The Beach Boys and Brian Wilson - The Disembodied Voices

Brian Wilson suffered throughout his life from a major dissociative disorder. He had been known to disappear for days at a time, turning up in other parts of Los Angeles without any money. Even by the best musicians in the business, like the Reichen crew, that he was a musical savant. The Beatles don't have two albums that even resemble the same band playing them Other than the voices you're hearing.