UNIVERSITY OF CINCINNATI

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1 UNIVERSITY OF CINCINNATI Date: I,, hereby submit this work as part of the requirements for the degree of: in: It is entitled: This work and its defense approved by: Chair:

2 A D A P T A B L E A C O U S T I C S I N M U L T I - U S E M U S I C P E R F O R M A N C E S P A C E S b y Scott Anthony Hand Bachelor of Science in Architecture, 2002 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Architecture School of Architecture and Interior Design College of Design, Architecture, Art, and Planning University of Cincinnati June, 2004

3 University of Cincinnati Abstract ADAPTABLE ACOUSTICS by Scott Hand Architectural acoustics entails creating a space in which the sound is both heard and thought about, j ust as visual aesthetics are also thought about in architecture. In a performance space, acoustics pl ay a major role i n t h e audience s perception of the performance. The conventional method of acoustic design is to develop t h e s p a c e for a balance of sound qualities f o r the primary performance. Sometimes, a limited amount of adjustability o f acoustic qualities allows a few of those qualities to be shifted from one listening setting to another. These adjustments help tune the space to m a t c h the performance and enhance the overall quality of the show, lecture, or performance. Acoustic and architectural research leads to a design of a system for adaptable acoustics. This system allows for a particularly wide range of adjustability within a music performance space both in performer numbers and type and in music style, type, and volume. This thesis research and design, for a multiuse performance hall and rehearsal spaces on a site in Fairfield, Ohio, push the physical limits of acoustic ranges, and adapts the space itself to the sound and the occupants within.

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5 TABLE OF CONTENTS SECTION 1 - THESIS 4 CHAPTER ONE 4 Problem and Central Questions CHAPTER TWO 7 Technological Background CHAPTER THREE 21 Hypothesis / Arguement CHAPTER FOUR 23 Adjustable Acoustics CHAPTER FIVE 32 Adaptable Acoustics CHAPTER SIX 35 Methodology SECTION 2 BUILDINGS PROGRAM 38 CHAPTER SEVEN 38 Program Requirements CHAPTER EIGHT 44 Background and Historical Review CHAPTER NINE 50 Program Precedents SECTION 3 - SITE 55 CHAPTER TEN 55 Site Description CHAPTER ELEVEN 58 Physical Analysis CHAPTER TWELVE 64 Site Precedents

6 Room acoustics, and especially concert hall acoustics, is a subject that belongs at the intersection of physical science, engineering, and art. - M.R. Schroeder Many of the most well-known music performance venues are recognized because of their successful acoustics. Yet in most of these spaces a single type of music is performed. Symphony Hall in Boston has symphonic recitals. The Festspielhaus in Bayreuth performs Wagner s operas. The Institut de Recherche et Coordination Acoustique Musique in Paris has contemporary, abstract works performed within its w a l l s. It is generally understood that when one tries to accomplish too many things well, none of the accomplishments are of aboveaverage quality. This concept has held true for music performance venues. Can a performance space be acoustically designed to meet the needs of many different types of music and performers and achieve excellent sound for each? This quality standard can be met by a multi-purpose performance facility through the use of adaptable acoustics. The space can have the ability to listen and adjust itself based on set parameters : the type of music being performed, the type of performer, the size of the audience, and the intentions of the performers. With this concept, an average-sized performance facility will be able to accommodate a wide variety of performances. This solution is beneficial to the owner of the facility for economic reasons and beneficial to the performers and the audience because it gives them the best sound quality possible. 2

7 Most of the technology for this type of evolutionary acoustic design already exists. A few facilities incorporate a degree of flexibility and adjustability in the acoustics. B u t there is a difference between adjustability and adaptability. Adaptability takes adjustability a step further and indicates that the system will have the capability of shifting itself along with the musical performance. The central idea of this project is fine-tuning the listening environment to match the ideals of each performer, music style, song performed, and how the audience perceives the sound. The act of a ltering the space to meet these demands should be an automatic process, so that a trained expert doesn t need to monitor the controls at every moment. The process of adjusting the space becomes an exercise in perception. Even if the sound characteristics a r e adjusted to fit two different types of music consecutively, the audience may not realize that the space has been altered at all. Without visual reinforcement, the acoustic properties of the space may be taken for granted. The design of a listening environment such as this places emphasis on the individual. E ach person in the audience and on the stage makes the judgment of how the space and the performance sound. Therefore, the adaptation of the space needs to be affected by what the individuals perceive. This thesis discusses using technology and architecture to create a space that can modify and adapt to musical performances occurring within it. It begins covering the concepts required to create an adaptable acoustic space, and then describes a building project that will utilize the hypothesis. 3

8 SECTION 1 - THESIS CHAPTER ONE There is no ideal listening environment. Hearing sounds is a physiologica l experience. The ears take in sound waves, and the brain processes them to determine noise, music, or sound. The activity of listening to music is an emotional and subjective process of hearing and processing the auditory impulses into thoughts and feelings. This is perception. One person s impression of a sound is not the same as another s. In order to study acoustics and its effects, we have to look past the subjective and delve into what can be measured. The field of acoustics isn t described with strictly objective answers, but research has established apparent good and bad decisions. Based on tests and surveys, the subjective experiences can be classified into meaningful data to establish a set of criteria to use when measuring an acousticall y significant space. There are studies and methods to determine what most people think sounds good and what they listen for when they go to a musical performance. The sound and the music affect the process of perception almost as much as the sense of sight. Try watching a movie with the sound turned off. The problem this research addresses is the limits and functionality of the acoustics in a multi-purpose musica l performance space. A traditional concert hall has predetermined acoustics, regardless of the musical selection or the performer. This really is the case for all structures. Acoustic design is rarely the guiding principle in architecture. The main design tool that architects use is the sense of sight. They work with light, massing, depth, and space. H o w e v e r, acoustics should a l s o be considered in designing any space, because sound plays a part in how we experience all places. This thesis focuses on 4

9 music performance spaces, because this is one of the few facilities in which the quality of sound is even more important than visual sens ation. F o r economic reasons, it can be valuable to create a space that accommodates a range of performance types acoustically. This did not become an issue until the last two centuries or so. P r i o r to the mid 1800s, practically all formal music performances were given in buildings owned by the royalty or the church. Neither of these entities worried about the economics of putting on shows. In a modern commercial performing facility, each performance needs to make money to pay for the upkeep of the facility. The more shows a facility can produce, the more people it can bring in to pay to hear/see a performance, the more economically viable the facility is. This led to the building of enormous performing arts facilities that hold severa l thousand audience members. Because of their size, they must physically adjust to support a multitude of different performance types. These factors powerfully constrain the acoustic design. It is much simpler to design a space that sounds good under one specific condition rather than for a plethora of diverse conditions. There are three options f o r meeting the acoustic requirements of a multipurpose space. The first is to compromise the acoustic parameters to a middle-g r o u n d between all of the different functions of the space. This is the least expensive option and has the advantage that nothing has to be controlled or changed after the construction is completed. However it produces nonoptimal conditions for some types of performances, which may not correlate with the design goals. The second option is to give the space optimal conditions for one kind of presentation, and try to alter it f o r others by electro-acoustical means. There are two main categories for electro-acoustic systems: v oice support systems for spaces with long and loud reverberations, and assisted resonance systems for spaces with little reverberation. The third option is to install changeable elements that help the space alter itself and its 5

10 natural characteristics to meet the desires of the current function. 1 The latter option is the one this project develops into a system that adapts and fine-tunes itself with the performance and its optimum acoustic presentation. The reasoning behind this third option returns us to the basics of hearing. Listening to sound is a perceptual experience, which is very intricately entwined with the other senses, especially sight. The term audio-visual reflects this connection and describes how the two perceptions are linked to create a deeper perception. Although it may be possible to trick the auditory experience with an elaborate electro acoustic setup, th e visual sense would not be tricked by seeing an array of loudspeakers projecting the sound throughout the hall, or by hearing sounds that don t fit the space. An adaptable hall would have the advantage of adjusting both of these senses to give the fullest perceptual experience. A listening environment affects sounds in many ways. Loudness, reverberance, clarity, spaciousness, envelopment, intimacy, warmth, and directionality are all important factors of sound and music that are determined by the design of a space. 2 By determining the architectural and technological factors that control these aspects, they can each be adjusted individually to create an environment that is truly flexible. 1 Heinrich Kuttr u ff, Auditorium Acoustics, The Acoustic Design of Multi-purpose Halls, Halstead Press, 1974, New York, p Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York, p. 47 6

