Room shape and distribution of sound quality in concert halls

The distribution of sound and acoustical quality inside concert spaces is not uniform. Source to receiver distances, as well as local conditions such as vicinity of sidewalls, balcony overhangs and balcony fronts make for substantial differences between listening positions. These differences can be measured by using the standard ISO 3382-1 acoustic parameters. These measurements show that the differences between these listening positions can very well go beyond the Just Noticeable Differences (JNDs). Traditional acoustical studies use the mean values and standard deviations to study concert spaces. Recent studies have shown that the distribution of most acoustical parameters inside concert spaces do not follow normal curves, hence mean values and standard deviations are not reliable.

A clear objective of good acoustic design is to provide optimal sound quality to all listening positions inside a room. This research employees computational search methods and parametric models to study room shapes that optimize the distribution of acoustical quality. The overall geometry of the room as well as specific components such as canopy reflectors, balcony fronts and overhangs are the subject of the parametric search. Traditional typologies of concert spaces with flat surfaces are studied by means of source image and ray tracing acoustic simulations, while complex curved surfaces are studied by means of NURBS geometry and ray tracing simulations. Statistical methods for the study of the distribution of optimal acoustical parameter values are proposed.

People

© Politecnico di Torino - Credits