Research and discuss acoustics, especially in relation to performing arts spaces, churches, movie theaters, home theaters, etc.
look at your syllabus for the reading assignments and schedule. Remember Dave Jones is subbing next week so bring a digital camera with a memory card.
E-mail me if you have questions about anything: todonnell@aii.edu
Off you go.
Thanks, T
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23 comments:
Should those of us in Lighting I and II still comment on Color & Light? Or is our topic now Acoustics as well?
We decided in class last time that we would concentrate on the Lighting II blog for everybody.
According to the D.L. Adams Associates web site, acoustics can serve many purposes for the facility in which they will be used. Some of those uses are as follows: reinforcement, recording, playback, intercommunication, language translation, and assistive listening. The places in which they can be utilized are as follows: auditoria, stadia, theaters, meeting rooms, assembly halls, conference centers, arenas, concert halls, athletic facilities and more. The company focuses on a few key aspects, which are reverberation, reflections, absorption-noise reduction coefficient, and isolation-sound transmission class. I have listed a short description of each below…
Reverberation is when the sound in a room is prolonged due to continued multiple reflections after the noise has ceased.
Reflection is when a sound strikes one or more surfaces before reaching the receiver. This is often cause by the shape of the room, esp. those with harsh angles or corners.
Noise Reduction Coefficient is a single-number for index rating for rating how absorptive a particular material is.
Sound Transmission Class is a single-number rating of a material’s or assembly’s barrier effect. Higher STC values are more efficient for reducing sound transmission.
Even after gaining some idea regarding acoustic properties and their uses, I am still a little intimidated about finding proper acoustics for a large theater. However, I am sure that this information will come in handy and a little trial and error might not hurt either.
http://www.dlaa.com/soundsystem.html
http://www.acoustics.com/101.asp
Acoustics by Design is a company that provides acoustics for many different venues. They go above and beyond the basics of just sound. They do Acoustical engineering, modeling, measurement, design, forensic acoustic and architectural acoustic.
Acoustical engineering services performance in acoustically demanding spaces. Our acoustical engineering services also include controlling, isolating, and mitigating structure-borne, equipment-generated, and environmental noise and vibration.
Acoustical measurement services sound transmission, reverberation, reflection, diffusion, absorption, vibration, and other acoustic metrics. (Jamie has given you guys these definitions in her blog)
Acoustical design affects the quality of structures that you build. It requires timely design decisions regarding size and shape of spaces and the materials to be used in those spaces.
Architectural acoustics allows engineers to analyze architectural plans, engineering calculations, and noise and vibration data to predict acoustic performance and to provide recommendation for optimal design of architectural acoustics.
Forensic acoustics involves acoustical measurement, modeling, and analysis to resolve legal issues regarding compliance with and formulation of noise ordinances, measurement and analysis of noise exposure, warning signal efficacy, and other dispute resolution.
There is a lot to know when dealing with sound. You just got to know how to create an acoustical atmosphere for the right space.
Here are some informative websites I would like to share
http://www.answers.com/topic/acoustics
http://www.acousticsbydesign.com/acoustics/forensic-acoustics.htm
http://www.acousticdimensions.com/
Christa,
Wow, I think forensic acoustics sound really interesting...I found a website devoted to the subject...and I never even knew the field existed!
http://www.ncac.com/foren.html
Also, environmental noise surrounding the theater might be a very important consideration when designing the acoustics. Thanks for mentioning that aspect, because I could have easily overlooked it.
I found some great information on theater acoustics (including tips and consideratioins) at acoustics.com. According to acoustics.com, the goal of achieving optimal acousitics in a theater space is "to properly balance absorption and reflection to provide a favorable acoustical environment. To address both the need to hear and understand speech, and to enhance musical performances."
Acoustics.com lists the recommended reverberation time as 1.0-1.3 seconds (which could be higher for some theaters depending on musical performances). Reverberation time should ideally be the same on stage as it is in the house. Since the ceilings are usually higher in the stage area, it is recommended to use more absortive materials particularly on the back wall of the stage and on one or both of the side walls.
