Resumen de Effect of diffuser locations on sound field in a 1:25 scale model hall
Shin-ichi Sato, Yong Hee Kim, Jin Yong Jeon
This paper investigates the effects of diffuser locations on sound field in a hall. A 1:25 scale model of a multi-purpose hall with 600 seats was used. Objective evaluation of sound field was carried out through measurement of acoustical parameters (RT, EDT, C80, G, and Ts). 375-mm diameter (in real scale) hemisphere diffusers were installed in the scale model hall. Impulse responses were measured under conditions with and without diffusers. Seven cases according to different diffuser locations (balcony front, ceiling reflector, lateral walls and their combinations) were considered. The absorption power increases as the number of diffuser is increased. Thus, the results of the measurement show that RT decreases as the number of diffuser is increased. Diffusers installed on the balcony front decreased EDT at the first floor. Decrease of EDT was larger than that of RT. Diffusers installed on ceiling reflectors increase EDT and decrease G at rear seat of the second floor, while the ceiling diffusers decrease EDT and increase G at frontal seat of the first floor. Diffusers on lateral walls close to stage decrease early sound energy, but diffusers on lateral walls at rear seats supplement the early reflections by redirection of sound ray.
