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."
Cairo Opera Ballet Company in 1971, followed by President Anwar Sadat severing Egypt's ties with Russia in 1972, led to a serious decline of the company. The company and its ballet school had a resurgence following the construction of the new Cairo Opera House in 1988. Since 2004, Erminia Gambarelli Kamel has been the company's artistic director. Trained at the La Scala Theatre Ballet School, Kamel joined the Cairo Opera Ballet Company as a principal dancer in 1982. One of the soloists is Mahmoud Atef El Henidy, since 2004–2013. Cairo Opera Ballet Company The Cairo Opera Ballet Company is the resident ballet company of