Modern Acoustics Research Articles

Italian opera house Mantua's Teatro Scientifico acoustical parameters measurements' comparison between Neumann KU 100 and Schoeps KFM 6 binaural recording systems

From the dawning of modern acoustics, researchers tryed to develop useful measurement techniques to describe acoustical field. Sound field measurement improvement's first endeavours implementing microphone capsule miniaturization technology date back to the thirtyes of the past century. Long human perception reproduction path through recording tecnique came to the attempt to position transducers similarly to the human natural hearing system, frequently obtaining as alluring results as difficult comparison among them and reapply. This paper describes processes, first results and comparison between as much as possible identical acoustical measurement sessions in Mantua's Teatro Scientifico opera house using Neumann KU 100 and Schoeps KFM 6 binaural recording systems at the same time.

Damage Detection in Composite Plates by Using an Enhanced Time Reversal Method

A damage detection technique, which does not rely on any past baseline signals, is proposed to assess damage in composite plates by using an enhanced time reversal method. A time reversal concept of modern acoustics has been adapted to guided-wave propagation to improve the detectability of local defects in composite structures. In particular, wavelet-based signal processing techniques have been developed to enhance the time reversibility of Lamb waves in thin composite laminates. In the enhanced time reversal method, an input signal at an excitation point can be reconstructed if a response signal measured at another point is reemitted to the original excitation point after being reversed in a time domain. This time reversibility is based on linear reciprocity of elastic waves, and it is violated when nonlinearity is caused by a defect along a direct wave path. Examining the deviation of the reconstructed signal from the known initial input signal allows instantaneous identification of damage without requiring the baseline signal for comparison. The validity of the proposed method has been exemplified through experimental studies on a quasi-isotropic laminate with delamination.

Time reversal active sensing for health monitoring of a composite plate

The applicability of a time reversal concept in modern acoustics to structural health monitoring was investigated. The time reversal method has been adapted to guided-wave propagation to improve the detectability of local defects in composite plate structures. Specifically, a wavelet-based signal processing technique has been developed to enhance the time reversibility of Lamb wave in thin composite plates. The validity of the proposed method is demonstrated through experimental studies in which input signals exerted at piezoelectric (PZT) patches on a quasi-isotropic composite plate are successfully reconstructed by using the time reversal method. The ultimate goal of this study is to develop a reference-free damage diagnosis technique based on the time reversal process so that defects can be identified without relying on any past baseline data.

A short history of physical acoustics at Brown

Modern acoustics at Brown began with Bruce Lindsay. Lindsay had been a student of atomic theory, but switched to acoustics during and after WWII. He found strong support from the Office of Naval Research (ONR), and brought to the department Arthur Williams, Peter Westervelt, Jordan Markham, Bob Morse, Rohn Truell, Wes Nyborg, and many others. Honors in the Society among this group included three presidencies, two gold medals, and several silver awards, as well as Lindsay’s role of 20 years as Editor-in-Chief. The author of this paper recently found himself described in a German publication as ‘‘Schatzmeister’’ (look it up) of the Acoustical Society of America. Rohn Truell moved to Applied Mathematics at Brown and developed a second acoustics group there, which included Charles Elbaum and Humphrey Maris. From acoustic filters to nanosecond technology, the subject moved forward. But, we were all following Bruce Lindsay.

Dialogue on ancient and modern music

Vincenzo Galilei, the father of the astronomer Galileo, was a guiding light of the Florentine Camerata. His Dialogue on Ancient and Modern Music, published in 1581 or 1582 and now translated into English for the first time, was among the most influential music treatises of his era. Galilei is best known for his rejection of modern polyphonic music in favor of Greek monophonic song. The treatise sheds new light on his importance, both as a musician who advocated a new philosophy of music history and theory based on an objective search for the truth, and as an experimental scientist who was one of the founders of modern acoustics.

Acoustics of early music spaces from the 11th to 18th century: Rediscovery of the acoustical excellence of medium-sized rooms and new perspectives for modern concert hall design

The acoustical characteristics of 50 rooms that played a prominent role in the history of music between the 11th and 18th centuries were studied. The rooms include basilicas, oratorios, organ churches, and the great halls and courts of the European palaces. The research provides an understanding of the acoustical features that suit the early music repertoire, and how these rooms achieved an enhanced emotional engagement through their unique acoustical characteristics. This paper provides a summary of the acoustic measurements, which include binaural and B-format recordings in each of the rooms, and presents a unique new approach to understanding their subjective characteristics through detailed analysis and auralization of their 3-D impulse response. The study shows that the timing and direction of reflections in three dimensions is critically important to defining the subjective characteristic of a room. The results emphasize the importance of developing techniques to understand the 3-D impulse response and using auralization techniques for interpreting results and making subjective judgments. The enhanced musical experience that is achieved in these early rooms offers an invitation to rethink modern acoustics and to develop a new design approach that focuses more strongly on the subjective response and emotional engagement of the music.

