The AF anechoic chambers at cherry hill

The RCA Victor Division Laboratories at Cherry Hill, New Jersey, include two "sound proof" rooms designed for acoustic measurements on television and radio receivers, phonographs, and loudspeakers. These rooms are located on the second floor of a steel and concrete building where headroom is limited. Each room is of the double-shell masonry construction. The outer shell consists of the concrete floor and ceiling of the building, and concrete-block walls. The inner shell is a complete masonry box weighing about 40 tons. It is completely isolated by steel springs under its floor and above its ceiling. This construction saved greatly needed headroom. Access to the inner chamber is through separate doors in each shell, specially designed and built for this application. Ventilation is provided through long multitubular treated ducts, spring suspended and isolated by felt and rubber. The internal acoustic treatment consists of Fiberglas wedges on the walls and ceiling and flat Fiberglas padding on the floor. This treatment is designed to produce the maximum absorption of sound in the available space. The over-all performance is adequate for making acoustic measurements at distances up to several feet from the source.