Non-standardized room acoustic metrics

The first edition of ISO 3382 was adopted in 1997. It already listed T30, Early Decay Time, Clarity, Definition, Center time, Lateral fraction and IACC as relevant room acoustic parameters. They are still up to date, only supplemented by the division into two dimensions of the spatial impression and by the stage support. In the last decade, new research has been conducted on sound perception in concert halls and the results seem to confirm that loudness, reverberation, clarity (intelligibility) and localization are the most important. More recently, auditory-visual interaction, loudness decay and directional reverberation have been found to be factors that describe dimensions of the overall experience of music in a concert hall. This paper highlights the challenges associated with some of the standard parameters and the opportunities presented by newly developed metrics.