Acoustic properties of different blending ratios of empty fruit bunch and oil palm frond

Abstract

The society understands the importance of using sound-absorbing panels to protect our health against the noise pollution. However, the repercussions of fibreglass as sound-absorbing panels on human health and the environment have increased year by year. Natural fibers are more environmentally friendly and have significantly lower production cost. This research emphasizes the acoustic properties of different blending ratios of Empty Fruit Bunch (EFB) and Oil Palm Frond (OPF at four different thickness. Their acoustic properties were tested by using the Impedance Tube Method (ITM) from frequency range of 0 - 6400 Hz. The findings show the Sound Absorption Coefficient (SAC) value increases as the frequency increases for all samples. Both blending ratios have good SAC results. For blending ratio of 30% EFB – 70% OPF, the SAC of the panels achieved 80% and above at frequency between 3500 - 6400 Hz for samples with thickness of 14 mm, 16 mm and 18 mm. However, for blending ratio of 20% EFB – 80% OPF, the SAC of all samples are found 0.8 and above at frequency between 3500 - 6400 Hz. Notably, the SAC values for both blending ratio are increased with increasing in thickness. It might be attributed to the effect of tortuosity. The SAC values for all samples are also found to achieve unity ( ∼ 0.96 ) at different frequency range. Furthermore, the frequency range for SAC to reach 0.8 and above has been increased from 4500 – 6400 Hz to 3500 – 6400 Hz with an increased in OPF contents.