Steven Garrett’s new book Understanding Acoustics: An Experimentalist’s View of Acoustics and Vibration is a substantial, highly readable graduate textbook on sound and vibration. The title indicates that the book is written from an experimentalist’s perspective, and it certainly has that feel. The author’s experience studying sound, vibration, and related topics shines though. Nearly every page contains a new insight or anecdote. Understanding Acoustics bears similarities to the classic 1950 textbook Fundamentals of Acoustics by Lawrence Kinsler and Austin Frey, now in its fourth edition. Both works contain a mix of physical acoustics, electroacoustics, and subjective acoustics. However, Garrett’s book is more coherent, accessible, and in my view, better.
Understanding Acoustics covers most of the essential material one would expect in a graduate textbook on acoustics and is liberally illustrated with high-quality diagrams and photographs. The book is divided roughly equally between vibration and acoustics and hardly mentions, for example, aero-, psycho-, and underwater acoustics. It also stops short of more advanced concepts such as Green’s functions and the Helmholtz–Kirchhoff integral equations linking structural vibration to sound radiation. Surprisingly, there is also not much on signal processing and spectral-analysis methods, which are the bread and butter of all experimental acousticians.
On the positive side, the book contains much valuable material that is often missing from conventional texts on sound and vibration. Chapter 1, for example, is a survey of five important mathematical techniques: linearity, Fourier principles, dimensionless groups, forms of error, and least-squares estimation. These are tools for experienced researchers, yet they are rarely found together in a single text.
The book is written in a clear, uncluttered style. However, some, including myself, may be irritated by the occasional lapse into idiosyncratic language, such as the title of the first chapter, “Comfort for the computationally crippled,” or the sentences aimed at illustrating equilibrium: “Close your eyes, count to ten, and then open your eyes. Probably not much around you has changed.” Those are relatively minor quibbles, however, about a book that is mostly formal in style.
Professors considering Understanding Acoustics for their courses may appreciate a quick overview of the book’s contents. After the first chapter on mathematical techniques, Garrett covers the simple harmonic oscillator and wave propagation along a string. From there, he moves on to the elasticity of solids; modes in bars; and membranes, plates, and the response of condenser microphones—this last a somewhat unusual topic in a textbook. The general presentation of the material is very clear, although the types and mechanisms of structural damping appear not to be treated extensively. Chapter 7 deals with waves in fluids; it also covers energy-conservation equations. Chapter 8 discusses lumped element modelling, including information about using DeltaEC software to predict how a given thermoacoustic apparatus will perform, and instructions for downloading and running the code. I found this to be the strangest inclusion in the book, and I’m not sure what purpose it serves. It interrupts the book’s flow and could date it in a few years.
The book then moves on to dissipative hydrodynamics, which deals with loss mechanisms in fluids, and to the essential elements of one-dimensional wave propagation, including energy density, sound intensity, and impedance. Later chapters cover plane-wave transmission and reflection across a planar fluid interface, sound radiation and source models, sound fields in 3D enclosures, and sound attenuation in gases. Chapter 15 concludes the main text with a discussion of nonlinear acoustics.
The danger with a book of this size and ambition is that the central principles of sound and vibration will become lost in the sheer quantity of material. That comprehensiveness will not be an issue for graduate students and more experienced researchers, but could be daunting for those at the undergraduate level. However, Garrett has managed to cover his material in a fresh and easy-to-follow way. The quirky aspects could annoy some readers, but overall I really liked this book for its attention to detail, its readability, and the frequent asides and footnotes. I have been teaching acoustics to second-year undergraduate students for many years. Understanding Acoustics is now my recommended text.
Phillip Joseph is professor of engineering acousticians and head of the Acoustics group at the Institute of Sound and Vibration research at the University of Southampton in the UK. His main research interest is in aeroacoustics but has also worked in underwater acoustics, room acoustics, and active noise control.
