Linear system approach to room acoustics

Taking the variables which affect the propagation of sound in a room, such as properties of the room confines, objects in the room, air absorption, etc., and assuming they are linear operators we can formulate a linear system approach to room acoustics. Given the impulse response of a linear system it is possible to find by analysis all the properties of the system, whether in the time domain or frequency domain. In relation to any two fixed points in a room, one for source input and the other for reception, by use of the principles of correlation a method is available to derive the impulse response of the room. It follows that by experimentally determining the impulse response function of the system considered one can obtain in situ values of transmission and reflection coefficients, energy decay rates, parameters required for prediction of sound levels from multiple coherent sound sources and isolation of sound energy due to border diffraction effects. Use is made of the correlation function a second time to generate from the available impulse response function standard acoustic quantities. Inherent effects of the source properties may be removed from experimental results by resort to deconvolution signal processing.