Jerald R. Hyde
Consultant on Acoustics, 1335 Main St., St. Helena, CA 94574
Over the last two decades, a set of ``modern'' room acoustic measures has been developed which utilizes the creation of an impulse response at various positions within a room. The idea has been to create a set of information for that space which facilitates correlation with subjective evaluation. Objective measures such as energy ratios, lateral energy fraction, and source strength have been reported frequently in the literature over the past decade, stimulating a concerted effort to standardize the methodology of both the measurements and the data analysis. The goal is to understand the effects of an almost endless set of variables on the data so that one will know which sets of information from different halls and measurement systems can be reasonably compared. This paper will report the results of different measurement systems data in the same auditorium as well as the difference in acoustical properties between the empty and occupied condition for the same space. An approach to how sets of data might be averaged will be explored along with a methodology for predicting full occupancy objective values from ``empty'' room data. Finally, a range of objective criteria for concert halls will be suggested.