Architectural Acoustic Design Research Articles

Acoustics in the partial deaf student school music classrooms

Music schools need some special acoustical design for good education. If this is also for children with disabilities, the effect is more important. Research is about musical education for partially hearing disabled children. At this point architectural acoustic design acquires importance. This is not only in the shape of the room but also in using covering materials and other solutions. The question is whether architectural acoustics solutions can affect the music education of partially hearing disabled children or not. Here the first discussion is whether we need some additional components of good classrom acoustics for partially hearing disabled children in the American National Standards Institute Standard S12.60 2002 for clasroom acoustics, and the cost impact of the Standard. Childhood hearing loss is a widespread problem with significant impact, an invisible condition resulting in communication problems that can ultimately interfere with learning and social development. Included are audio files that illustrate that even a mild hearing loss can have a significant impact on a child's ability to understand the teacher. Especially children with a partial hearing loss need a more lively room to amplify the instrument sound for improved hearing capacity.

Architectural Acoustic Design by Means of Computer Modeling Techniques

Architectural Acoustic Design by Means of Computer Modeling Techniques

A design of virtual sound field simulator based on acoustic ray tracing and wall impedance

The sound propagation analysis using an architectural scale model is an effective approach for architectural acoustic design of a concert hall, and so on. However, the scale model must be reconstructed together, changing the basic plan of the architectural design. To cope with this problem, an architectural sound field has been virtually designed on the computer by the sound field simulator in recent years. The acoustic ray tracing is one of the simulators based on geometric acoustics. It is an efficient solution from the viewpoints of simulation cost and time. However, it cannot simulate the wall materials, because it employs the delta function as the wall impedance. To overcome this problem, in this paper, we try to design the virtual sound field simulator based on acoustic ray tracing and wall impedance acquired by real measurements. We first measured the reflection characteristics of the wall with impulse response to acquire the wall impedance. Then, we designed the virtual sound field simulator by convoluting the acoustic rays with measured wall impedances. As a result of subjective evaluation experiments, the proposed simulator could realize a more realistic sound field than the conventional acoustic ray tracing. [Work supported by MEXT of Japan.]

New developments in speech privacy design

The design of architectural spaces for the purpose of speech privacy attainment has been quietly practiced over many years. In the late 1960s and 70s, with the introduction of open‐plan office layouts, the need for speech privacy became an issue of productivity, as well as one of confidentiality. Today, with the introduction of government regulations such as HIPAA, the need for confidential speech privacy in the healthcare industry has hit the mainstream of our consciousness, even as individuals. And, in this day of (in)security the issues of espionage and terrorism have implications for architectural acoustic design of spaces for speech security. This paper considers both the architectural design trends and issues, and the measurement and evaluation methods being developed in response to these needs for speech privacy, as we move boldly forward into the next 50 years.

From Architectural Acoustics to Acoustical Architecture Using Computer Simulation

Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in architectural acoustics and the emergence of room acoustic simulation programmes with considerable potential, it is now possible to subjectively analyse and evaluate acoustic properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to investigate the field of application that an acoustic simulation programme can have during an architectural acoustic design process and to set up a strategy to develop future programmes. The emphasis is put on the first three out of four phases in the working process of the architect and a case study is carried out in which each phase is represented by typical results – as exemplified with reference to the design of Bagsvaerd Church by Jørn Utzon. The paper discusses the advantages and disadvantages of the programme in each phase compared to the works of architects not using acoustic simulation programmes. The conclusion of the paper points towards the need to apply the acoustic simulation programmes to the first phases in the architectural process and set out a reverse strategy for simulation programmes to do so – from developing acoustics from given spaces to developing spaces from given acoustics.

