Unique Properties of an Open‐Plan Auditorium

An architecturally open concept was adopted in the design of a 500‐seat auditorium for a new school. The audience is seated on four shallow tiers that are adaptable for dining. The space is distinguished by a tall well over the forward seats, beyond which the ceiling is very low. At the back and sides, the arena is open to the student commons. Above and behind the stage, it is open to a spacious mezzanine. Deliberate acoustical provisions include absorptive finishes, lockers that act as barriers, a retractable curtain in place of a rear wall, reflectors to help stage‐audience communication, and controlled background noise. Investigations reveal several unique properties: short but remarkably uniform reverberation times, averaging 0.72 sec; distance‐depedent loudness that imparts a sense of dissimilar room size, depending on seat location; excellent intelligibility of stage sounds, with an average AI of 0.91 for raised voice; and excess attenuation of extraneous sounds on the order of 10 dB.