The Sydney Opera House’s Concert Hall still remains one of the premiere destinations for concerts and recitals in the world, thanks in the main to its great acoustics.
The Concert Hall has a very distinctive geometric design. Similar to a cathedral, the auditorium has an incredibly high vaulted ceiling, a long, stepped main seating array, raised organ platform, recessed sound stage, plus an elevated, staggered gallery. This layout, especially aided by the high ceiling, grants sound within the hall a bright quality with strong reverberation; with a full audience the reverberation time is approximately 2.2 seconds from 100 to 8,000 Hertz.
Complementing the geometric layout are the hall’s construction materials, which – ranging from the smallest to the largest aspect – were picked specifically to improve sound quality and dispersal. The walls and floors are made of laminated Australian brush box, the ceiling from white birch, while much of the ceiling’s crown is crafted from sculpted plywood. The extensive use of wood offers excellent control of reverberation and echo as well as generating a softer reproduction of sounds. In addition, each chair is made from white birch and lined with wool, the latter material providing excellent noise absorption at the critical point of contact.
Finally, the hall sports a unique feature: a fully height-adjustable canopy directly above the sound stage. This canopy comprises 18 doughnut-shaped acrylic rings that extend down from the ceiling and redirect sound waves that emanate directly up from the stage to other more beneficial areas of the room. This helps with the hall’s lack of early sound wave reflections due to its height, and also maintains the auditorium’s geometry.
Sydney Opera House facts
Clouds – 18 doughnut-shaped acrylic rings, or ‘clouds’, hang above the sound stage. These are used to reflect sound into more beneficial areas of the hall and back to the stage.
Angles – The surfaces immediately to the side of the stage are angled away and down into the seating area. These angles are used to prevent sound from bouncing back and forth across the room, which would create distortion.
Wood – The hall’s walls and floor are made of laminated Australian brush box. This material is used as it does not just reflect sound, but resonates slightly, granting it a much softer quality.
Wool – All the seats are lined with wool. This is used as the material is especially good at absorbing sound and, as the seats are the point of destination, stop it from ebounding and distorting.