Characterization of The Acoustical Absorption of Woven Agel Fibre Sheet (Corypha utan Lamk.) Based on The Woven Fibres Orientation and Thickness of Layers
The research presented is a study of acoustical characteristics of agel fibre. This study aimed to determine the effect of variations in thickness and orientation of agel fibre to its absorption coefficient (α).
Woven sheet of agel fibre with size of 3×1 m2 was used in this study. Sheets varies in its woven direction. This research used woven agel fibres by varying the thickness and the fiber orientation. Variations of thickness were with a single and double layer. As for variation of the woven orientation, sheets of double layer were stacked parallel and crossed. Testing was conducted in a Reverberation Chamber at frequency f 250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz.
Result of this research demonstrated that the agel fibre orientation does not influence acoustical characteristic of the absorber sheet. At frequency of 250 Hz, absorption coefficient of woven sheet with parallel direction is 0.19, 0.83 at frequency of 500 Hz, 0.86 at frequency of 1000 Hz, and 0.77 at frequency of 4000 Hz, while absorption coefficient of the woven sheet with cross orientation is 0.17 at frequency of 250 Hz, 0.83 at 500 Hz, 0.94 at 1000 Hz and 0.65 at 4000 Hz. Variations of fibre’s thickness results that double layer sheets has larger absorption coefficient than single layer. Absorption of coefficient of single layer woven sheet are 0.029 at 250 Hz, 0.337 at 500 Hz, 0.856 at f 1000 Hz, while absorption coefficient of double layer woven sheet results 0.189 at 250 Hz, 0.828 at 500 Hz. Based on all parameters tested, it can be concluded that fibre orientation does not affect the value of absorption coefficient, while variation of fibre thickness influence the value of α for low and medium frequencies.
