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   <H1>[SC-04-08] Moving mic again</H1>

    <B>John Woodgate</B> 

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<PRE>This is crucial:

​

 All the problems start with the room interaction. Here averaging and equalizing

and 

balancing with Mid-High section has been an exercise in trial and error in 

most cases. Experience counts.

​

​

This means that the process is an 'art', not a 'science'. There is no analytic

solution because the sound at a point well away from the sources has a mixture

of 'equalizable' and 'non-equalizable' defects. These can be distinguished in a

time-domain display, but EQ, i.e. changing the frequency response of the source,

cannot 'cure' the latter. If you include changing arrival times in the EQ

process, that can work for a certain region, but may well  make things worse

elsewhere.

​

Simple solution - eliminate the room. Put a loudspeaker in every seat back, so

everyone gets direct sound.  Patent applied for (in about 1898 I believe). Used

in the British Parliament building.

​

​

With best wishes DESIGN IT IN! OOO - Own Opinions Only

www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England

​

Sylvae in aeternum manent.

​

​

-----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 Ram---

via SC-04-08

Sent: Friday, January 20, 2017 1:31 PM

To: david murphy <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dmurphy at krix.com.au</A>>; Jean-Luc Ohl <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jl at ohl.to</A>>; Working group

on Measurement and equalization ofsound 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] Moving mic again

​

Hi All,

​

When the microphone is moved from front to back we normally encounter 

anomalies in the LF region caused by floor dips and boundary encounters. In 

the Mid and High frequency crossover region, in most cases there will be 

dips caused by displaced drivers. IMHO non of this can be solved by 

averaging.

​

As far as Mid and High frequencies are concerned, say from 1kHz to 20kHz it 

may be preferable to measure the direct arrival in the prime position 

usually 2/3 and equalize and correct signal arrival times for the best 

results. On the left and right sides(off axis) of the cinema the frequency 

response anomalies in the Mid-High section arises due to directivity 

problems. This again may not be made better by averaging and equalization. 

Precise loudspeaker polar data helps.

​

LF sections are mostly flat from 30Hz to 125Hz when close miked. All the 

problems start with the room interaction. Here averaging and equalizing and 

balancing with Mid-High section has been a exercise in trial and error in 

most cases. Experience counts.

​

I would look forward to experts comments on the above.

​

Thanks and regards,

​

Ram

​

​

​

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

From: david murphy via SC-04-08

Sent: Friday, January 20, 2017 5:19 PM

To: Jean-Luc Ohl ; Working group on Measurement and equalization ofsound 

systems in rooms

Subject: Re: [SC-04-08] Moving mic again

​

HI all,

I can see a bit of confusion here!

When John Woodgate said moving microphone I took that to mean that the 

microphone was placed in a position near the source (screen) and 

measurements taken at that position in space. Then it was moved to the 2/3 

back position (time consuming) and other measurements were taken at that 

position ie, microphone also didn't 'move'.

​

I didn't intend using a continuous signal and moving while measuring, with 

the test system presumably making repeated measurements ie periodically 

sampling the frequency response. I have encountered the technique before, 

and I s'pose it could give reasonably consistent results. I speed read one 

of the papers in the zipped upload, in which there was some diagrams showing 

a humanoid waving the microphone at arms length, and also waving it around 

on a short stick.

An interesting concept for cinemas. I wonder how big a stick you would need 

in order to get consistent results for the LFE, especially in the 30Hz 

region, wavelength ~11.5 metres, ~37.5 feet. To avoid a null I would think 

you would have to move over a range of at least 1/2 wavelength.

​

Anyway, the deadline time is fast approaching. I hope Mark and Richard can 

suitably condense our AES comments and send them to SMPTE before their 

deadline.

​

It seems to me there are two issues:

1) what technology /techniques you need in order to adjust to a consistent 

frequency response across a wide range of cinema (room) sizes and shapes and 

'reverberation' times.

