An opera house that “looks better than it sounds? ” Who ever heard of such contradiction? When one thinks about an opera house, some may think boring; others may think amazing sound quality, among other thoughts. If an opera house is built to produce “opera” events/productions, shouldn’t the sound quality be absolutely amazing? Named one of the world’s magnificent marvels ever built, the Sydney Opera Theater has been reported to have major acoustical problems. It was very interesting to find out that this 20th Century architectural icon has several adjustments to make to improve their acoustic environment.
The Sydney Opera Theater attracts millions of visitors on an annual basis, but musicians “insiders” have been muttering about the building’s acoustics for years. We can compare and diagnose opera house qualities by knowing what characteristics to look for in an opera house. After knowing what is needed to improve opera acoustics, we can detect what changes the Opera Theater must undergo to enhance their sounds. To begin, there are should a differentiation between concert hall acoustics and opera house acoustics.
A traditional concert hall may have the form of a “tall shoe box, with one or two balconies. Some characteristics of a good concert hall will include things like the clarity of music, reverberation, strength, and envelopment (Edwards & Kahn, 2012). A company called, Acoustic Dimensions, helps in the developments and architecture of different buildings and rooms, uses a geometrical acoustics model based on edge diffraction. They use these characteristics of a good concert hall to explain the associating qualities to a room shape through this model. The use of the geometrical acoustics model here is effective in concert halls due to the large wavelengths produced in this type of setting.
Also, the diffracted sounds from the edges of the balconies can be considered a small component of the sound field that may be ignored when conducting studies about the acoustics of the area (Edwards & Kahn, 2012). In contradiction with this type of method, when studying traditional opera house acoustics, this method would not be very efficient due to the structures of the area. The walls surfaces are usually exposed and heavily shaded by multiple balcony tiers, which create much smaller wavelengths.
The diffracted sounds from these balconies are a larger component in the sound field because of the nature of the balconies within the space and the very small distance, vertically, between them. When the company tests an opera house’s acoustics with the geometric model, the model will show the room shape is usually not something that will work well to distribute the sound around the entire area. The images on the website from the geometric model testing would result in false signs of the sound focusing in certain areas of the room and areas where the sound would be lacking.
In reality, the opera room shows greater sound acoustics than the one being presented by the geometric test. This model does not have the ability to appropriately show the effect of diffraction off of the balcony fronts in an opera room. Therefore, the diffraction of a sound wave at the fronts of a sphere shaped balcony play a key characteristic in comparing opera houses and concert halls. At the balcony fronts, the wave will diffract, while at a concert hall the waves will reflect. The opera house balconies become a second sound source that is being generated in the area.
When the company considers the sound arrival to the ear of a listener, they look at the propagation of the sound waves to locate at any given time and location, of where the diffracted sound is coming from. This can be seen by studying ellipsoidal volume intersections, rather than a sphere. To do this, the company uses a light source located at the intersections to visualize the type of sound diffractions involved in an opera house, resulting in an analysis of the acoustics in an opera house. This of course, is only one of many steps.
This will allow the company to diagnose and evaluate the acoustics of an opera house when consulting, building, or reconstructing. The website, ODEAN. dk, an acoustic software company, has a few useful sound demos which help in comparing the sound quality that an opera house should have. They compare the effects of a singer, and a cello and bassoon duet, when singing or playing, at different positions. The demos also help to explain directivity of a sound source. When one clicks on the right sound, we hear a clear “opera acoustic” sound.
This sound is compared to the sound it would create in an anechoic room. We can tell, that the reverberation sound is greatly minimized in compared to the anechoic room, which is absorbing all sound that is played or sung. They are able to minimize the reverberation to reverberation time at about 1. 3 second at 1000HZ. This website demonstrates the ideal acoustic sound that should be heard in an opera house (ODEON, 2012). By comparing our two online sources, we can see that opera house acoustics are much more different than those of a concert hall.
In a concert hall there is a much greater reverberation time, than the reverberation time desired in an opera house. This is of importance, so that the audience can enjoy an opera at great quality when there is a performance. Programs like the ones on from the Acoustic Dementions company, and the ODEAN can help facilitate what type of materials are needed to be put in place, or how an opera house should be built or designed to reach the maximum opera acoustic sounds. In relating this information to the Sydney Opera Theater, we can learn to examine the reason as to why the acoustics are not ideal for opera.
The sound reverberation for a concert hall is much more different that the sound needed for opera. In order to cut down reverberation time, “sawtooth wall panels need to be flattened,” to reduce the amount of reflection being produced in a performance (Kamenev, 2011). Another reason that leads to the difficulty in opera acoustics is the fact that the hall is too big. Currently the hall has a 25 meter ceiling with also about a thousand seats too many, which allows the sound to get become lost. In addition to the panels, adding an acoustic ceiling over the stage platform would benefit the hall greatly.
Unfortunately, due to other architectural difficulties and the weight of something like the acoustic panel on the roof, this is impossibility at the moment. The weight would be too much for the roof to handle (Kamenev, 2011). Seeing that the hall was actually constructed for other types of performances, rather than a performance for operas, is a major reason why there have been so many complaints throughout the years. The only way to change or reduce reverberation time in this concert hall is to implant more money, which is currently holding Sydney from continuing with the changes.
In finding these two websites, it can help speech and hearing majors realize the real life applications of how acoustics play a huge role for different situations. For example, a speech or hearing major can now take in to consideration the acoustics of a classroom to analyze why a child cannot hear, or how children can hear a teacher better. You would not want to place a huge audience in an area where sound is not being reflected properly to hear a speaker. In looking at all this, we can see that there is a greater knowledge for room acoustics that could have been useful long ago, even as the Sydney Opera House was being built.
This would have certainly reduced the amount of cost and discomforts that they concert hall is actually placing. Opera houses, and other different performing places, rooms, auditoriums, etc. , must consider strictly the room acoustics they need, before commencing a project. Again, the major mistake that Sydney’s Opera Theater, is not being able to have the opera in an adequate room built for opera acoustics, rather than a big concert hall with too much reverberation time.
Works Cited
Edwards, N., & Kahn, D. (2012). Why Do Traditional Opera Houses Work So Well for Opera? . Retrieved March 2012, from Acoustic Dimensions: http://www.acousticdimensions.com/Downloads/tech_papers/opera990114.PDF Kamenev, M. (2011, Oct 19). Sydney’s Opera House: Easy on the Eyes, Not the Ears. Sydney, Australia. ODEON. (2012). Opera House Acoustics. Denmark.