11 CHAPTER TWO A d i s c u s s i o n o f a c o u s t i c m e t h o d o l o g y HEARING Humans have a complex auditory system designed to receive and process sonic information. Our systems are most sensitive to the frequency range of 300 Hz to 5000 Hz. This is the range where most of our speech sounds are located and our ears are adapted to hear other humans speak. Our hearing system extends several octaves each way from that middle range from 25 Hz up to 20,000 Hz human ear. 1. outer ear; 2. ear canal; 3. ear drum; 4. cochlea; 5. auditory nerve The hearing mechanism begins with the visible outer ear that directs the sound waves towards the ear drum and mechanical transducer system in the middle 7

12 ear to the receptors in the cochlea. This receptor system converts the vibratory movement it receives into electro-neural impulses it sends to tell the brain what we are hearing. 3 A large amount of acoustic signal processing takes place in the receptor system itself. The coch l e a a n a l yz es the sound vibrations for frequency and intensity and sends coded messages of this analysis to the brain. Lower centers of the brain take the stereo information from the two ears and process it to determine the orientation of the sound. The highest center, the auditory cortex, is concerned with decoding the signals provided by language and communication. It determines the significance of sounds, stores them in memory, colors them with emotion, and determines when they should have access to the motor system. 4 This system allows the brain to use the sound input as a means of determining its surroundings. The decoding of the stereo signal results in the Inter- Aural Cross Correlation effect (discussed later) that pinpoints where the source of th e sound. QUALITIES Leo Beranek set out the interrelations between the musical qualities heard in a hall and the acoustical factors that affect those qualities. This correlation is the basis for developing the adaptability in a space with this thesis. The figure below is a summary of Beranek s findings. The musical factors are not good/bad terms. They are aspects of the sound that have a value, whether it is objective or subjective. The acoustical factors are the different characteristics of a space tha t determine how the musical factors are perceived. 3 Jack Orbach, Sound and Music, University Press of America, 1999, Lanham, Maryland, p Jack Orbach, Sound and Music, University Press of America, 1999, Lanham, Maryland, p

13 Musical Qualities Affected by Acoustics Musical Factors Fullness of tone or its antithesis, clarity Intimacy (audible) Spaciousness Timbre and tone color Envelopment Ensemble Dynamic range Acoustical Factors Reverberation time Ration of direct sound to loudness of reverberant sound Speed of music Short initial -time-delay gap (eighteenth century music room) Medium initial -time-delay gap (late nineteenth century concert hall) Very long initial -time-delay gap (cathedral) Difference in early sound at two ears at mid-frequencies Sound level at lower frequencies Richness of bass Richness of treble Tonal distortion Texture Balance Blend Irregular surfaces in wall Focusing Differences in reverberant sound at the two ears Musicians ability to hear each o t h e r Loudness of fortissimo Relation of background noise to loudness of pianissimo Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York, p. 38 9

14 The acoustical factors can then be tra nslated into scientific principles. Once those principles are understood, variability can be designed into the acoustic system. The process of using these principles to create an adjustable acoustic environment will be discussed later. COMMON PRACTICES Room Shape The most basic architectural determinant of acoustics is the room shape. It may have more impact than any other decision on how the space is perceived by the inhabitants. This is the case partl y because the room shape is a visual k e y a s w e l l as an acoustic key. Not only do the surface elements of the room s h a pe affect what is heard by the ears, but the eyes perceive them as the limits of the inhabitable space. The brain is accustomed to correlating the volume of a room with the sound produced within that room. 5 5 Yoici Ando, Architectural Acoustics: Blending Sound Sources, Sound Fields, and Listeners, Springer- Verlag, 1998, New York, New York, p

15 Fan-shaped Rectangular R e v e r s e -fan-s h a p e d Horseshoe-s h a p e d floor plans. NHK Hall Tokyo, Syphony Hall Boston, Concert Hall of the Sydney Opera House, and Teatro Alla Scala - Milan The acoustical properties of the room shapes that are commonly used primarily d e p e n d on the side walls, not the walls behind or in front of the stage. Room forms are fan-shaped, rectangular, reverse-f a n-shaped, a n d horseshoe-shaped. A fan-shaped room has walls that get farther apart, the farther away from the stage they are. This shape is excellent for gathering the audience as close to the stage as possible, as the layout is based on sightlines from the audience to the platform. I n a rectangular room, the side walls are parallel to each other. This is the typical layout for a traditional concert hall; long reverberation times are easy to achieve. The reverse-fan-shaped room i s a modification of the rectangular room, but the side walls angle towards each other as they get farther from the stage. This shape makes it easy to increase the number of sound reflections off the walls. A horseshoe-shaped room is the typical shape of an opera house, often with many balconies that wrap around the main floor in a U shape. Generally, the volume of the horseshoeshaped rooms is smaller and the sound absorption is much higher due to a 11

16 large amount of people in a small space than in other shapes, making it easier to achieve a shorter reverberation time. 6 STAGE LOCATION AND SIZE The location and placement of the stage, or performance platform, w o r k s w i t h the room shape to bring the performance to the audience both visually and audibly. There are two locations for the stage. One is behind a proscenium, which is how a standard theatre is set up. The proscenium is a wall that divides the audience seating area from the stage area. There is usually a series of curtains that can close off the opening between the two. This arrangement is ideal for dramatic performances because the proscenium opening acts as a window into the imaginary world of the performance. When it is used for a musical performance, wall and ceiling panels are often needed to reflect the sound from the stage into the audience; otherwise, the sound would resonate or be absorbed behind the proscenium. section plan With proscenium One acoustic volume 6 Michael Forsyth, Buildings For Music, The MIT Press, 2002, Cambridge Massachusetts 12

17 The other location for a stage is within the same room volume as the seating. This has the acoustic advantage of the sound originating closer to the audience, keeping the direct sound louder and more immediate. This design makes traditional theatrical performances more difficult because there often is no off-stage area to enter and leave the stage. Stage c urtains are difficult to place in this design. 7 M ATERIALS The second most influential attribute of a performance space is the surface materials. The materials work in tandem with the room shape to develop the acoustics and alter the space visually. Finish materials influence the sound b ecause of w h a t the sound waves do when they hit the surfaces: reflection, a b s o rption, o r ion. A common conception about materials is that wood is always the best choice. Many people believe that because most musical instruments are made of wood, the performance space should also be covered in wood. Although it is also selected for aesthetic reasons, wood is extremely complicated acoustically. If pieces of wood are small enough, they will diffuse the sound. If they are big enough, they may vibrate with the sound waves and either absorb or enhance the sound. Certain shapes reflect most of the sound energy. These factors make placing wood in a performance space complex from a design standpoint. 8 7 Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York, p Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York, p

18 wood properties. diffusion, absorption or enhancement, and reflection Apart from wood, most materials act acoustically in the way we would commonly think. A hard material gives a hard sound that is immediately reflected and colors the timbre harshly. A soft material softens the sound by absorbing some of the original sound and altering the timbre. Most people have recognized the correlation between different materials and the type of sounds they create. These connections between the visual and audible are a vital design consideration. Performance facil ities are generally built and finished with several materials, which enhance the quality of the sound within the space. If a room is finished completely in one material, it colors the sound too narrowly and does n o t allow for diverse expression. Wood is the most common interior finishing material because of its visual appeal and its ability to do many different things acoustically. Other common finishing materials are plaster, paint, stone, and fabric. 14

