Termed "the acoustic equivalent to Prozac", soft adult contemporary, a more adult-oriented version of AC, was born in the late 1970s and grew in the early 1980s. WEEI-FM in Boston was the first station to use the term "soft rock", with ad slogans such as, "Fleetwood Mac ... without the yack" and "Joni ... without the baloney". The vast majority of music played on soft AC stations is mellow, more acoustic, and primarily solo vocalists.