QUIETEST ROOM IN WORLD

Bay of Plenty Beacon, Volume 10, Issue 70, 8 January 1947, Page 8

QUIETEST ROOM IN WORLD

UNITED STATES NAVY YARD SPECIAL WALLS In an environment rife with shrilling whistles, pounding pneumatic riveting hammers, and the other assorted noises familiar in a busy shipyard, Brooklyn, N.Y., has what has been described as the quietest room in the world. The transmission of sound-carry-ing vibration is barred by mounting the room on 14 columns of rubber, specially developed and installed by engineers of the United States Rubber Company. These mountings, 16 inches in height, provide the only contact between the room and the outside world. The walls of the room are lined with deep layers of glass fibre and other sound-absorbing material. To minimise the reflection of sound within the chamber, the walls of the room are not at right angles, to one another an assymetrical room having less sound reflection than a boxlike chamber. ' Surrounding this air-tight room it a second room, with 12-inch brick walls and a concrete floor six inches thick. Entrance, to the inner chamber is had through a steel door weighing a ton and a-half. This outside room bars most outside noises from reaching the . inner chamber. All instrument testing is done by remote control, only a loud-speaker and the instrument to be tested remaining in the sound-proof room. Engineers conducting the test regulate the volume, pitch, etc., of the sound coming from the loudspeaker and devices connected electrically to the instrument being tested indicate its response to the signals emanating from the loudspeaker.