A Beatles engineer said nothing ever got past John Lennon. He noticed a minor change to a Beatles song because his singing was missing.
According to a Beatles audio engineer, John Lennon paid close attention when listening back to songs. Even though he derided some of The Beatles’ music after the band broke up, he was careful in the studio. While listening back to “Yellow Submarine,” Lennon realized that someone had made a mistake. His voice was missing from a part where it was meant to appear.
The Beatles spent a good deal of time messing around in the studio while recording “Yellow Submarine.” Still, Lennon tried to keep them focused. He put a great deal of thought into the song and made several alterations. Not all of these made it into the song’s final version, though.
“At a certain point, John decided that the third verse needed some spicing up, so he dashed into the studio and began answering each of Ringo’s sung lines in a silly voice that I further altered to make it sound like he was talking over a ship’s megaphone,” audio engineer Geoff Emerick wrote in his book Here, There and Everywhere: My Life Recording the Music of the Beatles. “The verse begins, ‘And we live/ A life of ease,’ but you don’t actually hear John’s voice until the third and fourth lines.”
Source: Emma McKee/cheatsheet.com