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   <H1>[SC-04-08] Minutes  & Actions of New York Meeting</H1>

    <B>Peter Mapp</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Minutes%20%20%26%20Actions%20of%20New%20York%20Meeting&In-Reply-To=%3C95f76da2344c4e5683916b12c1294994%40CP1-L1-MB-2003.CloudPlatform1.com%3E" TITLE="[SC-04-08] Minutes  & Actions of New York Meeting">peter at petermapp.com

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    <I>Tue Dec 19 11:19:40 EST 2017</I>

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<PRE>It was agreed at the New York meeting that we would leave anything to do with frequency / spectral response assessment/measurement (and hence EQ) until after InfoComm have revised their document (I have yet to find anyone who thought it was any use).  However, if you want to start working on an AES version that is more sophisticated Glenn - then I have no objection. Indeed the bare bones of what you think is needed would be good to have at the ready. So, as previously agreed Charlie.

​

Cheers

​

Peter

​

-----Original Message-----

From: SC-04-08 [mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] On Behalf Of Charlie Hughes via SC-04-08

Sent: 19 December 2017 14:12

To: Vessa, Brian; Working group on Measurement and equalization of sound systems in rooms; Glenn Leembruggen AD; Peter Mapp

Subject: Re: [SC-04-08] Minutes & Actions of New York Meeting

​

The InfoComm draft standard that was reviewed by some was a preliminary draft.  Based on the comments from many reviewers, it has been changed substantially.  It is still undergoing revision.  I suggest that SC-04-08 not spend time or energy worrying about that particular document until the finished draft it is ready for review or has been published.

​

Best regards,

​

Charlie Hughes

Excelsior Audio

Gastonia, NC

+1 704.675.5435 (tel)

+1 704.678.6570 (mobile)

www.excelsior-audio.com

​

​

-----Original Message-----

From: SC-04-08 [mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] On Behalf Of Vessa, Brian via SC-04-08

Sent: Tuesday, December 19, 2017 8:43 AM

To: Glenn Leembruggen AD; Working group on Measurement and equalization of sound systems in rooms; 'Peter Mapp'

Subject: Re: [SC-04-08] Minutes & Actions of New York Meeting

​

Hi all, I agree with Glenn, I reviewed that document also.

​

Cheers,

​

Brian

​

From: SC-04-08 <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>> on behalf of Glenn Leembruggen AD via SC-04-08 <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>>

Reply-To: "<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">Glenn at acousticdirections.com</A>" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">Glenn at acousticdirections.com</A>>, Working group on Measurement and equalization of sound systems in rooms <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>>

Date: Tuesday, December 19, 2017 at 4:57 AM

To: "<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>" <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">peter at petermapp.com</A>>, 'Working group on Measurement and equalization of sound systems in rooms' <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>>

Subject: Re: [SC-04-08] Minutes & Actions of New York Meeting

​

Hi All

I meant to post this a few weeks ago, but forgot.

There was some discussion in about using the InfoComm standard for equalisation for parts of our standard.

​

I was asked by InfoComm to review that document and I concluded it wasn't sufficiently sophisticated to represent a new stake in the ground that represented good progress in the art.

It is essentially for field technicians to use. But we are engineers with a whole lot more knowledge and I believe our document should be commensurate with that knowledge.

I therefore don't recommend that we use it.

​

Cheers

Glenn

​

Glenn Leembruggen

Acoustic Directions Pty Ltd

Consultants in acoustics and electroacoustics

tel:  +612 9810 7033

mob: +61 418 207 085

​

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   <H1>[SC-04-08] Definition of Large vs Small Room - Line of Demarcation</H1>

    <B>Peter Mapp</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Definition%20of%20Large%20vs%20Small%20Room%20-%20Line%20of%0A%20Demarcation&In-Reply-To=%3C9d450f5c1fed47a49250e5cf4a12a9c2%40CP1-L1-MB-2003.CloudPlatform1.com%3E" TITLE="[SC-04-08] Definition of Large vs Small Room - Line of Demarcation">peter at petermapp.com

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    <I>Tue Dec 19 11:35:05 EST 2017</I>

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<PRE>T30 is effectively the same as T60 - just potentially easier to measure. So same equations. In practice, T20 can be a little different depending on the source directivity & diffuseness of the space but should give similar results. I have measured true T60 in some large and v quiet spaces (Cathedrals).

