Abstract: A speaker installing holder comprising the device a fixed plate having at least two hook members upwardly projected at its ends, said hook members being detachably insertable into insertion holes formed on a chassis; a vertical wall vertically extended from the inside of said fixed plate; and an inclined wall inwardly extended from said vertical wall in an inclined manner, all the above parts being integrally formed. A speaker can be installed in a simple manner by placing a speaker into the space of the holder body, and press-fitting the hook members into the insertion holes, with the result that the productivity is improved.

Abstract: A speaker grill assembly, which comprises a grill constructed to support a speaker on a wall. The grill includes a body having an opening through which the speaker emits sounds and a passageway through which the body may be connected to the wall. A perforated screen constructed to cover the opening and passageway in the body of said grill detachably is connected to the grill. A pad is constructed to prevent viewing the opening and passageway in the body of the grill while permitting the sound emitted by the speaker to pass substantially unimpaired therethrough. The pad is disposed between the grill and the perforated screen when the grill and the preforated screen are fastened to one another.

Abstract: An isosceles shaped sound reproduction speaker 70 is illustrated in the accompanying drawings and described in the specification. The speaker has isosceles sides that extend upward from an apex 86 at an internal angle of between 74.5.degree. and 79.degree. and preferably 78.4.degree.. The width of the enclosure is substantially equal to the circumference of the piston diameter of the primary dynamic, direct radiation diaphragm, low-to-mid frequency range driver 94 mounted in the front wall. The height "C" of the enclosure 71 is substantially equal to or less than the width "B" of the enclosure. The speaker 70 has a secondary dynamic diaphragm driver 98 mounted in the rear wall that is connected electrically in series with the front wall driver 94. The enclosure 71 has an upper fundamental resonance frequency of 2978 Hz.+-.3%. The front and rear drivers 94 and 98 have free air resonance frequencies that are 55 Hz.+-.3%.

Abstract: The invention is a low frequency ported loudspeaker system comprising a hollow rectangular enclosure, the enclosure having a woofer driver airtight mounted to an aperature of the enclosure, changes in air pressure of the invention's enclosure's interior air mass are reduced by the coaction of a liquid mass contained within an open-ended manometer type structure, inlet of open-ended manometer type structure being attached to the enclosure and is in pressure conveyance with the invention's interior air mass.

Abstract: An ultrasonic sensor which is particularly suited to measuring the sound-pressure amplitude in the focus range of a lithotripter and includes in a region a piezoelectrically activated polymeric foil, which is coupled to electrodes. The polymeric foil is mounted in a housing, which has a convex curved, dome-shaped surface at least in one region located opposite one of the flat sides of the polymeric foil. A simple measurement of the sonic field is thus made possible directly on the rubber-diaphragm encased, water-filled delay path of the lithotripter.

Abstract: A speaker system has an acoustic diaphragm and an image projection screen provided on a surface of the diaphragm integrally therewith so as to enable the user to enjoy both realistic image on the screen and powerful sound reproduced through the diaphragm. The rear surface of the diaphragm is closed at a peripheral portion thereof while the central portion of the rear surface of the diaphragm is opened to the exterior, so that the speaker system can provide a high level of reproduced sound pressure in low-pitched region, while the thickness of the speaker is reduced remarkably. The diaphgram can be driven by a plurality of driving units so that the speaker system can operate only with an ordinary stereophonic amplifier.

Abstract: An arrangement of divergently mounted acoustic transducers in a hemispherical air tight enclosure, the enclosure being sized with regard to the loading requirements of the acoustic transducers to produce a small size speaker system having an omnidirectional sound radiation pattern and a flat frequency response without the need of a crossover network. The hemispherical enclosure being comprised of six flat equal sided pentagonal plates, five triangular shaped flat gussets and a flat base plate all of which when assembled forms a half dodecahedron polyhedron shaped enclosure with a closed base, with the base serving as the enclosure mounting surface.

Abstract: A sound reproducing apparatus is provided formed of an acoustic tube having first and second opposite ends, and having substantially a same inside diameter as that of an external acoustic meatus of the user who is wearing the sound reproducing apparatus. A loudspeaker unit is mounted to the acoustic tube intermediate the first and second ends such that a sound radiating surface thereof is directed to one side of the acoustic tube. The acoustic tube has at its first end an auricular attachment which is received at the external acoustic meatus. A second end is formed as a non-sound-reflecting end. The sound reproducing apparatus may also be adapted to have two loudspeaker units mounted to one or more acoustic tubes, respectively, and two auricular attachment sections may be provided, one for each ear. Left and right channel acoustical signals may be respectively input to the respective first and second loudspeaker units for stereo operation.

