Book Reviews (Sept 2019)

Audio and Speech Processing with MATLAB

Paul R. Hill
CRC Press, Taylor and Francis Group (2018)
329 pp., hardbound, US$140
ISBN 978-1-4987-6274-8

This is a very well-written book on an important topic of both academic and general interests. The book is intended not only as a textbook for engineering and computer science students but also as a book for audio engineers, technically based musicians, and general readers with science and engineering backgrounds. The book is comprehensive in its approach, including many real-world examples backed up by many MATLAB functions and code snippets in order to illustrate the key topics within each chapter.

A very nice introduction is given at the beginning of the book. Then the book is organized well into 12 chapters. Chapter 1 (along with Appendix B) provides an introduction to the basic capabilities of MATLAB for audio processing. Chapter 2 introduces some of the core concepts that are necessary to understand the techniques and methods described in the book. This is an interesting feature that the reader can focus on to understand the core concepts. Chapter 3 describes frequency analysis for audio. Fast Fourier transform and its applications including its use in MATLAB are well described in this chapter. The basics of acoustics through discussions on vibrations of strings and air columns are given in chapter 4. The descriptions of the auditory system basics, critical bands, and critical band models are given in chapter 5. In chapter 6, the fundamentals of psychoacoustics such as loudness, equal loudness curves, audio masking, and perception of pitch are discussed. Chapter 7 describes audio compression. ISO standards such as MPEG1 are described. Chapter 8 describes automatic speech recognition. The topics for chapter 9 are audio features for automatic speech recognition and audio analysis. Chapter 10 describes hidden Markov models, Gaussian Markov models, and deep neural networks for automatic speech recognition. Chapter 11 describes speech coding. A discussion of speech coding standards is included in this chapter. Till now the various chapters focus on the synthesis and manipulation of audio for utilitarian purposes whereas the last chapter, chapter 12, discusses musical applications with a focus on synthesis and manipulation of audio for creative purposes.

The figures, including spectrograms, and tables in the book are very clear. Each chapter includes both contents at the beginning and a chapter summary at the end. Important equations and figures are enclosed in boxes. A detailed bibliography is included at the end of each chapter. Helpful exercises are provided at the end of each chapter. In summary, this book is a highly valuable addition to the field of audio and speech processing.

Marehalli G. Prasad
Stevens Institute of Technology
Hoboken, NJ, USA

Noise in the Plastics Processing Industry, 2nd Edition

Bob Peters
CRC Press, Boca Raton, FL (2018)
318 pp., hardbound, US$110
ISBN 978-0-367-03025-4

The first edition of Noise in the Plastics Industry was published in 1985 and provided the plastics industry with a practical guide to reducing noise from common sources and reducing worker noise exposure. The work was 52 pages long, with about half the pages devoted to case studies in tabular format illustrating successful implementation of noise control techniques. The second edition, 318 pages long, provides additional background on basic acoustics, noise control, hearing conservation, environmental noise impact, standards, and specification while retaining a practical approach. This is not a text with equations but an industrial reference manual. A handy bullet-point summary at the end of each chapter provides a useful recap and practical advice both as reinforcement to those studying the information in the chapter and the busy professional. While the information presented is clearly focused toward the plastics processing industry, the explanations are applicable to other industries. The book is divided into 10 chapters, and while the basics presented in the early chapters are helpful to understand later discussion, each chapter can be read or referenced on its own.

Chapter 1, “Basic Concepts and Terminology of Sound and Vibration,” addresses topics like: What is a decibel, A-weighting, frequency, wavelength sound pressure, and sound power? How do sounds add and subtract? How is noise generated? How does it propagate? And what are some things you can do to reduce it including barriers, absorbers, dampers, and vibration isolation?

Chapter 2, “Principles of Noise Generation and Control,” provides commonsense methods to manage and reduce workplace noise. A wide range of noise control techniques is presented, such as vibration isolation, damping, lagging, adding screens, silencers, sound absorption with key items, and the expected range of noise reduction provided.

Chapter 3, “Noise Control in the Plastics Processing Industries,” provides specific examples of noise control techniques to various pieces of equipment, the noise reduction provided and the cost (1985 prices). While specific details of the treatments are not included, it does provide a handy tool for feasibility analysis and justification for buy-quiet purchases.

