Abstract: An acoustical device for damping and absorption of certain frequencies in a room and including a surface which functions as a low pass filter to maintain low frequency absorptive properties without reducing the acoustical brightness of the room. The device may be embodied as a piece of free standing room furniture. A capped tube of the device defines an internal ambient air chamber. Exteriorly of the tube is a perforate sound reflective member. The perforation size and spacing function as a mechanical low pass cross-over system. A cross-over option is presented to include an imperforate limp mass sheet covering at least partially the absorbent tube surface.

Abstract: A space divider and method for making same, the space divider comprising a peripheral frame, having at least two portions lying in different planes and a fabric sleeve stretched over and entirely covering the peripheral frame, forming at least two double-curvilinear surfaces. The peripheral frame may comprise side rail members and a plurality of braces connecting the rail members. The fabric sleeve may be impregnated with a resinous material, thereby providing a substantially rigid omni-directional sound reflecting and dispersing surface, or left soft, with fill or padding optionally disposed between opposite surfaces of the fabric sleeve, thereby providing a omni-directional sound absorbing surface. The fabric sleeve may be a one-piece, two-way stretch member, such as different types of knitted materials or a non-stretch member of different types of woven materials.

Abstract: The present invention relates to a process for making false ceilings comprising a series of parallel strips of fabric of reduced width, reinforced transversely, tensioned longitudinally and oriented vertically in a mean horizontal plane located at an appropriate height below the ceiling of the construction, wherein each strip is tensioned individually and independently of those strips which surround it. The invention also relates to the false ceiling made by carrying out said process.

Abstract: An acoustical panel construction which, in its preferred form, comprises a preformed body portion or shell, the outwardly extending edges of which are formed of thin, but dense, acoustical material. The density, thickness and configuration of the edges provides the necessary rigidity and structural strength to enable a panel formed from the body portion or shell to be properly edge supported on, and conform to, a grid system. The body portion or shell advantageously is formed with a central area of acoustical material which is thicker, but less dense than the edge areas, to enhance the acoustical properties of the finished panel. The body portion or shell is adapted to receive a sheet or layer of an acoustical material having a preselected density and thickness such that the finished panel will be able to meet the sound absorption and resistance to fire, among other demands, of the environment in which the panel is installed.

Abstract: A space divider and method for making same, the space divider comprising a peripheral frame, having at least two portions lying in different planes and a fabric sleeve stretched over and entirely covering the peripheral frame, forming at least two double-curvilinear surfaces. The peripheral frame may comprise side rail members and a plurality of braces connecting the rail members. The fabric sleeve may be impregnated with a resinous material, thereby providing a substantially rigid omni-directional sound reflecting and dispersing surface, or left soft, with fill or padding optionally disposed between opposite surfaces of the fabric sleeve, thereby providing a omni-directional sound absorbing surface. The fabric sleeve may be a one-piece, two-way stretch member, such as different types of knitted materials or a non-stretch member of different types of woven materials.

Abstract: An anechoic chamber having a rotatable corner in the nature of a rotating door which permits the selection of a desired one of four right angle corners to be introduced into operative engagement with the room. In the use of the anechoic chamber, with a selected corner in position facing into the chamber, a sound seal is provided about the periphery of the frame of the rotating door. The walls of the anechoic chamber are covered by sound absorbent material, and one of the four corners which may be positioned in the chamber through rotation of the rotating door contains surfaces similarly covered by sound absorbent material. Another of the four corners is a trihedral corner including a base, or floor, for supporting a corner speaker.

Abstract: A sound room having sound wave reflective front and side walls, and ceiling and a sound absorbent floor and rear wall arranged to form a wedge shaped room. Sound generating speakers are positioned at the upper front wall forming the small end of the wedge shaped room so that sound waves emanating therefrom will expand outwardly to fill the room.

Abstract: An acoustical system for damping and absorption of sound in rooms to provide a sound damping even at very low frequencies, e.g. 50 Hz, and simultaneously improve speech comprehension in the entire room by reduction of the resonance time. The acoustic absorption can be varied to vary the resonance time over the entire part of the frequency area. The sound absorbents 14 in the form of plates, mats or similar constructions, are arranged at an angle in at least one corner area 11 formed by the walls 12 and ceiling 13 of the room. In the corner area 11 behind the absorbent 14, an air volume is trapped so that the absorbent due to the sound influence has a membrane effect. The inclination and position of each absorbent 14 can be varied individually or in groups.