Issues for computer modelling of room acoustics in non-concert hall settings

The basic principle of common room acoustics computer models is the energy-based geometrical room acoustics theory. The energy-based calculation relies on the averaging effect provided when there are many reflections from many different directions, which is well suited for large concert halls at medium and high frequencies. In recent years computer modelling has become an established tool in architectural acoustics design thanks to the advance in computing power and improved understanding of the modelling accuracy. However concert hall is only one of many types of built environments that require good acoustic design. Increasingly computer models are being sought for non-concert hall applications, such as in small rooms at low frequencies, flat rooms in workplace surroundings, and long enclosures such as underground stations. In these built environments the design issues are substantially difference from that of concert halls and in most cases the common room acoustics models will needed to be modified or totally re-formulated in order to deal with these new issues. This paper looks at some examples of these issues. In workplace environments we look at the issues of directional propagation and volume scattering by furniture and equipment instead of the surface scattering that is common assumed in concert hall models. In small rooms we look at the requirement of using wave models, such as boundary element models, or introducing phase information into geometrical room acoustics models to determine wave behaviours. Of particular interest is the ability of the wave models to provide phase information that is important not only for room modes but for the construction of impulse response for auralisation. Some simulated results using different modelling techniques will be presented to illustrate the problems and potential solutions.

Teaching architectural acoustics to students of engineering versus students of architecture

The author currently teaches architectural acoustics at the University of Nebraska to students in the College of Engineering and to students in the College of Architecture. These two groups have different backgrounds and focuses: for example, engineers are more mathematically prepared, while architects are more visually oriented. However, the instructor’s goals for the members of both groups are similar, namely that they (1) master the fundamentals of good architectural acoustic design and (2) learn to respect and communicate well with each other during the design process, leading to more successful projects. This presentation will demonstrate the similarities and differences in the methods that are used by the author to address these two groups.

Shape optimization: Good looks and acoustics too!

One of the challenges in the architectural acoustic design of museums and other public spaces is to develop contemporary scattering surfaces that complement contemporary architecture in the way that statuary, coffered ceilings, columns, and relief ornamentation complemented classic architecture. Often acoustic surfaces satisfy the acoustics, but may or may not satisfy the aesthetics. One approach that has been successful employs a combination of boundary element and multidimensional optimization techniques. The architect supplies the desired shape motif and the acoustician supplies the acoustical performance requirements. The optimization program then provides an Arcousthetic surface, which simultaneously satisfies the architecture, the acoustics, and the aesthetics. The program can be used with diffusive or diffsorptive surfaces. Photos of installations using these acoustic tools and a description of the design of the National Museum of the American Indian will also be presented to illustrate the usefulness of these devices and their impact on architectural acoustics.

Case studies of computer model applications in consulting practice

Six case studies of computer model applications in a consulting practice will be presented to present the range of issues that can be studied with computer models as well as to understand the limitations of the technique at the present time. Case studies of elliptical conference rooms demonstrate basic acoustic ray principles and suggest remediation strategies. Models of a large themed entertainment venue with multiple amplified sound sources show how visualization of the acoustic ray paths can assist a consultant and client in value engineering locations and amounts of acoustic materials. The acoustic problems with an angled ceiling and large rear wall were studied when an historic church was converted to a music performance hall. The computer model of an historic hall did not present enough detailed information and was supplemented with physical model studies and full size mock-up tests of the insertion of an elevator door that would open directly into the concert room. Studies to demonstrate the amount of room model detail to obtain realistic auralizations were also conducted. The integration of architectural acoustic design and audio system design were studied in computer models of a large church sanctuary.

Blending architectural and acoustic factors in designing an event hall

In order to synthesize both architectural design and acoustic design consisting of temporal and spatial design, a design process in which these elements are all considered is proposed in this study. Using this design process, a multi-purpose event hall, which is part of a larger architectural complex, was designed. This hall was measured for both temporal and spatial orthogonal factors after construction, with favorable results. One goal of this study was to solve the acoustic problems caused by the rounded shape of the event hall, where the architectural design had already been determined by the theme and concept of the complex. In a worst-case scenario, had the acoustic problems been solved without unduly affecting the architecture of the hall, the process would have been considered to be successful. Remarkably, some knowledge about methods to solve acoustic problems caused by the round shaped architecture was obtained through the design process blending architectural and acoustic factors. Thesis advisor: Yoichi Ando Copies of this thesis written in English can be obtained Akio Takatsu, Showa Sekkei Co., 1-2-1-800 Benten, Minato-ku, Osaka 552-0007, Japan.

