Opera Australia Orchestra associated with working in the Sydney Opera House orchestra pit. The OAO provides orchestral accompaniment to Opera Australia and The Australian Ballet and is one of the few opera orchestras in the world that operates in a repertory style of operation over a period, or season, that can be some months in length. Other opera houses that operate this way are The Metropolitan Opera in New York City, The Royal Opera House Covent Garden in London and La Scala, Milan. 'Repertory style' also infers that over time, certain composers and operas become considered 'standard' to the working operation of the
Opera house (with 2,200), the Royal Opera House in London (with 2,268) and the Vienna State Opera (the new auditorium with 2,280). Modern opera houses of the 20th century such as New York's Metropolitan Opera House (with 3,800) and the War Memorial Opera House in San Francisco (with 3,146) are larger. Many operas are better suited to being presented in smaller theaters, such as Venice's La Fenice with about 1,000 seats. In a traditional opera house, the auditorium is U-shaped, with the length of the sides determining the audience capacity. Around this are tiers of balconies, and often, nearer to the stage,