Noise source identification: A comparison of seven different techniques

One of the most powerful tools that can be used in modern acoustics labs today is noise source identification. By identifying where the noise source(s) may be located, it becomes much easier then to try and reduce/remove/modify the overall dB level of a product. This is typically the end result of a noise reduction program, which is the typical goal of all NVH programs. Over the years many different techniques have become available as technology moves forward. In the beginning it was simple sound-pressure mapping techniques, then sound intensity added a new dimension to the art and science of NSI (noise source identification); last, multichannel applications such as acoustic holography and beamforming have given us tools that far exceed our capabilities of even 10 years ago. As with any advance in technology, each technique has strengths and weaknesses which must be understood to ensure proper measurement and analysis. This paper will offer an overview of seven commonly used NSI techniques along with a comparison of the strengths and weaknesses associated with each technique.

Analytical method for radiation and scattering problems in noncanonical domains

One of the tendencies in modern acoustics is to use analytical solutions of the Helmholtz equation to present the sound field around radiators and scatterers of noncanonical shapes. The T matrix and internal source density methods are examples. In the present paper a method called a partial domain method is discussed. An essential point of the method is the notion of general solution of the boundary-value problem for the Helmholtz equation. The boundaries of the objects under consideration are parts of coordinate surfaces in separable systems. However, surfaces may be either coordinate surfaces of different types (as in the case of a finite cylinder) or coordinate surfaces of different systems (as in the case of a cylinder with spherical lids). Theoretical problems of both the method and numerical implementation of one are discussed. Consideration of such aspects of the method as singularity of the field near corner points, nonuniqueness of the wave functions, and extension of boundary conditions gives a basis to make the computation process more effective. The numerical results for some cases of radiation by finite cylinder and cylinder with hemispherical lids are used to illustrate the method.

Producing speech: Contemporary issues for Katherine Safford Harris Ed. by Fredericka Bell-Berti and Lawrence J. Raphael (review)

