Paul conducts a 40-piece orchestra during the sessions for 'A Day In The Life' in studio 1, February 1967.
The orchestra was instructed to play 24 bars starting at the lowest note they could play, and ending with an E-major chord. "And whatever you do, don't listen to the fellow next to you because I don't want you to be doing the same thing" told producer George Martin them. The orchestra couldn't understand what George was talking about, or why they were being paid to go from one note to another in 24 bars. It didn't make any sense to them because they were all classically trained.
The orchestra was recorded 4 times and then mixed down to one, so as a result you hear 160 musicians playing.