Room Modes in Rectangular Rooms with Complex Impedance Boundaries

Abstract

In many calculation approaches in room acoustics, one models the reflection of surfaces via a positive, real absorption coefficient, neglecting the fact that the reflection coefficient can have a non-zero phase. For some sound-absorbing structures such as resonators, this simplification leads to erroneous results, e.g. when room modes are of interest.

This contribution presents an approach for the calculation of room mode frequencies in a rectangular room with complex and frequency-dependent acoustic impedance wall boundary conditions. The results are to be used for auralizations of different scenarios in which the modal behaviour of a room is modified, and for evaluation by listening tests.