2) what is the desired target frequency response - the X Curve, a 

modification thereof, a simple 'flat' response, or a gradually shelving 

response from lower frequencies to higher frequencies, as suggested by Floyd 

Toole.

​

regards and thanks

David

​

David Murphy

Loudspeaker Design Engineer

Commercial Cinema

​

Krix

14 Chapman Road | Hackham SA 5163 | Australia

T +618 83843433 | F +618 83843419

Email: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dmurphy at krix.com</A> | Web: www.krix.com

​

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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 Jean-Luc 

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

Sent: Friday, 20 January 2017 8:49 PM

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

Subject: [SC-04-08] Moving mic again

​

Dear all,

​

"in my experience the sound system calibration is usually done in a mad 

rush"

​

I already proposed last year to check the manual scaning method (moving 

microphone) and I insist because :

- it takes less time

- it will be adopted by some acoustics standards (ISO,...) because of 

accuracy and reliability

- it costs less : only one mic and preamp, and only one calibration to pay 

every year

​

Please read the papers I just 

<A HREF="//secure.aes.org/standards/documents/?ID=91&file=%2Fmoving%2Dmic%2">uploadedhttps://secure.aes.org/standards/documents/?ID=91&file=%2Fmoving%2Dmic%2</A>

Ezip&filesize=14880118

​

It is not a power response measurement, the obtained curves are near 

Predicted In Room (see Olive and Toole).

It does not give IR nor phase but the amplitude curve is the most important 

one especially if you are in a rush !

There is no commercial software optimised yet for this method, but it is 

very easy to use :

record the 20 or 30 seconds of pink noise played while you move the mic and 

use an averaging analyser

​

​

Cheers

Jean-Luc

​

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   <H1>[SC-04-08] Comments uploaded by David Murphy</H1>

    <B>Gunter Oehme</B> 

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<PRE>Hi David,

​

I have got a question for you.

Ref. section E "response target area" 

​

I agree with your comment that the theory of flat response when measured X

curve with RTA at 2/3 is discredited.

But then you are suggesting different response target areas for small and

large auditoriums with the roll-off knee at different frequencies.

What would be the rational for this difference in responses areas?

On which parameter would be small and large defined: number of seats, room

volume, size of floor area, length of auditorium, RT or ...?

E.g. the SMPTE 25css report does not show evidence that the DFT with shorter

windows measures a significant different high frequency roll-off than RTA.

Also the report does not show evidence for dependency on room sizes.

We should be aware that probably most dubbing stages will belong to the

category "small" and therefore the modified target area would apply to

dubbing stages.

My concerns is that those different target areas will not improve the

translation between dubbing studio and exhibition.

​

​

Ref section 1.9 "time alignment"

​

I agree that it is be difficult to interpret the phase response measured at

primary microphone position due to reflections at lower frequencies.

My concerns are that your suggestion to place the microphone to an elevated

position close to the speaker is time consuming and not workable in  the

field.

It looks easy on a section drawing. But it requires quite efforts in the

field to determine the exact elevation of the speaker and then to find the

proper microphone exactly on the connection line between acoustical center

of the speaker and the reference position because  the speaker is not

visible hidden by the screen.

The method is rather error prone. If the microphone is placed e.g. 0.5 m (

1.6' too high) in the non-stadium auditorium then we probable check the time

alignment for "seats" outside of the auditorium.

For many 3-way system time alignment is rather critical. Cinema systems

often are built "large scale" with a large distance of 0.5 m ( 1.6' )

between high and mid frequency drivers acoustical centers. For a 1200 Hz

crossover frequency you get a 180° phase shift at crossover frequency at +/-

15° vertical angle ideal time aligned axis.

Measuring at reference position and  looking for minimal frequency response

irregularities in the crossover region and the suggested maximal dip when

temporarily inversing the mids should work.