906 LANGUAGE, VOLUME 73, NUMBER 4 (1997) sketches up the development of the Indo-European ablaut (147). In morphology, B makes the following statements about substantival stems: The basic language had two stems only: o-stem and C-stem because the a-stem developed later and ended C [eH2]. The o-stem made a separate group with its own system of suffixes. B divides C-stem into two further types (hysterodynamic and proterodynamic) and discusses declination types in that framework (175). His ideas on the development of feminine and neuter adjectives deserve special attention (193). The chapter on conjugations , though, lacks important insights like those above. B's Indo-European linguistic introduction is a valuable , excellent work, useful for those interested in the results and the problems of modern Indo-European linguistics. Some of B's hypotheses may be disputable, but scholarship cannot exist without either hypotheses or disputes. [Imre Tóth, JozsefAttila University, Hungary.] Producing speech: Contemporary issues for Katherine Safford Harris. Ed. by Fredericka Bell-Berti and Lawrence J. Raphael. (AIP series in modern acoustics and signal processing, 4.) Woodbury, NY: AIP Press, 1995. Pp. xxi, 567. This festschrift for Katherine Harris is a collection of 34 papers by over 60 researchers in the field of speech production. As a whole, the volume is a survey of cuoent research in the field. In addition, a few of the chapters review ongoing issues in speech production. This book is thus useful for both the specialist and nonspecialist. The chapters discuss articulatory and acoustic data, data from adults and children, and data from normal and abnormal speech. 'Section 1: The segment' (3-165), contains eleven chapters examining the segmental organization of speech. Among others, papers by Sieb Noteboom and by Bell-Berti, Rena Krakow, Carole Gelfer, and Suzanne Boyce discuss effects of segmental lookahead and carryover. Catherine Browman and Louis Goldstein and Leigh Lisker examine positional effects on segment realization. Gary Weismer, Kristin Tjaden, and Ray Kent; Carole Gelfer and Sarita Eisenberg; and Michael McClean, Mary Cord, and Donna Levandowski discuss implications of abnormal speech on models of articulatory organization. 'Section 2: The source' (169-318), contains ten chapters on respiration and phonation during speech. Robert Porter, David Hogue, and Emily Tobey; R. J. Baken; and Ingo Titze examine the empirical adequacy of models of respiration and phonation. Dale Metz and Nicholas Schiavetti; Peter Alfonso ; MasaYUKi Sawashima, Kiyoshi Makiyama, and Naoko Shimazaki; and Christy Ludlow discuss respiration andphonation inpersons with abnormal production and audition. Kiyoshi Honda; Hajime Hirose; and Ronald Scherer, V. J. Vail, and B. Rockwell focus on the larynx, and examine laryngeal anatomy and measurement during speech production. 'Section 3: The utterance' (321-415) contains six chapters related to suprasegmental patterns in fluent and disfluent speech. Chapters by Angelien Sanderman and René Collier; Krakow, Bell-Berti, and Q. Emily Wang; and Carol Fowler examine acoustic and articulatory influence ofprosodie structure , including effects of both prosodie constituency and phrasal accent. Paula Square, Claude Chevrie -Muller, and Frances Freeman consider suprasegmental characteristics of three different types ofspeech disorder and find evidence for dissociations between organizational levels in these disorders. 'Section 4: Feedback' (417-65), contains three chapters on the role ofall types offeedback on speech production. Vincent Gracco proposes a new perspective on invariance, claiming articulatory instructions are invariant modulo contextual feedback information. Nancy McGarr and Melanie McNutt Campbell, and Emily Tobey examine the hypothesis that abnormal speech production in the hearing impaired is in fact normal speech production with a lack of feedback. 'Section 5: The segment (reprise)' (469-537) contains four chapters which discuss more theoretical issues in the segmental organization of speech. These chapters by Elliot Saltzman, Anders Löfqvist, Jeff Kinsella-Shaw, Bruce Kay, and Phillip Rubin; Richard McGowan; Betty Tuller and J. A. S. Kelso; and Kevin Munhall and J. A. Jones all focus on theories of the organization and parameterization of speech movements as a dynamical system . They are an appropriate closing to the volume as each of the chapters raises as many questions for investigation as it answers, providing new directions for future research. [Stefan Frisch, Indiana University .] A course in generalized phrase structure grammar. By Paul Bennett. London: UCL Press, 1995. Pp...

On sound diffraction by an impedance wedge

Diffraction of waves by a wedge is a problem of modern acoustics whose mathematical solutions provide a theoretical basis in analyzing sound radiation and scattering phenomena. Considerable attention has previously been attracted to this class of diffraction problems, especially to the particular cases of a perfectly reflecting wedge and half-plane. The model of an impedance wedge [G. D. Malyuzhinets, 1958 Dokl. Akad. Nauk SSSR 121, 436 (1958) in Russian] is a more general and realistic one that gives new opportunities for treating acoustic diffraction by irregular surfaces [A. D. Pierce and W. J. Hadden, J. Acoust. Soc. Am. 63, 17 (1978); A. V. Osipov, Sov. Phys. Acoust. 36, 287 (1990)]. This paper investigates the wave field excited by a line source in the presence of a wedge with arbitrary values of face impedances. Based on the Malyuzhinets’ solution, various exact representations for the Green’s function are deduced to generate a system of convenient formulas for any relative positions of the source and point of observation. A new representation of the Malyuzhinets’ solution in the form of double series [A. V. Osipov, Sov. Phys. Acoust. 37, 381 (1991)] is exploited to describe the wave field of the line source placed in the vicinity of edge. In the opposite case of large distances from the edge, a uniform asymptotic expansion is presented. Applications of the obtained results to problems of sound attenuation by wedge-like barriers and sound radiation from a line source located at the edge of a corrugated surface are described.

