Control of Sound - Absorbing Materials for Damping of Sound

Chapter 1

Abstract

each one.

1. Introduction

1.1 Acoustic quality

potentialities for the desired use.

understanding of the spoken word.

operational considerations [1].

3

1.2 Noise control and acoustic project

achieve the desired acoustic quality at the receiver.

Alice Elizabeth González

How Do Acoustic Materials Work?

Acoustic quality of closed spaces is an increasing concern all around the world, since noise pollution is one of the main nowadays pollutants, but also one of the less considered when building designing and construction. In 2011, the World Health Organization stated that noise pollution should be treated as a public health concern: about 1 million years of human healthy life are lost yearly because of the environmental noise pollution, emphasizing on traffic noise in the cities. There are some physics phenomena that are the rule of thumb for room acoustic projects. This chapter introduces the main concepts about them: sound absorption, insulation, and diffusion. Their principles, main implementation, and computing are presented for

Keywords: acoustic materials, sound absorption, sound insulation, sound diffusion

Under the term "acoustic quality," a set of characteristics (as sound pressure levels, spectral composition, and duration of the sounds perceived) is integrated, as well as others related to the space itself—for example, its reverberation time which allow to qualify how valuable this space is regarding its aptitudes or

One place can have good acoustic quality for a certain use but not for another. For example, the high reverberation time of Catholic churches is part of the characteristics of the space of meditation that is desired to be generated there and is suitable for interpreting/listening to sacred music; however, it conspires against the

The concepts of acoustic quality and noise control are often closely related. Noise control refers to a set of methods, techniques, and technologies that allow obtaining acceptable noise levels in a certain place, according to economic and

Noise control does not necessarily imply reduction of noise emissions; it refers to making acceptable the sound level in immission (i.e., the signal that reaches the receiver). To know if it is, some objectives and valid criteria must be selected and applied to compare with, in order to answer the question of "acceptable for what" or "for whom". There are different ways to attack a wide range of cases in order to