Abstract: A sound barrier for isolating a noise source of the type emanating from manufacturing areas for food. The sound barrier comprises a panel made of sound attenuating material having a plurality of longitudinally extending side by side co-planar sections separated by V-shaped ribs so as to define a plurality of longitudinally extending side by side cavities. The cavities are provided with acoustical absorptive material therein so that the sound waves emanating from the noise source are first absorbed by the acoustical absorptive material and thereafter partly attenuated by the panel and partly deflected thereby so as to be absorbed again by the acoustical absorptive material. The panel is preferably transparent and portions of at least some cavities may be left free of acoustical absorptive material so as to provide undistorted vision from one side of the panel to the opposite side thereof. The sound barrier is intended to be disposed so that the open faces of the cavities confront the noise source.

Abstract: An acoustic space absorber unit is provided in which Helmholtz resonators are mounted within an enclosure composed of sound absorbing material, with the orifices of the resonators near to but spaced from the enclosing material. The Helmholtz resonators are tuned to low audible frequencies such as 125 Hz. The Helmholtz resonators enhance the sound absorption at low frequencies while the entire unit provides sound absorption throughout the entire audible range.

Abstract: The panel includes a fibrous glass board, a channel-shaped metal frame, and decorative fabric or plastic film adhered to the lower surface of the board and frame. The frame has an upper flange cooperable with an inverted T-bar of a suspended grid and a lower flange which extends halfway across the head of the inverted T-bar in the mounted position of the panel. Each pair of adjacent mounted panels covers the T-bar therebetween. The board is supported mainly by tabs on the frame. Because the bottom of the board is flush with the bottom of the frame, the frame is unnoticeable behind the decorative covering. The adherence of the decorative covering to the board and frame reduces potential sagging of the board and permits the panels to be made larger.

Abstract: A sound barrier for isolating a noise source of the type emanating from manufacturing areas for food. The sound barrier comprises a panel made of sound attenuating material having a plurality of longitudinally extending side by side co-planar sections separated by V-shaped ribs so as to define a plurality of longitudinally extending side by side cavities. The cavities are provided with acoustical absorptive material therein so that the sound waves emanating from the noise source are first absorbed by the acoustical absorptive material and thereafter partly attenuated by the panel and partly deflected thereby so as to be absorbed again by the acoustical absorptive material. The panel is preferably transparent and portions of at least some cavities may be left free of acoustical absorptive material so as to provide undistorted vision from one side of the panel to the opposite side thereof. The sound barrier is intended to be disposed so that the open faces of the cavities confront the noise source.

Abstract: The present variable volume resonators have an inner volume enclosed by wall members constructed as Belleville springs. The wall members confine in said volume a pressure which is reduced relative to atmospheric pressure, whereby the springs have a small spring constant in response to a reduced pressure load. Each resonator is so constructed that it has a relatively large resonating surface and a relatively low resonating mass. The sound damping effect of the resonator volume is enhanced by means of various types of damping devices including a high viscosity residual gas, wire mesh members, or liquid drops in the volume interior. The present resonators also comprise features for compensating air pressure and/or the resonance frequency.

Abstract: A noise barrier wall having a transition area in the region of at least one unbounded edge and which employs controlled diffraction of sound to enhance the sound reducing properties thereacross. The transition area of the noise barrier is provided with either a row of absorptive shaped splitter panels, or a row of pickets, or other means of controlled transparency which provide acoustical shadowing equal to or greater than that of a solid wall for the frequency regions of interest.

Abstract: An acoustical panel for reducing acoustic noise is disclosed. The panel is comprised of a corrugated sheet of material. The sheet of material has a generally parabolic-sinusoidal configuration forming a plurality of corrugations. The corrugations extend in a first direction and form a plurality of peaks and valleys. At least one side of the panel has a surface adapted to face a source of acoustical noise. The surface acoustically diffuses acoustic waves striking the surface and causes acoustic wave interference to occur. The acoustic panel has a transaxial stiffness-compliance such that the panel is permitted to pump when low frequency acoustic energy is applied to the panel for the purpose of dissipating acoustic energy.

Abstract: A ceiling baffle includes a glass cloth faced fibrous glass board, grooved and folded to provide a double thickness of board. End caps for the folded board are each provided with blade portions extending between the two thicknesses of board and with a hole in an upper wall portion for receiving a barb portion of a suspension clip attachable to an inverted T-bar of a ceiling grid system for mounting ceiling panels.

Abstract: A fibrous glass board is longitudinally grooved on one side adjacent the center for folding. The folded board is provided with a pair of plastic end caps respectively on opposite ends. The exposed surfaces of the folded board are provided with a decorative facing material, preferably glass cloth. Means are provided for suspending the completed baffle by the end caps from a gridwork of inverted T-bars.