​

Best regards,

Gunter

​

-----Ursprüngliche Nachricht-----

Von: SC-04-08 [mailto:<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">sc-04-08-bounces at standards.aes.org</A>] Im Auftrag von

david murphy via SC-04-08

Gesendet: Donnerstag, 12. Januar 2017 12:48

An: '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>>

Betreff: [SC-04-08] Comments uploaded by David Murphy

​

Hi all,

I have just uploaded my comments to the upload/download website for

SC-04-08, named SMPTE_2096-1_Comment_David_Murphy_Jan_2017

​

A very short summary follows

I note that that in 2. Introduction: end of para 4 “

.The suite does not

define new standards or supercede current ones, but offers current

approaches and methodology using modern equipment to more accurately

calibrate within the tolerances of the existing standards.”

Accordingly I will try to comment only on the methodology, and hope a better

frequency response standard than the X Curve Standard can be developed.

​

Worthwhile improvement, more use cases for microphone placement, specifying

target area for frequency response and including LFE as well.

Big advance is using FFT measuring system allowing windowing etc.

Concern about hearing protection if operator is in theatre – to chase down

rattles and buzzes using frequency sweeps at -3dBFS (or -10dBFS) will be

very loud, exceeds operator’s noise dose? 

Concern about loose terminology for measuring variations of SPL in seating

area – needs more specificity. Loose terminology also re listening test

evaluation Fraught suggestions for verifying crossover integrity of screen

loudspeakers. refer uploaded doc for my suggestions!

In general the document is a bit Panglossian, assuming that everything is

best practice, such as infinite baffle mounting of screen loudspeaker

systems, well behaved loudspeaker systems, lots of absorption everywhere,

well behaved reflections and RT60, etc. 

I think it would be good to give some hints or guidance on what to do if any

or all of these conditions are not present. For example, how to select

appropriate window length and shape for the measurement.

​

best regards

David

​

David Murphy

Loudspeaker Design Engineer

Commercial Cinema

​

Krix

14 Chapman Road | Hackham SA 5163 | Australia T +618 83843433 | F +618

83843419

Email: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dmurphy at krix.com</A> | Web: www.krix.com

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   <H1>[SC-04-08] Moving mic again</H1>

    <B>philip newell</B> 

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<PRE>Dear John,

​

               I agree with what you say, except for the last point. The

sound and image need to be colocated or the perception of cinema is

un-natural. Distant image with close sound does not work!

​

               In Floyd's comments, last week, to the statement '*The

technician must knowledgeably interpret what is visually displayed, and

understand the meaning of the displayed response rather than simply

performing adjustments to a target response line or window*', he replied*

'These are very special technicians possessing insights that go beyond the

information available in a room curve'.* So yes, the 'insights' are

somewhat artistic, and technicians with the necessary experience to have

them will be somewhat rare in the rushed world of cinema calibration.

(Often, the managements allocate less than an hour to do a whole cinema!)

Consequently, reliable insights usually only come with specialist

consultants, which few cinemas wish to pay for.

​

              In reply to Jean-Luc, the manual waving of a microphone would

be limited to too small an area for large-cinema calibration, and, as Ram

has said, directivity problems would only be seen by measuring over a

greater area (although they are not equalisable, to any significantly

useful degree).

​

              I have been of the (well-published) opinion for a long time

that the key to consistent sound in the rooms lies in consistent sounds

leaving the loudspeakers, but the cinema-calibration industry is still not

set-up to do this. Therefore, the document under discussion, here, is an

attempt to indicate how to achieve the best consistency possible, from

theatre to theatre, using multiple microphone set back into the room

because that is how the existing international Standards require that they

should be calibrated. It may take some years to change the Standards, so a

short-term measure is to seek a more modern interpretation.

​

​

                                       Best wishes,

​

​

                                                                Philip

​

​

​

​

​

​

​

On 20 January 2017 at 14:52, John Woodgate 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> This is crucial:

</I>><i>

</I>><i>  All the problems start with the room interaction. Here averaging and

</I>><i> equalizing

</I>><i> and

</I>><i> balancing with Mid-High section has been an exercise in trial and error in

</I>><i> most cases. Experience counts.

