Abstract: An acoustic absorbing device includes a housing having a chamber formed by an outer peripheral wall and a bottom wall, a hood engaged into the housing, an absorbing member engaged into the hood, and a silencer engaged into the absorbing member, the silencer and the absorbing member may be selectively attached to the hood or may be easily replaced with the other ones or new or different ones according to different environment. The silencer may include an outer cap extended into or out of the absorbing member. The housing includes one or more couplers for selectively coupling the housing to the other coupling or supporting members.

Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: In accordance with the present invention an aircraft floor panel is provided comprising a honeycomb core element having an upper core surface, a lower core surface, and a core thickness. An upper face sheet assembly is mounted to and seals the upper core surface and includes at least one upper material sheet impregnated with an upper epoxy resin. A lower damping face sheet assembly is mounted to and seals the lower core surface and includes at least one lower material sheet infused with a highly damped lower epoxy resin. The lower damping face sheet assembly dampens vibrational noise.

Abstract: In order to provide a sound-absorbing body which has both a thin thickness and improved sound-absorption characteristics with regard to a low tone range sounds, the sound-absorbing body (1) includes: an organic hybrid sheet (2) constituted from an organic low-molecular material which is spread in a matrix polymer; and a gastight air cell (3) which is closely provided at a backside (2a) of the organic hybrid sheet, wherein the organic hybrid sheet indicates both a sound-absorption peak of a random incidence sound-absorption coefficient at a frequency band of 400 Hz or lower and another sound-absorption peak when the organic hybrid sheet is vibrated by applying air vibration caused by sound, because of adhering the organic hybrid sheet to the gastight air cell.

Abstract: An extended bandwidth folded well diffusor extends the diffusion bandwidth of a shallow, asymmetric diffusor by incorporating maximum-depth, folded L-shaped, half-width wells on both ends (sides) of a diffusor, thus providing increased maximum well depth without increasing the physical depth of the diffusor. When the inventive diffusor is placed in an array, the folded L-shaped, maximum-depth, half-width end wells form a novel T-shape, which offers a favorable impedance lowering the resonant frequency, thus extending the diffusor diffusion bandwidth. T-shaped recesses may also be located within a single diffusor. The front surface of the diffusor may be flat or curved or angled.

Abstract: A device including a membrane having first and second faces; a first substrate disposed on the first face of the membrane and having (i) a plurality of first absorptive regions and (ii) a plurality of first reflective regions formed as wells in a face of the first substrate, the first absorptive regions and the first reflective regions arranged in a pre-defined grid pattern; a second substrate disposed on the second face of the membrane and having (i) a plurality of second absorptive regions and (ii) a plurality of second reflective regions formed as second wells in a face of the second substrate, the second absorptive regions and the second reflective regions arranged in the pre-defined grid pattern.

Abstract: A composite structure, and method of manufacturing it, having a specified width, length, and height defining a top and bottom the composite structure. The composite structure includes a three dimensional structural core constructed of a polymer with a first series of a geometric pattern repeated along its length. The structural core also has a second series of the geometric pattern repeated along the width thereof. The geometric patter may be a sinusoidal curve or a substantially pyramidal shape. The composite structure also includes a first reinforcement layer made of a polymer positioned above the structural core and bonded thereto. It also includes a second reinforcement layer made of a polymer that is positioned below the structural core and bonded thereto. The composite structure may also include a decorative layer above the first reinforcement layer, an acoustical batting layer positioned between the first reinforcement layer and the structural core, and may include fire retardant chemicals.

Abstract: A soundproof panel for an impact sound insulation is disclosed, which is able to resolve an inter-floor noise by providing a soundproof panel for an impact sound insulation which has an excellent impact sound absorption performance. The soundproof panel for an impact sound insulation comprises a lower panel which is made of a porous material; a hexagonal soundproof material which is adhered to an upper surface of the lower panel, with hexagonal holes having different sizes passing through the hexagonal soundproof material; and an upper panel which is adhered to an upper surface of the hexagonal soundproof material and is made of an expandable polymer material.

