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A history of acoustical room model design Reverb & Delay Plugins
Old 29th December 2010
  #1
Gear Nut
 

A history of acoustical room model design

I was researching the various types of acoustical room models, and found this:

http://www.madebydelta.com/imported/...s/av126205.pdf

Enjoy,
John
Old 29th December 2010
  #2
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Thanks John.
Old 29th December 2010
  #3
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Thanks a lot!
Old 29th December 2010
  #4
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audiothings's Avatar
 

Thank you for sharing. thumbsup
Old 29th December 2010
  #5
Gear Nut
 

More info on the "controlled image design" model implemented by the BBC can be found here:

BBC - R&D - Publications - RD Reports from 1995

See articles 1995/3, 1995/4, and 1995/5

John
Old 29th December 2010
  #6
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johnbomb,

welcome to the forum! I've noticed some very precise and interesting post from you lately.

thanks for posting this. a great first read for nOObs & something that should probably be linked to often.

cheers,

John
Old 29th December 2010
  #7
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Quote:
Originally Posted by johnbomb View Post
More info on the "controlled image design" model implemented by the BBC can be found here:

BBC - R&D - Publications - RD Reports from 1995

See articles 1995/3, 1995/4, and 1995/5

John

From what I gather, it appears "controlled image design" has the pre 20msec. response of an RFZ model, but with no diffuse after bloom... rather specular energy from the back half.
Old 29th December 2010
  #8
Gear Nut
 

Thanks, John. I would most definitely place myself in the nOOb category. I'm in the build/design as I go phase of a home theater project, and I'm trying to soak up all I can from the talented and generous folks here.

I doubt that I'll be able to apply one of these models in its entirety to my theater, but hopefully an understanding of their principles will at least point me in the direction of audio nirvana!

John
Old 29th December 2010
  #9
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SörenHjalmarsson's Avatar
 

I can only second what evereybody has been saying, THANKS for sharing!

Iv'e only had the time to skimm through the article so i might have missed if they where in there somewhere, but i would have loved to see the Moulton room, the FTB Design (Front To Back) and the Hidley Room (and how it became the NE room) in there somewhere.

But maybe some of them are to secret or doesn't qualify for some reason. heh

Moulton Rooms

FTB:
Quote:
Originally Posted by Northward View Post
Different school here...

I think LEDE rooms send the wrong cues. I was never convinced by these.

Our ears work partly like a Fourier, and will focus on / enhance / neglect some areas more than others depending on the perceived environment. IMHO one of the issues with LEDEs is that they tend to put the listener's auditory system in a state of stress. And that has a major influence on perception especially in the 1kHz to 6kHz region (with some more negligible effect up to 12kHz).

Non-environmental rooms do send psycho-acoustical cues, which are on the other hand rather efficient at putting the brain / auditory system in a relaxed "neutral" state while still allowing a very controlled environment, which is an absolutely essential step.

When we first developed the FTB concept we soon realized that it had some elements in common with Non-environment rooms, particularly in the way we approached how the room is to be perceived by the listener and how it is 'perceived' by the speakers. FTBs have very specific cues that basically only aim at making sure the auditory system isn't stressed by the very controlled / specific environment.

If there is time I will try to develop that a bit more.
And the Hidley room is like the FTB (if i'm not much mistaken) also related to the Non Environment approach.

It would have been cool to at least include the how, why and when they came to be... and their essential features...


Cheers,
Old 29th December 2010
  #10
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avare's Avatar
 

A great article. Adding to the ommisions is Early Sound Scattering (ESS).

Andre
Old 29th December 2010
  #11
Gear Nut
 

Thanks for the additions, Soren and Andre. Here's a link to a discussion on Early Sound Scattering rooms:

Early Sound Scattering & Control Room Design

and, the same info with pictures:

Electroacoustic System Specialists


Here's additional info on Manny LaCarrubba's ultra-wide-dispersion loudspeakers and control room design:

THE WIDE-DISPERSION LISTENING SPACE: A NEW APPROACH TO CONTROL-ROOM DESIGN

John
Old 30th December 2010
  #12
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SörenHjalmarsson's Avatar
 

On closer examination there was quite a bit on Hidley in there... and it seems that he was not only working with NE related theories. More here: LEDE/RFZ/ - Hidley

Another explanation on the Moulton: Moulton Laboratories :: Discussion

FTB remains an NE rooted mystery...
Old 30th December 2010
  #13
SAC
Registered User
 

Sorry, but the first link (LEDE/RFZ/ - Hidley) couldn't be more incorrect in almost every reference!