</I>><i>

</I>><i>

</I>><i> This means that the process is an 'art', not a 'science'. There is no

</I>><i> analytic

</I>><i> solution because the sound at a point well away from the sources has a

</I>><i> mixture

</I>><i> of 'equalizable' and 'non-equalizable' defects. These can be distinguished

</I>><i> in a

</I>><i> time-domain display, but EQ, i.e. changing the frequency response of the

</I>><i> source,

</I>><i> cannot 'cure' the latter. If you include changing arrival times in the EQ

</I>><i> process, that can work for a certain region, but may well  make things

</I>><i> worse

</I>><i> elsewhere.

</I>><i>

</I>><i> Simple solution - eliminate the room. Put a loudspeaker in every seat

</I>><i> back, so

</I>><i> everyone gets direct sound.  Patent applied for (in about 1898 I believe).

</I>><i> Used

</I>><i> in the British Parliament building.

</I>><i>

</I>><i>

</I>><i> With best wishes DESIGN IT IN! OOO - Own Opinions Only

</I>><i> www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England

</I>><i>

</I>><i> Sylvae in aeternum manent.

</I>><i>

</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

</I>><i> Ram---

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

</I>><i> Sent: Friday, January 20, 2017 1:31 PM

</I>><i> To: david murphy <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dmurphy at krix.com.au</A>>; Jean-Luc Ohl <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jl at ohl.to</A>>; Working

</I>><i> group

</I>><i> on Measurement and equalization ofsound systems in rooms

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

</I>><i> Subject: Re: [SC-04-08] Moving mic again

</I>><i>

</I>><i> Hi All,

</I>><i>

</I>><i> When the microphone is moved from front to back we normally encounter

</I>><i> anomalies in the LF region caused by floor dips and boundary encounters. In

</I>><i> the Mid and High frequency crossover region, in most cases there will be

</I>><i> dips caused by displaced drivers. IMHO non of this can be solved by

</I>><i> averaging.

</I>><i>

</I>><i> As far as Mid and High frequencies are concerned, say from 1kHz to 20kHz it

</I>><i> may be preferable to measure the direct arrival in the prime position

</I>><i> usually 2/3 and equalize and correct signal arrival times for the best

</I>><i> results. On the left and right sides(off axis) of the cinema the frequency

</I>><i> response anomalies in the Mid-High section arises due to directivity

</I>><i> problems. This again may not be made better by averaging and equalization.

</I>><i> Precise loudspeaker polar data helps.

</I>><i>

</I>><i> LF sections are mostly flat from 30Hz to 125Hz when close miked. All the

</I>><i> problems start with the room interaction. Here averaging and equalizing and

</I>><i> balancing with Mid-High section has been a exercise in trial and error in

</I>><i> most cases. Experience counts.

</I>><i>

</I>><i> I would look forward to experts comments on the above.

</I>><i>

</I>><i> Thanks and regards,

</I>><i>

</I>><i> Ram

</I>><i>

</I>><i>

</I>><i>

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

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

</I>><i> Sent: Friday, January 20, 2017 5:19 PM

</I>><i> To: Jean-Luc Ohl ; Working group on Measurement and equalization ofsound

</I>><i> systems in rooms

</I>><i> Subject: Re: [SC-04-08] Moving mic again

</I>><i>

</I>><i> HI all,

</I>><i> I can see a bit of confusion here!

</I>><i> When John Woodgate said moving microphone I took that to mean that the

</I>><i> microphone was placed in a position near the source (screen) and

</I>><i> measurements taken at that position in space. Then it was moved to the 2/3

</I>><i> back position (time consuming) and other measurements were taken at that

</I>><i> position ie, microphone also didn't 'move'.

</I>><i>

</I>><i> I didn't intend using a continuous signal and moving while measuring, with

</I>><i> the test system presumably making repeated measurements ie periodically

</I>><i> sampling the frequency response. I have encountered the technique before,

</I>><i> and I s'pose it could give reasonably consistent results. I speed read one

</I>><i> of the papers in the zipped upload, in which there was some diagrams

</I>><i> showing

</I>><i> a humanoid waving the microphone at arms length, and also waving it around

</I>><i> on a short stick.

