成人時代（Adult Contemporary，簡稱AC）如字面所說，主要面向成年的成熟的聽眾。它整體上延續了六七十年代的輕音樂、輕搖滾樂風，也受到靈魂、R&B、搖滾等風格的不同程度的影響，同時順應時代適度融合流行/搖滾潮流。重抒情，特別是愛情。浪漫的、細膩的乃至是些許傷感的主題，和成人時代的舒緩氛圍、動聽旋律、優美和聲搭配絕佳。旋律上漂亮得足夠吸引人，然而又漂亮得很成人風范，謙遜穩重，不爭奪注意力，也非常適合用作背景音樂。在AC電臺，經典歌曲通常更受歡迎。多年來成人時代涌現了一批優秀的音樂家，包括Elton John, Billy Joel, Air Supply, Michael Bolton, Phil Cillins, Lionel Richie, Chicago, Celine Dion。Adult contemporary music (AC) is a style of music, ranging from 1960s vocal and 1970s soft rock music to predominantly ballad-heavy music of the present day, with varying degrees of easy listening, soul, rhythm and blues, and rock influence. Adult contemporary is rather a continuation of the easy listening and soft rock style that became popular in the 1960s and 1970s with some adjustments that reflect the evolution of pop/rock music. Adult contemporary tends to have lush, soothing and highly polished qualities where emphasis on melody and harmonies is accentuated. It is usually melodic enough to get a listener's attention, and is inoffensive and pleasurable enough to work well as background music. Like most of pop music, its songs tend to be written in a basic format employing a verse-chorus structure.Adult contemporary is heavy on romantic ballads which mostly use acoustic instruments (though bass guitar is usually used) such as acoustic guitars, pianos, saxophones, and sometimes an orchestral set. The electric guitars are normally faint and high-pitched. However, recent adult contemporary music may usually feature synthesizers (and other electronics, such as drum machines).AC radio may play mainstream music, but they will exclude hip hop, dance tracks, hard rock and some forms of teen pop, as they are less popular amongst the target demographic of these radio stations, which is intended for an adult audience. The AC Radio stations will often target the 25–44 age group, the demographic that has received the most attention from advertisers since the 1960s. Many adult contemporary stations play less newer music because they also give ample airtime to hits of the past, so the de-emphasis on new songs slows the progression of the AC chart.Over the years, AC has spawned numerous sub-genres: "hot AC", "soft AC" (also known as "lite AC"), "urban AC", "rhythmic AC", and "Christian AC" (i.e., a softer type of Contemporary Christian music). Some radio stations play only "hot AC", "soft AC", or only one of the variety of sub-genres. Therefore, it is not usually considered a specific genre of music; it is merely an assemblage of selected tracks from musicians of many different genres.