Sound reduction by needle-punched nonwoven fabrics

Abstract

Effect of area density, fabric type, source intensity, number of layers, distance of fabric from sound source, distance of fabric from the receiver and fibre type on sound reduction of various needle-punched nonwoven fabrics has been studied in an indigenously fabricated equipment. Nonwoven fabric shows higher sound reduction than the woven fabric. Jute-polypropylene (1:1) blend shows maximum sound reduction among jute, polypropylene, polyester and other jute-polypropylene blend (3:1 and 1:3) samples. Higher area density is responsible for higher sound reduction and there is a negative correlation between area densityor bulk density of needle-punched nonwoven and sound reduction. With the increase in number of layers of nonwoven fabric, the sound reduction through the fabric increases initially but after the maximum it remains almost unaltered. Sound reduction also increases as the distance between the fabric and the sound source increases, and the source decibel decreases.