Abstract: An acoustic barrier that achieves excellent noise insulating properties, and is relatively thin and relatively light in weight includes a flexible thermoplastic barrier layer having a plurality of apertures defining a latticed structure which includes apertures for pass-through components and non-pass-through apertures. The non-pass-through apertures are located where noise levels are expected or known to be relatively low. Effective acoustic performance can be maintained by completely eliminating material from the relatively thick and dense barrier layer at the low noise levels areas, and providing only absorptive decoupler material and/or lightweight sheet material such as plastic films in those areas.

Abstract: An acoustically absorbent porous panel with a layer constructed from a substantially continuous open-celled porous material comprising a cured foamed cementitious material including a first face and a second face. The first face has a surface with a substantially planar profile and the second face has a substantially geometric pattern of depressions formed therein comprising approximately 50% to approximately 90% of the layer by volume.

Abstract: The present invention provides a sound barrier 1 including a plurality of elongate panels 2 having first and second ends 3 and 4, each panel 2 being formed from a shell 5 defining an inner chamber 6 adapted to contain sound attenuating liquid, said plurality of panels 2 being supportable in a planar configuration by a first support means 7 adapted to engage said first and second ends 3 and 4 respectively. Preferably the shell 5 is constructed from plastic and/or fiberglass and the sound attenuating liquid is water which may optionally include other materials such as sand, slurry, concrete rubble, mud, etc. Some embodiments include second support means 9 which are attachable to the post 7 so as to engage the panels 2 and thereby transfer a, substantial portion, or all of, the weight of each panel 2 to the post 7.

Abstract: A panel structure for a transport machine is disclosed which is constituted by an integral combination of an outer panel and an inner panel. The inner panel has reinforcing protuberances and recesses, possessing a higher rigidity than the outer panel. The protuberances of the inner panel and a back side of the outer panel are bonded together through insulating layers present on the protuberances.

Abstract: An acoustic board with an improved composite structure (1), suitable for reducing the sound of aircraft engines, wherein an upper layer consists of a fabric (7) having a high sensitivity to sound velocity and a supporting sheet (4) having a certain porosity; the upper layer is combined, in turn, with an intermediate honeycomb layer (2) and with a lower layer (5) of the conventional type.

Abstract: A sound absorptive multilayer composite having an air-impermeable barrier, an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅔ the final composite thickness, and a semipermeable airflow-resistive decorative membrane having an airflow resistance of about 500 to about 4000 mks Rayls can provide improved acoustic performance while maintaining a low thickness.

Abstract: A multilayered, sound-insulating, mechanically strong sandwich element comprising two facing layers (1) substantially attached to a plastic foam core consisting of at least two layers (2) which are joined through contact points (also called bridges) (3) creating a gap or gaps (4) between the core layers (2), and in case of long spans and/or thin facing layers, travel stops inside the gap/gaps (4) to keep the core layers (2) at a certain distance from each other, wherein the core layer material is a semi-rigid, cellular material containing more tan 50 percent open cells, and has a tensile strength of more than 50 kPa, and has a compressive strength from 5 to 200 kPa, at 10 percent deformation. The distance between the contact points or bridges (3) is at least 350 mm. The new sandwich element can be used as a sound-insulating door, a partition element or a construction unit.

Abstract: The invention relates to a component part, especially a rear parcel shelf, and to a method for the production thereof, whereby the component part is provided with a honeycomb-like core layer (2) which is provided with a reinforcing layer (3, 4) on each side. This layer comprises a nonwoven that contains thermoplastic fibers. The core layer (2) is made of thermoplastic material and is connected to the thermoplastic fibers of the reinforcing layer (3, 4) b material fit. The reinforcing layer (3, 4) is precompressed and air permeable and has an air flow resistance ranging from 500 Nsm−3<R<3500 Nsm−3.

Abstract: An acoustic medium for temporary acoustic treatment of a room is formed from one or more continuous curtains, preferably, with pleated first and second major surfaces. Each pleated curtain preferably has one or more series of collapsible elongated tubular sections which form the pleats that make up the major surfaces of the curtain. Since the elongated tubular sections are collapsible, the curtain can be retracted by collapsing the elongated tubular sections and extended by opening the elongated tubular sections. The mat materials forming the elongated tubular sections and the pleated major surfaces of the curtain provide the curtain with an airflow resistance through the curtain, in a direction generally perpendicular to the planes containing the apexes of the pleats forming the first and second major surfaces of the curtain, that has the desired properties for absorbing or reflecting sound.