"LEDE was an interesting experiment that almost worked, but RFZ really does work, and seems easier to do" "RFZ was the original idea of Tom Hidely in the early 70s, arguably the father of studio design. LEDE followed later in the late 80s early 90s then faded away."
"The text (Acoustical Absorbers & Diffusers) also suggests that even the LEDE (even though it was in reverse order) concept was something that Thomas Hidley pioneered."

Huh??? :-S

Hidley was an early proponent of the dead room in the 60's! The NE room was just its evolution, literally. He had nothing to do with LEDE/RFZ
Old 30th December 2010
  #14
Gear Nut
 

I cannot reconcile the design goals behind the Early Sound Scattering model and the Moulton model- they seem diametrically opposed to me. Am I missing something here? Has anyone worked in both environments, and if so, would you please compare/contrast the two?

Thanks,
John
Old 30th December 2010
  #15
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Bob Olhsson's Avatar
 

Quote:
Originally Posted by johnbomb View Post
I cannot reconcile the design goals behind the Early Sound Scattering model and the Moulton model- .
Both strive for flat early reflection response. This is important because we hear the first 30 to 50 milliseconds as part of the direct response of the speaker. Most attempts at absorbing early reflections just create a low pass filter that alters the perceived frequency response of the speaker.
Old 30th December 2010
  #16
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audiothings's Avatar
 

Maybe its too early to add this to history's bag, and there are no white papers or publications on the method and the science as far as I know, but there is also Zero Reflection Acoustics by Delta H Labs.
Old 30th December 2010
  #17
Gear Nut
 

Quote:
Originally Posted by Bob Olhsson View Post
Both strive for flat early reflection response. This is important because we hear the first 30 to 50 milliseconds as part of the direct response of the speaker. Most attempts at absorbing early reflections just create a low pass filter that alters the perceived frequency response of the speaker.
Thanks, Bob.

John
Old 30th December 2010
  #18
Moderator
 
Northward's Avatar
Quote:
Originally Posted by SörenHjalmarsson View Post
FTB remains a NE rooted mystery...
Hey Sören,

There is no mystery... Just a major lack of time on our side to write anything lengthy about it. And it's also true that I much prefer discussing things face to face(s). It avoids misunderstandings or misinterpretations which can lead to complex situations. All the clients or prospects we meet get a detailed explanation if they want to, all of them get to listen to as many rooms as they want, and we'll show the maths if they're interested.

The rooms are out there, quite a lot of them by now when I think about it. It's nice to see for example that just last year a lot of major US and European acts were mastered (or mixed) in these rooms

We'll likely participate to a few "studio acoustics" workshops in 2011, which may lead to us releasing a couple papers, or at least the workshop presentation - which would include more info about the FTB approach. We're more used to giving workshops to architects or construction/engineering/industrial companies so we do have papers, but out of decoupling techniques it doesn't bring much on the table that would be of interest to this community.

It may be that we'll be at Musik Messe 2011, we'll see if that clicks or not with the work scheduled.

Next year a few GS members will finish or get FTB rooms. Circle Studios, HB Studios, Steffen Müller Mastering and Dirk Brouns come to mind. This should give opportunities to discuss a bit about the concept
Old 30th December 2010
  #19
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SörenHjalmarsson's Avatar
 

Quote:
Originally Posted by SAC View Post
Hidley was an early proponent of the dead room in the 60's! The NE room was just its evolution, literally. He had nothing to do with LEDE/RFZ
SAC,

In that case i guess i'm back where i started, after a little detour. heh
SAC do you know what the "Linear 10 Hz Infrasonic Room" is? I know it is connected to Mr Hidley, but i have no idea what it is all about.

Quote:
Originally Posted by johnbomb View Post
I cannot reconcile the design goals behind the Early Sound Scattering model and the Moulton model- they seem diametrically opposed to me. Am I missing something here? Has anyone worked in both environments, and if so, would you please compare/contrast the two?
John,

I see what you mean John! heh The Moulton room is quite the opposite of the 'common way'. Instead of deflecting or attenuating the early reflections, they are preserved and used as 'good data'. To add to Mr Olhsson, the Moulton room also dictates an attenuation of the later arriving reflections (as opposed to the LEDE/RFZ) which are said to create a negative 'reverberant wash'. This is from my second Moulton link:

"The real problem, in our opinion, is the playback room's reverberance, that wash of increasingly uncorrelated and unintegrated reflections that occur after the Precedence Effect (with its integration of early reflections into a coherent perceptual construct) has decayed. This begins to occur at approximately 40 ms. after the direct sound arrives at our ears. It is this reverberant sound from the playback room that we believe muddies up the playback of recordings, masking details and obscuring images, and that we should try to avoid in order to obtain "transparent" playback.