​

pm

​

-----Original Message-----

From: SC-04-08 [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 via SC-04-08

Sent: 19 December 2017 10:08

To: Peter Mapp; Working group on Measurement and equalization of sound systems in rooms; F.C.Schafer-Consulting

Subject: Re: [SC-04-08] Definition of Large vs Small Room - Line of Demarcation

​

I agree with the extract quoted below. Whether a room is 'large' or 'small' depends on what frequency is being considered.  One way to go is to define 'reverberant conditions' , where there is no sound below the Schroeder frequency and ' room mode conditions' where there is sound below the Schroeder frequency. These definitions may not be quite formal enough, bit if accepted in principle they can be 'polished'.

​

I am not quite sure that an actual frequency can be defined, unless it's the Schroeder frequency itself. But that isn't rouble-free, because it uses T60, which Peter tells me is a convenient fiction because no room behaves theoretically down to -60 dB. Can the equation be modified to use T20 or T30, which I understand to be rather better established?

​

John Woodgate OOO-Own Opinions Only

J M Woodgate and Associates www.woodjohn.uk Rayleigh, Essex UK

​

On 2017-12-19 09:38, Peter Mapp via SC-04-08 wrote:

><i> I would like to suggest that rather than try to definitively characterize a large vs small room we utilize these two references, to define the lowest frequency that is considered statistically valid for a particular test situation.

</I>

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   <H1>[SC-04-08] Definition of Large vs Small Room - Line of Demarcation</H1>

    <B>Thomas Lagö</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Definition%20of%20Large%20vs%20Small%20Room%20-%20Line%20of%0A%20Demarcation&In-Reply-To=%3C5EAE9B9E-FB31-4BE7-82A5-E1B0E268C79D%40msn.com%3E" TITLE="[SC-04-08] Definition of Large vs Small Room - Line of Demarcation">thomaslagoqirra at gmail.com

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    <I>Tue Dec 19 11:48:53 EST 2017</I>

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<PRE>Dear All,

​

If it is a “Sabine Room” (diffuse sound field) it is true. If not, it depends how “linear" the RT curve is. A curved curve will change the value.

​

Best regards,

Thomas

​

​

><i> On 19 Dec 2017, at 17:35, Peter Mapp via SC-04-08 <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>> wrote:

</I>><i> 

</I>><i> T30 is effectively the same as T60 - just potentially easier to measure. So same equations. In practice, T20 can be a little different depending on the source directivity & diffuseness of the space but should give similar results. I have measured true T60 in some large and v quiet spaces (Cathedrals).

</I>><i> 

</I>><i> pm

</I>><i> 

</I>><i> -----Original Message-----

</I>><i> From: SC-04-08 [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 via SC-04-08

</I>><i> Sent: 19 December 2017 10:08

</I>><i> To: Peter Mapp; Working group on Measurement and equalization of sound systems in rooms; F.C.Schafer-Consulting

</I>><i> Subject: Re: [SC-04-08] Definition of Large vs Small Room - Line of Demarcation

</I>><i> 

</I>><i> I agree with the extract quoted below. Whether a room is 'large' or 'small' depends on what frequency is being considered.  One way to go is to define 'reverberant conditions' , where there is no sound below the Schroeder frequency and ' room mode conditions' where there is sound below the Schroeder frequency. These definitions may not be quite formal enough, bit if accepted in principle they can be 'polished'.

</I>><i> 

</I>><i> I am not quite sure that an actual frequency can be defined, unless it's the Schroeder frequency itself. But that isn't rouble-free, because it uses T60, which Peter tells me is a convenient fiction because no room behaves theoretically down to -60 dB. Can the equation be modified to use T20 or T30, which I understand to be rather better established?

