“Elevator music” was once the sound of restaurants, offices, and elevators in mid-20th century America. But ironically these bland, string-driven instrumental tracks are never heard in elevators anymore. In this episode, we speak with Joseph Lanza, the author of “Elevator Music,” and Julian Treasure, chairman of The Sound Agency, about the sound of Muzak -- the company that changed the way we think public spaces should sound. Episode transcript, music, and credits can be found here.