On the Sound Absorption Improvement of Water Hyacinth and Coconut Husk based Fiber Reinforced Polymer PanelErni Setyowati, Iwan Yahya, Edi Supriyo, Intan C. Romadhona and Aris MinardiMATEC Web of Conferences, 159 (2018) 01004DOI: https://doi.org/10.1051/matecconf/201815901004