Deviations in sound absorption measurements in the reverberation room and impedance tube

Document Type : Original Article

Author

Tersa / Alharm /Giza

Abstract

This paper compares the two main methods for measuring sound absorption coefficients for different materials. Chemical and physical properties of the materials studied are vastly different (Carpet, rockwool, polyurethane foam, Gypsum, Rubber, Polyurethane sponge and wood). The impedance tube method and the reverberation room method were used to conduct the tests. To appear the difference between the two measurement methods, the study included weakly, median and high absorbing materials. The obtained results shows that, the effect of source's location and the sample position angle on the sound absorption of the material in the room, also the sound absorption coefficient measured in the impedance tube is higher than that measured in the reverberation room by an amount reach 40% for both rockwool and Polyurethane sponge (porous materials). While sound absorption coefficients for hard (non-porous) materials (Gypsum and wood) are roughly identical to those for solid materials, the sound absorption coefficient measured in the impedance tube is higher than that obtained in the reverberation room. The sound absorption coefficient measured in the reverberation room for median absorbing materials as rubber and polyurethane foam (materials with internal holes and non-porous surface) is higher than that measured in the impedance tube except at minor frequencies. The relative standard deviation in the reverberation room ranged from 0.01 to 0.035.

Keywords

Main Subjects

Journal of Measurement Science and Applications (JMSA)

Articles in Press, Accepted Manuscript
Available Online from 07 August 2022

Files

Share

How to cite

Statistics