19 Plaster is widely used for two main reasons. I t was a very common material in the era when many of the first world-class concert halls were being constructed. When existing designs were being copied and altered to build new facilities, plaster was often used strictly because of tradition. Pl a s ter has an interesting mix of properties that allow it to absorb, reflect, and diffuse sound at different wavelengths. The thinness of the plaster allows the lower wavelengths to pass through it and interact with the wall construction behind it. The hardness of the dried plaster causes it to reflect the middle and high frequencies back into the room. The texture commonly given to the plaster finish (slightly bumpy or speckled) causes it to diffuse the higher frequencies very well. This makes it an ideal ceiling material. 9 mids h i g h s lows plaster properties. middle frequencies are reflected; high frequencies are diffused; low frequencies pass through Paint can cover almost any other material. I t closes up even the smallest pores in a material and eliminates any absorbing properties of high frequencies. Paint is ideal to improve the sound reflectance of a surface, and designers enjoy the fact that it comes in any color. 9 Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York 15

20 terra cotta terra cotta with paint paint properties. when paint covers a porous surface like terra cotta, it becomes a highly sound reflective surface Stone and concrete a r e often used to do the opposite of wood, both visually and acoustically. They look cold and hard, while w ood is considered warm and soft. Acoustically, stone and concrete reflect almost all sound because of their mass, but they can be finished with a rough surface to slightly diffuse the sound. 10 stone or brick concrete concrete and stone. because of their mass and finish, they are good sound reflectors 10 Peter Lord and Duncan Templeton, Detailing For Acoustics, E & FN Spon, 1996, New York, New York 16

21 Fabric is used to cover other surfaces, such as absorptive materials. Fabric is considered to be acoustically transparent, because even though it is visible, it does practically nothing to alter the sound. It is ideal for creating a visual surface in front of the acoustic surface, defining space edges, or adding privacy fabric usage. 1. sound wave; 2. sound-absorbing insulation; 3. fabric covering R E F L E CTORS There are three things the designer can do with sound when outlining a space: absorb sound, diffuse sound, and reflect sound. Reflectors are necessary to bounce sound waves back at the audience and the performers. T h e s e reflections can add to the direct sound and greatly enhance the experience of live music. If there are no reflected sounds reaching the ears, it will be like listening with headphones, where only the direct sound is heard and there is no identifiable direction f rom which the sound is coming. Balcony fronts, suspended reflectors from the ceiling, and panels on the sides of stages are all 11 Peter Lord and Duncan Templeton, The Architecture Of Sound, The Architectural Press, 1986, London, p.43 17

22 used for the purpose of reflecting the sound. The sound reflections multiply and create reverberation within a space. 12 sound reflectors. sound reflects off of hard, solid, flat surfaces Both the reverberation time and the reverberation level are intrinsic to the characteristic sound of a performing facility. These two aspects are commonly considered to be the most significant characteristics of sound. Basically, the reverberation time is the length of time it takes for a sound to die out. The reverberation level is the loudness curve that defines what the reverberation sounds like between the source sound stops and the time when it is no longer audible Heinrich Kuttruff, Room Acoustics, E & FN Spon Press, 2002, London, p M. R. Schroeder, Reverberation and Diffusion, University of Göttingen, Germany 18

23 ABSORBERS Absorbing panels and finishes are used in performance spaces to keep the sound from reflecting when it would be detrimental to the acoustics and from building up the reverberation too much. O ften, the back wal l o f a performance space ( behind the audience) will be covered with an absorbing material or finish to prevent echoes. Even though the audience may not be able to hear those echoes because they are above the space where they are seated, they could be dis tracting to the performer. 14 sound absorbers. An absorptive surface captures the sound energy DIFFUSERS Sound diffusers reflect the sound, but not just in one direction like a reflector. A diffuser will scatter the sound energy, ideally in a uniform dis tribution over the room. Diffusing the sound can keep the sound energy higher in a space without creating echoes. Th is adds to the reverberation level and adds to the 14 Heinrich Kuttruff, Room Acoustics, E & FN Spon Press, 2002, London, p

24 reflected sounds reaching the audience. 15 The most commonly used traditional diffuser is a chandelier hanging over the main seating area. Although it is also there for visual reasons, the chandelier takes the sound p from the performer and because of its different angles and patterns, scatters the sound over the whole room. 16 sound diffusers. A diffusing surface will scatter the sound in many directions 15 M. R. Schroeder, Reverberation and Diffusion, University of Göttingen, Germany 16 Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York, p

25 CHAPTER THREE An architectural space can adapt itself to meet the ideal acoustic requirements of a range of functions through careful study, d e s i g n, and planning. Although there are limits to a space s adjustability, it is possible to maximize the range through this type of acoustic design. Acoustic limitations restrict the planned activities in existing multi-purpose spaces. A music performance space that has the ability to adapt to a multitude of different performance sizes, types and audiences has a clear advantage over a static facility in terms of acoustic success and patron enjoyment. The development of an adaptable acoustic space has difficulties that stem fr om the limited ability an architect to predict the outcome of a finished structure during and after the design process. Architects are trained to visualize their designs. All design tools throughout history have been based on the concept of projecting h ow the building will look, from scale models, to artistic renderings, to computer walk-throughs. The designer needs the ability to auralize how a finished space will sound in order to properly cope with the acoustic design requirements. Until now, archit ects and acousticians have relied on calculations and possibly inaccurate scale models to predict the acoustics of a room. With the combination of acoustic modeling software and an acoustic simulation setup, it is possible to hear how a design will sound, in a method similar to computer rendering programs. This auralization process is explained later. This combination will allow the designers to model the appropriate levels of adjustabl e functions within a space to hear if they are accomplishing the required goals. 21

26 Once a performance space is designed with the maximum amount of adjustability, the space can be programmed to adapt. At the completion of the design, and even the completion of the building construction, the proper methods of adaptation are not known. The space will have the ability to read the sounds, the audience, and the performers, and change itself accordingly. As the system works and gets used, it learns the best way to shape itself and the sound to create the ideal listening environment. This learning process is then used to tune the space to certain acoustic standards that are calculated by the system. The finished room will then be able to use a database created during the design of the space combined with the input gathered from a performance, to adapt itself to the different acoustic functions. The purpose for this adaptation is to present the performance in the most ideal way possible the ideal changes based on the music being performed, the intentions of the performer, and the responses of the audience. 22

27 CHAPTER FOUR Six aspects can be distinguished as defining the sound within a space, based on the studies done by Beranek (see figure on page 11): the volume or intensity of the sound, the range in the possible intensities, the reverberation time, the reverberation level, the interaural cross-correlation factor, and the color or timbre. By understanding these properties and determining how to alter each of these individually within a space, it will be possible to design f o r the maximum amount of adj ustability. VOLUME / INTENSITY (LOUDNESS) The intensity of sound is how loud the sound is when it reaches the listeners ears. The acoustics of a space help define this because they can limit the possible intensity. The space also has the ability to lower the intens ity based on the architectural acoustics. For different types of music, the ideal subjective listening levels are significantly different. The distance between the listener and the sound source is the basic principle that identifies the intensity. The f arther away they are from each other, the lower the sound intensity. The volume of the space is also very important. If the volume is small, the sound intensity will be much higher than it would be in a relatively larger space. Each sound source creates a certain amount of sound energy. The distance that energy travels, the volume of space it energizes, and the amount of absorptive surfaces within the room all decrease the intensity of the sound that the listener perceives. The intensity level is possib ly the primary characteristic perceived by the listeners. The preferred listening level depends on the music and the artist. In 23

28 general, the optimum level is lower for music with a slower tempo, and higher for music with a faster pace. 17 Altering the overall volume of the space is the most effective method of adapting the sound intensity. By lowering the overall volume of the space, the sound energy will have less air and surface to absorb it, and will be louder when it reaches the listeners ears. An electronic amplification system can also be utilized to raise the sound level intensity. RANGE OF INTENSITIES (DYNAMIC RANGE) This aspect is the range from the quietest part of a piece of music to the loudest part. Some pieces have very wide ranges, while others are v e r y small. The acoustics of a space help the performers represent that difference to the listeners. The background noise level is what defines the quietest possible performance. If there is absolutely no audible background noise, NC-1 ( the threshold of hearing), then every sound the performer makes, regardless of how small, will be heard. If the background noise level is an average NC-35 (Noise Criterion of 35), then any sounds created that are quieter than the criterion level will be partially masked. The upper limit of the intensity is defined in the same manner as the previous section, by the highest sound intensity reaching the listeners ears. If the background noise is low enough, and the musical passage is extremely quiet, it can even make the listeners hold their breath to try not to cover up the sound. Such a low sound intensity can be very dramatic, but can also be 17 Yoichi Ando, Architectural Acoustic: Blending Sound Sources, Sound Fields, and ListenersSpringer- Verlag, 1998 New York, p

