Research On Ceiling Design And Concert Hall Acoustics

Acoustical design of concert hall is related to many factors, such as the hall geometric, dimensions, seat capacity, layout of the audience area, and the acoustical treatment of hall surfaces, etc. Among these correlated factors, ceiling design is the more flexible one to be considered as it allows variety of design concepts for architects to develop. And the acoustical effect of the ceiling is important to the concert hall. For example, the height of ceiling relates to the reverberation time control, the ceiling design will affect to the low frequency reverberation time in the hall and also to the early reflections arriving at the audience area and the evenness of their distribution.Lighting and stage facilities in concert hall are not as complicated as in the opera house, but the acoustics quality in the concert hall is most the crucial one among all kinds of hall design which can not be evaluated with a single acoustical parameter. The seat capacity of a concert hall is usually around one thousand, or even over 2000 seats in some larger halls and their audience areas usually reach several hundred square meters. Therefore, the acoustic quality may vary over the whole audience area. Nowadays acoustical design usually presents an overall effect only. It is difficult to predict the result of an acoustical design in combining many acoustical parameters. Here the author suggests a criterion method by using the area coefficient counted in a multi-dimension rose graph, each dimension in the graph denoting an individual acoustic parameter, as the technique rule of the combined acoustical criterion. Therefore area has shown in the rose graph needs to be larger the better acoustics in the hall. Here all the acoustical parameters in the multi-dimension graph are treated as equivalent value.Measurement of the concert hall usually takes with international standard (ISO 3382-1997) processing the minimum test points by different scales. For qualification of the acoustics effect of a concert hall, we often take account of few selected positions only. Now we through digital simulation can predict the acoustics parameters even at every seat position in a hall. And therefore we can get the percentage of the optimum positions as criteria of hall acoustics. From there statistical data we not only can make compares with different acoustical design, and also know how to improve the acoustical design.This method has been used to optimize a medium-size hall project design from five different ceiling configurations. We would get more experience after the completion of that concert hall.