1. Descriptions of Sound

Acoustics is the science of sound. For most people, the word “sound” is synonymous with “hearing,” but the realm of acoustics is far greater than phenomena associated with audible signals. The signals we hear are sound waves, in which pressure fluctuates. Hearing is a complex process of detecting and decoding these signals. Our ability to hear is as marvelous as any of our other senses. Indeed, no mechanical device can match the auditory capability of the average person. Thus, it might be appropriate to say that those of us who have an undiminished ability to hear are already acoustical experts. Many individuals take this sense for granted, but the mere fact that you are reading this book indicates that you have some awareness of sound as a basic experience that needs to be better understood. Our emphasis will be ways that sound is generated and modified by the environment in which it occurs. The topics in this text are grounded in physics and mathematics. However, the way we interpret sound cannot be ignored because it dictates the properties of a sound signal that we must characterize and evaluate. Understanding this aspect of acoustics requires expertise in biology and psychology.