29 unnerving for the audience if it lasts too long. 18 Th e lower the background noise in comparison to the performance sound, the easier the listeners can h e a r the intended performance with greater fidelity. There is no noticeable reason to adjust the background noise during a performance. The ability to lower it immediately before a performance begins would allow the audience members to feel more at ease as they wait in their seats before the show starts. This change could even cause any chatter to cease, as the persons talking in the audience would perceive their own voices as louder. 19 Th is noise floor (the term for the background sounds) could also be raised after the show is over to enhance the applause. REVERBERATION TIME The reverberation time is the time it takes a sound to die away 60 db, or o n e millionth of its initial sound pressure value. The reverberation time is frequency depende nt. This means that sounds at different frequencies reverberate for different lengths of time. The reverberation time is based on the volume of a space and the amount of absorption inside. 20 Throughout history, music has been composed to suit the locations where it was performed. In the Baroque era, music was very intricate with few sustained notes. This music was performed in small rooms with a small numbers of musicians, a relatively small number of audience members, and had a short reverberation time. In the Middle Ages, music was primaril y plainsong, which was a single voice melody with long, drawn-out notes. This music was performed in stone cathedrals, for large numbers of church-g o e r s, 18 Jack Orbach, Sound and Music: For the Pleasure of the Brain, University Press of America, 1999, New York, p Jack Orbach, Sound and Music: For the Pleasure of the Brain, University Press of America, 1999, New York, p Duncan Templeton, Acoustics in the Built Environment, Butterworth Architecture, 1993, Oford, p

30 and had a very long reverberation time. 21 The differences in these musical styles are emphasized by their traditional architectural acoustics. A plainsong piece does not sound correct if performed in a dead room with a very short reverberation time. A Baroque piece will sound muddy and washed out if performed in a live room with a long reverberation time. This basic connection between music and acoustics means the reverberation time is a very important aspect that controls how the sound is perceived. Being able to adjust the reverberation time would allow a much greater range of pieces to be successfully performed within a space. This connection has already been studied thoroughly. There is a general standard reverberation time for most types of music. 22 Rock music < 1.5 secs Orchestral Music in the modern style secs Music in the Classica l style ~ 1.7 secs Music in the Romantic style ~ 2.1 secs Organ music 5 10 secs The reverberation time can b e adjusted by altering the amount of soundabsorbing surfaces and the volume within the space. When there is more surface area of absorption, the reverberation time is shorter. This is traditionally done with banners or curtains hung from the ceiling or along the rear wall of the space. Reverberation chambers can also be used. By opening up the standard volume of the performance space and coupling it with another volume, the reverberation time can be increased. Electronic amplification can also be used, in what is called assisted resonance systems. The system 21 Michael Forsyth, Buildings For Music, The MIT Press, 2002, Cambridge Massachusetts p Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York 26

31 electronically adds in the reverberation as if it were in a more reverberant space. 23 REVERBERATION LEVEL The reverberation level is the resonant sound that is heard immediately after a sound source is cut off. The reverberation time measures the length of the reverberation, and the reverberation level describes how this sounds. It is often measured by using the ratio of the EDT to the reverberation time. The EDT is the Early Decay Time and is the first 10 db of sound decay. (The reverberation time is the first 60 db of sound decay.) Comparing these two, shows us that the shape of the reverberant sound is very important when judging the acoustic quality of halls. 24 The EDT is multiplied by 6 and then divided by the reverberation time in order to create the ratio. This is also referred to as the Early-to -Late Sound ratio. The reverberation level influences the listeners clarity of the sound. The higher the ratio is, the clearer the perception. For speech, this ratio should be as high as possible. F or music, it varies based on the musical style, and the extent to which the reverberant sound should be apparent. 25 The shape of the space has the biggest influence on the reverberation level, because much of the early sounds that contribute to the EDT are heard from reflective surfaces. In a fan-shaped hall, the walls do not reflect the sound into th e middle of the space, and do not give many early reflections. Because of 23 Michael Forsyth, Buildings For Music, The MIT Press, 2002, Cambridge Massachusetts p Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York p Charles M. Salter Associates, Acoustics: Architecture Engineering The Environment, William Stout Publishing, 1998, San Fransisco p. 101,

32 this, the reverberation level in a fan-shaped room is lower than in a shoe-box shaped room, which uses its parallel walls to reflect the sound into the audience. The EDT is strongly influenced by early reflections ; it therefore depends noticeably on the measuring position and is very sensitive to the room geometry. 26 Reverberation level can be adjusted by altering the room shape primarily the surfaces that provide early reflections to the listeners. This includes the walls of the space nearest the stage, and the ceiling. This process requires great care because the perception of the reverberation level changes dramatically based on where the listener is seated within the space, especially in relation to the reflecting surfaces. INTERAURAL CROSS-CORRELATION (IACC) This aspect deals with the differences between the two ears of a listener. A large part of how a sound is perceived is based on the difference the brain picks up from the left and right ears. If the signals are the same, the sound is very f l a t. If the signals are too different, then the brain has trouble locating the sound sources. The IACC is a measurement of how the listener identif ies where the sounds are coming from, creating balance from left to right, and sensing overall sound envelopment. The IACC also helps identify the apparent source width. This is the perceived size of th e sound source and adds to the subjective awareness of the spaciousness of the hall. There is a complex method for determining the IACC; and in th e end the result is a number ranging between 0 and 1, where 0 represents no distinction between the two ears, and 1 would be the highest level of dissimilarity possible. Existing halls that are rated positively i n Beranek s studies have a higher IACC (around 0.7) compared to lower rated 26 Heinrich Kuttruff, Room Acoustics, 4 th edition, Spon Press, 2000, New York p

33 halls (0.4). This indicates that audiences prefer to hear a very spacious sounding room and like the sound to envelope them, creating the perception that the sound is coming from all around. 27 The reason for altering the IACC is to increase or decrease the spaciousness of the sound based on the performers desire and historical context. For rock concerts, the performers may want to have a definite directivity from the stage to the audience. A symphonic performance may want to maximize the envelopment of the listeners with sound. Special circumstances, such as Tchaikovsky s 1812 Overture, which begins slow l y and marches into the battle, could begin with a narrow apparent source width, as if the orchestra is farther off in the distance, and then gradually increase the apparent source width to bring the listeners into the sound. The IACC can be controlled by altering the locations from which the sound is being reflected. A greater IACC and apparent source width can be achieved by maximizing the lateral side wall reflections to the listeners. As mentioned earlier, the side walls and the ceiling assist the most in directing early reflections to the listeners. L ate sound reflections can be achieved by properly angling reflective surfaces throughout the hall. The diffusing surfaces also assist in creating a high IACC. When sound hits a diffusing surface, it is scattered evenly, and can create a highly enveloping sound field. 28 COLOR / TIMBRE Timbre is the combination of attrib utes that distinguishes different sounds that have the same pitch and volume. It is what defines the difference between two instruments playing the same note. The color of the sound is a 27 Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York p Y o i c hi Ando, Architectural Acoustic: Blending Sound Sources, Sound Fields, and Listeners Springer- Verlag, 1998 New York, p

