To accurately predict sound fields in rooms using computational models, reliable quantitative data of the sound absorption characteristics of the materials in the room must be available. Obtaining this data can be challenging. Perhaps the most commonly used approach is to rely on tables of random incidence absorption coefficients, which are typically measured in a reverberation chamber. However, this data can change when materials are installed; thus, there are ongoing efforts within the community to measure the absorption characteristics of materials in situ. In theory, it is possible to utilize a field index to estimate the absorption characteristics of surfaces. The field index considered in this work is the ratio of the acoustic intensity to the sound energy density. Interestingly, this field index can be written in terms of a normal impedance. This work will examine how this field index might be used to estimate the impedance or absorption coefficients of material samples in simulated reverberant rooms. While efforts will be made to simulate the practical application of the proposed estimation approach, experimental validation will not be addressed at this stage of the work.
Albert Prinn (Wed,) studied this question.