 Jacob trained union sound operator Michael "Mike" O'Keefe to run the mixer for "Jesus Christ Superstar"; O'Keefe and Jacob continued to work together off and on for decades.Union sound operators in New York were called assistant electricians at the time – there was no separate sound department.Having started his career as an electrician, O'Keefe later said of "Jesus Christ Superstar", "It was my first experience with a sound console; it had sixteen faders.