Acoustical Consultants Research Articles

The successful auditorium: Some acoustics and a lot of psychology

Remedial measures to a large, well-known concert hall produced acoustics that, the acoustical consultants believe, are as good as any in the world today. Performers, concert goers, and critics were unanimous in their expressions of delight during the first concert season. There were high hopes of it becoming one of the world's great auditoria. But, all is not well and opinions are changing even though the acoustic characteristics remain unchanged. The paper discusses the other factors involved in producing a successful auditorium and suggests reasons for the demise of this hall and for the popularity of some others in which the acoustics, to be polite, can only be described as “interesting.”

National Council of Acoustical Consultants announces 1979–1980 officers

National Council of Acoustical Consultants announces 1979–1980 officers

Consultants in acoustics

Consultants in acoustics

Electroacoustic systems in multipurpose auditoria in Japan

The function and the performance of electro‐acoustic system have a great effect on the multiple way of use of an auditorium. Up to several years ago, their plans and designs were mostly conducted under contractor's side. But as their scales grow larger, and have a significant influence upon the performance of an auditorium, there rises such recognition that the electroacoustic system should be planned and designed as a part of acoustic design of an auditorium. However, their designing system is not fixed yet, as compared with room acoustic design and noise control. Recently, a study group was made up by the cooperation of acoustic engineers, consultants, and contractors, and several studies have started on the standardization of the facilities, performance specifications, loudspeaker requirements, and test program, etc. This paper describes these studies and investigations as well as the plans and the performance of the electro‐acoustic systems in multi‐purpose auditoria in Japan.

Review of the roles of noise control and the environmental engineer in building services design

This paper discusses the recent changes in environmental standards and the associated rise in importance of the building services industry. The increasing responsibility that faces the engineer is discussed, along with future needs. The relationship that has existed between acoustics and noise control and systems design is discussed, including the evolution of acoustic consultants, their present importance and future developments in that field. The involvement of acoustics in future equipment design is discussed and some speculative developments for the future put forward.

Music building for a small liberal arts college

Lebanon Valley College, Annville, PA has had a strong music program for many years. Recently it felt the need for new facilities to complement the program. The new building was occupied in the fall of 1975. It contains a 400-seat recital hall, band room, organ-choral room, faculty offices and studios, classrooms, and individual and group practice rooms. The building was designed by Bogar and Bink, Lemoyne, PA. The acoustical consultant was engaged early in the planning process. This made possible a high degree of interaction between the architect and consultant throughout the planning, design, and construction process. This paper reviews the acoustical design considerations and solutions to the many room acoustics, sound isolation, and mechanical system noise control problems typical of a music building. Measured data on ambient noise and room-to-room noise reduction will be shown, in comparison with the design criteria. One unusual feature of the recital hall is the methodology of varying easily the hall reverberation time for small and large group performances. Measured reverberation times versus calculated will be shown.

Building acoustics in America, 1920–1940

The period following the pioneer work of W. C. Sabine was marked by widespread application of the basic principles of room acoustics and sound absorption to practical problems. Factors in this development were the building of laboratories for full scale acoustical testing of materials and structures, the extensive publication of textbooks, articles, and test data, the rapid growth of an acoustical materials industry, and the contributions to advancement and dissemination of the state of the art by acoustical consultants and laboratory directors. Important new developments during this period include the formulation of theory and practice for the measurement of sound transmission through walls and floors, the establishment of exact criteria for the intelligibility of speech in auditoriums, and the application of the concepts of acoustic impedance and normal modes to new theoretical models of the interaction of sound waves with room boundaries.

Acoustical considerations for structures with air-supported roofs

Air-supported roof systems for large facilities such as arenas and stadiums are relatively recent developments in the search for economical methods for enclosing such spaces. However, such roof systems provide acoustical problems relating to reverberation, focused reflections, exterior-to-interior noise reduction, and interior ambient noise levels as established by pressurizing blowers. This paper discussed these concerns with primary reference to the new Pontiac Metropolitan Stadium in Pontiac, MI, and the new Uni-Dome at the University of Northern Iowa, Cedar Falls, IO. For the Uni-Dome project, Ranger Farrell was the acoustical consultant.