</I>><i> 

</I>><i> John Woodgate OOO-Own Opinions Only

</I>><i> J M Woodgate and Associates www.woodjohn.uk Rayleigh, Essex UK

</I>><i> 

</I>><i> On 2017-12-19 09:38, Peter Mapp via SC-04-08 wrote:

</I>>><i> I would like to suggest that rather than try to definitively characterize a large vs small room we utilize these two references, to define the lowest frequency that is considered statistically valid for a particular test situation.

</I>><i> 

</I>><i> _______________________________________________

</I>><i> SC-04-08 mailing list

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</I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>>

</I>><i> 

</I>><i> _______________________________________________

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   <H1>[SC-04-08] Definition of Large vs Small Room - Line of Demarcation</H1>

    <B>Floyd Toole</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Definition%20of%20Large%20vs%20Small%20Room%20-%20Line%20of%0A%20Demarcation&In-Reply-To=%3C970987270.1703301.1513711085044%40mail.yahoo.com%3E" TITLE="[SC-04-08] Definition of Large vs Small Room - Line of Demarcation">soundnwine at sbcglobal.net

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<PRE>Complicating matters is the fact that the "small" rooms in which we listen for recreation and in which recordings are mixed do not have consequential "diffuse" reverberant sound fields. There is simply too much absorption. The sound arriving at a listener from a normally directional forward-firing loudspeaker is dominantly direct sound at high frequencies, and a combination of direct and a few early reflections through the mid frequencies. This is true also in typical cinemas where the direct sound is dominant above about 600-800 Hz. This is explained, with examples, in the third edition of my book "Sound Reproduction"(Focal Press 2017) and in the cited references.

If RT is measured using an omni sound source, the result is an irrelevant number in typical small-room listening situations. If RT is measured using a typically directional loudspeaker, it is not RT in the classic sense- the sound field is not diffuse. The calculated Schroeder frequency is incorrect for typical small rooms - it is too high - because Schroeder described the frequency as being applicable in large auditoriums. I call it a "transition" frequency, for lack of a better term.

We need some new metrics: Cumulative energy time? 

​

    On Tuesday, December 19, 2017 8:49 AM, Thomas Lagö via SC-04-08 <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>> wrote:

​

 Dear All,

​

If it is a “Sabine Room” (diffuse sound field) it is true. If not, it depends how “linear" the RT curve is. A curved curve will change the value.

​

Best regards,

Thomas

​

​

><i> On 19 Dec 2017, at 17:35, Peter Mapp via SC-04-08 <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>> wrote:

</I>><i> 

</I>><i> T30 is effectively the same as T60 - just potentially easier to measure. So same equations. In practice, T20 can be a little different depending on the source directivity & diffuseness of the space but should give similar results. I have measured true T60 in some large and v quiet spaces (Cathedrals).

</I>><i> 

</I>><i> pm

</I>><i> 

</I>><i> -----Original Message-----

</I>><i> From: SC-04-08 [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 via SC-04-08

</I>><i> Sent: 19 December 2017 10:08

</I>><i> To: Peter Mapp; Working group on Measurement and equalization of sound systems in rooms; F.C.Schafer-Consulting

</I>><i> Subject: Re: [SC-04-08] Definition of Large vs Small Room - Line of Demarcation

</I>><i> 

</I>><i> I agree with the extract quoted below. Whether a room is 'large' or 'small' depends on what frequency is being considered.  One way to go is to define 'reverberant conditions' , where there is no sound below the Schroeder frequency and ' room mode conditions' where there is sound below the Schroeder frequency. These definitions may not be quite formal enough, bit if accepted in principle they can be 'polished'.

</I>><i> 

</I>><i> I am not quite sure that an actual frequency can be defined, unless it's the Schroeder frequency itself. But that isn't rouble-free, because it uses T60, which Peter tells me is a convenient fiction because no room behaves theoretically down to -60 dB. Can the equation be modified to use T20 or T30, which I understand to be rather better established?

