Acoustic properties of natural fiber of oil palm trunk

Natural fibers are being used as substitutes of synthetic material for sound absorbing material as it is more environmentally friendly and renewable. This paper presents the investigation of Sound Absorption Coefficient (a) of Oil Palm Trunk (OPT) natural fiber as an acoustic material. The experiment was carried out using Impedance Tube Method (ITM) where all samples of OPT are tested for Sound Absorption Coefficient. The natural fiber of OPT was fabricated to form panel in three different thickness of 8 mm, 12 mm and 16 mm with an average density of 100 kg/m(3). From the result, it is found that OPT has a very good acoustic performance where all samples almost reached unity (alpha approximate to 0.9) at a high frequency above 3000 Hz. The result also shows that at low frequency, below 500 Hz, the Sound Absorption Coefficient ranges from 0.5 to 0.85. The natural fiber panel with a thickness of 12 mm is found to have the highest sound absorption coefficient, a. 0.99 at frequencies of 3000 Hz, 6000 Hz, and 6400 Hz, hence Oil Palm Trunk is a very promising natural fiber to be used as a sound absorbing material. (C) 2018 The Authors. Published by IASE.