The pore structure and sound absorption capabilities of Homalium (Homalium foetidum) and Jelutong (Dyera costulata)

In recent years, researchers have pushed to develop an eco-friendly sound-absorbing material derived from natural products capable of reducing noise in indoor sound environments. Wood may fill this niche. In the cross sections of diffuse-porous wood, vessels are widely distributed, a circumstance that provides advantages from a sound absorption perspective. Based on preexisting data concerning the physical properties of various woods, two hardwoods, Homalium (Homalium foetidum) and Jelutong (Dyera costulata), were selected and their sound absorption capability was examined. Gas permeability, pore sizes, and pore types were investigated, and their sound absorption coefficient was calculated. It was shown that Homalium and Jelutong are more gas permeable compared to other hardwoods, especially Jelutong as its pores were larger and its through-pore porosity was greater than that of Homalium. These properties, in fact, are responsible for its superior gas permeability and sound absorption compared to Homalium. It was also determined that an air back cavity was more effective in improving sound absorption in the samples of both woods than increasing the thickness of the samples. Ultimately, this study concludes that Homalium and Jelutong cross sections are well suited for use as sound-absorbing functional building materials.