Acoustic Properties of Selected Tropical Wood Species

Acoustic properties such as specific dynamic Young's modulus (E'/gamma), internal friction (Q (-1)) and acoustic conversion efficiency (ACE) of wood are important properties frequently examined by researchers. Vibration technique is one of the non-destructive evaluation techniques used as an alternative method for measuring the acoustic properties of wood. The objectives of this study are to determine acoustic properties of selected low density tropical wood species namely Endospermum Diadenum, Cratoxylum Arborecens, Dyera Polyphylla, Macaranga Gigantea, Commersonia Bartramia and Alstonia Pneumatophora and their suitability for making violin and guitar (acoustic instruments). The acoustic properties were determined by using free-free flexural vibration method. The results show that there are significant and good relationship between log Q (-1)/(E'/gamma) and log E'/gamma with negative gradient for each and overall wood species studied. The P-value of regression equation is less than 0.01 whereas the coefficient of determination (r (2)) is in the range of 0.565 to 0.894. The mean value of E'/gamma, Q (-1) and ACE of wood species studied are in the range of 1.69x10(10) Pa to 2.73x10(10) Pa, 0.017 to 0.035 and 1.50x10(7) to 3.56x10(7) respectively. Based on the mean value of E'/gamma, Endospermum Diadenum, Cratoxylum Arborescens, Macaranga Gigantea and Dyera Polyphylla are preferred for making all component of violin and guitar except for the top plate of violin. Commersonia Bartramia is preferred for making the back plate of violin and guitar, whereas Alstonia Pneumatophora is only preferred for making the back plate of violin.