Abstract: The invention relates to a loudspeaker arrangement in which, in front of the loudspeaker (5) or another sound source, when viewed in the direction of the sound projection, two, preferably plane, sound guide surfaces (2,3) are disposed which, in a bow-like manner, are inclined towards one another at an obtuse angle. The projected sound is better distributed hereby and a good stereophonic effect is achieved. This applies particularly to a stereophonic arrangement with at least two loudspeakers (5).

Abstract: A vented speaker enclosure for use in the ear pockets of motorcycle helmets is disclosed which carries off parasitic sound waves emitted from the rear side of an enclosed audio loudspeaker in order that the parasitic sound waves not be allowed to enter the motorcycle rider's ear and distort the primary sound waves issued from the audio loudspeaker. The vented speaker enclosure consists of a pair of joined together cup-shaped housing assemblies adapted to enclose and secure the audio loudspeaker, having openings in one face of the housing assemblies to allow passage of the sounds waves from the contained louspeaker, and a venting tube connected to an opening through the peripheral wall of the speaker enclosure, the vent tube carrying off and away the parasitic sounds emanating from the rear of the loudspeaker. The venting tube is situated in creases of the helmet inner cushion leading to the outside.

Abstract: The enclosure comprises inner and outer wall members with a vacuum space therebetween. The space is sealed by an O-ring and a flange of a loudspeaker at the mouth of the enclosure. The enclosure has the form of a vacuum-flask. It reduces unwanted propagation of sound by the enclosure.

Abstract: A cover system covers the radiating faces of a loud speaker enclosure. It includes a sheet of flaccid material, such as a sheet of textile fabric printed with an ornamental design and provided with a border of "VELCRO" felt. The speaker radiating face carries either a complete peripheral border or segments of the hook component of a "VELCRO" fastener that is engagable with the felt. In use, the borders of the sheet are rolled up and stuck onto the hook strips to hold the sheet in place. The system makes the customizing of domestic and other loud speaker enclosure very simple.

Abstract: The present invention discloses a ported reflex speaker enclosure for use in the automotive audio systems industry. The ported reflex speaker enclosure is a design that factors the audio and thermal design considerations as found in the automotive operating environment as well as factoring the audio and mechanical mounting considerations as found in the automobile audio systems. The ported reflex speaker enclosure is primarily intended for six (6) by nine (9) inch standard speaker chassis used in automotive audio systems that typically are found as non-enclosed suspended speakers in the trunk compartment of automobiles.

Abstract: A mobile speaker system for mounting on a rear parcel tray attachment portion of a vehicle, the speaker system includes: a bottom casing elongated along a vehicle's width; an upper casing mounted over the elongated bottom casing so as to form a speaker cabinet, the bottom casing having a plurality of first ribs projecting in a first direction, and a plurality of second ribs projecting in a second direction which is substantially perpendicular to the first direction; and fixing metal fittings attached to at least one of the ribs so as to prevent transformation of the bottom casing. In one embodiment, the upper casing includes a recess portion at a central portion thereof, an opening portion formed in the recess portion for mounting a woofer unit, and two ducts for a bass-reflex type cabinet are formed at opposite sides of the opening portion.

Abstract: A speaker system mounted on a rear portion of a vehicle compartment. The speaker system has an elongated cabinet extending in horizontal direction, and an elongated buffle plate coupled to a front open end of the cabinet for providing a cabinet chamber. Within the chamber, a woofer speaker is provided. A vibration surface of the woofer speaker extends in a direction perpendicular to a longitudinal direction of the cabinet, and a speaker frame of the woofer speaker is interposedly supported between the cabinet and the buffle plate.

Abstract: An improved loud speaker mounting frame having a continuous conic shape in cross section, so that by means of the conic and apertures along the apex on one side of the conic cross section shape the interference of negative sound waves within the cabinet is reduced and resonance problems of the cabinet are eliminated. Efficiency of the loud speaker system is thereby improved. The concept of conic formation includes an improved V-shaped filtering wave modulation plate utilized in small speaker cabinets.

