Quadraphonic sound – equivalent to what is now called 4.0 surround sound – uses four audio channels in which speakers are positioned at the four corners of a listening space. The system allows for the reproduction of sound signals that are independent of one another.

The LP is an analog sound storage medium, specifically a phonograph record format characterized by: a speed of 33+1⁄3 rpm; a 12- or 10-inch diameter; use of the "microgroove" groove specification; and a vinyl composition disk. Introduced by Columbia Records in 1948, it was soon adopted as a new standard by the entire US record industry and, apart from a few relatively minor refinements and the important later addition of stereophonic sound in 1957, it remained the standard format for record albums, during a period in popular music known as the album era. LP was originally a trademark of Columbia and competed against the smaller 7-inch sized "45" or "single" format by RCA Victor, eventually ending up on top. Today in the vinyl revival era, a large majority of records are based on the LP format and hence the LP name continues to be in use today to refer to new records.