 During their career, the Beatles introduced more innovations into popular music than any other rock band of the 20th century.Some of these include one of the first uses of guitar feedback in music ("I Feel Fine"), the first use of a fade-in in a pop song ("Eight Days a Week"), use of tape loops ("Tomorrow Never Knows"), using the recording studio as an instrument ("Revolver" and "Sgt.Pepper") and popularising the Indian sitar in pop music ("Norwegian Wood"); Harrison further embraced Indian music on songs such as "Love You To", "Within You Without You" and "The Inner Light".