Development of automated acoustic absorber panel utilizing coir fiber

Abstract

An alternative sound absorber panel is proposed which can be automatically controlled and tunable with impinged noise frequency. In the proposed design, a multilayer panel is considered which contains perforated plate (with high porosity), thin wire mesh (with very low porosity), coir fiber, perforated plate, air gap and moving back plate, sequentially. Thickness of the panel is considered as 44 mm which makes the panel more useful for limited space structure. Controlling the air gap thickness provide a tunable acoustic absorber which create wideband absorption. Natural coir fiber is used as a porous material which gives an advantage as it is an agro-based fiber and also available as waste material in Malaysia. Additionally, it makes the panel cost effective as it requires very cheap material to construct. Simulation results show that it can produce absorption more than 80% at 800-5000 Hz frequency band and more than 0.6 (60%) at 500-800 Hz. To make the panel automatically controllable with the frequency a sensible precise controlling system is proposed. Moreover, it is suggested that the performance of the panel and robustness of the control system would be analyzed using error microphone at the end of the panel.