Community noise study of a pet hospital

The proposed conversion of an existing commercial building into a veterinary hospital was met by stiff opposition from the adjacent homeowners. They feared that offensive noises and odors would emanate from the building. In this paper, the roles of the hospital owners, their lawyers, and acoustical consultants; the residents, their lawyers, and their acoustical consultants; and the planning commission and their representatives are discussed. Criteria used to evaluate the severity of the potential nuisance, measured ambient noise levels, and predicted interior noise levels are presented. The architectural modifications incorporated into the building to control noise are evaluated. Costs incurred by the owners and the residents are discussed.

Assisted resonance in the United States

The paper describes Assisted Resonance installations designed to provide variable reverberation time in two different types of situation. The first, in Concord, California, consists of a 3500-seat pavilion with a backstage wall, but with the other sides open. The acoustic consultant has designed this space to provide ideal acoustic conditions for a full range of activity from drama through to symphonic presentations. The second, in Scottsdale, Arizona, is a smaller enclosed space but once again it is designed to accomodate a wide range of presentations. At the time of writing the abstract, the Concord installation is completed and believed to be successful but the Scottsdale installation is still under way and the outcome will not be clear until the paper is presented. The paper does not discuss the overall acoustic design, but is restricted to the role of Assisted Resonance, which deals with only one parameter, and the potential and limitations of the technique will be discussed.

Results of a design effort to control building HVAC equipment noise

An Acoustical Society paper [J. Acoust. Soc. Am. 54, 273(A) (1973)] delivered in Boston on 10 April 1973 discussed the noise control design for a building requiring the exterior installation of its major mechanical and electrical equipment. Our primary concern was noise impact from three aircooled chillers, a transformer, and an emergency engine-generator located in an open outdoor equipment yard across the street from a quiet residential neighborhood. This study was particularly note-worthy because of the extensive interaction required between the architect, mechanical and electrical engineer, mad acoustical consultant. The systems configuration engineered by our firm two years ago is now in operation. For the major equipment we compare our predicted noise levels to the measured noise levels, both nearfield and in the community. We also appraise community opinion to the new noise source, and compare it to our predicted community response. Costs information for the noise control treatment is also presented.

Changing role of the ’’expert’’

The evolution of acoustical consulting over the past 40 years is traced from the early days of simple measurement and little technical information through to the emergence of the consultant as a central participant in the quieting of large machines and airfleets that affect the lives at work and at home of large segments of the population. The part the acoustical consultant plays in national noise regulation and control is discussed. Acoustical consultants are urged to take a broader view of their intraprofessional relationships and raise their level of professionalism, not only to their clients but also to each other.

Noise control in school auditoriums, gymnasiums, and multipurpose rooms

Most multipurpose rooms in schools do not have adequate acoustical control. These rooms are often used as auditoriums, cafeterias, and gymnasiums. Acoustical consultants and architects in the past have usually attempted to control the reverberation time and absorption in these rooms via unit wall absorbers on the side walls. This has not always been practical, and often the unit absorbers are susceptible to damage or there just is not enough wall area to control the noise. A practical and economical way of controlling the reverberation time suitable for multipurpose rooms has been developed. It incorporates an impact‐resistant acoustical ceiling system for these types of rooms and other high‐abuse areas. This system combines lighting, aesthetics, and acoustical control; yet allows access to the plenum area. Reverberation time can be controlled so as to provide a better acoustical environment for multipurpose rooms. This paper discusses details of the components used for making up this system and the acoustical benefits realized.

