Acoustic Properties of Gmelina arborea (Roxb.) Wood

Abstract

G. arborea wood is a preferred choice for making musical instrument in Nigeria. However, its utilization is solely dependent on indigenous knowledge. Meanwhile, for optimum acoustic performance there is need to study acoustic properties of wood. Thus, this work aim to study the acoustic properties of G. arborea wood. Three trees of G. arborea with 25 ± 2 cm in diameter at breast height (DBH) were obtained. From each tree, bolts of 60cm in length were collected axially, and wood sample of (R x T x L) were obtained radially from each bolts. The samples were then prepared for testing. Fundamental frequency longitudinal vibration method was used to determine acoustic properties of the wood. Hence, necessary model and equations were used to calculate other acoustic parameters. The fundamental frequency, velocity of sound, longitudinal elastic modulus, specific longitudinal elastic modulus, damping factor, acoustic coefficient (K), sound quality, acoustic conversion efficiency, and impedance obtained in this study were 1095.02 ± 20 Hz, 4848.58 ± 77 m/s, 9.34 ± 0.35 GPa, 23.57 ± 0.74 GPa, 0.0039 ± 0.00, 12.30 ± 0.29 m4kg-1s-1, 279.64 ± 21.64, 3435.66 ± 278 m4kg-1s-1, 1.9119 x 106 ± 4.8 x 103 kg/m2s respectively. Meanwhile, no significant differences were recorded for acoustic variables tested axially and radially, except for K. Furthermore, values obtained in this work compared favorably with some known acoustic species. Conclusively, this work was able to conduct a study on some acoustic properties of Gmelina arborea wood and thus found G. arborea wood suitable for acoustic purpose. However, selection of wood for acoustic function should be purpose driven.