acoustic privacy
n. A state or condition in which external sounds are reduced or eliminated.
A recent study conducted by Bosti Associates, a workplace analysis firm based in Buffalo, N.Y., suggests that despite all the drawbacks, people prefer cubicles to open space. The company surveyed 13,000 workers at Fortune 500 companies and found the most important issue for them was acoustic privacy. "In the modern office there's so much noise, what with speaker phones, desktop video and voice-activated computing," explains John Olson, president of Bosti Associates. "Enclosure seems to be the only way to avoid all that."
—“Thinking out of the cube,” Silicon Valley/San Jose Business Journal, November 16, 2001
1984 (earliest)
As for ceiling fixtures, attendees said that the familiar 2 x 4-foot troffer not only throws fat patches of white reflection onto screens, but also tends to bounce more sound into work areas than is proper for acoustic privacy.
—Walter A. Kleinschrod, “Coping with the computer in the open plan,” Office Administration and Automation, September 01, 1984
A troffer, by the way, is metal fixture that holds a fluorescent light and is usually recessed into a ceiling.