The Acoustical Properties of Indonesian Hardwood Species

Abstract

Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The acoustical properties of four Indonesian tropical hardwood species were evaluated in this study. The objectives were to determine acoustical parameters e.g. logarithmic decrement, sound absorption, sound velocity as well as density and wood stiffness; and to evaluate the potential of those species for acoustical purposes. Sonokeling ( Dalbergia latifolia ), Mahoni ( Swietenia mahagony ), Acacia ( Acacia mangium ) and Manii wood ( Maesopsis eminii ) were selected in this research. Three different cutting plane patterns of sawn timber (quarter-sawn, flat-sawn, and plain-sawn) were converted into small specimens. The methods for determining acoustical properties were longitudinal vibration testing and time of flight of ultrasonic wave method. The result showed no significant difference (α=0.05) of acoustical properties in logarithmic decrement, sound absorption, and ultrasonic velocity means on quarter-sawn, flat-sawn, and plain-sawn for all wood species tested. It was found that Mahoni and Sonokeling had good acoustical properties of logarithmic decrement, ultrasonic wave velocity, and ratio of wood stiffness to wood density; and is preferred for crafting musical instruments. Acacia and Manii wood are recommended for developing acoustic panels in building construction because those species possess higher sound absorption values. Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Keywords : acoustical properties, logarithimic decrement , sound absorption, ultrasonic wave velocity, tropical wood species