medium sized theater" curve as a fixed reference for all cases, then 9 appear to be reasonable, while 5 appear bright, 5 appear dull, and 1 just seems odd (cine8). Without further information, that's over 50% apparently miscalibrated. However, this paper does not indicate the size of the rooms and so it is not possible to correlate the room size with the curve produced on an RTA, which might have been helpful. Philip - in summary, I am agreeing with your concluding remark that, "... it seems to be clear that there is ample justification for a thorough reassessment of the current cinema alignment procedures." But you haven't proved that the ST 202 X-curve requires a roll-off. Sincerely, Mark Yonge vice chair, SC-04-08 On 2014-11-04, I wrote: ><i> Dear SC-04-08, </I>><i> </I>><i> This discussion of the SMPTE ST 202 X-curve, developed in the late 1970s, would only be of arcane historical interest, except for the suggestion that it might be perpetuated in the Modern Calibration draft using a different measurement technique. </I>><i> </I>><i> In the late 1970s I aligned many cinemas for Dolby Laboratories, who were active in developing the X-curve as a pragmatic tool to calibrate the B-chains of mix rooms and cinemas. The intent was to take full advantage of the essentially-flat A-chain frequency response in Dolby Stereo films. The measurement equipment that was available seemed like rocket science at the time, but now looks very dated. The measurement technique produced reasonably consistent results, but relied heavily on some working assumptions, many of which are also now outdated. </I>><i> </I>><i> The following assertions are fully supported by SMPTE ST 202:2010 (and its close cousin, ISO 2969). I am happy to go into this in more detail, developing the presentation I gave to SC-04-08 in Rome, May 2013. Meanwhile: </I>><i> </I>><i> • The purpose of the X-curve is to predict a flat frequency response for direct (first-arrival) sound; </I>><i> • The X-curve is a measurement artifact and not an audio roll-off; </I>><i> • The X-curve represents a display on a real-time audio analyser (RTA), comprising a flat spectral component of the direct sound overlaid at lower frequencies by a higher-amplitude reverberation contribution from the cinema auditorium. (The direct sound comprises instantaneous energy at the microphone, while the reverberant energy has been integrating for perhaps as long as a second in a "typical" cinema, building up to a higher amplitude). </I>><i> </I>><i> The X-curve is directly useful ONLY under the following circumstances: </I>><i> • A "typical" cinema - in the 1970s this meant between approximately 200 and 2000 seats with the typical reverberation characteristics of a vaudeville theatre; </I>><i> • Continuous pink noise - other stimuli exist that will not produce the same reverberation component and will not produce a satisfactory X-curve display; </I>><i> • 1/3-octave real-time audio analyser (RTA). </I>><i> </I>><i> The X-curve is NOT useful under the following circumstances: </I>><i> • Small cinemas, screening rooms, preview theatres, music studio control rooms, home theatres; </I>><i> • Very large cinemas; </I>><i> • Open-air cinemas, sports stadia; </I>><i> • Any cinema acoustically treated to reduce its reverberation; </I>><i> • Discontinuous test signals; </I>><i> • Any spectrum-analysis tool that isn't a 1/3-octave RTA. </I>><i> </I>><i> In such circumstances where the X-curve is not useful, the X-curve should be ignored and the best available measurement technique should be used to produce a flat frequency response for direct (first-arrival) sound arriving at a typical audience position. </I>><i> </I>><i> Let me be clear: An auditorium equalised to the X-curve inappropriately is very likely to lack high-frequency energy and will sound dull. </I>><i> </I>><i> I do not believe that references to the X-curve should be continued in this Modern Calibration draft now that the measurement tools and cinema acoustics have changed sufficiently to take its application out of the main stream - it is, in effect, obsolete. </I>><i> </I>><i> Correspondence on this reflector has invoked various alternative explanations for the X-curve, referring to external papers unavailable to this group. If these papers contain some engineering wisdom relevant for this discussion, then it would be appropriate to post those papers to this group AND to identify the relevant text with reference to the corresponding clause numbers in ST 202. </I>><i> </I>><i> A bit of rigour would be appropriate - as engineers, we have a duty to keep science and folklore se... Expand This file was truncated for preview. Please download to view the full file. 0 Comments Public All Members My Connections Only Me PublicAll MembersMy ConnectionsOnly Me Public All Members My Connections Only Me