Abstract: A multi-layer acoustically absorptive mat includes a base layer having a peripheral portion with a plurality of apertures formed in the peripheral portion in adjacent, spaced-apart relationship. A face layer disposed adjacent the base layer. An acoustic absorbing layer is interposed between the peripheral portion of the base layer and the face layer. The acoustic absorbing layer includes a respective exposed portion that extends across each of the apertures.

Abstract: An acoustical panel formed from a fibrous, open-celled material comprised of up to about 50% by weight fibers, between about 3% and about 10% by weight binder, between about 20% and about 75% by weight filler and about 0.01% to about 2.0% by weight surfactant. Additionally, voids are formed within the panel having an average distribution size diameter of about 50 &mgr;m to about 250 &mgr;m. The acoustic panel achieves very high sound absorption properties without the need for additional surface perforations, while maintaining a very high surface hardness.

Abstract: A panel-shaped loudspeaker includes a panel (1) and an exciter coupled to the panel. The panel is provided with two parallel extending thin walls (1a, 1b) which are interconnected by a structure of thin strip-shaped partitions (1c) situated between the walls. The longitudinal axes of all partitions extend parallel to each other and give the panel an anisotropic bending stiffness. The material of the walls and the partitions of the panel has an internal damping which is at least 2.5% of the critical damping of the relevant material, used in the panel.

Abstract: A foam-type acoustic panel is designed to be mountable on a stand having a shaft. The acoustic panel includes a main body portion. The main body portion has a first end, a second end, a front surface, a rear surface, a top surface, a bottom surface, and first and second interlocking members. The first and second interlocking members define a multi-segment cut that extends between the top and bottom surface. The multi-segment cut includes a first end disposed at one of the front and rear surfaces, and a second end disposed interiorly of the other of the front and rear surfaces. The second end of the multi-segment cut defines an elongated aperture extending between the top and bottom surface for receiving a shaft of a stand.

Abstract: The invention relates to an ultralight, sound and shock absorbing component set comprising at least one base layer (2), an intermediate layer (3) and a covering layer (6). The intermediate layer (3) consists of a plurality of hollow bodies (4) arranged next to each other, whose walls are perforated and which thus form a complex labyrinth of hollow spaces. The covering layer (6) preferably has a microporous stiffening layer (8) which generates an airflow resistance of 900 Ns/m3<Rt<2000 Ns/m3. The dimensions of the walls of the hollow bodies (4) are such that they allow for compression of at least 50% at a maximum plateau tension of 0.5 Mpa<&sgr;<1.2 Mpa and inelastically and fully convert an impact energy of approximately 0.5 MJ/m3 into deformation work.

Abstract: A sound absorbing structure including a sound absorbing member, an air layer, and a resonant sound absorbing structure. The air layer is formed in the rear of the sound absorbing member. The resonant sound absorbing structure includes a slit and is formed in the rear of the sound absorbing member. The sound absorbing member is a surface plate covering the rear air layer and the resonant sound absorbing structure, and the sound absorbing member is shaped in one of a plate and plane.

Abstract: An acoustic absorber includes an enclosure having a front opening and having a chamber communicating with the front opening for receiving an acoustic absorbing member which includes a housing having a number of apertures for receiving and dissipating noises. The housing may include a circular cross section or the other cross sections, and may include a casing having a number of apertures for receiving and dissipating the noises. The housing may be detachably secured to the enclosure with one or more catches which may engage with the lock grooves of the enclosure.

Abstract: The invention relates to a viscoelastic damping foam with an adhesive surface for adhesion coupling to vibrating surfaces, for solid-borne sound absorption. The viscoelastic damping foam is obtained through the stoichiometric reaction of a polyisocyanate with at least two polyols of the polyether type which are incompatible with one another.

Abstract: In the manufacture of a noise attenuation panel for an aeroengine nacelle an adhesive film is applied to a front face of a cellular component of the panel. The adhesive film is caused to reticulate to the ends of the walls of the cells at the front face of the cellular component. A perforate facing component of the panel is bonded to the front face of the cellular component by adhesive flow from the cell walls to the facing component. To avoid unpredictable adhesive flow giving rise to cosmetic spots on the front face of the facing component the two components are brought together with the interposition of an adhesive flow control sheet and the reticulated adhesive caused to bond the two components together by adhesive flow under the control of the adhesive flow control sheet.

