The recordings from this tour reveal further strain in Robert Plant 's voice that began on the previous tour of Japan . He struggled to sing " Over the Hills and Far Away " at the Oxford show , and for all remaining live performances of this song through 1979 , he changed the melody to a lower register . Plant also changed the melody of the song " Rock and Roll " , singing it in a lower register and moving the song to the start of the set
previous tour of Japan
Led Zeppelin Japanese Tour 1972
Led Zeppelin United Kingdom Tour 1972–1973