Using the standard on objective measures for concert auditoria, ISO3382, to give reliable results

ISO3382 (1997) includes a series of quantities to measure in auditoria beyond the traditional reverberation time. These new measures are now used extensively for acoustic design of spaces from classrooms to full-sized concert halls. They are however more difficult to measure than the reverberation time: they vary with position of both source and receiver, they are sensitive to occupancy of the seats and stage etc. The evidence from viewing reports produced by others using these measures is that measurement methods are often not consistent and the values produced are therefore not completely comparable to those provided by others. This paper lists the potential pitfalls involved in making measurements of the new measures, discussing such things as audience occupancy, stage occupancy, source directivity, receiver positions and measurement frequencies. Because these measures vary with receiver position, measurements of five or more quantities over a range of different frequencies at ten or more positions implies a large amount of data produced. A major issue therefore is to what degree is it acceptable to average results. The question of interpreting the results is also addressed, with the overall aim of making the measurement process and reporting of results more reliable.