" At one point a research firm was called in to do a study of the excessive, inescapable noise, and they concluded that the hum of the air conditioner was so bothersome because there weren’t enough competing noises — so they fixed the machines to make them give off a loud, continual hiss. In Greenblatt’s words, this change “was not a win,” and the constant hiss made the long hours on the ninth floor rather nerve-racking for some. Add "

― Steven Levy , Hackers: Heroes of the Computer Revolution