34 subjective term that applies to how the timbre of music is altered by the materials of the space that it is sounding within and reflecting from. It is influenced by all of the previous aspects, but also deals with the materiality of the finish materials and the intimacy of the space. This aspect is sometimes referred to as warmth of the sound when referring to the lower freq uencies, and the brilliance of the sound when referring to the higher frequencies. The tone color is a highly subjective characteristic of sound within a space, and incorporates many different acoustic attributes. Because of this characteristic s subjectivity and complexity, many different factors can be involved in it. Most noticeable is the balance of the frequency spectrum. If the space absorbs more high frequencies than low frequencies, then the listener will hear an emphasis on the low end tones. This could be categorized as a richness of bass, or if done too much, could create a tone that is boomy. The same can happen with the high frequencies, creating either a richness of treble, or a tone that is tinny. 29 The IACC influences the tone color by shaping the way the sound reaches the listeners ears. The materials from which the sound reflects can have different absorptive/reflective properties and can color the tone in the manner discussed above. Another large part of this attribute is a musical characteristic. Tonal distortion, consonance, and dissonance are created through musical instruments and can either be enhanced or impeded by the use of the architectural acoustics. If the reverberation level is high and the reverberation time is long, a fast musical passage full of many different notes may b l u r together and create a muddy dissonance. If a piece of music that jumps quickly between very high and very low notes is performed in a space that has 29 Leo Beranek, Concert And Opera Halls How They Sound, Acoustical Society Of America, 1996, Woodbury, New York p

35 an imbalance of frequency response, the listeners will not hear what the composer anticipated. 30 The tone color can be adjusted by altering the finishing materials and by utilizing all of the precious characteris tics together. The performers can decide how they want their performance to sound to the listeners. The adjustability within this characteristic is almost equivalent to mastering a recording. The tonal color is most noticeable when it is altered and can be compared to something previously heard. 30 Jack Orbach, Sound and Music: For the Pleasure of the Brain, University Press of America, 1999, New York, p

36 CHAPTER FIVE Once the space has the ability to adjust to the widest array of acoustic conditions, this is combined with a feedback system that incorporates the intentions of the performer, the responses of the audience, and the sound and style of the music itself. This interaction between the space and the performance creates an adaptable acoustic environment. PERFORMER The intentions of the performer are preprogrammed into the system. There can be limits set so that the space does not reach levels that would not be desired, and could be aimed in certain directions. An engineer would sit down with the musicians before a performance and discuss these goals. This sound engineer will be working with the performers to help shape their performance. The engineer and the adaptable system will also be able to gather information from the performers during a show and change the space accordingly. As in a typical show that uses an electro-acoustical sound system, the sound engineer controls the basics of the sound. In the adaptable system, the engineer directs those basics, and the computer system is in control of the specific details that shape the sound and perception of the performance. AUDIENCE A big part of controlling the audience s perception of the performance is being able to interpret how the audience perceives it. Although this seems like an obvious connection, it is the most complicated part of the process. Different methods of audience interaction are possible. Heat given off by the whole 32

37 audience can be measured through infrared cameras. Metal strips could be placed in the armrests of the seats to measure the moisture and temperature of the audience s hands. Pressure sensors can be set in the seats to determine how fidgety they are. And motion cameras can be used to see how much the audience is moving in time with the music. The results from these readings do not yet have specific purposes, because they would need to be tested to show how different performances affect different audiences. The statistics would not be used to track any personal attributes of the audience or anything beyond adapting the musical performance to the audience s reaction. This data is then compared with the performer s intentions and combined to control the space. The details of this process are available to the system from the very onset, but over time it will learn which ways audiences react to different performances and be able to guide the show better over time. MUSIC The musical performance is the basis for this entire idea. Most music has an inherent ideal acoustic situation based on the genre, style, orchestration, and time period in which it was written. These ideal situations can be adhered to strictly, used as a starting point, or completely ignored. They can be used as a starting point to adjust the acoustic environment. The time period and genre often depict a setting for which the composer originally wrote a piece. All of Haydn s symphonies were written specifically for four different concert halls which he consistently performed. 31 A jazz piece would have roots in a small club. And Gregorian chants were written to be performed in large cathedrals. 31 Michael Barron, Auditorium Acoustics and Architectural Design, E & FN Spon Press, 1993, London, p

38 The style of the music is taken into account to optimally tune the space. Performances that contain either a majority of high or low frequencies are balanced correspondingly to give the appropriate balance. Music with a fast, rhythmic pace needs a space that has a shorter reverberation time than mu s i c with a slower tempo. Pieces that have a wide range of volumes and intensities throughout need a space that allows the quiet parts to be hea rd as well as the loud. The orchestration of a performance also gives a strong direction to how the space should perform acoustically. A solo piano has different sound requirements than a 25-piece brass ensemble. The instruments have different sound properties that need to be taken into account by the adaptability system. Intensity capabilities, tone color, diffusion and direction of the sound, and frequencies created are all characteristics that differ with different performance groups. These varying c haracteristics are understood by the adaptability system and are programmed into the calculations to determine the adjustments. OVERALL The adaptable acoustic system has the capabilities of listening to the performance and analyzing the preset limitations, the audience s reactions and perceptions, the performers intentions, and the sound being created within the space. The system will take that information and use it to adjust the listening environment accordingly. 34

39 CHAPTER SIX The building design project incorporates the ideas from this thesis and uses them to give a physical solidity to the theoretical ideas. The building design and the thesis work together to give the full impression of the ideas and to help the reader and critic best understand the investigations. AURALIZATION All traditional and contemporary architectural design tools use the sense of sight to organize, develop, and visualize the finished building. The sense of sound can be added to the arsenal of tools to help guide a structure through the design process. A technology that can be adapted to meet these needs is auralization. Auralization is the process of predicting and altering a base sound to sound as if it were inside the space being designed. During the schematic design phase the technology is used to auralize the room to hear if it is meeting the client s and designer s expectations. The current space design is programmed into the computer in three dimensions and th e materials and finishes applied to all of the surfaces. Then the room data is calculated from specific sound source and listener source locations. This data is then applied to a sound file that was recorded without any of the room data. This produces an accurate depiction of what the room would sound like under these conditions. The three-dimensional model is very close to what is used in visualization and rendering software. The surfaces are defined and then labeled with materials 35

40 and finishes. The finishes in visualizing software tell the computer how each surface reacts to light waves hitting it. In the auralization method, the computer determines how the surfaces react to sound waves hitting it. Multiple sound sources are calculated just as multiple light sources would b e. After the calculations determine how the model works with the sound sources at that specific listening location, they can be saved. Those calculations are an algorithm that specifies what happens under those circumstances. That algorithm can then be a pplied to an anechoic sound file. Anechoic sound is recorded in an anechoic chamber. There is no reverb eration, echoes, or extra coloring to sound. The chamber has one hundred percent absorption in every direction. So the recordings sound as if they were recorded nowhere. These anechoic sound files can then be manipulated by the algorithms to determine how one would hear that sound if it were played or performed from the locations determined in the three-dimensional model. DESIGN This technology can be incorporated into the design process. Different room shapes and finishes can be explored to determine how different alternatives will sound. If a client is having trouble deciding between different physical layouts of a room, the auralizations may help them decide based on how they want their finished facility to sound. An advanced version of software able to accomplish this task would also be able to recommend finishes and detect possible problems with the acoustic design and be able to calculate nois e transfer through walls and mechanical systems. All of these would be extremely beneficial to the design of a structure, since they are not evident through any traditional graphic methods. 36

41 This technology was used to determine the success and the variability of the adaptability in the design of a performance space for the program and site described in the next two sections. Incorporating adjustments to a space that correlate to the six aspects of sound stated earlier and a feedback system to listen to th e performance will allow the performance space to adapt itself to meet the needs and goals of the performances. 37

