Sustainable multiple resonator sound absorbers made from fruit stones and air gap

Abstract

This article investigates the sound absorption coefficient of materials manufactured from natural wastes. Fruit stones from some crops are one of the most available natural wastes in the Mediterranean Region. Recycled and vegetable products are becoming an interesting alternative to traditional materials to be used as sound-absorbing panels.Fruit stones can be profitable for a number of applications, such as biomass to produce energy. This research work intends to demonstrate that one of their applications can be ecological sound absorbers in building acoustics.Different four fruit stone samples, with different air gap volume percentages, display similar behaviour to multiple Helmholtz resonators (MHRs). By adding a 40 mm-thick rockwool layer, the sound absorption coefficients are compared for each sample.The experimental results allow establishing some analogies between MHRs and the new absorbing materials according to thickness, fruit type and the air gap volume. These fruit stones have been demonstrated as a good choice from acoustic and sustainable points of view.