Abstract: Prefabricated element arranged on a single wall of a room for forming a double sound insulating and sound absorbing wall. The prefabricated element provides efficient sound insulation of the room and a total sound absorption of sound waves whose frequency is centered at one of the natural frequencies of the room. The element comprises a frame supporting a flexible panel by means of elastic sealing means, the flexible panel being maintained at a predetermined distance from the single wall due to the thickness of said frame whereby the resonant frequency of the double wall becomes equal to a natural resonant frequency of the room corresponding to sound waves propagating perpendicularly to the single wall. In addition, the prefabricated element may also comprise an additional element placed in the middle of the panel which permits equalization of the natural resonant frequency of the assembly comprising the flexible panel and the additional element to the low natural frequency of the room.

Abstract: A noise barrier wall having a transition area in the region of at least one unbounded edge and which employs controlled diffraction of sound to enhance the sound reducing properties thereacross. The transition area of the noise barrier is provided with either a row of absorptive shaped splitter panels, or a row of pickets, or other means of controlled transparency which provide acoustical shadowing equal to or greater than that of a solid wall for the frequency regions of interest.

Abstract: An upright space divider panel having a rigid rectangular frame, and first and second thin sheetlike skins fixed to opposite sides of the frame and extending across the region defined therein. A honeycomb core structure is disposed within the frame and confined between the skins. The honeycomb core structure comprises a cellular honeycomb layer having a plurality of cells formed therein and extending across the width of the layer, so that opposite ends of the cells are closed by the skins. The first and second skins are identical and each have a plurality of openings formed therethrough. The openings in the first skin communicate with a first plurality of the cells for forming a first plurality of sound absorbing chambers which open outwardly through one side of the panel. The openings in the second skin communicate with a second plurality of the cells for forming a second plurality of sound absorbing chambers which open outwardly through the other side of the panel.

Abstract: The present noise reducing apparatus includes resonators which have a small and variable volume as well as a high admittance. For this purpose the resonators constitute vibrating systems having at least one volume wherein the pressure is reduced below atmospheric pressure to provide a reduced volume stiffness. The volume is confined by wall elements having a very small or a negative spring rate under reduced pressure inside said volume.

Abstract: The sound absorbing and diffusing unit is provided for assembling an acoustic screen which can be placed in front of a wall inside an acoustic room for improving a sound effect therein. These units are detachably joined together with each other so that they can be easily separated and assembled again to form an acoustic screen or partition having another shape or construction to adjust or modulate a sound effect. A decorative sound absorbing porous panel having a desired picture or pattern can be easily hung against a wall. The decorative panel can be reversely hung on the wall to provide another interior ornamention. Accordingly, an acoustically correct room and a desired ornamentation on a wall inside the acoustic room can be easily obtained and changed without providing a rigid reverberating surface of the room.

Abstract: A shield for an assembly includes a member of generally corrugated construction, which is uniquely configured to substantially prevent the passage of liquid contaminants impinging thereon. The invention is especially concerned with the provision of an acoustical assembly employing such a shield.

Abstract: A sound barrier and sound-absorption panel preferably of a transparent nature so as not to interfere with vision of and light for the machine or other noise-emitting device, to be shielded or enclosed by one or more of the panels. The panel is formed of transparent sound-reflecting material and sound-absorbing material so arranged relatively that the sound waves are received by the panel and deflected into the sound-absorbing material. The reflecting material and sound-absorbing material are arranged to provide one or more sound-receiving pockets or cavities each of which has an outwardly-diverging sound-reflecting wall surface which faces toward the sound-emitter. The sound-absorbing material is in the form of an outwardly-extending member so located in the pocket or cavity as to absorb sound waves which are received in the pocket or cavity and are deflected into the sound-absorbing member by the sound-reflecting wall surface.

Abstract: A device for reducing noise interiorly of air distribution ducts is comprised of at least one sound attenuating module which is adapted to be placed adjacent to a noise source or installed interiorly of conventional air distribution ducts. The module has a plurality of adjacently sandwiched glass fiber layers which are separated from each other by aluminum side walls. Each one of the layers is sealed by an aluminum membrane enclosure (with the outer membranes being substantially airtight to prevent any resultant friction between air passing through the duct and the glass fiber). Noise is reduced as the sound pressure (developed by the conditioned air flow in the duct) alternately contracts and expands the compliant glass fiber media interiorly of the module, thusly dissipating energy in the form of friction between the glass fibers that are in each layer.

Abstract: A lightweight sound absorbing panel is disclosed. The panel comprises front and rear faces mounted to a supporting frame and having a core therebetween. The core is at least partially free airspace throughout a substantial portion of the area of the panel whereby weight reduction and increased sound absorption are obtained.