It is also important to control reflections from the back wall. If not properly controlled, it can be particularly disruptive to the people on stage. Because of this, it's usually necessary to treat the back wall with an absorptive material. A concave back wall could add to this problem. If a concave back wall can't be avoided, it's imperative that it be treated with absorptive material.
Another tip listed is to consider faceting the ceiling to help with sound dispersion.
People sitting far beneath a balcony might experience auditory distortion. In an ideal situation, the balcony should not be any deeper than its height. However, it may also be avoided if the balcony is no deeper than twice its height.
Also, it is recommended that the surfaces of vertical planes be "splayed" or irregular to avoid flutter echoes. Flutter echoes occur when parallel reflective surfaces exist and can allow sound to ricochet back and forth between the surfaces. This can be avoided by constructing non-parallel surfaces or by adding absorptive materials to the surfaces.
There are more great tips and considerations on the site. Acoustics can really get tricky in a theater space. I'm glad we are getting a little more in depth with our acoustics research. Before this class, my knowledge on acoustics was limited to a very informative Armstrong presentation in Materials and Codes.
In our materials and codes class awhile back we had a rep from Armstrong come and discuss ceilings and acoustics, so here are a few of the notes that I had taken:
Jamie touched upon the definition of Reverberation time, which is the amount of time for a sound to disapate-
-Class rooms are .3-.5 seconds
-Conference rooms are .5-1.5 seconds (in this case more reverberation time is waneted
-Liturgical 3.5-5 seconds
Open plenum (open ceiling with rafters and plumbing, etc.) has a reverb time of 3.45 seconds, Cuvered panels is 1.65 secs, flat square panels is 1.1 secs, and flat ceilings are up to .5 sec depending on material.
There is also an acoustical design process which I'm sure will be helpful with designing any ceiling
1. Understanding basic acoustical needs
2. Apply correct acoustical strategy
3. Choose appropriate acoustical materials
I also think its interesting what happens to sound when it hits a surface- usually 80% is absorbed, 10% reflected, and 10% transmitted
Another thing that might affect a space such as theaters where there will be louder noises in one area, is the amount of sound that is transmitted to spaces outside of the auditorium area, such as a lobby or restrooms. CAC (Ceiling Attenuation Class) measures the ceiling's ability to block sound from one room to the next, sound typically can travel over walls due to AC and walls that stop shortly above the ceiling treatment. Also the STC (Sound Transmission Class) refers to the amount of sound can travel through openings in walls, like electrical outlets and lights.
Heres a link for some of the sustainable commercial ceiling products at armstrong, most of the products will show the item in application, some are awesome.. they also include spec sheets with the NRC info
http://www.armstrong.com/commceilingsna/article46309.html
You all are finding great information and Cassie I am impressed that you keep notes from previous classes. see how everything ties into one another?
Awesome!
~T
Everyone has such great information!
I wanted to find info that combined last week and this week -
Sustainable acoustic design.
Recycled Wall Acoustic Materials:
http://www.buildingdesign.co.uk/facil-group3/acoustic-solutions/acoustic-solutions.htm
http://www.soundprooffoam.com/acoustic.html
www.carpetrecyclinguk.com/downloads/acoustic_underlay.pdf
Article from acoustics.com about sustainable acoustic design:
http://www.acoustics.com/ra_sustainable.asp
Then on a different note-
http://dae.cstb.fr
I found some interesting articles that described successful acoustic design in theaters - especially the article from the theater in China- This article has many models and diagrams that show how they designed the theater. I found the design to be reminiscent of the U- Theater. It may be useful for our project to get an understanding of how the sound works in a real situation.
http://interact.uoregon.edu
This neat journal has an article beginning on page 10 about transforming the Paramount theater and modernizing its acoustical design. There is also a paragraph about the lobby acoustics on page 11.
http://query.nytimes.com/gst/fullpage.html?res=9506E3D7143CF93AA35751C1A9679C8B63
And, finally this NY Times article about a theater acoustic design.