</I>><i> 

</I>><i> John Woodgate OOO-Own Opinions Only

</I>><i> J M Woodgate and Associates www.woodjohn.uk Rayleigh, Essex UK

</I>><i> 

</I>><i> On 2017-12-19 09:38, Peter Mapp via SC-04-08 wrote:

</I>>><i> I would like to suggest that rather than try to definitively characterize a large vs small room we utilize these two references, to define the lowest frequency that is considered statistically valid for a particular test situation.

</I>><i> 

</I>><i> _______________________________________________

</I>><i> SC-04-08 mailing list

</I>><i> <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">SC-04-08 at standards.aes.org</A>

</I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>>

</I>><i> 

</I>><i> _______________________________________________

</I>><i> SC-04-08 mailing list

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   <H1>[SC-04-08] Definition of Large vs Small Room - Line of Demarcation</H1>

    <B>Floyd Toole</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Definition%20of%20Large%20vs%20Small%20Room%20-%20Line%20of%0A%20Demarcation&In-Reply-To=%3C970987270.1703301.1513711085044%40mail.yahoo.com%3E" TITLE="[SC-04-08] Definition of Large vs Small Room - Line of Demarcation">soundnwine at sbcglobal.net

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<PRE>Complicating matters is the fact that the "small" rooms in which we listen for recreation and in which recordings are mixed do not have consequential "diffuse" reverberant sound fields. There is simply too much absorption. The sound arriving at a listener from a normally directional forward-firing loudspeaker is dominantly direct sound at high frequencies, and a combination of direct and a few early reflections through the mid frequencies. This is true also in typical cinemas where the direct sound is dominant above about 600-800 Hz. This is explained, with examples, in the third edition of my book "Sound Reproduction"(Focal Press 2017) and in the cited references.

If RT is measured using an omni sound source, the result is an irrelevant number in typical small-room listening situations. If RT is measured using a typically directional loudspeaker, it is not RT in the classic sense- the sound field is not diffuse. The calculated Schroeder frequency is incorrect for typical small rooms - it is too high - because Schroeder described the frequency as being applicable in large auditoriums. I call it a "transition" frequency, for lack of a better term.

We need some new metrics: Cumulative energy time? 

​

    On Tuesday, December 19, 2017 8:49 AM, Thomas Lagö via SC-04-08 <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>> wrote:

​

 Dear All,

​

If it is a “Sabine Room” (diffuse sound field) it is true. If not, it depends how “linear" the RT curve is. A curved curve will change the value.

​

Best regards,

Thomas

​

​

><i> On 19 Dec 2017, at 17:35, Peter Mapp via SC-04-08 <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>> wrote:

</I>><i> 

</I>><i> T30 is effectively the same as T60 - just potentially easier to measure. So same equations. In practice, T20 can be a little different depending on the source directivity & diffuseness of the space but should give similar results. I have measured true T60 in some large and v quiet spaces (Cathedrals).

</I>><i> 

</I>><i> pm

</I>><i> 

</I>><i> -----Original Message-----

</I>><i> From: SC-04-08 [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 via SC-04-08

</I>><i> Sent: 19 December 2017 10:08

</I>><i> To: Peter Mapp; Working group on Measurement and equalization of sound systems in rooms; F.C.Schafer-Consulting

</I>><i> Subject: Re: [SC-04-08] Definition of Large vs Small Room - Line of Demarcation

</I>><i> 

</I>><i> I agree with the extract quoted below. Whether a room is 'large' or 'small' depends on what frequency is being considered.  One way to go is to define 'reverberant conditions' , where there is no sound below the Schroeder frequency and ' room mode conditions' where there is sound below the Schroeder frequency. These definitions may not be quite formal enough, bit if accepted in principle they can be 'polished'.

</I>><i> 

</I>><i> I am not quite sure that an actual frequency can be defined, unless it's the Schroeder frequency itself. But that isn't rouble-free, because it uses T60, which Peter tells me is a convenient fiction because no room behaves theoretically down to -60 dB. Can the equation be modified to use T20 or T30, which I understand to be rather better established?