Abstract: A speaker enclosure assembly is disclosed, which comprises an enclosure provided with a baffle plate, to which a speaker unit is attached, characterized in that the enclosure is provided with a bellows-like sound pressure buffer member.

Abstract: A base for a loudspeaker enclosure is formed of a lower base disk, an upper support disk and an interposed spacer element which together define an internal hollow space to which structure-borne sound is transmitted. The area of contact between the spacer element and the disks is relatively small is comparison to the area of the disks which defines the hollow space at top and bottom sides thereof. In a preferred embodiment, the disks are formed of a sound-insulating material, preferably rubber, and the spacer element is a spacer ring that peripherally defines the hollow space. Also, a bracing foot, preferably of an inverted frustoconical shape, may be carried upon the upper support disk, for which purpose a support plate is centrally mounted thereon.

Abstract: A loudspeaker having means for acoustically impeding excursion of the transducer diaphragm and means for acoustically attenuating the output of acoustic vibrations of frequencies above a preselected frequency. The loudspeaker includes first and second subchambers separated by a dividing wall in which the transducer is mounted. A first port acoustically couples the first subchamber with the second subchamber and a second port acoustically couples the second subchamber with the outside environment surrounding the loudspeaker.

Abstract: A speaker system especially designed to improve the characteristics of low sound bands. The speaker system desirably includes a partition dividing the interior of a cabinet into a speaker chamber and a resonance chamber, and two radiation ports. One radiation port is formed on the partition and the other one on the walls of the resonance chamber which do not face each other.

Abstract: A speaker system provided with a globular glass enclosure to which a speaker unit is attached, wherein the enclosure is mounted elastically on a support member which consists of an elastic material and has an opening to accommodate a bottom part of the enclosure therein. The direction of the speaker unit can be freely changed under a stable posture and the occurrence of box noise due to the insufficient contact between the enclosure and the support member is prevented. In the speaker system, the enclosure may be fixed firmly at the position of its notch opening to a baffle board made of a highly rigid and/or highly oscillation-damping material for fixing the speaker unit to the baffle board, and thus the occurrence of box noise coming from the transmission of the vibration of the speaker unit to the enclosure and also coming from the deformation of the opening of the enclosure to receive the speaker unit can be prevented.

Abstract: A flat speaker device having a flat speaker unit fitted into a through-hole for mounting a speaker of a wall surface board having its back secured to a wall surface leaving a specific spacing therebetween, the flat speaker unit comprising a total-drive type flat speaker comprising a plurality of magnets juxtaposed on a plane and a diaphragm formed from a plurality of projections for respectively covering the plurality of magnets, a speaker frame with a mounting flange mounted on the flat speaker so as to encircle the outer periphery of the flat speaker, rod-like screw members mounted so as to pass through the speaker frame from the front surface towards the back, and swining blades each disposed on the back of the speaker frame with one end threadedly engaged with a respective rod-like screw member and having a length such that when the blade is swung outwardly of a diagonal line of the speaker frame, the tip portion of the blade extends outwardly from the speaker frame.

Abstract: The invention comprises a microphone and loud speaker system in which the components include a cylinder having a center section and an end section at each end of the center section in axial alignment with one another. The adjacent ends of the center and end sections are elliptical and lie in planes oriented at an angle of 35.degree.16' to the longitudinal axis of the module, the long axes of the ellipses are oriented at 45.degree. to horizontal. The planes of the elliptical ends are substantially isomorphic to the tympanic membrane of the human hearing structure and represent half the dihedral angle of a regular tetrahedron. All of the loudspeaker transducers are shielded by sheilding cylinders with elliptical end faces lying in planes oriented, at half the dihedral angle of a regular tetrahedron, namely, 35.degree.16' to the axes of the cylinders, with the long axes of the ellipses oriented at 45.degree. to the horizontal.

Abstract: A horn assembly for installation within an opening in a boat structure having an exterior surface and an interior surface, is disclosed. The horn assembly includes a noise generator component whose output is directed through a trumpet member having an inlet section and an outlet section. A flared element adapted to extend through the opening in the boat structure has an inner end connected to the trumpet member and an outer end with a peripheral flange that bears against the exterior surface surrounding the opening. A grille element extends over and secures the flared element and thus the horn assembly to the boat structure leaving only the grille element visible on the boat exterior.