Hospital Design Procedure Incorporating Early Acoustical Inputs

Traditionally, an architect initiates the work of the mechanical, electrical, and acoustical consultants during the preliminary design phase of a project. At this time the location of spaces in the building has been almost entirely finalized. Thus, the consulting engineers are often forced to incorporate their systems and equipment into the already formalized building layout in an uneconomical manner. This paper enumerates the specific benefits an architectural firm expects to derive by involving the acoustical consultant during the schematic and design-development phases of each project. Case histories of hospital projects are presented to illustrate cost savings due to acoustical consultant involvement in the first phases of design. A suggested acoustical check-list and the phasing of this information are also presented.

Interdisciplinary Design Effort to Control Building Mechanical Equipment Noise

When locating a government building complex with its requisite power generating capabilities in a very quiet residential community, extensive interaction was required between the architect, mechanical and electrical engineers, and acoustical consultant. The success of the design was dependent on achieving acoustical compatibility with the neighborhood consistent with aesthetic, legal, and budgetary considerations. This case study is presented to highlight the interdisciplinary effort necessary to satisfy the various constraints imposed by the community, client, and designers. The maximum noise-level criterion established for the mechanical and electrical equipment was based on the existing ambient, and guidelines contained in U. S. Army Manuals TM 5-805-4 and TM 5-805-9. The noise levels of the air-cooled chillers, transformer, and engine-generator, all located in an outdoor equipment yard, were estimated using procedures elucidated in the Army manuals. This information was augmented by acoustic field measurements of similar equipment, plus manufacturers' SPL and power-level data. The noise-control treatments required to achieve the aforementioned acoustic criterion and their individual costs are discussed along with a description of the engineering modifications to the equipment.

Subjective assessment of noise spectra from large industrial sites

This paper gives details of the criterion felt to be applicable, in the light of present knowledge, for the control of boundary noise at large industrial sites, and should be read in conjunction with the British Standard 4142: 1967. It is suggested that this Standard can form a basis for the criterion, provided its limitations for the assessment of discernible tonal characteristics, narrow-band energy concentrations and amplitude and time modulations present in the noises are recognised. These problems are discussed in the paper and it is felt that the use of sophisticated noise analysing methods and the services of an acoustical consultant are only likely to be required when source identification or the degree of attenuation required to conform to acceptability are in some doubt. This latter point regarding the amount of source attenuation required in a situation not adequately covered by existing criteria ought to receive further research effort, if effective control of boundary noise is to be economically achieved.

Criteria for Control of Community Noise: a Candid Appraisal of Some Unresolved Questions as seen by One Acoustical Consultant

The acoustical consultant frequently finds himself on both sides of the problem in situations concerned with community noise. In either case, he must develop a criterion to evaluate the particular problem area—considering not only the physical control measures that are practical relative to the type source, but also the probable noise reduction requirements to achieve the subjective approval of the receiver. Each situation is likely to be complex regardless of whether the objective is to prevent a complaint or to correct one that already exists. There is a tendency on the part of municipal governments and other regulating agencies to establish noise limits on a basis which is too generalized or oversimplified to handle the broad range of individual situations encountered. An example is the ordinance of Coral Gables, Florida, which limits the noise level of residential air conditioning equipment installed outdoors. A comparison is made between this ordinance and noise data obtained on a large number of units operating, without complaint, in that city during the summer of 1966. General comments are made in connection with this survey which bear on the more fundamental problems faced in developing objective criteria for control of community noise.

Problems of Field Measurement of Transmission Loss as Illustrated by Data on Lightweight Partitions Used in Music Buildings

Field measurements of airborne sound-transmission loss involve several practical difficulties and limitations as compared to the laboratory standard test procedures for such measurements. Data from field measurements are valuable to architects and acoustical consultants, in spite of these limitations. A workable procedure for field measurements is described, along with a discussion of the difficulties. Measured transmission loss data are presented for double plaster walls on cork isolation, double plaster walls on concrete slabs, double concrete block walls, double brick walls, single concrete block walls, and a floor slab with resiliently suspended plaster ceiling.