Opera house electronic libretto systems have begun to be used in some opera houses, including New York's Metropolitan Opera, Milan's La Scala, and the Crosby Theatre of The Santa Fe Opera, which provide two lines of text on individual screens attached to the backs of the seats so as to not interfere with the visual aspects of the performance. A subtle type of sound reinforcement called acoustic enhancement is used in some opera houses. Acoustic enhancement systems help give a more even sound in the hall and prevent "dead spots" in the audience seating area by "...augment[ing] a hall's intrinsic acoustic characteristics."
Central City Opera House structural changes in 1903. In 1929 a dedicated band of Denver preservationists and music lovers formed the Central City Opera House Association to perform a renovation and re-open the opera house. It was a volunteer-driven effort led by Ida Kruse McFarlane, Edna Chappell and Anne Evans that resulted in an extensive restoration of the Opera House in 1932. In the 1980s and 1990s, the entire structure was restored, including the foundation and replacement of the 1920-era lighting relic by a computerized lighting system. In 1999, wooden chairs were replaced with plush new theater seating. With the 1878 grand opening, Central