A client insisted that the new air conditioning system for the acoustically and visually splendid hall be noiseless and invisible. The engineers complied.

Almost a century after its original opening, Carne­gie Hall has made a stunning second debut. Ever since Tchaikovsky conducted the first performance there in 1891, the legendary New York City concert hall has been in constant use. Not only has it withstood the wear and tear of enthusiastic music lovers and the normal depredations of time, but it has suffered abuse as well. Re­tail stores were built at street level during the Depression, and in 1946, when a movie about Carnegie Hall was made, a large section of the shell above the stage was chopped away. In 1960, it was threatened with destruc­tion and was rescued only at the elev­enth hour.

Read the full article (originally appeared in Mechanical Engineering magazine)