A review on the taxonomy, factors associated with sound absorption and theoretical modeling of porous sound absorbing materials

The sound is the pressure disturbance created over air particles above and below atmospheric pressure. It is a mechanical wave which requires a medium to propagate. The sound can generate from a source, then travels through a medium and finally is received by the receiver. The noise is an unpleasant or unwanted sound that is undesired by the receiver. This unwanted sound is absorbed by the sound absorbing (SA) materials. This paper presents a complete comprehensive literature survey for the SA materials and organized the information in the following manner. First, the phenomenon behind SA mechanism is being explained, then the detailed information of existing SA materials with their classification is reported. After that, the factors associated with the sound absorption that influences the sound absorption coefficient (SAC) is being presented. Finally, the theoretical models for porous materials are being discussed followed by the details of price comparison of natural and synthetic fiber-based sound absorbers and the applications of SA materials of various acoustical products. There are a lot of researches going on to develop new acoustic materials and hence this paper will help the researchers to know about the existing SA materials and also help them to develop new acoustic materials by considering significant information related to sound absorption.