Utzon had grand plans for the interior of the opera house halls. Huge windows would overlook the harbor in common areas. Patrons would gather here before performances. Hallways and sweeping granite staircases would lead patrons into the performance areas. The interiors of the performance areas were to be decorated with strong colors that reflected Australia’s natural beauty.
But appearances were only part of the plan. Acoustics (the science of how sound travels) is important in buildings used for music, singing, and acting. Utzon wanted the buildings’ acoustics to be designed to fit with the architecture. He began work on a system of plywood wedges that followed the shape of the roof. Sound waves traveling from the stages would reflect off the plywood. The wedges would provide perfect acoustics.