The expansion of the oil palm industry has affected the environment and the poor handling of oil palm waste has greatly endangered the habitat. The oil palm natural fibre waste can be put to good use as sound absorber owing to its amazing acoustic properties. This research focuses on the acoustic properties of mixing Empty Fruit Bunch (EFB) and Oil Palm Frond (OPF) in a thickness of 12 mm, 14 mm, 16 mm, and 18 mm. The fibreboard has been fabricated at a density of 120 kg/m3. The Sound Absorption Coefficient (SAC) and morphologies of all the samples were examined using the Impedance Tube Method (ITM) and Scanning Electron Microscope, (SEM). The findings of this research show the sample’s SAC value increased with thickness. It is noteworthy that this combination percentage of natural fibres of EFB and OPF show good acoustic performance where the SAC values above 0.8 at wide frequency 3000-6400 Hz. Sample thickness 14 mm and 18 mm achieved unity (1.0) at frequency 4000-5500 Hz. In addition, all the samples were found to exceed 90 % of the absorption rate in the range of 4500-6400 Hz. The morphology content of EFB and OPF helps in enhancing the absorption rate.