Electronic architecture: Historical perspectives, current thinking, and future implications for architectural acoustic design

Few subjects in acoustics generate more controversy than electronic architecture, that is, the use of electronic tools to alter the acoustics of a performance space, church, rehearsal hall, or other facility. And yet, few advances in acoustics offer the promise of electronic architecture. This paper will trace the development of electronic architecture from the first tentative and highly creative experiments in the 1930s to the mature technologies that have evolved in recent years. What precipitated the development of electronic architecture? Who were the pioneers? How did the technology develop? And where do we stand today? Paralleling these technological advances has been an on-going philosophical debate. Is there ever a place for electronics in the concert hall or opera house? When and where should these systems be used? What obligations do acoustical design professionals have to performers? To the concert-going public? To the art of acoustical design? Finally, what does the continuing evolution of these techniques hold for the future of architectural acoustic design?

ON THE ACOUSTIC ABSORPTION OF POROUS MATERIALS WITH DIFFERENT SURFACE SHAPES AND PERFORATED PLATES

In architectural acoustic design, perforated plates are often used to protect porous materials from erosion. Although porous materials are usually applied to passive noise control, the effects of their surface shapes are seldom studied. To study the acoustic absorption of porous materials with different surface shapes and perforated plates, an efficient finite element procedure, which is derived by the Galerkin residual method and Helmholtz wave propagation equation, is used in this work. The two-microphone transfer function method and the modified Ingard and Dear impedance tube testing system are employed to measure the parameters deemed necessary for the finite element analysis, such as complex wave propagation constant, characteristic impedance and flow resistivity. For verifying the finite element results, the two-microphone transfer function method is also applied to measure the absorption coefficients of the discussed acoustic absorbers. Four surface shapes of commercially available porous materials, i.e., triangle, semicircle, convex rectangle and plate shapes, are chosen for analysis. The porosity of perforated plates is then evaluated. Finally, the distinct effect of the flow resistivity of porous materials on the acoustic absorption is demonstrated.

Optimal classroom design applied in the OSU Fisher School of Business Graduate Studies Gerlach Hall

On endowing the recent expansion of the Ohio State University College of Business, Max M. Fisher said that his interest was not in buildings; they did not excite him. Rather, his interest was in value-added programs to improve the product, education in this case. We followed this philosophy in the architectural acoustics design. The graduate studies program included many classrooms of 40 to 100 seat capacity, as well as stock market and communications laboratories. The classrooms were to include distance learning that required teleconferencing capability. To these ends, all classrooms were designed for NC-25 background noise and [1+log(V)]/10 reverberation time. Measurements of the background noise of three classrooms and the reverberation time of one classroom are presented. In October 1998 associate professor David Greenberger remarked ‘‘The acoustics are awesome. Anyone can hear you if you talk in a soft voice. That’s great for faculty.’’

Classroom acoustics III: Acoustical model studies of elementary school classrooms

A 1:4 scale model was constructed with a series of interchangeable wall and ceiling panels to allow a battery of acoustical tests to be conducted for a variety of classroom designs. The walls and ceiling of the room could be changed from sound absorbent to sound reflective materials quickly. Scale furniture was also constructed for the room. The walls of the model could be adjusted from approximately 7 to 10 meters in length and from 2.5 m in height to 7 m in height. Acoustical measurements of speech transmission index, reverberation time, early reverberation time, early-to-late energy ratios, loudness (or relative strength), and articulation index were made in a number of simulated elementary school classrooms using both a TEF analyzer and impulse spark techniques. Classrooms where field measurements were taken as described in Classroom Acoustics II were modified to attempt to improve acoustical conditions in the rooms. The location and amount of absorbent material, the location and amount of sound reflective material, and the room volume were the major variables considered. In general rooms that followed good architectural acoustics design principles produced favorable acoustical measurements.

Alternate venues for opera performances. Wagner started it...should we retreat now?

