A method for predicting acoustic indices in long enclosures

There is a recognised need for an accurate method of predicting acoustic indices in long enclosures. The existing theoretical formulae or computer simulation models, however, appear to be only applicable for relatively simple conditions. In this research, a semi-empirical method has been developed and, correspondingly, a computer program has been written, The basic idea of this method is to correct the calculations of existing theoretical formulae or computer simulation models with an empirical database based on physical scale model or site measurements. Particular attention is given to the speech intelligibility of multiple loudspeaker public address systems in underground stations. This method has been validated in a typical station. (C) 1997 Elsevier Science Ltd.