ISSN:0001-4966    

DOI:10.1121/1.381315

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

The beginning of architectural acoustics as an engineering science began with Joseph Henry, when he was requested by Congress to design a new lecture hall for the Smithsonian Institution in Washington. Henry’s preliminary investigations led him to the discovery of what is now known as the ’’precedence effect,’’ setting limits on the permissible time lags in successive acoustic signals before echoing is evident. Henry’s design of the lecture hall made skillful use of his discovery for the location and shape of wall and ceiling surfaces to produce much ’’early reflected sound’’ to enhance the direct impulses. The next great advance in architectural acoustics was made by Professor Wallace C. Sabine of Harvard in his quantitative studies of reverberation, and in his masterful use of these discoveries in the acoustical designs for many notable buildings especially Boston Symphony Hall—still considered one of the world’s finest. After Sabine’s untimely death in 1919 his work was extended and applied by many others in the next decade, notable, Dayton C. Miller, F. R. Watson, Paul E. Sabine, Carl Eyring, R. F. Norris, and Vern O. Knudsen. The early development and application of architectural acoustics as an exact science was primarily an achievement of the New World, and one of which we can be justly proud in the bicentennial year.

ISSN:0001-4966    

DOI:10.1121/1.381316

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

This paper reviews the progress in building acoustics in America between the two World Wars. Special emphasis is laid on the development of improved methods of measuring reverberation times, and the development of acoustical materials and methods of measuring their absorption coefficients. Reference is also made to normal‐mode calculations, noise quieting applications, and transmission through walls.

ISSN:0001-4966    

DOI:10.1121/1.381317

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

This article is a review of important developments in psychological and physiological acoustics, primarily in the United States in the period 1920–1942. It includes a reference to the early work of Harvey Fletcher and his co‐workers at the Bell Telephone Laboratories on the psychoacoustics of speech and hearing, leading to the definitive exploration of the ’’auditory area’’ and the development of the audiometer. The replacement of the Weber–Fechner psychophysical law by the Stevens power law is mentioned. In the domain of physiological acoustics the importance of the investigations of Békésy, Wever and Bray, and Galambos on acoustical nerve transmission is emphasized.

ISSN:0001-4966    

DOI:10.1121/1.381318

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

The historical context of acoustical and motional impedance was conceived and applied on a large scale before the Acoustical Society was founded in 1929. It seems appropriate at this time to review for the Society some of the people and their devleopments which contributed to the advancement of transducers by application of the impedance concept.

ISSN:0001-4966    

DOI:10.1121/1.381319

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

A few selected topics will be discussed. Each had a major influence in setting a new trend. The discussion will include the significance of Wente’s condenser microphone in freeing acoustic measurements from the constraints of contemporary microphones; the effect of Maxfield and Harrison’s paper on the analysis and synthesis of acoustic devices; and the evolution of the reciprocity principle into a measurement tool.

ISSN:0001-4966    

DOI:10.1121/1.381320

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

For much of the first four decades of the twentieth century (with the exception of an impulse effort during World War I), undersea acoustics had limited financial support and a small number of practitioners. During 1940–1950 this situation changed. A massive effort funded by the U. S. Navy enabled a large multidisciplined group of civilian scientists to transform a previously relatively simple pragmatic ’’art’’ into an increasingly complex emerging science.

ISSN:0001-4966    

DOI:10.1121/1.381321

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

A narrow bundle of monochromatic acoustic waves is reflected from an irregular sea surface. The elevations of the surface are normally distributed with a relatively narrow power spectrum. The characteristic width of the active scattering area is small as compared to the correlation distance of the irregular waves. A stochastic model is devised for the surface waves in which the amplitude and frequency of these waves vary linearly over the active scattering area. Starting from the Helmholtz equation and using the Kirchhoff approximation, first‐order expressions are derived for the average amplitude and phase variation of the reflected waves. The expression for the average amplitude of the reflected waves depends on the width of the incoming sound bundle. However, for short waves this expression becomes independent of the width and reduces to the familiar result of Eckart when the angle of incidence is equal to the angle of observation. The phase variation is independent of the width of the scattering area and has its largest values when the inverse acoustic wave number has the same order of magnitude as the root‐mean‐square value of the surface‐wave height.

ISSN:0001-4966    

DOI:10.1121/1.381322

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

The reflection of plane waves by a layered cylindrical shell in water is investigated theoretically. Either or both of the two layers of elastic material may be absorptive. The solution as a function of frequency is examined for several combinations of inner and outer layers.

ISSN:0001-4966    

DOI:10.1121/1.381323

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

The acoustic radiation field of an axisymmetric spherical radiator with mixed surface boundary conditions is determined numerically. The general problem consists of a sphere comprised of a radially vibrating polar cap and a contiguous pressure release belt mounted on a rigid baffle (the remainder of the sphere). Two limiting cases, a vanishing belt or a vanishing baffle, are also considered. The radiation field is developed using both a least‐mean‐square‐error method of analysis and a point matching or boundary collocation analysis. The radiation characteristics of the general problem are found to be intermediate between those of the two limiting cases.

ISSN:0001-4966    

DOI:10.1121/1.381324

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP