Perforated Plate Backing With Coconut Fiber as Sound Absorber For Low and Mid Range Frequencies

摘要

A material's sound absorbing properties can be described as a sound absorption coefficient in a particular frequency range. Porous absorbers are the most commonly used sound absorbing materials, however they do not have good absorption properties at low and mid frequencies. In order to increase the absorption properties at low and mid frequencies, porous absorber should have larger thickness and size. By using perforated plates backing with porous absorber, it is possible to gain higher noise absorption at low and mid frequencies. This study was conducted to investigate the effect of perforation size ratio, mass, air gap and holes diameter of perforated plates as backing plate for porous absorber. Coconut fibres were used as backing medium for perforated plates.