ABSTRACT
The wave theoretical description of sound fields in closed spaces, as outlined in the preceding chapter, is certainly correct from a physical point of view. Nevertheless, it is not very profitable when it comes to solving practical problems in room acoustics such as designing a concert hall or analysing a given situation. This is because of the tremendous number of normal modes that need to be calculated in order to cover a wider frequency range and also the difficulty in calculating even one of them when the room has non-rigid walls or a more complicated shape (see Section 3.3). Furthermore, as we have seen, the knowledge of individual normal modes with the associated eigenfrequencies is pointless for the frequency range above the Schroeder frequency, i.e. in the frequency range which is usually of main interest in room acoustics.