Abstract: A vehicle having a passenger compartment with a moulded headlining to which an exciter is coupled and together forming a distributed mode acoustic radiator, the headliner providing a bass acoustic response when resonating. A mid/high frequency acoustic radiator also may be carried by the headlining. Other interior components of the vehicle (seats, door panels, visors, etc.) also may comprise acoustic radiators.

Abstract: A surface wave apparatus is disclosed having reduced sound attenuation across a surface along a known path having a path distance when compared to sound attenuation along a same path distance through air. The surface wave apparatus includes a plurality of cells defining a first surface. Sound presented at the first surface forms a surface wave over the surface and proximate thereto. Each cell includes four bounding walls and a bottom. Two of the bounding walls act to guide the sound within the known path and two are disposed across the known path to form a structure supporting formation of surface waves.

Abstract: An acoustically significant composite panel having a general sound-absorbing face (or a general sound-diffusing face) and a tuned sound-absorbing face. Such a panel includes a sandwich or composite of a first layer of molding media, a honeycomb of cells and a second layer of molding media. The first layer has at least one or more apertures in it that convert the corresponding cells into Helmholtz resonators. These Helmholtz resonators can be tuned to the same or different frequencies. The second layer is generally sound-absorbing. A general diffuser structure can be attached to the second layer. These panels can be attached to the walls and/or ceilings of a room to control its sonic quality. Also, these panels can be suspended vertically below a ceiling to control noise.

Abstract: An acoustic liner is made by placing a raw adhesive septum between a pair of opposite honeycomb cores, and curing the septum to integrally bond the cores thereto.

Abstract: A barrier for containing an explosion in a room or the like. The barrier is a structural panel comprising a base sheet, a plurality of truncated polyhedral elements secured to and projecting from the base sheet, and a face sheet covering and secured to the truncated apexes of the polyhedral elements. The face sheet is constructed to separate from the polyhedral elements to expose them in the event of an explosion. Each polyhedral element is constructed to collapse in the event of an explosion, is filled with a liquid, and has an opening therein that is closed by a closure device that is openable or removable in response to the collapse of the polyhedral element caused by an explosion. The openings in the polyhedral elements are of a size to effect a misting action of the liquid therein when it is ejected from the openings by the collapse of the polyhedral elements caused by the explosion. The liquid mist serves to absorb and dissipate the heat and energy of the explosion.

Abstract: A panel form loudspeaker/microphone combination has a distributed resonant bending wave member and two transducers mounred on the member at sites where the number of vibrationally active resonance anti-nodes is relatively high. One transducer is capable of vibrating the member to couple to and excite resonant bending wave modes in the member and cause the member to produce an acoustic output. The other transducer also is capable of coupling to he resonant bending wave modes in the member, but it produces an output signal in response to resonance of the member due to incident acoustic energy. The combination may be part of a loudspeaker system including an amplifier for the source signal coupled to the first transducer, and a signal receiver coupled to the second transducer for treating the output signal.

Abstract: A sound-absorbing cellular component is produced in multiple-chamber array, using a grid of spaced elongate rods, and by engaging to the rods of said grid a foil of deformable sheet material which is then drawn by deformation through spaces between rods, to thereby define adjacent partition walls of adjacent chambers. Various embodiments are described, involving retention and/or removal of the rods, and/or involving application of one or more insulating or finishing materials continuously over outwardly facing bottoms of the chambers of the array.

Abstract: An acoustic panel having at least two compressible, flexible, acoustic foam damping layers separated by at least two rigid layers. In one preferred embodiment, a first rigid layer has a second flexible foam layer spray applied, with a further spray application of a rigid third layer, followed by a spray application of a flexible foam fourth layer, followed by a spray application of a rigid fifth layer, followed by a spray application of a sixth flexible foam layer, finally followed by a spray application of a rigid seventh layer. Sound transmission through this embodiment is especially well attenuated at high audio frequencies.

