Tropical wood acoustics: impregnation effects on Cajuput, Mangium, and Mango woods for sustainable building materials

This study explores the acoustic properties of three tropical woods—Cajuput (Melaleuca cajuputi), Mangium (Acacia mangium), and Mango (Mangifera indica)—as sustainable materials for sound absorption. The wood samples were prepared in a standardized cylindrical shape, impregnated with zinc chloride (ZnCl₂), engine oil (EO), or coconut oil (CO), and subjected to heat treatment at 105 °C for 3 h. Acoustic analyses using an impedance tube revealed that CO treatment notably enhanced the Sound Absorption Average (SAA), with Cajuput wood showing a remarkable 53% improvement. Sound absorption performance varied across frequency ranges, with EO and CO treatments notably improving low, medium, and high-frequency bands in most woods, while ZnCl₂ exhibited less pronounced effects. However, all treatments reduced Sound Transmission Loss (STL), indicating a trade-off between sound absorption and insulation properties. Statistical analysis using two-way ANOVA confirmed the significant influence of wood type and treatment on acoustic performance across all parameters. These findings underscore the potential of tropical woods, particularly when treated with eco-friendly substance like coconut oil, as sustainable acoustic materials.