Encompassing a wide variety of post-Romantic styles composed through the year 2000, 20th century classical music includes late romantic, modern, high-modern, and postmodern styles of composition. Modernism (18901930) marked an era when many composers rejected certain values of the common practice period, such as traditional tonality, melody, instrumentation, and structure. The high-modern era saw the emergence of neo-classical and serial music. A few authorities have claimed high-modernism as the beginning of postmodern music from about 1930. Others have more or less equated postmodern music with the "contemporary music" composed from the late 20th century through to the early 21st century.
When did modernism take place?
18901930

The United States Air Force (USAF) is the aerial warfare service branch of the United States Armed Forces and one of the seven American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on 18 September 1947 under the National Security Act of 1947. It is the most recent branch of the U.S. military to be formed, and is the largest and one of the world's most technologically advanced air forces. The USAF articulates its core functions as Nuclear Deterrence Operations, Special Operations, Air Superiority, Global Integrated ISR, Space Superiority, Command and Control, Cyberspace Superiority, Personnel Recovery, Global Precision Attack, Building Partnerships, Rapid Global Mobility and Agile Combat Support.
How many uniformed services are there in the United States?
seven

Under the direction of recording engineer C. Robert Fine, Mercury Records initiated a minimalist single microphone monaural recording technique in 1951. The first record, a Chicago Symphony Orchestra performance of Pictures at an Exhibition, conducted by Rafael Kubelik, was described as "being in the living presence of the orchestra" by The New York Times music critic. The series of records was then named Mercury Living Presence. In 1955, Mercury began three-channel stereo recordings, still based on the principle of the single microphone. The center (single) microphone was of paramount importance, with the two side mics adding depth and space. Record masters were cut directly from a three-track to two-track mixdown console, with all editing of the master tapes done on the original three-tracks. In 1961, Mercury enhanced this technique with three-microphone stereo recordings using 35 mm magnetic film instead of half-inch tape for recording. The greater thickness and width of 35 mm magnetic film prevented tape layer print-through and pre-echo and gained extended frequency range and transient response. The Mercury Living Presence recordings were remastered to CD in the 1990s by the original producer, Wilma Cozart Fine, using the same method of 3-to-2 mix directly to the master recorder.
For which company did C. Robert Fine work for?
Mercury Records