</I>><i> 

</I>><i> John Woodgate OOO-Own Opinions Only

</I>><i> J M Woodgate and Associates www.woodjohn.uk Rayleigh, Essex UK

</I>><i> 

</I>><i> On 2017-12-19 09:38, Peter Mapp via SC-04-08 wrote:

</I>>><i> I would like to suggest that rather than try to definitively characterize a large vs small room we utilize these two references, to define the lowest frequency that is considered statistically valid for a particular test situation.

</I>><i> 

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   <H1>[SC-04-08] Definition of Large vs Small Room - Line of Demarcation</H1>

    <B>John Woodgate</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Definition%20of%20Large%20vs%20Small%20Room%20-%20Line%20of%0A%20Demarcation&In-Reply-To=%3C08c286eb-97e4-1283-8569-4064e7b49b0c%40woodjohn.uk%3E" TITLE="[SC-04-08] Definition of Large vs Small Room - Line of Demarcation">jmw at woodjohn.uk

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    <I>Tue Dec 19 14:28:09 EST 2017</I>

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<PRE>Hi, Floyd. Re: We need some new metrics: Cumulative energy time?

​

I'd agree, if I knew what it meant. It's just a bit too terse for me. I 

think of summoning my resources from 7 AM onwards so that I can actually 

get out of bed at 7.30. CET = 30 min.

​

John Woodgate OOO-Own Opinions Only

J M Woodgate and Associates www.woodjohn.uk

Rayleigh, Essex UK

​

On 2017-12-19 19:18, Floyd Toole wrote:

><i> Complicating matters is the fact that the "small" rooms in which we 

</I>><i> listen for recreation and in which recordings are mixed do not have 

</I>><i> consequential "diffuse" reverberant sound fields. There is simply too 

</I>><i> much absorption. The sound arriving at a listener from a normally 

</I>><i> directional forward-firing loudspeaker is dominantly direct sound at 

</I>><i> high frequencies, and a combination of direct and a few early 

</I>><i> reflections through the mid frequencies. This is true also in typical 

</I>><i> cinemas where the direct sound is dominant above about 600-800 Hz. 

</I>><i> This is explained, with examples, in the third edition of my book 

</I>><i> "Sound Reproduction"(Focal Press 2017) and in the cited references.

</I>><i>

</I>><i> If RT is measured using an omni sound source, the result is an 

</I>><i> irrelevant number in typical small-room listening situations. If RT is 

</I>><i> measured using a typically directional loudspeaker, it is not RT in 

</I>><i> the classic sense- the sound field is not diffuse. The calculated 

</I>><i> Schroeder frequency is incorrect for typical small rooms - it is too 

</I>><i> high - because Schroeder described the frequency as being applicable 

</I>><i> in large auditoriums. I call it a "transition" frequency, for lack of 

</I>><i> a better term.

</I>><i>

</I>><i> We need some new metrics: Cumulative energy time?

</I>><i>

</I>><i>

</I>><i> On Tuesday, December 19, 2017 8:49 AM, Thomas Lagö via SC-04-08 

</I>><i> <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>> wrote:

</I>><i>

</I>><i>

</I>><i> Dear All,

</I>><i>

</I>><i> If it is a “Sabine Room” (diffuse sound field) it is true. If not, it 

</I>><i> depends how “linear" the RT curve is. A curved curve will change the 

</I>><i> value.

</I>><i>

</I>><i> Best regards,

</I>><i> Thomas

</I>><i>

</I>><i>

</I>><i> > On 19 Dec 2017, at 17:35, Peter Mapp via SC-04-08 

</I>><i> <<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>>> wrote:

</I>><i> >

</I>><i> > T30 is effectively the same as T60 - just potentially easier to 

</I>><i> measure. So same equations. In practice, T20 can be a little different 

</I>><i> depending on the source directivity & diffuseness of the space but 

</I>><i> should give similar results. I have measured true T60 in some large 

</I>><i> and v quiet spaces (Cathedrals).

