Using Non-wave based modelling to explore how much acoustic diffusion is too much in a concert hall.

Abstract

This paper explores the relationship between acoustic surface diffusion and acoustical character in concert halls by using non-waved based modelling. Measurements were undertaken in a small concert hall to use as a baseline, which is then transferred into ODEON to experiment with the acoustic parameters further. Using the ODEON modelling results, the relationship between amount of diffusion vs scattering coefficient to achieve optimal objective parameters in a concert hall according were visualised. These trends were then tested on existing famous concert hall models, e.g. Musikvereinssaal. The experiments showed that when considering how much diffusion is too much in a concert hall, the statistical amount of diffusion is less of a factor, when compared to retaining strong early reflections from side walls and ceilings and the amount of scattering provided by diffuse surfaces. For example, a hall with a high amount of diffusion, can still be a subjectively "good" hall, if it still has strong early reflections on the side walls and ceilings when compared to a hall with geometry that does not provide strong lateral reflections.