Acoustic properties of biodegradable materials in the low and medium frequency range

Materials commonly used in various public spaces are characterized by sound-absorbing or insulating properties. Natural fiber composites are an eco-friendly promising alternative to conventional synthetic fiber composites. For specialized rooms, it is essential to provide good insulation and properly selected sound-absorbing materials. This article presents the results of tests on the acoustic properties of selected natural, biodegradable materials. The aim of the research was to find biodegradable composites that would have good insulating and absorption properties in the low- and medium-frequency ranges. Firstly we tested several configurations of composites made of various wood-based materials in terms of sound pressure vs. frequency. Then, the sound absorption coefficients of the best natural fiber composites used were measured by the technique of two microphone transfer functions in the impedance tube. It was concluded that multi-functional composite materials can be made by natural fibers so that both the good acoustic insulation together with appropriately high sound absorption coefficients in the low and medium frequency range can be achieved.