Improvements in or relating to acoustical arrangements for studios, concert halls and the like

摘要

510,522. Modifying acoustic properties of studios. OELSNER, W., (trading as OELSNER & CO., W.). Jan. 31, 1938, No. 2973. Convention date, Sept. 9, 1937. [Class 13] An arrangement for modifying the acoustic properties of studios, concert rooms and the like which is adapted to provide selective absorption of sound and air oscillations of low frequency and which wholly or partly prevents the boundary surfaces of the room or the like from imparting vibration to, or receiving vibration from, a closed room, comprises a number of sound-reflecting units in the form of plates or substantially flat slabs disposed at a suitable distance from the inner side of the boundary surface and constructed of such a size, mass and material and supported in such a way that they do not resonate at frequencies within the audible range and are able to follow mainly as a unit the low frequency oscillations of the air in the room. The oscillations of the plates are damped so that the main part of the oscillation energy received is absorbed and the low-frequency oscillation energy produced within the room, or arising from low frequency vibration of the walls of the room, is dissipated. The plate units, which may be corrugated or formed with ribs on one or both surfaces, may form a structure separate from the walls of the room or, as shown in Fig. 5 may be supported on laths h with interposed sound-absorbing pads i and springs f mounted on securing bolts k. Additionally a sheet r of sound-absorbing material, such as felt, may be mounted on the inner surface of the plate p. In a modification, Fig. 8, a vibratory plate e of thin wood, metal or impregnated porous material is mounted in front of the plate member p. The members p may be formed of corrugated sheetiron coated with an asbestos cement and may have a slightly rough surface. The surface of the sheets may be glazed, varnished or polished or may be covered with a thin layer of lead or a layer of fibrous material such as paste-board. The plate units may be disposed in the space between the walls of a building and false walls provided for the purpose' of modifying the acoustic properties of a room or studio. The Specification as open to inspection under Sect. 91 states that the plate units may be located in cavities in the walls or floor of a building. This subject-matter does not appear in the Specification as accepted.