Development of Impedance Tube to Measure Sound Absorption Coefficient

Abstract

An acoustic property of textile material can be measured using an impedance tube, is the most popular technique to measure normal sound absorption and transmission loss. This method consuming less time and a very small sample is required to assess the acoustic properties of the materials. Unfortunately, the cost of the impedance tube and software used for measurement is very high. This paper gives information about how to develop a cost-effective impedance tube suitable for researchers. The design, development, and fabrication of the impedance tube suitable for different frequencies with technical details are present here. Information related to some software which can be used to measure sound absorption coefficient also provided. To validate the testing results obtained from custom-build impedance tube, same samples were tested on commercially available impedance tube at PSG College, Coimbatore. It was observed that both the instruments provide almost same results, no statistically significant difference found in results. Base on the results design of customized impedance tube recommends to student and researcher interested in measuring acoustic properties of textile material

Analysis and Experimental Investigation of Sound Absorbing Materials for Industrial Noise Control

“…The second method states about transfer function theorem which utilizes reflection co-efficient of waves. According to Bhattacharya & Bihola, transfer function is more suitable than any other method as it intregates the differential parts of a propagated wave [5]. They had used pyrax glass impedance tube apparatus reflecting an idea that uses various materials as the impedance tubing and measured the acoustics of lower ranged systems and found about 89.67% of more effectiveness rather than expensive setup.The factors along selecting sound absorbing natural material Nordin et al quoted properties like toxicity, fiber size, density and porosity.…”