# Acoustics: An Introduction to Its Physical Principles and Applications

*Acoustics: An Introduction to Its Physical Principles and Applications*

Allan D. Pierce

Acoustical Society of America, 1st ed. (1981), reprint (1989)

678 pp., hardcover, 33 USD

ISBN: 978-0-88318-6121

**Overview and Purpose**

This has become a classic textbook in the ﬁeld of acoustics. Originally published in 1981, there have been new or revised editions published in 1989 and 1994. This latest version, published by the Acoustical Society of America, is a reprint of the 1994 edition. One of the useful additions to the later editions has been the inclusion of solutions to the problems at the end of each chapter.

I have used this book for some time and have found it to be well written and useful in teaching classes, and as a resource when dealing with unusual or difﬁcult acoustic issues. It is in all sense a textbook. There is a series of problems at the end of each chapter. The author begins the text with fundamental principles and builds from basic examples at the beginning of each chapter. It is deﬁnitely appropriate for a graduate level class with rigorous treatments and complex mathematical derivations and explanations. The ﬁnal governing equations are not simply presented, but their development and underlying principles are described in detail. As a textbook of considerable depth, the text provides limited examples of applications and does not attempt to provide convenient approximations or rules of thumb for easy computation.

This is not a noise control textbook in the sense that numerous practical examples are provided or recommendations are made for noise attenuation in common control problems. While the performance of barriers, silencers, and other control devices are described and governing equations are developed, the goal is not to recommend or describe practical applications. It is, however, an excellent text to understand the principles behind common controls and understand how they will perform. This text is highly recommended as a graduate level text in acoustics or as a component in a graduate level course in noise control.

**Organization and Material Presented**

*The Wave Theory of Sound*This chapter is a comprehensive introduction to acoustics. It begins with a brief historical overview and takes the student through a comprehensive derivation of the wave equation. Beginning with basic principles, the student is taken through the concepts of both atmospheric and underwater acoustics. In addition, the concept of sound power is presented.

*Quantitative Measures of Sound*This chapter begins by deﬁning frequency and frequency bands. Measures such as levels, weighting, and ﬁlters are also described. As would be expected in such a segment, the concepts of level addition are discussed. The concepts of transfer function and stationary process are also introduced in discussing signals and measurement.

*Reﬂection, Transmission, and Excitation of Plane Waves*This chapter begins with basic principles discussing wave reactions with solids. The basic concepts of plane waves are provided and explained. The important concepts of coincidence frequency and transmission loss are also introduced. A thorough mathematical deﬁnition of the phenomena is provided. The transmission loss segment introduces the concepts and examines the performance of common materials.

*Radiation from Vibrating Bodies*Once again starting from basic principles, the author builds a description of sound radiation from simple to more complex bodies. Radiation from classic shapes and the complex radiation patterns from realistic radiation surfaces are described for the student. The use of the Helmholtz equation to describe radiation is discussed in some detail. A ﬁnal segment presents the concept of reciprocity and discusses microphone calibration.

*Radiation from Sources near and on Solid Surfaces*This chapter presents a very comprehensive discussion of both the near ﬁeld and far ﬁeld effects of sound radiation from a source near a reﬂecting plane. The classic concept of a piston in a reﬂecting plane is described and analyzed in considerable detail with mathematical formulations for both the near and far ﬁeld.

*Room Acoustics*This is one of the most comprehensive room acoustics treatments of which this reviewer is aware in a single text. From basic principles such as the energy balance in the room it shows the relevance of the classic formulation for describing the sound ﬁeld in a room. The important principles of reverberation time, diffusivity, and energy correlation in a room are presented. The measurement of absorption and transmission loss is also described and discussed in considerable detail. The modal analysis of a room is presented with the discussion of special cases at low and high frequency. In the ﬁnal segment of the chapter, the principles of statistical energy analysis are discussed and the use of this method in room acoustics is demonstrated.

*Low-Frequency Models of Sound Transmission*This chapter is a comprehensive treatment of sound transmission in ducts and the use of silencers. Since the author focuses on the basic principles and does not use industrial examples, the context may be a little difﬁcult to see in the beginning of the chapter. However, this is a comprehensive treatment including horns, duct terminations, Helmholtz or side branch resonators, expansion chambers, and oriﬁces.

*Ray Acoustics*This chapter presents a thorough introduction to ray acoustics. The propagation of sound in a moving ﬁeld, the effects of density gradients, and multiple types of reﬂecting surfaces are discussed. The basic principles of ray tracing computations are provided in this chapter. The practical application of these principles is not discussed in detail, nor are there speciﬁc examples provided.

*Scattering and Diffraction*Both scattering and diffraction are discussed in detail in this chapter. Speciﬁc geometric and resonant condition of scattering are described, and detailed mathematical descriptions are presented. The concept of Doppler shift is presented and its use in measuring ﬂow velocities is described. A thorough treatment of diffraction is provided for a number of well-deﬁned geometric concepts. The treatment of barriers and edge effects is a perfect example of how this text provides a detailed mathematical description instead of the approximation of rules of thumb found in many noise control texts.

*Effects of Viscosity and Other Dissipative Processes*Beginning with the Navier–Stokes model, this chapter looks at sound dissipation in multiple ways. The concepts of dissipation in a tube with multiple modes and reﬂections are discussed. The concept of sound absorption materials is examined in considerable detail with discussions of many of the fundamental principles.

*Nonlinear Effects in Sound Propagation*This chapter focuses on the nonlinear waveform, the “N” wave, and the impact of propagation. Ballistic shocks and sonic booms are also discussed in this context.

*Appendix*Answers and Hints to Problems

*Indices*Name Index and Subject Index

James K. Thompson

Williamsburg, VA, USA

jktprof@outlook.com