</I>><i> >

</I>><i> > pm

</I>><i> >

</I>><i> > -----Original Message-----

</I>><i> > From: SC-04-08 [mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A> 

</I>><i> <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 

</I>><i> Woodgate via SC-04-08

</I>><i> > Sent: 19 December 2017 10:08

</I>><i> > To: Peter Mapp; Working group on Measurement and equalization of 

</I>><i> sound systems in rooms; F.C.Schafer-Consulting

</I>><i> > Subject: Re: [SC-04-08] Definition of Large vs Small Room - Line of 

</I>><i> Demarcation

</I>><i> >

</I>><i> > I agree with the extract quoted below. Whether a room is 'large' or 

</I>><i> 'small' depends on what frequency is being considered.  One way to go 

</I>><i> is to define 'reverberant conditions' , where there is no sound below 

</I>><i> the Schroeder frequency and ' room mode conditions' where there is 

</I>><i> sound below the Schroeder frequency. These definitions may not be 

</I>><i> quite formal enough, bit if accepted in principle they can be 'polished'.

</I>><i> >

</I>><i> > I am not quite sure that an actual frequency can be defined, unless 

</I>><i> it's the Schroeder frequency itself. But that isn't rouble-free, 

</I>><i> because it uses T60, which Peter tells me is a convenient fiction 

</I>><i> because no room behaves theoretically down to -60 dB. Can the equation 

</I>><i> be modified to use T20 or T30, which I understand to be rather better 

</I>><i> established?

</I>><i> >

</I>><i> > John Woodgate OOO-Own Opinions Only

</I>><i> > J M Woodgate and Associates www.woodjohn.uk Rayleigh, Essex UK

</I>><i> >

</I>><i> > On 2017-12-19 09:38, Peter Mapp via SC-04-08 wrote:

</I>><i> >> I would like to suggest that rather than try to definitively 

</I>><i> characterize a large vs small room we utilize these two references, to 

</I>><i> define the lowest frequency that is considered statistically valid for 

</I>><i> a particular test situation.

</I>><i> >

</I>><i> > _______________________________________________

</I>><i> > SC-04-08 mailing list

</I>><i> > <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>>

</I>><i> > <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>>

</I>><i>

</I>><i> >

</I>><i> > _______________________________________________

</I>><i> > SC-04-08 mailing list

</I>><i> > <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>>

</I>><i> > <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>>

</I>><i>

</I>><i> _______________________________________________

</I>><i> SC-04-08 mailing list

</I>><i> <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>>

</I>><i> <<A HREF="http://standards.aes.org/sc.cfm?ID=91">http://standards.aes.org/sc.cfm?ID=91</A>>

</I>><i>

</I>><i>

</I>

</PRE>

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   <H1>[SC-04-08] Minutes  & Actions of New York Meeting</H1>

    <B>Glenn Leembruggen AD</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Minutes%20%20%26%20Actions%20of%20New%20York%20Meeting&In-Reply-To=%3C011701d378c8%24bb291360%24317b3a20%24%40acousticdirections.com%3E" TITLE="[SC-04-08] Minutes  & Actions of New York Meeting">Glenn at acousticdirections.com

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<PRE>Hi All

I meant to post this a few weeks ago, but forgot.

There was some discussion in about using the InfoComm standard for

equalisation for parts of our standard.

​

I was asked by InfoComm to review that document and I concluded it wasn't

sufficiently sophisticated to represent a new stake in the ground that

represented good progress in the art.

It is essentially for field technicians to use. But we are engineers with a

whole lot more knowledge and I believe our document should be commensurate

with that knowledge.

I therefore don't recommend that we use it.

