Kentucky natives Bob (1931—) and Sonny (1937—) Osborne made their mark on bluegrass and country music by combining innovative, jazzy instrumental work on the mandolin and banjo, respectively, with precise and powerful harmony singing. Intent on finding steady work before country audiences, they were dogged by controversy in bluegrass circles over their use of country instrumentation (drums, pedal steel guitar, strings) and electric amplification in the 1960s and 1970s. Nevertheless, the Brothers achieved enduring popularity by creating a vocal style that emphasized Bob's clear, high voice, placing two harmony parts underneath his leads; known as "high lead," this form of arrangement found widespread use by female singers in country and bluegrass. The Brothers would become the first bluegrass band to perform for a college audience when they played at Antioch College in Ohio in 1960, and they were the first bluegrass band to play at the White House when they played for President Nixon in 1973. Though it was only a modest commercial success when released, their 1967 recording of "Rocky Top" has since become one of the most recorded song in bluegrass music history.