Abstract: A sound attenuating element is provided which comprises a closed cell foam layer (2) having a plurality of channels (4) formed therein. The element is, in use, placed adjacent a surface such that an air gap is formed between the foam layer and the surface. The channels couple to the air gap to form a plurality of Helmholtz resonators.

Abstract: A sound absorbing hollow core panel of structural material based on Helmholtz resonator properties consisting of two exterior skins connected by spacers or structural connections and bounded by perimeter skins or structural connections with internal cavity or cavities that communicate with the exterior sound field through a plurality of orifices in one or both exterior skins as well as the perimeter of the panel and that have a plurality of Helmoltz resonators of different shapes and sizes tuned to specific frequencies that control the sound absorption characteristics of the hollow core panel. The internal cavity or cavities are defined by external skins and perimeters as well as internal structural elements acting as interior dividers, interior sub-volumes and perimeter structures, each of which may contain a plurality of orifices for sound communication forming a sequence of first order Helmholtz acoustical resonators with respective natural frequencies for sound absorption.

Abstract: A multilayered insulating panel having improved acoustic insulating properties and mechanical strength has two outer facings and a soft synthetic foam core having cavities. The foam core with the cavities is in intimate contact with the facings. The cavities are arranged so that the gaps between the core material and the outer facings are in alternate patterns with respect to the opposing outer facings.

Abstract: An acoustic absorbing component comprising a fiber-reinforced thermoplastic resin expanded body having a percentage of void not less than 50 vol %, and a resin molded body. The fiber-reinforced thermoplastic resin expanded body is fused under a pressure to at least a part of a surface of said resin molded body.

Abstract: A cellular material, preferably a low density foam material, having an initial average normal incidence sound absorption coefficient for a selected frequency range is perforated to form a perforated cellular sound absorption material. The perforated cellular sound absorption material formed has an average normal incidence sound absorption coefficient for the selected frequency range greater than the initial average normal incidence sound absorption coefficient of the cellular sound absorption material. The depth(s), diameter(s), shape(s) and pattern of the perforations provide the cellular sound absorption material with the improved sound absorption properties that are reflected in the increased average normal incidence sound absorption coefficient of the material.

Abstract: A vehicle acoustic system is attachable over a vehicle interior sheet metal component. The system includes a bubble pack which has a first film layer and a second film layer secured to the first film layer, wherein the first and second film layers cooperate to form a plurality of pockets therebetween. The pockets include a gas disposed therein, such that the pockets are at least partially compressible. The bubble pack is adapted to be positioned in direct contact with the sheet metal component. The gas disposed in the pockets could be air or any other lightweight gas. A plurality of kinetic energy dissipating granules may be disposed within the pockets for enhanced noise isolation. Alternatively, damping liquids or gels may be disposed in the pockets. Various embodiments are described.

Abstract: An improved panel structure wherein at least one face of the panel is perforated with small holes and where it is desirable to minimize the number of holes that get filled in with adhesive. For example, an improved noise reducing acoustic panel (30) (FIG. 3) constructed of a nonperforated inner skin (14), a perforated outer skin (16) having small holes (18), two sections (12, 12a) of honeycomb core material which are bonded or spliced together by a partially or fully encapsulated foaming adhesive (32e) which has been foamed and expanded, thereby forcing a supported film adhesive (34c) against the walls (24, 24a) of the honeycomb cells in the area of the gap (22) whereby the supported film adhesive (34c) bonds to the walls (24, 24a) of the honeycomb cells in the area of the gap (22). The nonperforated inner skin (14) has been adhesively bonded by a film adhesive to the honeycomb core sections (12, 12a).

Abstract: An acoustic absorber is made of a pot-shaped lower part with a pot bottom and side wall as well as an upper part having a horn. The horn projects into the bottom part and tapers in the direction of the pot bottom. Undesired noise is effectively reduced by the absorber. A relatively broadband, and at a given size, a relatively low-frequency absorption effect is achieved that is capable of protecting human hearing from injury or reducing the impact of noise such as on technical equipment and components.

