Contribution to the acoustic study of theater auditoriums transformable for different types of productions

The auditorium of the Bucharest National Theater has been equipped with devices permitting it to be transformed into three functional types of rooms for different types of productions. In view of the purpose of the room (spoken theater) and the volume of the room (3,000-3,600 cu m 3) the optimum reverberation time is 0.95 sec at a frequency of 1,000 Hz. By applying the different types of acoustic treatment, a reverberation time ranging from 0.96 to 1.06 sec was obtained. The problem of flutter echoes in the arena was solved by applying semispherical bodies to the fixed ceiling. The level of noise transmitted to the auditorium was reduced down to the Cz25 curve.