42 SECTION 2 BUILDINGS PROGRAM CHAPTER SEVEN The building type chosen to best portray the th esis idea is a multi -purpose music venue. It is designed with a seating capacity of five hundred fifty people. The hall can be configured to support a range of performances, from a soloist to a medium-sized chamber orchestra to a contemporary rock band. The seats are fixed within the hall, and are one of the few unmoving parts of the project. The hall is the main public space within the building. A large entrance lobby and gathering space opens to the ticket booth, coat check room, a merchandise store, and a refreshment center. Backstage is a green room off the stage and storage for materials, equipment, and props used on the stage. A loading dock serves the storage space and the stage for quick and easy access and removal of equipment for performances. Dressing rooms are near the green room. Several offices serve the manager and assistants. The building also houses rehearsal rooms that can be rented out. Twelve rehearsal spaces range in size from individual practice rooms to large group rehearsal rooms. A separate office and lock -up storage are located near these rooms to serve this part of the facility. The rehearsal rooms can be used at any time of the day, possibly even during a performance in the main hall. A parking structure is required to fulfill the appropriate number of parking spots for the facility. The structure is simply laid out and allow for easy access 38

43 into the lobby. A specific area will aid in traffic flow for drop-off and pick-u p of people in the front of the building. The audiences that attend performances in this facility will vary with the specific artists performing. They will mostly be from the immediate suburban vicinity, but may draw crowds from much further away depending on the popularity of touring artists. The main hall will be used almost every day of the week, with local artists and groups performing during the week and more popular acts scheduled on the weekends. It is easily possible for the facility to handle multiple performances in a day, as long as adequate time is left in between them for the changing of the crowds and cars to occur. The rehearsal rooms will be used by local musicians and teachers. The larger rooms are perfect for different groups to meet and rehearse together. The groups will range from neighborhood choirs, instrumental ensembles, to teenage rock groups. The smaller rooms will be used by private lesson teachers as a space outside of the home to promote professionalism. Pianos are available in many of the rooms for use by whoever is renting the space at the time. Alth ough the facility is run as a private venue, a major goal is to promote local performances in any and all types of music styles and fashions. The hall has a very open policy for being able to perform there. 39

44 SQUARE FOOTAGE REQUI REMENTS Hall Stage 500 sf Seating (550 people) 6500 sf Control Booth 150 sf L o b b y Gathering Space 2500 sf Ticket Booth 250 sf Coat Check 250 sf Refreshments 800 sf Merchandise 800 sf Restrooms (4 x 250) 1000 sf Backstage Loading Dock 800 sf Green Room 400 s f Dressing Rooms (4 x 100) 400 sf Storage 500 sf Administrative Offices (4 x 200) 800 sf Rehearsal Spaces (12) 2500 sf Storage/Lock-up (2 x 250) 500 sf Mechanical (15%) 2800 sf Circulation (10%) 1900 sf TOTAL INTERIOR SPACE ~23000 sf 40

45 Exterior Gathering Space sf Parking (200 spaces) ~58000 sf SPACE DESCRIPTIONS Hall The main hall is the centerpiece of the facility, the focus of the design, both inside and in the exterior massing. Here the performers meet with the audience visually and acoustically; its importance depends not just with how it sounds, but how it performs as a social setting. The seating wraps around a stage that is not set behind a proscenium, but is pushed into the same volume as the audience. This locates the performers closer to the audience. The patrons in the balcony do not feel isolated from the people on the lower level; they just get a different view of the action. The control booth toward the back on the main floor is used to fine-tune the room manually and a djust the electro-acoustic levels. L o b b y The lobby space is the central hub. It collects the patrons entering from outside and directs them to the many different places they can visit. Immediately inside the doors are the ticket booth and the coat check rooms, situated so that way-finding is never a problem. Off the lobby is a refreshment center, designed to accommodate a large group of people in the short time periods during intermission and the milling about before and after the show. A small store sells merchandise related to the facility and its recent and upcoming performances. These two spaces are locked during the time between performances. The lobby will also have easily identifiable restroom entrances, as well as a staircase and elevator leadi ng up to the balcony level, where there are restrooms. 41

46 Backstage The loading dock is easily accessible to vehicles to load or unload supplies, equipment, instruments, and props to the stage and hall area. Supplies for the refreshment and merchandise areas are delivered through the lobby space. The loading dock has a lockable storage area. The dock and storage room are located directly off the stage, and will only be occupied by employees and performers. The green room is a lounge where the performers rel ax before and after shows. It needs to be large enough to accommodate all of the members of a medium-sized chamber orchestra (thirty people) comfortably, but also not feel too big for smaller groups. The green room is also connected to the stage area, a nd is connected via a hallway to four dressing rooms. These small spaces give the performers more privacy than the green room. The facility will employ eight to ten technical support staff members that keep the hall, lobby, and backstage running smoothly. These positions will include vendors for the lobby, janitorial staff for the entire building, and stage controllers that will keep each performance moving smoothly. There will also be four employees that operate the adaptable acoustic systems throughout the building. There will usually be at least one present for each performance and one in charge of the rehearsal spaces. Administrative There are four to six administrative staff members that run the business aspect of the facility. Four offices are designed to house the staff and employees of the facility. A conference room allows the staff to hold meetings and to meet with performers and their agents. Twelve rehearsal rooms vary in size from 75 square feet up to 700 square feet. They are often rented for private lessons by independent music teachers or as rehearsal space for local groups. Each rehearsal room is sound-proofed and has a piano in it. The larger rooms have independent public address (amplification) systems. A separate office controls and oversees the renting and maintenance of the rehearsal rooms. Two 42

47 storage and lock-up areas store equipment for those rooms. The rehearsal rooms are accessible through the main lobby area, and also through a side entrance, in case a performance is occurring in the main hall. There are plans for future development of a recording studio to be placed near this area. Exterior A gathering space is located outside the main entrance. This gives the patrons a place to congregate before and after performances when the weather is pleasant. The gathering space is visually connected to the lobby, and in close proximity to the parking area. A drive connects the parking lot with the loading dock. A parking structure is necessary to accommodate the required number of parking spots. The entire site is carefully designed to allow good transitions between the different aspects of the facility. The connections between the parking, drives, drop-offs, and outdoor gathering space need to be laid out cautiously with care given to the safety of pedestrians amid a circle of cars. 43

48 CHAPTER EIGHT The history of acoustics is s e t i n two categories: the history of the science, and the development of building typology. Written r ecords begin with Aristotle referring to the nature of sound around 360 BC, and Vitruvius stating some acoustical concepts for outdoor theatres around 25 BC. In the eighteenth century, mathematicians began uncovering the mathematical intricacies. T w o key figures, Lord Rayleigh and Wallace Sabine, are considered the founders of the modern acoustic science in the late 1800s and early 1900s. Sabine noted that room acoustics have so powerful an effect on the perception of music that the acoustics o f dwellings and worship spaces have fundamentally influenced the type of music that developed in different parts of the world. Regional music tended toward either predominantly rhythmic or melodic depending on whether the people were historically housed or unhoused, dwelling in reed huts or in tents, in houses of wood or stone, in houses and temples high vaulted or low roofed, of heavy furnishings or light. 32 As music developed through thousands of years, if a habitation was a stone structure, the acousti c s enhanced vocal and instrumental melodies by creating reverberation and echoes that could be heard by a performer. In a grass hut, sounds are either absorbed or allowed to escape to outside, making the spaces acoustically ideal for percussive performanc es. Music created today can fit into any genre, style, or type because we have the ability to manipulate how it will sound in a recording studio. 32 Wallace Clement Sabine, Collected Papers on Acoustics, Harvard University Press, 1922, reprinted Dover, New York, 1964, p

49 Some of the earliest spaces designed specifically with acoustics in mind were ancient Greek and Roman theatres. The Greek theatres had semi-circular or semi-elliptical plans and raked seating surrounding a small stage (see fig. 1.) The goal of the space was to keep the audience close enough to discern the actor s facial expressions and keep the dialogue audible. The Romans built more ambitious projects with a steeper seating rake on a masonry base, rather than in a hillside. They also pioneered a masonry backdrop called the scena, behind the stage to help direct the sound towards the audience. 33 They also developed the fully elliptical amphitheatre, which never exceeded the size that allowed speech to be intelligible. They recognized the importance of the acoustics within the space and placed clay jars in the seating areas that were tuned to the correct frequencies to enhance the voices from the stage. plan for an ancient Greek theatre Peter Lord and Duncan Templeton, The Architecture of Sound, The Architectural Press, 1986, London, p.7 34 Peter Lord and Duncan Templeton, The Architecture of Sound, The Architectural Press, 1986, London, p.7 45

