Due to their varied properties and diverse end uses nonwoven fabrics comprise a very significant proportion of total world textile output. In applications such as floor and wall coverings or as automobile carpets, nonwoven fabrics not only must serve as carpet, but also must function as sound insulation material. In this work the effect of fiber variables, together with the influence of fabric production parameters on sound absorption properties of polypropylene needled floor covering having different surface effects have been investigated. After a brief introduction to nonwovens, relevant information on acoustic is presented. An instrument to measure noise absorption coefficient (NAC) of the experimental samples has been designed and built. A total number of 164 samples of fabric with three different surface effects were produced. A commercial melt spinning line was used to manufacture staple polypropylene fibers of different fineness. A two cylinder carding machine together with a horizontal cross-lapper was employed to obtain the required batts of fibers. A laboratory needle loom equipped with felting needles was used to consolidate the fibrous batts into plain surface samples. Structuring needle looms quipped with fork and velour needles were used to manufacture the cord and the velour surfaced samples. Results showed that, NAC increases with an increase in fiber fineness. This phenomenon was also observed when the weight per unit area (g/m 2 ) of the samples was increased. Additionally it was found that, NAC increases when the total punch-density received by the samples during initial stage of needling is increased. As far as surface structure of the samples was concerned, it can be confirmed that, under given conditions plain and cord surfaced samples produced the highest and the lowest NAC respectively. The value of NAC obtained for the random velour samples laid in between of the values of plain and cord surfaced fabrics. Results also indicated that, while at frequencies of 500Hz and 4000Hz all samples exhibited the highest NAC value, at frequencies of 1000Hz and 2000Hz the least value of NAC was recorded for all the samples.
