Sound Absorption Coefficients of Micro-fiber Fabrics by Reverberation Room Method

Abstract

The sound absorption properties of materials are important not only for noise reduction, but also for controlling reverberation time for speech intelligibility in rooms and for promoting fuller sound in concert halls. Industrial textiles are focusing on these materials' application for sound absorption, thus new textiles were to be examined in relation to this performance. Micro-fiber fabric has fine fibers and a high surface area and it has been used in such applications as wipers, thermal insulator, filters or breathable layers. It can be also used for sound absorption. This paper examines the possibility of using micro-fiber fabrics as sound absorbent materials. We tested the sound absorption coefficients of five micro-fiber fabrics and one regular fiber fabric by the reverberation room method. The results showed that the micro-fiber fabrics' sound absorption is superior to that of conventional fabric with the same thickness or weight, and the micro-fiber fabrics' structure was found to be important for controlling sound absorption according to sound frequency. Fabric density was found to have more effect than fabric thickness or weight on sound absorption, and the Noise Reduction Coefficient increases to its highest value at a fabric density of about 0.14 g/cm3, and it decreases thereafter.

Sound absorption property of nonwoven based composites

“…The density of material exerts, however, a greater influence on sound absorption than the fabric thickness or weight [10]. In the case of composites, the values of sound absorption coefficients are small for low frequencies and usually they increase with increasing frequency.…”

“…Nonwovens owing to their great surface area, especially those made on the basis of natural fibres or active carbon fibres, are often mentioned beside spacer knitted fabrics as fibrous materials with a relatively good acoustic behaviour [5][6][7][8][9][10][11][12] with respect to conventional materials such as foams.…”

“…Composites, depending on their structure, can fulfil various expectations connected with their strength, rigidity, resistance, weight, thickness or surface quality. However, there are still only few research results available concerning composite materials with sound absorbing properties [10].…”

Designing and Manufacturing a Noise Controlling Silencer for the Cooling Tower Pump of Sarcheshmeh Copper Power Station

“…Furthermore, the rise in the thickness of absorbent materials leads to a decline in the number of peaks and causes some changes in the transmission loss peak frequency (14). Lancaster et al (2007) studied the impact of microfiber cloth on absorbing noise and concluded that the density of microfiber cloth plays a more important role than its thickness and weight in reducing noise (15). We found that silencers with higher density are better noise absorbents, a finding that is in line with the results of previous studies.…”

Preparation and Properties of Foamed Cellulose-Polymer Microsphere Hybrid Materials for Sound Absorption

“…Relationship between Cellulose Morphology and Beating Degree Figure 5 shows the effects of beating degree on the fines content, kink index, and crimp index. Compared with the raw pulp fibers, the kink index and crimp index decreased with increasing beating degree, as measured by the Schopper-Riegler method (Li and Xu 2011), from 14 °SR to 68 °SR, but the fines content increased as well (Attenborough 1971;Na et al 2007;Beg and Pickering 2008). As for the fines content test, measurements controlled by computer were based on the direction of polarized light.…”