Despite all modern technological achievements, creation of acoustically acceptable environment both at work and resident has become a challenging issue for human being. Elimination and reduction of unwanted noise can be achieved by vast array of porous materials one of which are textile fabrics. Textiles in addition to conventional end-use of apparels are used as curtains, floor coverings and items of upholstery. In these applications, textiles can serve as sound absorbent material. Currently non-woven and knitted fabrics are used as sound absorbent in various end-uses. In this work, acoustic properties of woven polyester fabrics were investigated at various frequencies using impedance-tube apparatus. Additionally in order to study the effect of fabric layering on sound absorbency, experiments using three layered fabric systems were conducted. Results were analyzed using commonly used statistical methods. Results showed that factors such as warp fineness and warp fabric density together with factors such as weft yarn twist and type in addition to fabric cover factor influence Noise Absorption Coefficient (NAC) at 2000Hz. It was found that while weft yarn type and twist affect NAC at 250Hz, NAC is affected by fabric mass at 1000Hz. Results also confirmed that both layering of fabric and used frequency affect fabric NAC. Parameters such as fabric thickness, cover factor, number of layers and frequency were selected as inputs to the multi layer feed forward Error-Back Propagation algorithm used for modeling and predicting of (NAC) of the samples. In order to achieve the best prediction, 17 structures were used and on the basis of Cross-validation technique, 270 data in 8 groups were justify; MARGIN: 0in 0in 0pt" Key Words: Acoustic, porous absorbent, noise absorption coefficient, impedance tube, neural network, polyester curtain fabrics