50 The Middle Ages brought a very close relationship between the music being developed and the Gothic cathedrals being constructed. Bo t h the music and the architecture meant to be expressions of the medieval concept of cosmic order, which was ordered by the whole-number Pythagorean ratios, or musical consonances. This system led the cathedrals to emphasize certain tones and give acoustic harmony to the liturgical plainsong melody through its own reverberation. section through a gothic cathedral 35 These acoustics begot a special tradition of organ music, incantation, and recital. The different types of worship spaces that developed throughout the world directly guided the direction of music development within that region Peter Lord and Duncan Templeton, The Architecture of Sound, The Architectural Press, 1986, London, p Peter Lord and Duncan Templeton, The Architecture of Sound, The Architectural Press, 1986, London, p.8 46

51 The Renaissance brought about the development of the opera and the opera house. The classical amphitheatre gained a roof and the baroque horseshoeshaped opera house developed. The arc of raked seating elongated into a U, and evolved into a wall of boxes to contain the sound. Since the interiors were filled with elaborate costumed patrons and performers, the furnishings were luxuriously upholstered, and the spatial volume was proportionally small relative to the number of people inside, the Italian opera houses became known for their clear, intimate acoustics. This, in turn, influenced the heavily ornamental baroque arias. 37 In the eighteenth century, both the music and the listening environments shifted from the very ornate and intricate to the more sweeping Romantic movement. It was at this time that the concert hall developed to accommodate music that was written for spaces with longer reverberations times and louder bass frequency response. The (now traditional) shoebox design is basically a large rectangular volume that allowed Romantic music to be heard as the composers desired Michael Forsyth, Buildings For Music, The MIT Press, 1985, reprinted 2002, Cambridge, Massachusetts, p.8 38 Michael Forsyth, Buildings For Music, The MIT Press, 1985, reprinted 2002, Cambridge, Massachusetts, p

52 plans and section through Boston Symphony Hall, a shoe -box concert hall Up until this point in history, the performance spaces were being designed and constructed without a sophisticated understanding of room acoustic principles. There was a general understanding of how sound traveled, but not how it acted within enclosed spaces. Only broad generalizations were offered by the physics experts. This changed when Sabine began investigating the experience of sound in rooms. His statistical discoveries began the modern science of acoustics. It is noteworthy that although Sabine conducted most all of his experiments with just an organ pipe, a stopwatch, and his ears, the 48

53 greatest gain in the science would be electronic measuring devices like microphones to help get past the subjective instrument of the ear. 39 The design of performance buildings is still largely based on precedent. Many of the great buildings throughout history are known because they were the g o o d-sounding ones. Their forms and properties were copied and manipulated as new structures were built. In modern times, the reverberation time and a few other factors can be roughly predicted using architectural drawings and applying the discoveries of the past century. But many of our recent facilities still need remedial tuning after construction is finished. Even though our scientific knowledge allows acoustical design for a particular u s e and occupancy, this is often not economically viable because the facility would not get the fullest possible use. Multi -use buildings often encounter acoustic problems by not addressing all of the requirements of all of the uses. It is interesting to follow the evolution of performance spaces throughout history to see the development of the shapes, form, and materials. Even though architectural fashion changes, there are always many examples to consider for new designs. Since some of the understanding of acoustics is based on precedent studies, part of the problem acoustic design has for the future is to predict new functions, situations, and noise sources that defy precedent. 39 Michael Forsyth, Buildings For Music, The MIT Press, 1985, reprinted 2002, Cambridge, Massachusetts, p

54 CHAPTER NINE Since the thesis concept is adaptable acoustics, it directly influences the building program. The design project is of a multi-purpose music performance facility. This combines different elements of previous designs, but I have found none so far that have exactly the same program details I have proposed. I will identify several precedent buildings that have similar programs. ~500 SEAT RECITAL HAL L Faculty of Music Concert Hall, Cambridge, United Kingdom by Sir Leslie Martin, Colen Lumley, and Ivor Richards. The facility is used for teaching, music rehearsal, and public performance, for groups ranging from soloists to full orchestra and choir. The concert hall can seat either 439 or 499 people, depending on whether or not the stage extension or orchestra pit is in use. The stage is 57-0 w i d e by 28-6 deep. The stage extension makes it 37-4 deep, while the orchestra pit makes it 22-3 deep. A rectangular curtain track allows a heavy curtain to be used both across the rear stage wall or brought forward to act as a stage curtain. Alternatively, it can be bunched behind movable triangular towers. There are also rotating panels over the stage that can act as acoustic reflectors for music performances or placed vertically to allow for stage lighting or scenery hanging. 50

55 plan and section through the Faculty of Music Concert Hall - Cambridge, UK The form of the hall is basically rectangular in plan. The cross-section includes a partly-gabled soffit. Both features are considered acoustically beneficial for this size of a performance facility. Surfaces are generally hard and sound reflective, except for the curtain and the gallery sides, which are of timber paneling. The major elements of acoustic significance in this hall are the overall volume of the space, and the nature of the ceiling spa c e, w i t h i t s ducting and structural elements creating a good diffuse sound field Michael Barron, Auditorium Acoustics and Architectural Design, E & FN Spon, 1993, London, p

56 ADJUSTABLE CONCERT HALL / THEATRE Jesse H. Jones Hall for the Performing Arts, Houston Texas by Caudill, Rowlett, and Scott, with Bolt, Beranek, and Newman and George C. Izenour as acoustic consultants. sections through the Jesse H. Jones Concert Hall - Houston, Texas The theater ceiling is a network of 800 movable hexagons. These hexagons, or pods, can be adjusted to fine-tune the acoustics to match the type and size of the show. The pods can also be lowered so that the balcony is completely closed. This design -- created by noted theater physicist George Izenour -- was the first of its kind and remains an engineering marvel today. The auditorium can also literally shrink from 3000 seats to 1800 seats based on the 52

57 configuration of the ceiling pods. The walls are lined with teak paneling, and the seats are upholstered with red velvet. 41 CONTEMPORARY MUSIC / ELECTRO-ACOUSTIC SETUP Musictech College Concert Hall, St. Paul, Minnesota by? View from the mixing console at the Musictech College Concert Hall This 300-seat concert hall is designed as a classroom for the students to work in. It is home to several important classes, including regular weekly concerts, student performances, seminars, and touring artist performances. In has a top-of-the-line 20,000 watt electro-acoustic sound system that could be used for a system four times the size. The over-design allows the system to be run at reasonable levels with an astounding level of clarity and precision. OPERA HOUSE LOBBY Paris Opera House (1874) Paris, France 41 Michael Forsyth, Buildings For Music, The MIT Press, 1985, reprinted 2002, Cambridge, Massachusetts, p

58 View across the grand staircase in the Paris Opera House Gar diniére lobby The Paris Opera House is one of the most famous opera houses in the world. It is renowned for both its acoustics and for its lavish architectural design. The lobby of the huge cultural facility is just as amazing as the hall itself. It is meticulously detailed and ornate, expressing its cultural significance. The lobby expresses the grandeur of the space, and greets the visitor with an air of aristocracy to possible in different circumstances. This air is part of the experience of attending a performance at the opera. It is an occasion where the audience is as dressed up as the performers, and is a s much as social activity in the lobby as the performance is an entertainment activity in the hall. 54

59 SECTION 3 - SITE CHAPTER TEN The site for the building project is a flat, 150,000 square foot corner lot in the city of Fairfield, Ohio. Fairfield is a suburb of Cincinnati, at the northern tip of the I -275 loop. It is locally known for Jungle Jim s International Food Market, and the plethora of car dealerships along State Route 4 that runs through the city. The city has approximately 43,000 residents over 20.5 square miles. Regional map of southwestern Ohio showing the location of the City of Fairfield 55