The design solution? Support accurate specular early reflections for 50 ms. or so, and then employ broadband suppression of all reflections and reverberance after that. It turns out this leads to an easy and dirt-cheap control room design topology (I call it a "Moulton Room") that works quite well with almost all types of speakers. It works extraordinarily well with wide-dispersion speakers.

The problem with the incoherent diffusion created by quadratic residue diffusers and similar devices in this application is that such diffusers convert direct energy into early reverberant energy. This creates a reverberant wash in the playback room precisely during the time period when we should be integrating early reflections as part of our localization."


Quote:
Originally Posted by Northward View Post
Hey Sören,

There is no mystery... Just a major lack of time on our side to write anything lengthy about it. And it's also true that I much prefer discussing things face to face(s). It avoids misunderstandings or misinterpretations which can lead to complex situations. All the clients or prospects we meet get a detailed explanation if they want to, all of them get to listen to as many rooms as they want, and we'll show the maths if they're interested.

The rooms are out there, quite a lot of them by now when I think about it. It's nice to see for example that just last year a lot of major US and European acts were mastered (or mixed) in these rooms

We'll likely participate to a few "studio acoustics" workshops in 2011, which may lead to us releasing a couple papers, or at least the workshop presentation - which would include more info about the FTB approach. We're more used to giving workshops to architects or construction/engineering/industrial companies so we do have papers, but out of decoupling techniques it doesn't bring much on the table that would be of interest to this community.

It may be that we'll be at Musik Messe 2011, we'll see if that clicks or not with the work scheduled.

Next year a few GS members will finish or get FTB rooms. Circle Studios, HB Studios, Steffen Müller Mastering and Dirk Brouns come to mind. This should give opportunities to discuss a bit about the concept
Mr Jouanjean,

What i ment of course was that the FTB design still is a mystery to me. heh To those who use it i hope there is no mystery left. heh Sorry if i made the FTB sound like quackery, which was not my intent.

Looking forward to learning more about the FTB design. I think there are many of us who would love to hear more about this design approach, i know i'm curious about it.

Cheers,
Old 30th December 2010
  #20
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johndykstra's Avatar
 

Quote:
Originally Posted by SörenHjalmarsson View Post
I think there are manny of us who would love to here more about this design approach, i know i'm curiois about it.

Cheers,
+1thumbsup
Old 31st December 2010
  #21
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PaulP's Avatar
 

Some better pictures of the (only ?) Moulton room : here.

The 'acoustic lens' on the monitors is a key part of the design.

See also : acoustic lens and BeoLab 5 Active Loudspeakers.

The French were into super high dispersion tweeters at least 40 years ago.
Old 14th October 2012
  #22
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johndykstra's Avatar
 

This thread is the first hit on a google search of CID (controlled image design). An approach I find to be very similar to RFZ in many aspects. A design that Dan finds acceptable, yet dismisses the idea of RFZ.

I find this vexing.
Old 14th October 2012
  #23
Gear Guru
Undo

Unvex yourself sir!

Hit Command Z. Your creativity is exceeding reality.

Quote:
A design that Dan finds acceptable, yet dismisses the idea of RFZ.
I find this vexing.
I have never been in a CID room, but the principles and tests are convincing. I have never dismissed or dissed the idea of RFZ.

That would be kind of, well,...., mad.

DD
Old 14th October 2012
  #24
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johndykstra's Avatar
 

Quote:
Originally Posted by DanDan View Post
Unvex yourself sir!

Hit Command Z. Your creativity is exceeding reality.



I have never been in a CID room, but the principles and tests are convincing. I have never dismissed or dissed the idea of RFZ.

That would be kind of, well,...., mad.

DD
So you do not find the principles of CID to be remarkably similar to RFZ? You have never dissed or dismissed RFZ? Seriously.
Old 15th October 2012
  #25
Gear Guru
Nuts

Quote:
So you do not find the principles of CID to be remarkably similar to RFZ?
Of course I do. To quote Cleese, 'Specialist topic, the bleedin obvious'

Quote:
You have never dissed or dismissed RFZ? Seriously.
Nope, seriously and again obviously.
DD
Old 15th October 2012
  #26
Gear Maniac
 

Quote:
That would be kind of, well,...., mad.
Well...I kinda think this whole forum is heading that way.
Old 15th October 2012
  #27
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johndykstra's Avatar
 

Quote:
Originally Posted by DanDan View Post
Nope, seriously and again obviously.
DD
well than ef it.
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