Noise Control, 2nd Edition

1

Fundamentals

LEARNING OBJECTIVES

In this chapter, the reader is introduced to:

• fundamentals and basic terminology of noise control;

• noise-control strategies for new and existing facilities;

• the speed of sound and the wave equation;

• plane and spherical waves;

• energy density; sound intensity and sound power;

• decibels and sound pressure level;

• frequency analysis and sound spectra;

• adding and subtracting sound pressure levels and combining level reductions; and

• three kinds of impedance.

1.1 Introduction

The World Health Organisation (Goelzer et al., 2000) has recognised noise as the most significant health hazard to the working population in terms of the number of people affected. In many industries there is much that can be done to alleviate ...