</I>><i> An interesting concept for cinemas. I wonder how big a stick you would need

</I>><i> in order to get consistent results for the LFE, especially in the 30Hz

</I>><i> region, wavelength ~11.5 metres, ~37.5 feet. To avoid a null I would think

</I>><i> you would have to move over a range of at least 1/2 wavelength.

</I>><i>

</I>><i> Anyway, the deadline time is fast approaching. I hope Mark and Richard can

</I>><i> suitably condense our AES comments and send them to SMPTE before their

</I>><i> deadline.

</I>><i>

</I>><i> It seems to me there are two issues:

</I>><i> 1) what technology /techniques you need in order to adjust to a consistent

</I>><i> frequency response across a wide range of cinema (room) sizes and shapes

</I>><i> and

</I>><i> 'reverberation' times.

</I>><i> 2) what is the desired target frequency response - the X Curve, a

</I>><i> modification thereof, a simple 'flat' response, or a gradually shelving

</I>><i> response from lower frequencies to higher frequencies, as suggested by

</I>><i> Floyd

</I...

​

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   <H1>[SC-04-08] Comments uploaded by David Murphy</H1>

    <B>philip newell</B> 

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<PRE>Dear Gunter,

​

                   You ask David, '*But then you are suggesting different

response target areas for small and large auditoriums with the roll-off

knee at different frequencies. What would be the rational for this

difference in responses areas?*'

​

                   Perhaps the greater question is 'what is the rationale

for the Knee', other than that the Standard requires it?

​

​

                                        Best wishes,

​

​

                                                      Philip

​

​

​

​

On 20 January 2017 at 15:02, Gunter Oehme 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> Hi David,

</I>><i>

</I>><i> I have got a question for you.

</I>><i> Ref. section E "response target area"

</I>><i>

</I>><i> I agree with your comment that the theory of flat response when measured X

</I>><i> curve with RTA at 2/3 is discredited.

</I>><i> But then you are suggesting different response target areas for small and

</I>><i> large auditoriums with the roll-off knee at different frequencies.

</I>><i> What would be the rational for this difference in responses areas?

</I>><i> On which parameter would be small and large defined: number of seats, room

</I>><i> volume, size of floor area, length of auditorium, RT or ...?

</I>><i> E.g. the SMPTE 25css report does not show evidence that the DFT with

</I>><i> shorter

</I>><i> windows measures a significant different high frequency roll-off than RTA.

</I>><i> Also the report does not show evidence for dependency on room sizes.

</I>><i> We should be aware that probably most dubbing stages will belong to the

</I>><i> category "small" and therefore the modified target area would apply to

</I>><i> dubbing stages.

</I>><i> My concerns is that those different target areas will not improve the

</I>><i> translation between dubbing studio and exhibition.

</I>><i>

</I>><i>

</I>><i> Ref section 1.9 "time alignment"

</I>><i>

</I>><i> I agree that it is be difficult to interpret the phase response measured at

</I>><i> primary microphone position due to reflections at lower frequencies.

</I>><i> My concerns are that your suggestion to place the microphone to an elevated

</I>><i> position close to the speaker is time consuming and not workable in  the

</I>><i> field.

</I>><i> It looks easy on a section drawing. But it requires quite efforts in the

</I>><i> field to determine the exact elevation of the speaker and then to find the

</I>><i> proper microphone exactly on the connection line between acoustical center

</I>><i> of the speaker and the reference position because  the speaker is not

</I>><i> visible hidden by the screen.

</I>><i> The method is rather error prone. If the microphone is placed e.g. 0.5 m (

</I>><i> 1.6' too high) in the non-stadium auditorium then we probable check the

</I>><i> time

</I>><i> alignment for "seats" outside of the auditorium.