Abstract: A truss type extruded aluminum section (1) is formed of a pair of planar plates (2)(3) and ribs (4)(5)(6), wherein hollow portions (7)(8)(9) are formed within the section (1) by the ribs (4)(5)(6) and the planar plates (2)(3). Vibration-damping resin is provided on the inner surfaces of hollow portions (7)(8)(9), and particularly on the inner surface of the planar plate (3) and on a single surface of the inclined rib (4). With this arrangement, the vibration energy bending the planar plate (3) and the rib (4) is converted into a heat energy. In the case of manufacturing such truss type extruded aluminum vibration-damping section (1), for making easy the insertion of the vibration-damping resin in the hollow portion, the vibration-damping resin is stuck on a plastic film (11) to form a long planar body. The plastic film (11) serves as a cover or an adhesive.

Abstract: By means of this acoustic protection it is possible to protect the payloads of expandable launch vehicles effectively against noise emissions from the rocket propulsion system which result in damage of the payloads. For this purpose acoustic absorbers (8) tuned to a defined frequency range are provided and are arranged in foamed plastic mats (7) disposed on the insides (6) of the payload fairing (1). The acoustic absorbers (8) are composed of a cup-shaped lower part (12) and an upper part (13) having a horn (18). The horn (8) tapers in a curved-conical manner from a larger diameter (D.sub.m) to a smaller diameter (D.sub.t) and projects into the lower part (12) by a defined distance (a) from a bottom (14) thereof. Slits (21) for the dissipation of the directed flow energy occurring in the horn (18) are disposed in the wall of the horn in the area of the smaller diameter (D.sub.t).

Abstract: Process for the production of a composite sheet (90) comprising a cellular core (41) and at least one outer layer (42) by bonding the outer layer (42) to the cellular core (41), for example with the aid of an adhesive film (84) under pressure and at elevated temperature, where the adhesive film (84) may initially extend over the entire surface and breaks up in the region of the honeycomb interior under the action of heat and on exposure to a gaseous medium, concentrating at the points of contact between the cellular core (41) and the outer layer (42). The outer layer (42) itself has an adhesive layer or an adhesive film (83) on the side facing the cellular core. The outer layer bonds to the cellular core under pressure and at elevated temperature.

Abstract: A method of using a material as an acoustical barrier in an ambient medium. The material comprises microbubbles having average outer diameters of 5 to 150 microns, bound together at their contact points. The material is characterized by either a porosity of 20 to 60 percent, or by voids between the microbubbles which have characteristic diameter within an order of magnitude of the viscous skin depth of the ambient medium, as calculated at 1 kHz; an air flow resistivity of 0.5.times.10.sup.4 to 4.times.10.sup.7 mks rayls/meter, and an attenuation of sound comparable to mass law performance. The microbubbles can be sintered into direct contact with each other, or one of many types of binder material can be used to support the microbubbles within a composite material.

Abstract: An engine compartment casing element (1), in particular for sound absorption, with a foamed material element (2) attached to a wall element (3) which is preferably reverberant, the foamed material element (2) having a skin-like covering (5) on the side facing away from the wall element (3). The foamed material element (2) is perforated, the foamed material element (2) is also covered on both sides with an air-impermeable plastic sheeting (5) or (6) respectively which also covers the perforated areas (holes 4), and the foamed material element (2) is installed so that it runs at least in part at a distance (a) from the wall element (3).

Abstract: This invention deals with novel sound collecting blocks and their use, in conjunction with novel connector blocks, to build inexpensive, decorative sound walls. This invention also deals with retaining walls which are constructed from the novel connector block, and other non-sound absorbing solid blocks.

Abstract: The invention describes a foamed material panel, in particular a shaped part composed of one or several foamed material panels. These panels consist of a soft and, if appropriate, elastic foamed material comprising cellular webs and/or cellular walls that are permanently deformed at least in some areas. A central area of the foamed material panel is plastically deformed to a higher volumetric weight than at least one intermediate area of the formed material panel.

Abstract: An acoustic board including a front panel formed with a plurality of large openings and small openings, a rear panel having a distance from the front panel, an intermediate panel fitted between the front panel and the rear panel thereby forming a front chamber between the front panel and the intermediate panel and a rear chamber between the intermediate panel and the rear panel and having a plurality of large holes and small holes, and a plurality of sound collecting devices each including a conical hood, a cover, an outer housing and a front silencer, whereby the noise can be effectively isolated from one side to another.