After Progressive Bluegrass bands caught on in the 1960s and '70s, a backlash of New Traditionalists brought Bluegrass closer to its roots. This meant using all (or mostly) acoustic instruments and adhering as closely as possible to the traditional lineup of fiddle, banjo, guitar, mandolin, standup bass, and lots of high-tenor singing. Some of this generation of players, like Del McCoury and Larry Sparks, first gained professional experience playing in the bands of greats like Bill Monroe and Ralph Stanley. They've since gone on to be master singers, songwriters, and bandleaders in their own rights. Country boy Ricky Skaggs brought the Bluegrass sound to the top of the charts during the '80s by infusing it with a more mainstream country sound. But he's since returned to a firm traditional approach. During the '90s, Singer-Songwriter Alison Krauss became the top-selling Bluegrass artist in history.