Chapter 4, “Noise in the Workplace,” covers how the ear works, the impact of noise on hearing, types of hearing loss, and a summary of the EU Noise at Work regulation. Sections of the regulation are summarized in easy-to-understand sections. Although the requirements are different from those promulgated in non-EU countries, there are still good, solid recommendations for an effective hearing conservation program. Also included is a brief history of noise-induced hearing loss from the early 1700s.

Chapter 5, “Hearing Protection and the Use of Personal Hearing Protectors,” starts with a summary of hierarchy of controls. Although it is common to start with PPE, this should be the last step. Next is a summary of the different types of hearing protectors and the different methods to determine the noise reduction provided—both in the laboratory and in the real world and the advantages/disadvantages of each type. The author does include a discussion on overprotection; however, the reviewer would have preferred this be included with the earlier section discussing the optimum range of sound pressure level at the protected ear.

Chapter 6, “Noise in the Environment,” discusses potential noise issues with workplace neighbors, including standards and codes, noise-impact assessment methods, criteria, strategies for minimizing noise emissions and disturbances, and additional information on the noise effects on health and BS 8233:2014. While much of the information is based on British standards, there is still good information presented for manufacturers globally.

Chapter 7, “Prediction of Noise Levels,” discusses prediction methodology, providing enough information to understand the process and typical levels. Simple calculations, such as calculating the sound pressure level at a distance, given the sound power level, and how to determine the noise reduction from a barrier, are presented. More complex calculations, such as determining the sound pressure level reduction due to the addition of sound absorption, ray tracing, ground attenuation, and including atmospheric effects with outdoor sound propagation, are discussed in a simple fashion.

Chapter 8, “Specification of Noise Emission from Machinery and Machinery Noise Regulations (The European Union Machinery Noise Regulations),” presents an explanation of noise test standards, why specifying noise levels is important, and how noise from equipment should be specified. All the standards referenced are ISO or British adoptions of a European standard.

Chapter 9, “Towards a Quieter Workplace,” focuses on the administrative element of noise control: buy quiet, separate quiet and noisy machines to minimize employee noise exposure, add barriers and sound absorption in the space, enclose noisy machines and use automation when possible.

Chapter 10, “Case Studies,” as the name implies, presents case studies for various plastics industry noise reduction projects in the United Kingdom. Some of these case studies have been published in other references, and some come from consultants’ files. Here, the experienced and novice reader can learn from various projects—learning what treatments were applied, the noise reduction obtained, and the treatment cost.

I enjoyed this book and will personally recommend it to manufacturing and safety managers as well as other noise control professionals who work in the plastics industry.

Charles Moritz
Vice President—Research and Development
Blachford Acoustics Group

The Sense of Hearing, 3rd Edition

Christopher J. Plack
Routledge (2018)
329 pp., hardbound, $US140
ISBN 978-1-138-63258-5

This book presents an accessible and comprehensive account of most everything related to the auditory system. It would be of interest to students studying any field related to hearing, especially for students new to the subject, but would also be relevant to students who have some experience in acoustics. As the author notes in the preface, the book is focused on explaining human perceptions rather than providing a comprehensive description of auditory anatomy and physiology. While the book does include details of the anatomy of the ear, the author provides a focus and thorough account of the sense of hearing.

The first two chapters provide an overview of the book as well as an introduction into the nature of sound, providing the reader with some basic terminology and concepts. Chapter 3 continues with an introductory feel and describes items such as resonance and sound propagation as well as providing a primer on digital signal processing.

Chapter 4 presents a journey through the auditory system and provides an excellent description of the human ear and how it works, including everything from explaining the purpose of the pinna (and how Van Gogh did not make himself deaf when he cut his “ear”) to the auditory nerve.

After this the book moves into a territory that might be described as the sense of hearing. The following chapters discuss frequency selectivity, the ability of the ear to separate out different frequency components (chapter 5), loudness and intensity coding (chapter 6), and pitch and periodicity coding (chapter 7). Chapter 8 discusses how the ear can interpret rapid changes in a sound over time as well as its ability to combine information about sounds over much longer durations to improve understanding. Chapter 9 presents details on spatial hearing and provides an excellent overview of how we can discern the direction from where a sound may be approaching (the key is listening with two ears!).

