Sgt. Pepper's Lonely Hearts Club Band "Being for the Benefit of Mr. Kite!" and "A Day in the Life". Producer George Martin and engineer Geoff Emerick helped realise the group's ideas by approaching the studio as an instrument, applying orchestral overdubs, sound effects and other methods of tape manipulation. Recording was completed on 21 April 1967. The cover, depicting the Beatles posing in front of a tableau of celebrities and historical figures, was designed by the British pop artists Peter Blake and Jann Haworth. "Sgt. Pepper" is regarded by musicologists as an early concept album that advanced the use of extended form in popular music while
Sgt. Pepper's Lonely Hearts Club Band that point." Harrison added that, having enjoyed recording "Rubber Soul" and "Revolver", he disliked how the group's approach on "Sgt. Pepper" became "an assembly process" whereby, "A lot of the time it ended up with just Paul playing the piano and Ringo keeping the tempo, and we weren't allowed to play as a band as much." After finishing "Sgt. Pepper", the Beatles took an acetate disc of the album to the American singer Cass Elliot's flat off King's Road in Chelsea, where at six in the morning they played it at full volume with speakers set in open window frames.