</I>><i> For many 3-way system time alignment is rather critical. Cinema systems

</I>><i> often are built "large scale" with a large distance of 0.5 m ( 1.6' )

</I>><i> between high and mid frequency drivers acoustical centers. For a 1200 Hz

</I>><i> crossover frequency you get a 180° phase shift at crossover frequency at

</I>><i> +/-

</I>><i> 15° vertical angle ideal time aligned axis.

</I>><i> Measuring at reference position and  looking for minimal frequency response

</I>><i> irregularities in the crossover region and the suggested maximal dip when

</I>><i> temporarily inversing the mids should work.

</I>><i>

</I>><i> Best regards,

</I>><i> Gunter

</I>><i>

</I>><i> -----Ursprüngliche Nachricht-----

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

</I>><i> david murphy via SC-04-08

</I>><i> Gesendet: Donnerstag, 12. Januar 2017 12:48

</I>><i> An: 'Working group on Measurement and equalization of sound systems in

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

</I>><i> Betreff: [SC-04-08] Comments uploaded by David Murphy

</I>><i>

</I>><i> Hi all,

</I>><i> I have just uploaded my comments to the upload/download website for

</I>><i> SC-04-08, named SMPTE_2096-1_Comment_David_Murphy_Jan_2017

</I>><i>

</I>><i> A very short summary follows

</I>><i> I note that that in 2. Introduction: end of para 4 “….The suite does not

</I>><i> define new standards or supercede current ones, but offers current

</I>><i> approaches and methodology using modern equipment to more accurately

</I>><i> calibrate within the tolerances of the existing standards.”

</I>><i> Accordingly I will try to comment only on the methodology, and hope a

</I>><i> better

</I>><i> frequency response standard than the X Curve Standard can be developed.

</I>><i>

</I>><i> Worthwhile improvement, more use cases for microphone placement, specifying

</I>><i> target area for frequency response and including LFE as well.

</I>><i> Big advance is using FFT measuring system allowing windowing etc.

</I>><i> Concern about hearing protection if operator is in theatre – to chase down

</I>><i> rattles and buzzes using frequency sweeps at -3dBFS (or -10dBFS) will be

</I>><i> very loud, exceeds operator’s noise dose?

</I>><i> Concern about loose terminology for measuring variations of SPL in seating

</I>><i> area – needs more specificity. Loose terminology also re listening test

</I>><i> evaluation Fraught suggestions for verifying crossover integrity of screen

</I>><i> loudspeakers. refer uploaded doc for my suggestions!

</I>><i> In general the document is a bit Panglossian, assuming that everything is

</I>><i> best practice, such as infinite baffle mounting of screen loudspeaker

</I>><i> systems, well behaved loudspeaker systems, lots of absorption everywhere,

</I>><i> well behaved reflections and RT60, etc.

</I>><i> I think it would be good to give some hints or guidance on what to do if

</I>><i> any

</I>><i> or all of these conditions are not present. For example, how to select

</I>><i> appropriate window length and shape for the measurement.

</I>><i>

</I>><i> best regards

</I>><i> David

</I>><i>

</I>><i> David Murphy

</I>><i> Loudspeaker Design Engineer

</I>><i> Commercial Cinema

</I>><i>

</I>><i> Krix

</I>><i> 14 Chapman Road | Hackham SA 5163 | Australia T +618 83843433 | F +618

</I>><i> 83843419

</I>><i> Email: <A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dmurphy at krix.com</A> | Web: www.krix.com

</I>><i>

</I>><i>

</I>><i>

</I>><i> DISCLAIMER:

</I>><i> This email and any files transmitted with it are confidential to the

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</I>><i> _______________________________________________

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

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</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>

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</I>><i>

</I></PRE>

​

​

​

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   <H1>[SC-04-08] Moving mic again</H1>

    <B>John Woodgate</B> 

    <A HREF="mailto:sc-04-08%40standards.aes.org?Subject=Re%3A%20%5BSC-04-08%5D%20Moving%20mic%20again&In-Reply-To=%3C04d301d2732b%24752fcaa0%245f8f5fe0%24%40btinternet.com%3E" TITLE="[SC-04-08] Moving mic again">jmw1937 at btinternet.com

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<PRE>My proposal was not very serious, but in any case modern processing would allow

the sound to be perceived as 'distant' when necessary.

