Advanced Procedure Used for Determining the Absorption Coefficient of Sonic-Absorbent Materials

Solving the acoustical problem and improving the impact indoor environmental quality represents a priority for many researchers and manufacturers of materials with a high noise reduction of coefficient rating. The paper presents a real solution for determination the sound-absorption coefficient of materials with acoustical properties from the gypsum family. The procedure used for test is standing wave method into a Kundt tube. The experiment setup used a complex installation of a Kundt tube containing a loudspeaker for emitting the sound waves at a well-defined frequency by a first PC, a microphone for detecting and transmitting the signal to a second PC for analyzing and processing the data. All of these were performed by using MATLAB Programs. Tests were conducted with two material samples with original receipts, one from gypsum and other from special gypsum plaster with sound-absorbent properties. The frequency was set separately for each material from 50 Hz to 1250 Hz to determine their sound-absorption coefficients. The result of experiments shows the efficiency of installation and superiority of special gypsum plaster vs. gypsum along entire frequency range of testing that can be carrying on to other materials with sound properties.Copyright © 2011 by ASME