Experimental study to measure the transmission loss of double panel natural fibers

Abstract

In this paper, the transmission loss (TL) of the natural fiber materials will be measured experimentally at one third octave band harmonic and broadband frequencies. The different natural fibers used in this study are jute fibers, kenaf fibers, banana fibers, coconut coir fibers, and hemp fibers. An acoustic soundproof cabin has been fabricated to measure the transmission loss of natural fiber material. A one-dimensional duct is placed inside the soundproof cabin. Inside the duct there is a specimen of natural fiber materials. A loudspeaker is used to generate acoustic harmonic and white noise disturbances at various frequencies. The generated acoustic sounds then passed through the double panel natural fiber specimens. A sound pressure level (SPL) meter is used to measure the noise levels inside the duct. In this paper, a double panel natural fiber material specimen is proposed for testing. The double panel specimens are a combination of two natural fiber materials. In the double panel, the two panels are made from same or different natural fibers and also air is enclosed between them. The main objective of this paper is to measure the transmission loss and equivalent continuous A-weighted sound pressure level of fiber-air-fiber type specimens so that in future these types of combinations can be used for various engineering and other applications. It is observed that the combination of jute-air-kenaf is absorbing more sound as compared to jute-air-banana fibers and hemp-air-coconut coir fibers.