Wood is a sustainable renewable material that widely used in the building sector. Due to recent trends green initiatives European and other countries, wood waste becoming more popular for sound absorption insulation because of its renewability. Recycled granulated charcoal an effective acoustic treatment. In this study, we investigated coefficients raw species: birch (Betula pendula), pine (Pin...

This study aims to investigate the sound absorption ability of Acanthopanax senticosus wastes as an eco-friendly sound-absorbing material. The coefficient was examined with different heights A. filling (40, 60, 80, and 100 mm) in impedance tubes. peaks shifted a lower frequency height inside tubes increased. at 80 mm obtained 0.3M 0.5M grades, respectively, based on KS F 3503. results suggest t...

An acoustic plate-valve resonator is developed and optimized to maximize absorption by enhancing the Helmholtz resonance with coincident structural vibrations of plate-valve. The current research initially examines concept experimentally a 3D printed valve. Then use analytical numerical modeling, analysis performed, which allows eigenmodes eigenfrequencies be determined. When properties are mod...

Low-frequency noise is difficult to deal with by traditional porous material due to its inherent high acoustic impedance. This study seeks to extend the effective range of sound absorption to lower frequencies by filling a low density gas, such as helium, in the porous material. Compared with conventional air-filled absorption material, the helium-filled porous material has a much reduced chara...