Chapter 10 introduces the reader to the concept of an auditory scene. By way of introduction, the reader is reminded that the only time you hear a single sound by itself is when doing sound psychoacoustic experiments in a soundproof booth! The auditory system must perform the difficult task of grouping together or separating sound components that originate from either the same or different sound sources—a process called auditory scene analysis.

Chapter 11 is devoted to the main means of human communication, speech. The reader is introduced to the basics of speech production as well as speech perception. Chapter 12 then moves on to music, and the book attempts to explain how some musical rules might be a natural consequence of the way the auditory system operates.

The penultimate chapter deals with the important topic of hearing impairment—the most common physical disability in the West. It discusses different types of hearing impairment as well as describes issues such as tinnitus and hyperacusis. The book finishes with some concluding remarks. Here, the author notes that the book aims to provide an account of human perceptions and as such focuses more on the behavioral aspects rather than physiological aspects (although it is also recognized that the two are heavily interdependent). The book also includes an appendix detailing how research related to the ear is generally undertaken.

Overall, this book is an invaluable resource to any student interested in the ear and the mechanism of hearing but would also be relevant to those studying topics such as acoustics, audiology, and audio design. It is written in a very comfortable style and includes a lot of interesting nuggets that will keep the reader engaged throughout.

Eoin A. King
Acoustics Program and Laboratory
University of Hartford
West Hartford, CT, USA

Whole Body Vibrations: Physical and Biological Effects on the Human Body

Redha Taiar, Christiano Bittencourt Machado, Xavier Chiementin, Mario Bernardo-Filho, editors
CRC Press (2018)
252 pp., hardbound, $US160
ISBN 978-1-138-50001-3

This interesting and well-written book deals with an important area: namely, whole body vibrations and their physical and biological effects on the human body. The book is edited by well-known authors, who are researchers and practitioners. The book has 11 chapters contributed by 35 authors. The book is very comprehensive on the topic of whole body vibrations. The book provides not only an understanding of the fundamentals of whole body vibrations but also its effects on humans with various health conditions. The titles of various chapters in the book are well chosen and very clear.

Chapter 1 deals with instrumentation and mechanical vibration analysis. The chapter describes various transducers with their specifications and performance. International standards are discussed. Vibration measurements on the human body are described. Chapter 2 describes the various signal processing approaches with applications to the analysis of vibrations transmitted in the human body. This chapter also describes case studies. Chapter 3 describes the numerical and experimental modeling of mechanical vibrations. Basic vibration analyses based on single, two, and multiple degrees of freedom models are described in this chapter. This chapter also includes experimental modal analysis. Chapter 4 discusses the effects of mechanical vibration on performance. Effects of vibration in sports and motion are discussed. Chapter 5 describes the effects of whole body vibration on the various physiological systems in the elderly. Chapter 6 describes the effects of whole body vibrations in individuals with diabetes and diabetic neuropathy. Chapter 7 describes the effects of whole body vibrations in patients with chronic obstructive lung disease. Chapter 8 describes the effects of whole body vibrations on cognition and the brain. The chapter discusses studies on both animals and humans. Chapter 9 describes the effects of whole body vibrations in adult individuals with metabolic syndrome. Chapter 10 describes the effects of whole body vibrations on bone tissues. Bone mechanics and vibrations are included in this chapter. Discussions include studies on animals and humans. The effects on children, adolescents, women, and adults are also discussed. The last chapter, chapter 11, describes the undesirable and unpleasant adverse side effects of whole body vibration exercises. The chapter also discusses approaches to the safety and care aspects of exercises.

It is nice that at the beginning of each chapter, the contents of the chapter are given clearly, which helps the reader obtain an overview of the chapter. The figures and tables are very clear in each chapter. Another important feature is that each chapter has an exhaustive list of references. This will be highly useful to researchers and students. In summary, the editors and authors have produced an excellent book on this important topic, providing not only the basics of whole body vibrations but also their effects on humans. The book is a highly welcome addition to the literature on this important topic.

Marehalli G. Prasad
Stevens Institute of Technology
Hoboken, NJ, USA