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Vertical ceiling foam panels in a school canteen (cafeteria?). How they work?

xaviescacs

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Hi folks,

I have a question about acoustics for you.

Yesterday I attended a meeting with other kid's parents in a school canteen (cafeteria in USA? ).

I took a picture of the ceiling:

ceiling_panels.jpg


I'm assuming they have an acoustic purpose from now on.

It seems a low density foam of about 4 cm thick, 20 cm high and 30 cm apart from each other, more or less.

What is this about? Is this relation between thickness and separation done on purpose? What's the rationale on this?

Yes, I could grab a book on acoustics and start digging, but it's easier for me and funnier for you If I ask here instead :D
 
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xaviescacs

xaviescacs

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Never seen anything like this, so I'm assuming it's either not finished yet or a modern art experiment :D.
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It doesn't look like something unfinished... at least not more unfinished than anything else in a public school :)

Rationalism is no longer in vogue, so I don't think it's a piece of art either... ;)
 

maverickronin

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I would guess that it kills flutter echo and makes conversation more intelligible.

I'm just putting that out here now because no one with a proper understanding of architectural acoustics has taken notice of this thread yet.
 
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Hi folks,

I have a question about acoustics for you.

Yesterday I attended a meeting with other kid's parents in a school canteen (cafeteria in USA? ).

I took a picture of the ceiling:

View attachment 205777

I'm assuming they have an acoustic purpose from now on.

It seems a low density foam of about 4 cm thick, 20 cm high and 30 cm apart from each other, more or less.

What is this about? Is this relation between thickness and separation done on purpose? What's the rationale on this?

Yes, I could grab a book on acoustics and start digging, but it's easier for me and funnier for you If I ask here instead :D

It looks like an absorber array designed to minimize echos.
You will find similar constructs in some movie theatres and larger meeting rooms.
 

Berwhale

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Katji

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^^^Some of that looks very nice. ...Nice spaces.
 

Zoomer

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Is this a concept that works for a normal sized listening room or living space as well? Or is this specifically aimed at treating problems in ginourmous spaces?
 

Doodski

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Is this a concept that works for a normal sized listening room or living space as well? Or is this specifically aimed at treating problems in ginourmous spaces?
I've only seen this used in rec centers over pools and other large echo'y environments. I suppose it could be used anywhere but is that suitable for a living room, rec room, man cave, sound room? I'm going to guess that flat wall panels are better for smaller rooms.
 

DonH56

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The reputedly do a better job of breaking up/absorbing sound from multiple emitters (i.e., people). Would work OK in a small area but take up space and need to hang down a ways to be effective. Think "cone of silence". :) I have seen installations that varied the spacing with the idea that an asymmetric array works better over a wider bandwidth. This is not my area of expertise, however.

iu
 
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Doodski

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I done something very similar in my living room recently and it improved on reverb and made conversations more intelligible.
Definitely interesting! I like it. :D I used 2, 3" x 6' x 3' heavy duty office panels. Created a cozy warm sound that had very little echo and was comfortable like turning the lights down low is. I put the panels directly behind my head against the wall behind the sofa.
 
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xaviescacs

xaviescacs

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I done something very similar in my living room recently and it improved on reverb and made conversations more intelligible.
That reminded me of how pleasant is to hold a conversation in those modernist spaces, without any symmetries, round corners and ceiling decoration...

Why we stopped doing architecture like this? :)

pedrera1.jpeg

pedrera2.jpg

pedrera3.jpg
 

restorer-john

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I've seen vertical panels like that in several airports, even some theatres and performance spaces, especially ones with hard reflective floor surfaces and high ceilings. Clearly for taming multiple path return reflections.
 
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Thomas_A

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Looks like paper-cement plates and some regular spaced diffusors.
 

Thomas_A

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iMickey503

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I installed a few of these. In fact the Restaurant I had my first job in had these wooden slats so it would make the Air cleaners quieter back in the day when we had smoking sections in restaurants. So you saw them a lot more often in the past being installed then today.

There was a formula from what I understand that works on the same principle as calculating port length or box tuning. It would target those frequencies, and in some cases provide acoustic cancelation of a target frequency range.

You notice them more often in older builds since they use to take into account the way a space sounded as well.
This goes back to the days where an architect would take into account all aspects of the structures design and it was deemed a very important part. Something that goes to the wayside these days as costs for doing this often are axed due to cost overruns.

Firms such as SSA acoustics specialize in materials such as metal panels being tuned in order to be used as sound absorption facades. This is sort of the reason why its not so popular these days since it does take quite a bit of money and time to get all of this up and running and us usually left for Big funded construction such as civic projects that don't bother with cost as these building projects tend to be permanent lasting buildings that often won't see any further updates after final construction.
1653131210912.png


The slats from what I understand are tuned Monochords.
The slats (Tuned metal in this instance) is made to a length, size or shape to give it a desired tuning. This tuneing can either act as a sound absorber, (attenuation) or amplification (reinforcement of frequencies) .
--------Hence why you will see ones made out out of wood with shapes trimmed into them to get them to resonate as a certain frequency desired. Therefore, they either amplify or cancel out room acoustics or tune them in such a way for either speech, music etc. Ala, Symphony Hall is a 2,262 seat concert venue in Birmingham, England.