Sustainable acoustics! Wendy, you are awesome.
~T
Hey Everybody! You all have some awesome research posted! Thanks for sharing your hard work. This has made it difficult for me to find something to blog about, but I got creative and found a tidbit of information that might help.
I found some info on Standing waves, which are, "pressure nodes created when a sound wave reflected from a wall collides with the direct sound emanating from the loudspeaker." He says that this will either enhance the sound or make it quieter or muffle it out altogether. He is talking from a mixer/soundboard tech’s point of view. I found this website interesting because he talks about how people treat a space acoustically for higher frequencies of sound waves. Like a person clapping its hands or talking and there being no echo. He mentioned that this is not enough because, though you may not hear them; there are still low frequency sound waves and bass that can be bouncing around and causing a certain amount of distortion. He talks about an easy acoustical treatment called “bass traps”. The bass traps are built from plywood panels, and designed to vibrate over a broad range of bass frequencies. Fiberglass is mounted behind the panels to damp the vibration, thus absorbing the bass energy from the room. Or, standing waves can be reduced with non-parallel walls and an angled ceiling, like a theater is naturally set up. Is this an accident? Hmmm…
Oops... here is my source for those of you who are interested:
http://www.ethanwiner.com/basstrap.html
Research on Acoustics
Speech intelligibility depends on the level of speech in relation to the level of background noise. An indicator of speech intelligibility in a room is called signal-to-noise ratio or SNR; the higher the SNR, the greater the speech intelligibility.
There are several ways to increase the signal-to-noise ratio. Reduce reflected sound, reduce noise traveling through the plenum, and reduce noise traveling through the walls.
This website also has some great diagrams of the flow of sounds in a space. You can hear both direct and reflected sounds. The diagrams show how sound travels in a hard surface situation and in an acoustically treated classroom. “The addition of sound absorbing materials reduces late arriving reflected sounds, lowers reverberation time, and improves speech intelligibility.”
Some helpful definitions:
Noise Reduction Coefficient (NRC) - A measure of the average percentage of noise that a material absorbs in the mid-frequency range.
Articulation Class (AC) - Rates a ceiling's suitability for achieving normal speech privacy in open office spaces by absorbing noise reflected at an angle off the ceiling into adjacent cubicles.
Ceiling Attenuation Class (CAC) - Rates a ceiling structure's efficiency as a barrier to airborne sound intrusion between two closed rooms, over the speech frequency range.
http://www.armstrong.com/commceilingsna/article7851.html
Video Notes:
Relationship between architecture and acoustics; three S’s: Size, Shape, Surface Materials.
Sources of Sound: direct & reflected. Reflected sound is affected by the materials that reflect it.
Speech intelligibility is affected by: ratio of directed and reflected sound. (reverberation time), signal to noise ration (dba).
New ANSI Standard/Performance Specification – factors affecting speech intelligibility within a space. Background Noise: 35 dba max. Reverberation time: 0.6 seconds max
http://www.armstrong.com/commceilingsna/article5750.html link for video
''In a small room, the 100 decibels don't have time to dissipate,'' he said. ''You'll feel it on your eardrum. Larger space is better able to blend the sound so it's not perceived as loud,'' said Mr. Cooper of Belding Theater.
For a comparison, if one claps in Grand Central Station, it will take 5 seconds for the sound to dissipate. If one claps in a living room, the sound is gone in about a second. In the new Belding Theater, a clap during a chamber music concert lasts 1.8 seconds, but a clap during a jazz concert lasts 1.2, Mr. Cooper said.
The most significant elements of the acoustics are the 10 reflectors, also known as clouds in the business, that are suspended from the theater's ceiling and can be tilted to change the acoustics. The reflectors, made of wood veneer, are of varying sizes: from 9 to 10 feet long and 4 to 7 feet wide.
