Bureau of American Ethnology in the context of "Recorded music"

Sound recording and reproduction is the electrical, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording.

Acoustic analog recording is achieved by a microphone diaphragm that senses changes in atmospheric pressure caused by acoustic sound waves and records them as a mechanical representation of the sound waves on a medium such as a phonograph record (in which a stylus cuts grooves on a record). In magnetic tape recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current, which is then converted to a varying magnetic field by an electromagnet, which makes a representation of the sound as magnetized areas on a plastic tape with a magnetic coating on it. Analog sound reproduction is the reverse process, with a larger loudspeaker diaphragm causing changes to atmospheric pressure to form acoustic sound waves.

Frances Theresa Densmore (May 21, 1867 – June 5, 1957) was an American anthropologist and ethnographer from Minnesota. Densmore studied Native American music and culture, and in modern terms, she may be described as an ethnomusicologist.

John Wesley Powell (March 24, 1834 – September 23, 1902) was an American geologist, U.S. Army soldier, explorer of the American West, professor at Illinois Wesleyan University, and director of major scientific and cultural institutions. He is famous for his 1869 geographic expedition, a three-month river trip down the Green and Colorado rivers, including the first official U.S. government-sponsored passage through the Grand Canyon.

Powell was appointed by US President James A. Garfield to serve as the second director of the U.S. Geological Survey (1881–1894) and proposed, for development of the arid West, policies that were prescient for his accurate evaluation of conditions. Two years prior to his service as director of the U.S. Geological Survey, Major Powell had become the first director of the Bureau of Ethnology at the Smithsonian Institution where he supported linguistic and sociological research and publications.

American popular music (also referred to as "American Pop") is popular music produced in the United States and is a part of American pop culture. Distinctive styles of American popular music emerged early in the 19th century, and in the 20th century the American music industry developed a series of new forms of music, using elements of blues and other genres. These popular styles included country, R&B, jazz and rock. The 1960s and 1970s saw a number of important changes in American popular music, including the development of a number of new styles, such as heavy metal, punk, soul, and hip hop.

American popular music is incredibly diverse, with styles including ragtime, blues, jazz, swing, rock, bluegrass, country, R&B, doo wop, gospel, soul, funk, pop, punk, disco, house, techno, salsa, grunge and hip hop. In addition, the American music industry is quite diverse, supporting a number of regional styles such as zydeco, klezmer and slack-key. Though these styles were not always in the sense of mainstream, they were commercially recorded and therefore are examples of popular music as opposed to folk or classical music.