Sam Bush, considered by many to be the father of newgrass, the more progressive form of bluegrass music, brings his band to the Lyric Theatre Saturday night, February 13. Like the founding father of bluegrass, Bill Monroe, Bush grew up on a farm in Kentucky surrounded by a family of musicians. Both fell in love with the mandolin and with traditional music. There the comparison ends. Monroe grew up in the 1920s, while Sam Bush came of age in the era of television that brought the stars of country music right into his home.