In addition to the reflectors, Mr. Cooper said he has variable acoustics in the theater to absorb sound, including velour banners, curtains, acoustic lofts at the sides that can be opened and closed.
Every single aspect of the theater was taken into account when designing the acoustics, from the carpet density, to the seats, the glass, the wood, the air, the human mass, angles, curves, hardware, lighting fixtures. ''We touch almost everything, even to making sure the air conditioning is quiet with no rattles,'' Mr. Cooper said.
http://query.nytimes.com/gst/fullpage.html?res=9506E3D7143CF93AA35751C1A9679C8B63&sec=&spon=&pagewanted=2
After searching the web and researching different sites, I found the Arup Acoustics website to be very helpful and informative. Their focus is primarily on Acoustical design, research and innovation. Their goals are to provide design integration, innovative solutions to difficult problems, and to remain as practical and cost effective as posssible. They are world leaders in sustainable acoustical design. They are world wide, with locations in the United States, China and many parts of Europe. Some of their most well-known projects consist of Copenhagen Opera house, Sydney Theater, The Bridge Arts Centre and many more. For example, the Sydney Theatre shows how the volume and form of the auditorium has been designed to provide acoustics that are suitable for unamplified voice, very low background noise, which means the person speaking normal can be heard all the way in the back of the theater, which I found to be quite amazing.
This websites provides many different services and has many examples of projects that they have been involved in. I found this one to be very useful.
www.arup.com
As soon as I read what our blogging assignment for the week was I, as Cassie did thought about Interior Materials and Codes class last quarter. The guest speaker we had from Armstrong gave some great information and was more than willing to answer any questions we had. I learned a lot about what’s important in a space when it comes to acoustical qualities as well as the differences between things such as reverberation time and NRC.
Something I distinctly remember the guest speaker discussing was the ability to figure out the appropriate acoustical qualities for a specific room before it was even completed. The following website http://home.tir.com/~ms/index.html helped describe this technique called Acoustical Simulation more technically.
Acoustical simulation is a technique that assists the acoustical consultants in the evaluation of room acoustics or the performance of the sound systems. This acoustical program can simulate the sound as it would be heard after the project is built. This is called auralization. The physical data of the room is entered into the program. AutoCAD file can be used to transfer the data to the program. The data entry includes surface materials, background noise, and the seating layout. Some of the acoustical factors that can be studied in these acoustical programs include reverberation time, intelligibility, echo, and sound levels over the seating areas.
I think this technique is amazing and it must be quite helpful!
With the increase in technology today, although quality lighting or acoustics still seem far from simple to accomplish it makes me wonder how much more difficult it must have been years and years ago to accomplish this.
The Auditorium (1886) in Chicago, IL by Louis Sullivan and Dankmar Adler which is now a part of Roosevelt University is a space that went above and beyond the bare minimum requirements. In fact this building was referred to as the eighth wonder of the world when it first opened. As described in A History of Interior Design by John Pile, The sightlines and acoustics of the auditorium were excellent and there were ingenious arrangements for moveable ceiling panels that could be lowered to reduce the 4,200 seat capacity when an event did not require so large a hall. Obtaining and displaying both functional and aesthetic qualities this structure is sure to spark any ones interest on the subject of acoustics and lighting. There is a DVD available in the library titled: Architectures 3, it discusses The Auditorium and all of its qualities in depth. I loved it!
Sorry for posting so late, I am looking forward to another week of classes!
- Nicole
You have all done great research!!
What I am finding seems to be things that you have all already discovered, more specifically, I was looking into the Acoustical Stimulation that “Deanda” found and Architectural Acoustics.
According to http://www.zainea.com/knudsen.htm,
Sound is as much a part of man's man-made environment as heat or light. It can now be' effectively managed, notably in rooms where music is heard, by applying the principles of acoustical physics.
