Environmental music for public spaces (including telephones and elevators) was introduced by the Muzak Corporation in the 1940's. Muzak's background music was advertised as "programming," and designed to be unobtrusive and unnoticed by visitors to the space, except to remind them of some familiar past experience. In 1981, the Muzak Corporation moved from producing background music and introduced 'plans to enter the foreground music market' to compete with major record labels' sales to institutions. While background music consisted of orchestrated string arrangements of popular tunes, foreground music consists of the popular tunes themselves picked for the particular clientele of the place, and played at a louder volume, 'with just enough presence to be an active, enjoyable part of their dining, service or shopping experience.' Whether background or foreground, Muzak is an uninterrupted flow of sound, played at a constant volume with no obtrusive silences or breaks, designed for particular clientele and times of the day. (The beat is faster in the morning to energize the workers and the consumers and slower in the afternoon to provide that end-of-the-day feeling.) Muzak is usually played through smallish speakers which emphasize the mid to high range, overlapping the sounds most present in human speech. Installed in the ceilings, the Muzak sound system surrounds the people and serenades them from above. Shops selling hip clothing for the L.A. clubbing scene play the dance music of the clubs making you want to dance into the clothes; Victoria Secret plays "bedroom music"-- classical music designed (and marketed to the clientele) as intimate music-- making you want to slip into something more comfortable; and the Price Center plays a commercial radio station with a boppy announcer and contemporary soft rock, presumably making you want to consume Wendy's french fries.
Quoted text is from Elevator Music: A Surreal History of Muzak, Easy-listening, and Other Moodsong, by Joseph Lanza, University of Michigan Press, 2004.