Sound absorption coefficient measurement based on the Transfer Function Method specified by the standard ISO 10534-2 using low-cost alternatives

Thaynan Oliveira, Paulo Mareze, Matheus Pereira, Sergio Aguirre, William D', A Fonseca, Eric Brandão, Rogério Pirk
Porous materials are usually employed since they are a well-known and effective passive approach. This class of material converts the acoustical energy into heat by viscous and thermal effects. That is, this transduction is carried out by the particles' friction and movement inside the pores. Considering this scenario, it is clear that characterization of porous materials plays an important role in noise control. A common way to estimate their properties is via Kundt's Tube measurements, where
more » ... easurements, where the sound absorption coefficients are extracted by applying a normal incidence acoustic wave over the sample. The method is standardized by the ISO 10534-2, which recommends Class 1 instrumentation. This work presents two groups of measurements. The former case is the fruit of a low-cost measurement system, applied to a custom Kundt's Tube constructed in the Acoustical Laboratory of the Federal University of Santa Maria, in south Bra-zil. In the latter case, a commercial Kundt's Tube together with Class1 instrumentation is applied to the approximately same situation. The results are discussed and the analyses point out that the developed low-cost system has a satisfactory performance (considering the frequency range studied), achieving similar results.