Abstract: An elbow silencer is disclosed comprising a casing and a baffle defining a flow channel. The elbow silencer is constructed to be modular so that two or more complementary elbow silencers are capable of engaging in a nesting relationship. The nested, complementary elbow silencers comprise substantially similar flow channels to produce predictable acoustic attenuation, self generated noise and pressure loss.

Abstract: A substantially enclosed sound absorbing unit for an anechoic chamber is disclosed. The sound absorbing unit includes a substantially flat panel member comprising a layer of sound absorptive material. An anechoic member is disposed adjacent to the flat panel member. The anechoic member is disposed adjacent to a base and a generally spaced apart sound transparent wall member. The wall member includes a layer of sound absorptive material and a cover sheet made of perforated, substantially sound reflective material. The free space of the perforated cover sheet is at least 7 percent of the total area of the cover sheet.

Abstract: In a room that is RF shielded and acoustically insulated, a plurality of panels are fastened together to form a self-supported structure. The panels are fabricated from a continuous metal sheathing and filled with acoustic insulating material. The panels are fastened together by joiners and compression clamps. Structural steel tubing can be fastened between the panels when additional structural strength is required. Access to the interior of the room is provided by a metal door that is filled with acoustic insulating material. The door also includes both RF and acoustic seals. The door is equipped with special hinges that enable the door to be flush mounted and to be opened 180.degree..

Abstract: A sound silencer for insertion in a duct having a fluid medium flowing therethrough includes an outer housing having an open entry end, an open exit end, a base portion, a roof portion, and a pair of opposed sidewalls. The silencer further includes a plurality of spaced apart sound attenuating members which are disposed upright within the housing. The sound attenuating members are arranged in columns and rows, each of the sound attenuating members being disposed substantially normal to the housing base and extending from the base to the housing roof such that the sound attenuating members define a first plurality of through passageways substantially parallel to the direction of the main flow of the fluid medium and extending from the entry end of the housing to the exit end thereof and a second plurality of through passageways disposed substantially perpendicular to the direction of the main flow of the fluid medium and extending from one of the housing side walls to the other side wall.