​

Cheers

Glenn

​

Glenn Leembruggen

Acoustic Directions Pty Ltd

Consultants in acoustics and electroacoustics

tel:  +612 9810 7033

mob: +61 418 207 085

www.acousticdirections.com

​

-----Original Message-----

From: SC-04-08 [mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] On Behalf Of

Peter Mapp via SC-04-08

Sent: 01 December 2017 05:54

To: Working group on Measurement and equalization of sound systems in rooms

<<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>>

Subject: Re: [SC-04-08] Minutes & Actions of New York Meeting

​

Just a gentle reminder that the end of the year deadline is approaching and

if this project is to move on, some input will be needed

​

" In order to make and maintain progress, the chair asked for volunteers to

head up the writing of the topics listed above and set a deadline of the end

of the year for initial drafts of the sections"

​

Regards

​

Peter Mapp

​

-----Original Message-----

From: Peter Mapp 

Sent: 03 November 2017 11:13

To: 'Working group on Measurement and equalization of sound systems in

rooms'

Subject: RE: Minutes & Actions of New York Meeting

​

I meant to have added, If others not present at the New York meeting would

like to contribute their expertise & material, and if they have a particular

topic in mind, then please contact me.

​

Best regards

​

Peter Mapp

​

-----Original Message-----

From: SC-04-08 [mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] On Behalf Of

Peter Mapp via SC-04-08

Sent: 03 November 2017 11:09

To: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08 at standards.aes.org</A>

Subject: [SC-04-08] Minutes & Actions of New York Meeting

​

SC-04-08 Working Group on Sound Systems in Rooms, Meeting Report, New York -

143rd Convention, 18 October 2017 The meeting was chaired by Peter Mapp In

attendance were:

Richard Cabot, AES Standards Manager

Jeffery Bamford, Engineering Harmonics

David Murphy, Krix loudspeakers

Joel Brito, Vikel

Charlie Hughes, Excelsior Audio

Peter Mapp, Peter Mapp Associates

Bruce Olson, Olson Sound Design

Neil Shaw, Menlo Scientific

Ramakrishnan M K, R&S Electronics India

Brian Vessa, Sony Pictures Entertainment Fred Schafer, F C Schafer

Consulting Kazuho Ono, NHK Eddy Brixen, EBB Consult Steve Martz, THX David

Blore, Bose David Weinberg, Tobias Engineering Aldo Soares, ARS Tecnologia

As there was no formal meeting of the group at the previous convention in

Berlin, there were no minutes to approve, other than Peter Mapp had agreed

to chair the group AES -X218 - Measurement & Calibration of sound systems in

rooms The chair pointed out that since the last meeting in New York

(31-10-2015) there has been no progress. Despite the agreement of those

present at the New York meeting to comment on the list of parameters

proposed at the meeting and assign themselves to writing groups relating to

these parameters, no response whatsoever had been received. On this basis,

the parent committee, SC04 had therefore debated whether to close the group

but had decided to give it one more go as it was felt to be an important

topic.

The Chair went through the list of agreed measurement parameters as below :

​

*         Frequency Response

​

*         Sound Pressure Level (SPL)

​

*         Max SPL

​

*         Coverage

​

*         Speech Intelligibility

​

*         Distortion

​

*         Background Noise (Acoustical)

​

*         System Noise (Acoustical)

​

*         Reverberation Time

​

*         Gain Structure

​

*         Temporal Response / Impulse Response

After discussion it was decided to temporarily leave writing the section on

Frequency Response, as it was understood that the InfoCom draft spectral

balance standard was being revised and there was no point in duplicating

effort. Additionally, it was agreed that the Temporal Response / Impulse

response item would not be considered at the moment as there would likely be

duplication with AES-X219 (Method of measurement for frequency and impulse

response of sound systems in auditoria) though echoes / generation of

focused late reflections may be considered.

The size of room to which the project relates was discussed and although not

restricted it was felt that the objective was for large rooms (as opposed to

small rooms).

Cinema could / would be a specific subset of the work The scope relates to

what to measure and how to measure not what the result should be (though

some basic commentary may be provided).

May need to split into basic & advanced tests, bearing in mind the likely

test equipment that an average contractor is likely to have.

In order to make and maintain progress, the chair asked for volunteers to

head up the writing of the topics listed above and set a deadline of the end

of the year for initial drafts of the sections. The chair also commented

that unless the attendees at the meeting took an active role, there was

little point in them being there!

The table below lists the topics to be covered and writing group members

Topic

​

Task leader / author

​

Comment

​

​

​

​

​