Prediction of reverberance in rooms with simulated non-single-exponential sound decays

It has been known that the application of diffuse field theory to the sound field with a non-single-exponential sound decay did not comply well with listeners’ experience. Recent researches have concentrated on quantifying and controlling the non-single-exponential decay processes in rooms. However, the effect of non-single-exponential sound decay on listeners’ reverberance has not been clearly known in spite of its importance. The present work tried to explore the relationship between the non-single-exponential decay of sound in rooms and the listener's reverberance, and further to develop a simple way of predicting subjective reverberance caused by non-single-exponential decay processes. A series of listening experiments were carried out with various computer generated non-single-exponential sound decay patterns using a two alternative forced choice (2AFC) paired comparison method. A simple way of predicting listeners’ reverberance for non-single-exponential sound decays was proposed by combining the results of subjective tests and the analysis of Schroeder decay curves using decay rates at multiple fixed intervals and their effects on listeners’ reverberance. The correlation analyses suggested that the proposed method could predict listeners’ reverberance caused by non-single-exponential sound decays better than conventional parameters within the range of non-single-exponential decay patterns examined in the present work.