​

With best wishes DESIGN IT IN! OOO - Own Opinions Only

www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England

​

Sylvae in aeternum manent.

​

​

-----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 philip

newell via SC-04-08

Sent: Friday, January 20, 2017 2:32 PM

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] Moving mic again

​

Dear John,

​

               I agree with what you say, except for the last point. The

sound and image need to be colocated or the perception of cinema is

un-natural. Distant image with close sound does not work!

​

               In Floyd's comments, last week, to the statement '*The

technician must knowledgeably interpret what is visually displayed, and

understand the meaning of the displayed response rather than simply

performing adjustments to a target response line or window*', he replied*

'These are very special technicians possessing insights that go beyond the

information available in a room curve'.* So yes, the 'insights' are

somewhat artistic, and technicians with the necessary experience to have

them will be somewhat rare in the rushed world of cinema calibration.

(Often, the managements allocate less than an hour to do a whole cinema!)

Consequently, reliable insights usually only come with specialist

consultants, which few cinemas wish to pay for.

​

              In reply to Jean-Luc, the manual waving of a microphone would

be limited to too small an area for large-cinema calibration, and, as Ram

has said, directivity problems would only be seen by measuring over a

greater area (although they are not equalisable, to any significantly

useful degree).

​

              I have been of the (well-published) opinion for a long time

that the key to consistent sound in the rooms lies in consistent sounds

leaving the loudspeakers, but the cinema-calibration industry is still not

set-up to do this. Therefore, the document under discussion, here, is an

attempt to indicate how to achieve the best consistency possible, from

theatre to theatre, using multiple microphone set back into the room

because that is how the existing international Standards require that they

should be calibrated. It may take some years to change the Standards, so a

short-term measure is to seek a more modern interpretation.

​

​

                                       Best wishes,

​

​

                                                                Philip

​

​

​

​

​

​

​

On 20 January 2017 at 14:52, John Woodgate 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> This is crucial:

</I>><i>

</I>><i>  All the problems start with the room interaction. Here averaging and

</I>><i> equalizing

</I>><i> and

</I>><i> balancing with Mid-High section has been an exercise in trial and error in

</I>><i> most cases. Experience counts.

</I>><i>

</I>><i>

</I>><i> This means that the process is an 'art', not a 'science'. There is no

</I>><i> analytic

</I>><i> solution because the sound at a point well away from the sources has a

</I>><i> mixture

</I>><i> of 'equalizable' and 'non-equalizable' defects. These can be distinguished

</I>><i> in a

</I>><i> time-domain display, but EQ, i.e. changing the frequency response of the

</I>><i> source,

</I>><i> cannot 'cure' the latter. If you include changing arrival times in the EQ

</I>><i> process, that can work for a certain region, but may well  make things

</I>><i> worse

</I>><i> elsewhere.

</I>><i>

</I>><i> Simple solution - eliminate the room. Put a loudspeaker in every seat

</I>><i> back, so

</I>><i> everyone gets direct sound.  Patent applied for (in about 1898 I believe).

</I>><i> Used

</I>><i> in the British Parliament building.

</I>><i>

</I>><i>

</I>><i> With best wishes DESIGN IT IN! OOO - Own Opinions Only

</I>><i> www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England

</I>><i>

</I>><i> Sylvae in aeternum manent.

</I>><i>

</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

</I>><i> Ram---

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

</I>><i> Sent: Friday, January 20, 2017 1:31 PM

</I>><i> To: david murphy <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">dmurphy at krix.com.au</A>>; Jean-Luc Ohl <<A HREF="https://secure.aes.org/mailman/listinfo/sc-04-08">jl at ohl.to</A>>; Working