A 1/10 Scale model studying the effects of the balcony in an auditorium

To study the effects of the balcony to the acoustics in performing halls, real hall measurements is a popular solution. However, only built halls with their as-built conditions can be measured. Thus, scale model is one of the alternatives to study the effects of the balcony with the possibility to change the balcony configurations for comparisons. In this study, a 1/10 scale model study was done to compare the measured parameters with and without the balcony. The model was built with reference to an existing Hall with a balcony, with a total seating capacity over 1000. A spark source was used as the high-frequency sound source in the experiment while 1/8-inch microphones were used for signal recording. The mono-aural results were then calculated using MATLAB. There were four cases in this experiment: concert setting and proscenium setting, with and without the balcony. The setting conversion was done by installing a sound canopy on the stage. 120 and 86 receiver points in different seating zones were measured in cases with and without the balcony respectively. The balcony effects (BE) of the reverberation times and energy ratios were used to represent the effects of the balcony. The BEs of both the RTs and energy ratios were different with the two different stage settings. Still, similar variation patterns across the frequency bands can be found in the early energy ratios C80 and D50. They showed similar variation patterns across the frequency bands at particular seating zones. The experiment results show that the balcony does not have much effect to seats closer to the stage, i.e. further from the balcony. However, the balcony structure helps increase the early energy to the seats right before and under the balcony. The balcony can also shorten the time gap between each reflection.