The 1988 Rayleigh medal lecture: Fluid loading—The interaction between sound and vibration

As with virtually all phenomena studied in modern acoustics, fluid loading of a vibrating structure caught the attention of Lord Rayleigh. In his “Theory of Sound” [l, Art 3021, he analyzed the “reaction of the air on a vibrating circular plate”, showing that reaction to be equivalent to a virtual mass and radiation damping, to be added to the plate mass and the mechanical damping. His calculation was for the case of specified uniform motion of a plane, circular piston embedded in a rigid baffle, which permits immediate evaluation of the radiation field by quadrature over the values of normal velocity, known over an infinite plane. Nonetheless, his description of the fluid loading in local added mass and radiation damping terms is general, and complete. However, it does not exhaust interest in fluid loading problems because the integrated result, over a large vibrating structure, of such local effects (usually phased by some travelling wave mechanism) can have a quite diflerent qualitative form, and also because the added mass and radiation damping depend on the vibration mode shape and mustin a fully coupled problem with significant fluid loading-be determined simultaneously with the structural vibration and fluid motion. Techniques for dealing with such fully coupled motions of elastic plates and shells immersed in air or water were simply not available in Rayleigh’s time, but have become available in the past three decades or so. On the analytical side, much progress has been made using complex integral transform techniques and methods of asymptotic singular perturbation theory, while finite-element and boundary-integral-equation methods have clearly emerged as leading computational techniques in this field. A standard reference (though not including the most recent results) on the analytical modelling is the book of Junger and Feit [2], while developments in computational acoustics have been described in reference [3]; mention should also be made here of the “doubly asymptotic approximations” (DAA, , DAA2) which form a hybrid analytical-computational scheme (see, e.g., the paper by Geers and Felippa [4]). These advances in scientific understanding have been driven by widespread occurrence of technological processes in which fluid loading of vibrating structures is important; examples abound in marine engineering (vibration and acoustic fields of ships and submarines, vibration of oil rigs and submerged pipelines), in aeronautical engineering (aircraft and helicopter structures vibrating in air, and the internal loading of aircraft fuel tanks), and in mechanical and nuclear engineering (vibrations of ventilating systems

Prospects in modern acoustics, education and development—How to teach acoustics

Prospects in modern acoustics, education and development—How to teach acoustics

A new wave of acoustics

In 1946, Richard Feynman, giving a contributed paper at a meeting of the American Physical Society, remarked that the allotted time was not long enough for him to read his abstract (it was a peculiarly long one), but only enough for him to point out the errors in it. In a similar vein, modern acoustics is so broad that the space allowed here is scarcely enough to reprint the PACS classification of the subject, let alone to instruct or entertain. Acoustics today is a festival of the applications of physics, both theoretical and experimental. We must therefore restrict ourselves to a sampling of topics, ranging from acoustical devices as ancient as the guinea pig's ear (figure 1) to others as modern as the electron‐acoustic microscopic (figure 2).

Historical Lute Bellies from the Standpoint of Modern Statics and Acoustics

Historical Lute Bellies from the Standpoint of Modern Statics and Acoustics

The story of acoustics.

The historical progress, of the science of acoustics is surveyed from the earliest recorded phenomena and theories to the present status of the subject. Considerable attention is paid to the development of both mathematical and experimental tools for studying the production, propagation, and reception of sound, particularly in the 18th and 19th centuries. The impact of Rayleigh's work on modern acoustics is estimated. Contemporary developments are treated only briefly. The endeavor has been made to refer in almost all cases to original sources.

Principles of Modern Acoustics

Principles of Modern Acoustics

Principles of Modern Acoustics

<i>Principles of Modern Acoustics</i>

The Partnership between Music and Modern Acoustics

Research Article| July 01 1949 The Partnership between Music and Modern Acoustics Arnold M. Small Arnold M. Small Search for other works by this author on: This Site PubMed Google Scholar Journal of the American Musicological Society (1949) 2 (2): 102–106. https://doi.org/10.2307/830075 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Arnold M. Small; The Partnership between Music and Modern Acoustics. Journal of the American Musicological Society 1 July 1949; 2 (2): 102–106. doi: https://doi.org/10.2307/830075 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentJournal of the American Musicological Society Search This content is only available via PDF. Copyright 1949 The American Musicological Society Article PDF first page preview Close Modal You do not currently have access to this content.

The Partnership between Music and Modern Acoustics

The Partnership between Music and Modern Acoustics

A Musician Looks at Modern Acoustics

The musician of today often finds himself somewhat at the mercy of the sound engineer, the radio control operator, or the designer of electronic musical instruments. He is bewildered by the language of the cycle and decibel and by the complexity of the circuits, controls, and equipment. The engineer on the other hand is frequently unable to appreciate the viewpoint of the artist, whether through lack of training or by virtue of his temperament. The purpose of this paper is to emphasize the community of interest between the two fields, and to indicate the directions which the writer feels acoustic and electro-acoustic research might take in order to contribute most effectively to the aesthetic development of music.