Abstract: A speaker system includes a thin plate type vibrating element mounted in, and brought into contact with, a balloon formed of a synthetic rubber or resin film. The balloon comprises a balloon member formed of a flexible film such as a vinyl chloride resin or synthetic rubber film and having therein a pocket, in which an inner film forming the pocket has an area somewhat larger than that surrounded with a laminating line on an outer film forming the pocket, whereby the inner film is brought in pressure contact or engagement with the outer film, when the balloon assembly is inflated.

Abstract: A parametric loudspeaker utilizes nonlinearity of air relative to ultrasonic waves for producing an audio frequency having super directivity, and to thus provide a limited listening area public address system subject to a large listening area by safeguarding listeners by the provision of a framework for intercepting powerful ultrasonic waves and an acoustic filter. The depth and energy consumption of the parametric loudspeaker are reduced by the use of a reflective plate. Arbitrary directivity is obtained by the provision of a mechanism to move an ultrasonic wave radiator or the reflective plate. The parametric loudspeaker and any other loudspeaker may be combined.

Abstract: An acoustic damper for substantially reducing the reverberation echoes at the junction between an acoustic signal propagating fluid and a material having an acoustic impedance substantially different from that of the fluid. The damper, which is particularly adapted for use in ultrasonic transducers, is formed of a material having an acoustic impedance which substantially matches the acoustic impedance of the fluid, such material preferably being a foam plastic material having sufficient hardness to be acoustically stable. For preferred embodiments, the damper is formed of a laminate of the layer described above and a second layer of a material which provides high acoustic attenuation, such as cork material.

Abstract: A loud-speaker is combined with a device for producing lighting speakers is covered by two discs provided with openings and, for example, being formed of a grating. The inner disc of the discs, which is facing the speaker cone is rotatable, whereas the outer disc is stationary. Rotation of the rotatable disc is driven either via a motor or via driver members fixed to the speaker cone of the loud-speaker which are actuated by transmission of the vibrations of the speaker cone to the rotating disc in order to provide rotating movement. Light sources for illuminating the surface of the inner or, respectively, outer disc, which is facing the light sources, are provided either within the speaker cone or outside of the loud-speaker. The lighting effects are then generated by the rotation of the inner disc.

Abstract: A device for fitting a loudspeaker (17) into a cut-out of a sound panel, in particular into cut-outs of the most varied types of sound panel of motor vehicles. The loudspeaker can be fitted by its frame border (15) in each case into a mount adapted to the cut-out and which mount has a sound passage (3) in the shape and size of the frame border (15). The frame border is secured to the mount in the region of the border of the sound passage (3). The mount is in the form of an intermediate plate (1) which has mechanisms (7, 27) for the quick fastening of a loudspeaker frame border of the same shape and size.

Abstract: A loudspeaker enclosure which is adapted to be easily assembled with other like enclosures. The loudspeaker enclosure comprises a front wall through which sound can emanate, two essentially parallel end walls, each end wall being in the shape of a trapezoid and a back wall. The enclosure further includes two side walls extending between the end walls, each of the side walls having a plurality of outwardly projecting linear ribs extending on a line between the front wall and the back wall.

Abstract: A speaker enclosure characterized by a curved back wall and top and bottom planar surface members which together define a front opening. A speaker member, a horn member and a tweeter member are adapted to be mounted within the front opening. At least the curved back wall is made from wood of a specified range of thicknesses and of a particular range of radii of curvature to achieve increased power output for the speaker and enhanced quality of sound.

Abstract: For years efforts have been made to construct acoustically completely dead loudspeaker cabinets. Interest has of course been taken in a neutral reproduction of the signals transmitted to the loudspeaker system, without the acoustic image being changed by cabinet resonances or other irrelevant sources of noise. According to the invention one or several of the cabinet walls are constituted by a hollow body (2), into the interior of which a foamed plastic material mixed with grains of comparatively high specific gravity is injected. These grains are sound and vibration absorbing, so that the walls are practically without resonances, and the weight is simultaneously reduced.

Abstract: Acoustic wave "diffractor" labyrinth(s) are positioned obliquely in front of sound producing transducer(s) to cause very wide angle dispersion of the sound waves projected from said transducer(s) into said labyrinths. The labyrinths may consist of a complex of bent and folded chambers. This system causes depolarization of the sound waves projected from the transducer(s).

