Utilization of biomass for green products is still progressing in the effort to provide alternative clean technology. This paper presents the utilization of natural waste fibers from paddy as acoustic material. Samples of sound absorbing material from paddy waste fibers were fabricated. The effect of the fiber density, that is, the fiber weight and the sample thickness, and also the air gap on the sound absorption coefficient is investigated through experiment. The paddy fibers are found to have good acoustic performance with normal incidence absorption coefficient greater than 0.5 from 1？kHz and can reach the average value of 0.8 above 2.5？kHz. This result is comparable against that of the commercial synthetic glass wool. Attachment of a single layer of polyester fabric is shown to further increase the absorption coefficient. 1. Introduction Use of synthetic porous and fibrous acoustic materials is still frequently found especially in building acoustics as well as in noise control applications. The products such as foam, rock wool, and glass wool made from minerals are known for their toxicity and polluting effects which are harmful to human health as well as to the environment. It has been presented that their production can release more carbon dioxide into the atmosphere compared to those made from natural materials [1]. In order to support “green” environment campaign, acoustic absorbers from natural materials are therefore of interest due to their biodegradability and sustainability. Several works have been published which studied the potential of natural materials to be employed as sound absorbing materials. The bamboo fibers are found to have absorption coefficient similar to that of the commercial glass fiber. The fibers were also used to develop a fiber board of a resonant-type absorber and are found to have better acoustic performance compared to plywood [2]. The sound absorption of kenaf fibers was investigated by D’Alessandro and Pispola [3] through a reverberant room test showing absorption coefficient of 0.85 above 1？kHz. Ersoy and Kü？ük [4] studied the potential of waste industrial tea leaf and found that the absorption coefficient of the waste fibers increases significantly when backed with a single woven cotton cloth. For 10？mm thickness, the acoustic performance of the tea leaf fiber at high frequency is superior to that of polyester and polypropylene. Waste ramie fibers treated and nontreated with alkalization can also produce promising results with an average absorption coefficient of 0.6 at frequency range of 500？Hz–3.2？kHz [5].
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