They have also written an article to describe the objective acoustical elements that have led to the design of many fine music halls and auditoriums. The application of acoustical knowledge to architecture dates back barely 60 years. Until about 1900 the design of a successful music room was almost entirely a matter of luck. Today the design can be based on well-established principles of physics and engineering.
Acoustics is one of the oldest branches of physics. It originated in the study of music, which probably began with Pythagoras more than 2,500 years ago.
Acoustics first became associated with architecture when men began to assemble in groups to hear speeches, listen to music and see and hear plays. To create a favorable setting for such activities the Greek and Roman open-air theaters and forums evolved, and many of them have survived to this day. The typical open-air amphitheater consists of steeply banked benches arranged in a semicircle (in front of a platform. With the passage of time the platform evolved into a stage with massive rear and sidewalls of masonry (and sometimes a ceiling) that served the acoustical purpose of reflecting, directing and thereby reinforcing the sound intended for the audience. Vitruvius, the first-century Roman architect and engineer, wrote that large vases tuned as resonators were often located in the seating area to reinforce certain sounds.
I can honestly keep going with this but I would actually enjoy it more when we discuss it in class. What I do find fascinating however, is how so many of our classes are closely related. We are doing research for this lighting class and I have found that we are having to use many subjects together to get to the core of Acoustics. This should become more and more interesting!!! C yall soon!!!
I decided to take a look into church acoustics and I found out the basic information translates well into theater acoustics as well. Today I am sharing a few tidbits of info. about the difference between circular and flat walls.
There are two problems with circular sound reflecting surfaces. One
is that sound travels very well around the curve of the wall. The
other is that sound that starts from a location out somewhere in front
of the curve gets reflected back to a focal point, something like a
magnifying glass. The location of that focal point moves around,
depending on where the sound source moves or is located. Refocused
echoes are very loud at the focal point and when you hear it,
the sound seems to come from some mysterious place, some odd
direction which usually doesn’t make any sense.
A traditional flat wall does not focus sound, it lets sound continue to
expand and get weaker with distance. But a curved wall does the
opposite, the sound gets stronger as it travels away from the wall.
With flat walls, acoustic tuning of the space usually gets done only by
using a pattern of alternating absorption and wall reflections. This
acts to thin and scatter the sound that is bouncing off the flat wall.
When working with churches and most public spaces, the sound
reflecting wall is never completely covered with absorption. This
causes a “dead acoustic” effect that is very undesirable for people to
hear. However, the focusing effect of curved walls is so strong that
applying a “normal” amount of sound absorption to the wall barely
effects the sound at the focal point. One then adds more and then
more again until you find the wall to be completely absorptive. The
focal point problem went away but now we have the “dead wall”
effect, also a disagreeable sonic effect.
When working with curved walls, the thinning effect of absorption is
not enough. Here, two different acoustic functions are needed to get
the job done.
1) Some of the sound needs to be absorbed at the surface of the
curved wall, as with any back wall.
2) The remaining sound needs to be scattered, reflected in directions
away from the focal point.
Source: http://www.church-acoustics.com/pdf/church-acoustics-booklet.pdf
After seeing all of these posts, I thought that I wouldn't rehash covered ground, but I would add something new. And, as it turns out, something that I have personal experience in.
The area of church acoustics probably has one of the largest impacts on people on a regular basis. At least once a week, millions of people of many faiths gather to worship. The acoustics of their house of worship can have a significant impact on their worship experience. I found a website dedicated to church acoustics, www.church-acoustics.com.
This site has a rather in-depth faq section which I won't copy all down here, but I will hit a few highlights.
Many churches have carpeted floors, including mine. This is not good for singing, because carpet absorbs the high frequencies but does nothing to the low, creating a flat, bassy sound. As a member of the music team, I was vastly interested to find out that when our congregation does not get into the music, it might not be because the music sucks... :) Instead, it might be because the sound in the room makes everything sound muddy and dull.
It was also interesting to find that a vaulted ceiling, going side to side, is best. This is encouraging, because that is the design of my church. this gathers sound up above and amplifies it toward the back, allowing those in the rear to hear.
