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Show Soundproof Laboratory So Quiet a Dollar Bill Makes Noise When It Falls on Floor i cutting out most "f the outside noises. The walls are further lined with soundproofing materials, and the heavy carpet is underlaid with thick felt Entrance is through a vestibule which closes when the "quietness hunters" pass through a door from it into the room proper. The long supporting rods do not touch the roof. They are connected with steel springs set in rubber to prevent them from acting as sound and vibration conductors. A person with indigestion in this room does not have to tell his friends what is the matter. His stomach can be heard rumbling. One result of this kind of work is super quiet electric fan blades. There's not a single entirely fiat area on their faces. Neither do their curves at any cross section equal those of any other area. Their greatest width is almost at the tip. A dollar bill makes a noise when dropped on the inch-thick carpet of a new soundproof laboratory room, writes a Schenectady, N. Y., correspondent cor-respondent in the Boston Globe. The bill gives out a sharp whack if it falls flat; it can be heard scraping scrap-ing if it comes down at an angle. The room is something new in soundproofing. It weighs 30 tons, and is hung from the roof of the research laboratory by four rods. Sleeves make a creaking sound when they brush against a coat A watch chain clinks when its wearer walks. Tightening a trousers' belt sounds like harnessing a horse. The idea of the room is to take uie last small noises out of rotating machinery. ma-chinery. It was built after scientists thought they had all the noises out because none could be 'leard in the ordinary laboratory quiet But these same motors, taken into the country on a quiet night were still audible. The hanging room was thereupon constructed to imitate the country at Its stillest In cities and large buildings there always is a slight rumble of noise even-at the quietest moment The soundproof room is built jf steel and concrete, its mass alone |