Color surrounds us. It is a sensation that adds excitement and emotion to our lives. Everything from the clothes we wear to the pictures we paint revolves around color. In this chapter, methods of producing and manipulating color through the use of paints, dyes, filters, and lighting will be explored.

The Caribbean steel pan is likely the single most significant new acoustic musical instrument of the 20th Century. Some major developments incorporated by Felix Rohner of Panart have led to important instrument modifications. Among the differences to be discussed are as follows: using specified steel alloys in the sheet metal to replace commercial 55 Gal drums, sinking the pan in a press rather than by hand, surface hardening the playing surface in a nitride bath, dispensing with chiseled note section boundaries, adding a central dome to each note section, replacing the pan by a Hang (a lap-held instrument played by hand), and finally an additional air volume enclosed, to enhance low frequency resonances (the Gubal).

Percussion instruments are an important part of every musical culture. Although they are probably our oldest musical instruments ( with the exception of the human voice), there has been less research on the acoustics of percussion instruments, as compared to wind or string instruments. Quite a number of scientists, however, continue to study these instruments. Over the years we have written several review articles on the acoustics of percussion instruments [9.1, 2] as well as a book [9.3]. They are also the subject of chapters in most books on musical acoustics and on musical instruments [9.4-8].

Modal analysis is widely used to describe the dynamic properties of a structure in terms of the modal parameters: natural frequency, damping factor, modal mass and mode shape. The analysis may be done either experimentally or mathematically. In mathematical modal analysis, one attempts to uncouple the structural equations of motion so that each uncoupled equation can be solved separately. When exact solutions are not possible, numerical approximations such as finite-element and boundary-element methods are used.In experimental modal testing, a measured force at one or more points excites the structure and the response is measured at one or more points to construct frequency response functions. The modal parameters can be determined from these functions by curve fitting with a computer. Various curve-fitting methods are used. Several convenient ways have developed for representing these modes graphically, either statically or dynamically. By substituting microphones or intensity probes for the accelerometers, modal analysis methods can be used to explore sound fields. In this chapter we mention some theoretical methods but we emphasize experimental modal testing applied to structural vibrations and also to acoustic fields.

This brief introduction may help to persuade the reader that acoustics covers a wide range of interesting topics. It is impossible to cover all these topics in a single handbook, but we have attempted to include a sampling of hot topics that represent current acoustical research, both fundamental and applied.Acoustics is the science of sound. It deals with the production of sound, the propagation of sound from the source to the receiver, and the detection and perception of sound. The word sound is often used to describe two different things: an auditory sensation in the ear, and the disturbance in a medium that can cause this sensation. By making this distinction, the age-old question If a tree falls in a forest and no one is there to hear it, does it make a sound? can be answered.

In the third edition of The Science of Sound, we included a list of “Experiments for Home, Laboratory, and Classroom Demonstrations” at the end of each chapter. Some of the demonstrations are done by the instructor in class, some are done by students for extra credit, some are intended to be done at home. We describe a representative number of these, many of which can be done without special equipment.

Although there are certainly some good historical treatments of acoustics in the literature, it still seems appropriate to begin a handbook of acoustics with a brief history of the subject. We begin by mentioning some important experiments that took place before the 19th century. Acoustics in the 19th century is characterized by describing the work of seven outstanding acousticians: Tyndall, von Helmholtz, Rayleigh, Stokes, Bell, Edison, and Koenig. Of course this sampling omits the mention of many other outstanding investigators.To represent acoustics during the 20th century, we have selected eight areas of acoustics, again not trying to be all-inclusive. We select the eight areas represented by the first eight technical areas in the Acoustical Society of America. These are architectural acoustics, physical acoustics, engineering acoustics, structural acoustics, underwater acoustics, physiological and psychological acoustics, speech, and musical acoustics. We apologize to readers whose main interest is in another area of acoustics. It is, after all, a broad interdisciplinary field.