It doesn't seem that there would be many things necessary to fix our acoustic problems, and I am guessing the same could be said of many, many other churches.
Seth
Thank you for sharing your research and opinions, it has been an interesting topic...and thanks to Wendy for leading us to her findings on sustainable acoustics...that is awesome!
There is a particular venue in which I wanted to learn more about that I encountered almost a decade ago…The Colosseum at Caesar’s Palace. I had the opportunity to observe as it was being built as well as partake in a few sound checks. I was amazed visually and audibly when entering the venue. It has so far been my inspiration for our theatre design elements. The materials were the first thing I noticed. The velvet lined seating, walls and overhead speakers give the feeling that you know the sound you are about to experience will be incredible. So how do they live up to that first impression...
The stage posed the biggest challenge... ‘The stage covered over 22,000 sq.ft., and is crowned by an enormous proscenium arch measuring 120 feet wide by 44 feet tall.’
I looked into finding out how the acoustics were designed. The world renowned Meyer Sound (www.meyersound.com) generates an array of speakers in a 5.1 surround system with some terminology that would fill this blog… which has been designed and redesigned for this venue to accommodate for its performances.
‘The sound system was conceived by Denis Savage, the Dion’s show’s sound designer. For assistance with the intricate details of the loudspeaker configuration, Savage worked in close collaboration with renowned system designer, veteran SIM engineer, François Desjardins. The Colosseum underwent a redesign, which resulted in a revision to the sound system configuration to provide an optimized audio visual experience for the 4,300 fans who occupy the theatre for each performance. The new system also allows for a seamless transition for the theatre's three other resident performers who include Elton John, Cher and Jerry Seinfeld. "We had to create a system to accommodate all four artists," says Dave Torti, The Colosseum's Head of Audio. "The Meyer Sound system provides great overall coverage, and is a lot more flexible for us."’
Overall...I thought I had an...ear for sound... but I will leave it up to the professionals and hire a consultant. :)
Hey Wendy, I do not know how sustainable this really is but I found 100% natural hemp fiber acoustic cones. Here are some of the benefits:
(1)Environmentally sound wood pulp and synthetic composite alternative
(2)These 100% natural fibers are harvested from a renewable resource, Cannabis Sativa.
(3)Higher tensile strength than: wood pulp, banana fiber, or glass fiber.
(4) One of the highest strength mass ratios.
(5)Naturally breaks up cone resonances that plague other cone materials.
(6)More natural sounding tone, when compared to paper, kevlar, kenaf, aluminum, magnesium, ceramic, carbon fiber or any material we have researched.
(7)Can be custom manufactured to your specification including being dyed in different colors.
Source: http://www.hempacoustics.com/techno.php
Johna, I actually saw Celine Dion’s show there. It was a while back and I wasn’t into any of this at the time, however, I remember being completely engulfed by the sound. They did do a fantastic job with it.
As for most ascoutics today seem to be sustainable .I founf a site where design is a big part of there product also.Not to say that cork isn't a great product but some products I found seem to replace wood and plastic use aswell but in a more sustainable way. Check out the site bellow to see what I mean.
A theater space that I enjoy is Cal State Fulleton that used acoutical panels from 3 calledform :3form ecoresin.
Many other studies have already been notted from armstrong which I learned much about from the armstrong rep.who came into Materials and Codes class. It's great that they are finding out that kids were not bad students but they couldn't hear in the back of the class room what the teacher was saying. Once they put in the right amount of acoutical wall panels .It seemed like everyones grades went up aswell.
As far as movie theaters and home theaters go.Most of them are only conserned with wall panels. I did find a theater though in New York called Linder Theater at the American museum of Natural History in New York that uses Acoustical Reflectors to create more even sound.They used the company called ceilings plus which is alot like armstrong but probably more affordable then them.
www.ceilingsplus.com
www.3form.com
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