Although there has been a resurgence of interest in opera over the last 15 years in America the current outlook for continued financial support for this form of musical theater as well as classic concerts is bleak. At one time opera was enjoyed by the unwashed as well as sophisticates and a number of today’s creative opera directors are trying to appeal to a broader segment of the market. This paper will discuss the break with tradition that Richard Wagner and Adolph Appia succeeded in achieving at Bayreuth in terms of architectural acoustic design and how these changes were integrated with new approaches to scenic design and stage lighting. In addition, examples of contemporary opera companies that are creating a more intimate and emotionally powerful experience for their audiences by breaking out of the picture-frame productions of proscenium theater are given. Among these companies are the Colorado Opera and the Opera Theatre of Saint Louis.

Acoustical design of the National Center for the Performing Arts of Perú.

This project is based in the design of a cultural complex for the National Center for the Performing Arts, which includes a 1200-seat opera house, a 750-seat concert hall, a small auditorium for master classes, and an amphitheatre for 1500 locations. The interest in this project came from the lack of cultural facilities in Perú. Furthermore, it established a methodological alternative for the architectural acoustic design, so the Center is consequently of the integrity of a two-design process in only one: architectural and acoustical design. The site for the project was determined from the evaluation of several possibilities through analysis of successive approximations. The analysis includes the urban acoustical study of the metropolitan area of Lima. The final decision about the site was made using acoustical measurements of urban noise. The acoustical design of the auditoria includes ray-diagram analysis, reverberation time, early decay time calculation, and final sound level in some positions.

Acoustical design of the National Center for the Performing Arts of Peru

The project is based on the design of a cultural complex for the National Center for the Performing Arts which includes a 1200-seat opera house, a 750-seat concert hall, a small auditorium for master classes, and an amphitheatre for 1500. The interest in this project came from the lack of cultural facilities in Peru. Furthermore, it is an established methodological alternative to the architectural acoustic design; so the Center is the result of the integrity of a two-design process combined into one architectural and acoustical design. The site for the project was determined from the evaluation of several possibilities through analysis of successive approximations. The analysis includes the urban acoustical study of the metropolitan area of Lima. The final decision about the site was done through acoustical measurements of urban noise. The acoustical design of the auditoria includes ray-diagram analysis, reverberation time, early decay time calculation, and final sound level in some positions.

Teaching architectural acoustics by clarifying goals and demonstrating sound behavior

There are three separate, often conflicting goals in architectural acoustic design: (1) good sound distribution in rooms designed for hearing; (2) sound isolation; and (3) noise reduction within spaces. Architects often seem to confuse these goals and the means of achieving them. For example, they often tend to “treat” all types of rooms with absorptive ceilings. A teaching method is described that aims at clarifying the goals by building a conceptual framework while demonstrating the physical nature of sound; i.e., waves that travel slowly. The consequences of wave behavior and slow speed are related to the goals by showing how each characteristic becomes an asset or liability for achieving each goal. To demonstrate wave behavior, a clear plastic tray containing about 3/8 in. of water is placed on a conventional overhead projector. The image of waves generated in the water, interacting with strips of modeling clay representing reflective surfaces are thus projected onto a wall screen. With this method, one may demonstrate diffraction, focusing, flutter, reverberation, resonance, transmission, etc., but not differential absorption or wavelength‐related effects. Live demonstration allows repetition and variation in response to student queries and class discussion, and vividly backs up theory.

The architectural acoustics design of Sherwood Hall, Salinas, California

This paper describes the architectural acoustics design of a recently completed multipurpose performing arts hall. The facility, known as Sherwood Hall, is part of the Salinas Community Center in Salinas, California (located approximately 100 miles south of San Francisco). In order of priority, the program requirements called first for a space to accommodate banquets, dances, and community activities, and then for a theater and music hall. The design response to these requirements yielded a space consisting of a platform-stage area with a fixed, flat main floor and a permanent balcony. Folding theater-type seats on movable risers stored under the balcony allow the flat floor to be converted to sloped audience seating. The most difficult challenge acoustically was to control reflected sound energy for speech-oriented events occurring on the flat floor and to encourage reflected sound from the stage to the audience for events in the theater/music configuration.