SymphonyHallPanorama.jpg





Architectural acoustics​


A book from 1932:
Page 419 goes over school buildings in detial.
1653129837482.png


It was also used for outdoor applications such as Art installations and Exhibits.
Here is Pioneer Courthouse Square that has this really cool space where everything sounds like you're echoing back to yourself. More like Binaural sound but without headphones. You have to have 2 working ears to hear this.
pioneer-courthouse-square-art-echo-chamber.jpg



photo-1.jpg


pioneer-courthouse-square-031.jpg





Some cool people who were the pioneers of this stuff as far as I can find and read up on in the past.

RussJohnson (1).jpg
Frederick Russell (Russ) Johnson
1653132231586.png





The O.G. Greek Accoustian. 570 – c. 495 BC
220px-Pythagoras_in_the_Roman_Forum%2C_Colosseum.jpg
Pythagoras of Samos

In the 6th century BC, the ancient Greek philosopher Pythagoras wanted to know why some combinations of musical sounds seemed more beautiful than others, and he found answers in terms of numerical ratios representing the harmonic overtone series on a string. He is reputed to have observed that when the lengths of vibrating strings are expressible as ratios of integers (e.g. 2 to 3, 3 to 4), the tones produced will be harmonious, and the smaller the integers the more harmonious the sounds. For example, a string of a certain length would sound particularly harmonious with a string of twice the length (other factors being equal). In modern parlance, if a string sounds the note C when plucked, a string twice as long will sound a C an octave lower. In one system of musical tuning, the tones in between are then given by 16:9 for D, 8:5 for E, 3:2 for F, 4:3 for G, 6:5 for A, and 16:15 for B, in ascending order.[6]



Honorable Mention:
250px-Jean_Nouvel_2009_Vienna_frontal.jpg
Jean Nouvel, French architect.

Jean Nouvel​





Archaeoacoustics

Truly fascinating reading on how this sort of field evolved over the years. I sometimes wonder why on earth they don't have people from colleges go into schools for and teach this fundamental of sound to kids. If they did? I bet you music today would be a lot more interesting. And so the same with architecture.


That reminded me of how pleasant is to hold a conversation in those modernist spaces, without any symmetries, round corners and ceiling decoration...

Why we stopped doing architecture like this? :)

View attachment 207920
View attachment 207921
View attachment 207922

There are more sheep farmers in the world then there are acousticians. Sadly...
.
You don't get these spaces to often as our culture has delved into a throw away Society.
instead of improving the Acoustics we simply use speakers to mask the environment around us instead of improving it. Active noise cancelation being the new fad as its cheaper to install tech then do the proper job of improving the space above.

There are also real world limitations on what you can actually do as far as architecture that will work in the acoustic environment / space. The first being finding anyone that is able to pull it off. You also have to take into account building codes. If the building is in an area that has earthquakes for example? It would be hard to pull something like this off to code.

Example:
-Section R102 Modifications to ASTM C 635 — Standard Specification for the Manufacture, Performance, and Testing of Metal Suspension Systems for Acoustical Tile and Lay-In Panel Ceilings

-Support and Bracing Requirements for Ceiling Suspension Systems with Lay-in Panels

-PRESCRIPTIVE STANDARDS FOR SUSPENDED CEILING ASSEMBLIES

-Grid Ceiling Construction Guidance Suspended Acoustical Grid Ceilings 2009 International Building Code




Why did it become such a thing to do in buildings? Well. Its due the 19th century thought that items that suronded people have a way of absoribing their "Soul" voice or aura. This was popularized by a few people back in the day. One notable person that I could find is, Charles Sanders Peirce who wrote back in 1902:

"Give science only a hundred more centuries of increase in geometrical progression,
and she may be expected to find that the sound waves of Aristotle's voice have somehow recorded themselves"





OTHER Sources:

https://asa.scitation.org/journal/jas


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The Journal of theoretical and computational acoustics


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X0022460X.jpg
Journal of Sound and Vibration

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Applied Acoustics is a leading international journal that reports original scientific research in acoustics with broad impact in engineering applications
 

Astoneroad

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It doesn't look like something unfinished... at least not more unfinished than anything else in a public school :)

Rationalism is no longer in vogue, so I don't think it's a piece of art either... ;)
"Rationalism is no longer in vogue"... ding... ding... ding... we have a winner for the most understated observation since someone said that Savonarola had a little BBQ... vanitas... vanitas... omne vanitas. (Sorry... been binging on Durant's Volume VII)
 
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