60 Over the past few years, the city has been building up a town center area of commercial, residential, and municipal buildings. The site is surrounded by a firehouse, some small offices, a large Catholic church, and a retirement community building. It is near the new library, the Village Green Park, and the new commercial development. There is also a new Community Arts facility being constructed that will house classrooms, studios, and a very small theatre for children s plays. The selected lot is owned by the city of Hamilton for access to their underground well system, and this project assumes purchasing the property from them. I t is ideally situated in the center of the city, near other community-oriented structures, and the city s public school system has a very strong music and arts program. QUICK FACTS ABOUT THE CITY OF FAIRFIELD Demographically, the city of Fairfield is 93% White, 5% Black, 1% Asian, and 1% other. The population is 51.5% female, and 48.5% male. The average age is 35 years old. 85% of the population resides in a family household, 13% resides without a family, and 2% live in group quarters. The average household income is about $62,000 / year (18% higher than Ohio), and the per capita income is about $25,000 (20% higher than Ohio). The unemployment rate is 2.7% (Ohio s is 4.2%). Only 3% of the households do not own a vehicle. 30% own 1 vehicle, 49 % own 2 vehicles, and 18% own 3+ vehicles. 87% of the workforce drives alone to work. 9% carpool, 1% walk, and 2% work at home. The average travel time to work is about 21 minutes (same as Ohio and US a v e r a g e s ). 56

61 The median property value is about $86,000 (Ohio s is $63,000). The average rental unit is $438 / month (Ohio s is $296). In 1992, only 3% of the structures in the city were built before 1950 (Ohio has 35%). 11% during 1950s, 12% during 1960s, 38% during 1970s, 32% during 1980s, and 6% since The city is predominantly upper -middle class white baby-boomers with a family. They use their vehicles for almost all of their transportation. The city s building boom stopped in the mid-1980s, and most new construction within the city is in the form of developer-based residences. The city of Fairfield was first incorporated as a village in 1954, and officially became a city on October 20, Prior to 1955, it had been sparsely populated by settlers and farmers since the late 1700s. In 1979, the citizens voted and approved a council -manager form of government. 57

62 CHAPTER ELEVEN The chosen site is a nearly flat corner site 372 x 405. It is situated in the Village Green city center development area in the city of Fairfield, Ohio. CLIMATE Th e temperature fluctuates from an average low of 21ºF in January (record of -25ºF) to an average high of 86ºF in July (record of 103ºF). The average dew point is 22ºF in January and 64ºF in July. The average rainfall is in between 3 and 4 inches per month for a yearly average of 40.6 inches. NATURAL AREA Fairfield is situated in the Miami Valley, between the Great Miami River and the Little Miami River. This creates a very plentiful and rich underground water supply. The area usually withstands several s evere thunderstorms each year, but little else. It is in an area where tornadoes are a possibility, but are so rare that there are no building codes or restrictions that acknowledge them. BUILT CONTEXT There are very few architecturally important buildings in the city of Fairfield. Practically all of the non-residential buildings are located behind large parking lots. Off-street parking is a signature of the suburban city. Buildings around the site have more than adequate parking. 58

63 Figure - Ground diagram of the downtown area of the City of Fairfield This building site is located near the middle of the city close to several municipal building structures. To the west of the site is an interesting fire house built in It is built in the same general style as the church addition also added in 1989 to the Catholic Church across Nilles Road to the north. They both have large sloped roofs and are angled 45º to the street in plan. The church was added to an existing church and school complex built in a n d 1963, respectively. They are both two-story brick and stone structures. The church has the largest congregation in the city (several thousand parishioners attend Mass every weekend), and the school is a private K -8. To the east, across Wessel Drive is a brown single story office strip built in This 59

64 houses small professional businesses; dentist, chiropractor, real estate service, etc. To the south is the new Village Green development area. The lot directly adjacent has a two-story retirement community structure built in It is a sprawling building made of brick with a surprisingly small parking lot that encircles the exterior. Further south along Wessel Drive is the newly constructed library, the Village Green Park, a Community Arts Center under construction, a Kroger s grocery superstore, and two newer strips of small businesses. The library is a towering structure finished in Although the floor plan is only one story, the exterior is a forty-foot tall dark brick façade wit h a clock tower and sloped roofs. The Village Green Park is mostly hardscaped with a set of terraces, benches, fountains, and sundials. There is a grassy area in front of an outdoor, covered performance stage. Single family residences surround these facilities on the southwest side. For three years since the park was built, the city has filled it with concerts, art fairs, movies, and similar events. The commercial strips are designed in the same style as the library, with tall brick facades and sloped shingled roofs. There are businesses such as jewelers, fitness stores, hair dressers, and electronics firms. Kroger s moved their Fairfield location into the Village Green area in It is one of the busiest places in the area, attracting people from most of the city for their usual grocery shopping. Fairfield Lane Public Library - Main Branch 60

65 Fairfield Fire Department - Nilles Road Station Fairfield Village Green Park (water drained from pool for winter months) Sacred Heart Catholic Church and Elementary School 61

66 Shopping strip along Wessel Drive Along Nilles Road, tall poles carry the electric and communication lines. On Wessel, those lines get buried in the easement along the street. The transition from suspended to underground happens in the project site. Currently, the City of Hamilton uses the site as maintenance access to the underground wells. A metal box, approximately 6 x 10 and 8 tall, is placed on the site for that purpose. I may presuppose that my project buys out the c ity and they no longer have access here, or I can relocate their access building, and assume that logistically things will still function. LEGAL A 25-f o o t front yard setback is required, which applies to both streets that the site fronts. At least five feet is required between the sidewalk and the parking lot. The maximum height for a building is three stories or 35 feet, a l t h o u g h that requirement may be extended one foot for every one foot increased in yard setbacks, up to 10 stories or 110 feet. Only one curb cut is allowed, not to exceed 35 feet in width. Wessel Drive has a median in the road, so any access drive connecting to Wessel will be right-hand-in and right-hand-out only. Because the site is in the downtown district, any building design will also be 62

67 reviewed by the architectural review board. This district has a set of codes and regulations about the materials and design of the structure. ECONOMIC This building project assumes a patron who wishes to build a facility and plans to own and opera te it themselves. A mid-sized music performance facility can easily be a multi-million dollar project. 63

68 CHAPTER TWELVE SUBURBAN CORNER SITE Alvar Aalto Architect s Studio, , Munkkiniemi, Helsinki Basic plan of Aalto's Architectural Studio - Munkkiniemi, Helsinki Located on a gracefully curving street, the lot is shaped like a blunted fan, with its narrow end facing inward. The formal concept of the studio reiterates one of Aalto's favorite motifs, the "L" configuration, with its play on both the 64

69 vernacular farm typology and the modern, De Stijl/cubist aesthetic. The longer leg of the "L" lies perpendicular to the street; it contains the service floor and entry, and the studio above. The shorter leg houses Aalto's meeting and work room, and runs parallel to the street, shielded from it by an enclosed garden. The "L" opens to the southwest but at slightly less than a ninety- degree angle, so that the perimeter walls can follow the setback requirements of the local zoning code. The building is shaped into a complex form due to solar orientation, the flowing pattern of the street, and the irregularity of the plot. 42 INTEGRATION INTO SUBURBAN LANDSCAPE LSA Design Inc., Burnsville Transit Station, , Burnsville Minnesota Photo of Burnsville Transit Station exterior façade The Minnesota Valley Transit Authority (MVTA) decided to build a fully integrated mixed-use transit facility, which was one of the first of its kind in 42 Michael Trencher, The Alvar Aalto Guide, Princeton Architectural Press, 1996, New York 65

70 the state of Minnesota. By utilizing the land surrounding the station for transit compatible private development, revenues from retail/commercial/housing land sales as well as shared parking leases can be used to operate and maintain the transit facility. The transit hub building provides heated/cooled shelter f or transit riders as well as office space for MVTA and Dakota County Service Center. Goals of the site design included facilitation of pedestrian circulation as well as minimizing walking distance from parking to the transit facility. Phase II includes a daycare facility and 150 units of market rate housing. SUBURBAN DOWNTOWN DEVELOPMENT RTKL, Bowie Town Center, , Bowie, Maryland Photo of Bowie Town Center while under construction 66