the studio practices of the beatles evolved during the 1960s, and in some cases, influenced the way popular music was recorded. some of the effects they employed were sampling, artificial double tracking (adt) and the elaborate use of multitrack recording machines. they also used classical instruments on their recordings and guitar feedback. the group's attitude toward the recording process was summed up by paul mccartney: "we would say, 'try it. just try it for us. if it sounds crappy, ok, we'll lose it. but it might just sound good.' we were always pushing ahead: louder, further, longer, more, different."