Abstract: A hollow enclosure that suspends a bidirectional microphone element within, in such a fashion as to improve the unidirectional characteristics, of said bidirectional microphone.

Abstract: A simulated rock speaker cabinet in the form of a natural rock has build-up portions of modeling clay which include a pattern of small diameter holes to form speaker grills at longitudinally spaced positions. A chicken wire ring provides structural reinforcement to the speaker cabinet. The artificial rock cabinet may be molded of various hydrolitic cements, magnesite cement, a suitable catalytic plastic resin to which pigment or other colorants may be added along with glass or rock chips, to provide the simulated rock cabinet with an external appearance which corresponds to various natural rocks. The speaker cabinet has speakers and the various electronic components of the speaker system housed within the speaker cabinet and may be coated with water-proofing and weather-proofing material with the speakers molded into the wells and facing the grills. An end plug may be adhesively sealed to the opening within the base of the speaker cabinet and suitably sealed by Hydrostone or other cementous material.

Abstract: A loudspeaker enclosure is configured in trapezoidal shape, with one angular end wall supporting an electromagnetic or electrostatic loudspeaker of the type having both front and back acoustic waves, with the front of the loudspeaker registering with a front wave opening in the angular end wall and the back of the loudspeaker communicating through a transmission line cavity with an acoustic port in the opposite angular end wall. Said opposite angular end wall supports a tweeter spanning said acoustical port. The port is dimensioned larger than the tweeter to provide a port opening having a cross sectional area of about 0.5 to about 2.0 times the operative area of the loudspeaker, and the centerlines of propagation of sound waves from the front waves of the loudspeaker and port form an included angle of about 90.degree.. A mounting base is configured to support the enclosure removably at the port end with the parallel sides extending vertically.

Abstract: A transducer includes a cup-shaped diaphragm having a planar portion in the form of a flange. The internal space of the cup is closed by a metallic support plate. A disc-shaped piezoelectric element has electrode layers on its front and rear surfaces, and the front electrode layer is joined to the inner bottom of the cup. An electrical lead is connected to the rear electrode layer of the piezoelectric element and extends along the external surface of the support plate after it is passed through the thickness of the plate and then bent at a right angle. A resilient member is joined to the external surface of the support plate, and an aluminium sheet is joined to the resilient member. The diaphragm is connected to the ground through the support plate, and the aluminium sheet is also connected to the ground.

Abstract: A speaker enclosure is configured internally so as to minimize the generation of unwanted audio waves inside the enclosure, as well as to promote dissipation of those waves which are generated inside the enclosure. There is provided at the forward portion of the enclosure an isolation structure which converges in a rearward and inward direction and is located about the speaker diaphragm. There is further provided at a rear portion of the enclosure a structure for deflecting audio waves which are generated rearward from the speaker. The deflection structure reflects the audio waves against the sidewalls of the speaker, with the internal walls of the speaker being nonparallel so as to cause increased reflections of these audio waves and their eventual dissipation.

Abstract: An ultrasonic rangefinder capable of detecting a distance between a vehicle and an object with high accuracy is shown. The measurements for microphones for transmitting and receiving ultrasonic waves are chosen so that detour waves are restricted.

Abstract: The invention presents a method for improving overall efficiency and quality in sound reproduction systems by providing a system which establishes positive phase control over the many and varied resonant characteristics encountered in the reproduction and presentation of audio energy. The apparatus embodying the present method primarily consists of speaker structures within which drivers such as conventional cone drivers are acoustically coupled to both air and to the materials from which the enclosure of the speaker structure is formed by optimizing existing atmospheric pressure differentials and induced audio vibration readily available within these structures. The coupling is obtained through the use of acoustical resonator structure placed within a speaker enclosure and through particular distribution of mass in the enclosure and in the materials.

Abstract: A loudspeaker system employing a diaphragm type loudspeaker mounted in an opening in one of a plurality of walls of a hollow enclosure, the walls of the enclosure consisting of a plurality of layers disposed between surfaces thereof, the layers comprising a plurality of elongated strands of wood in a mass of solid resin, the axes of elongation of the strands in layers adjacent to the surfaces being generally parallel to a common plane and generally parallel to each other, the strands in adjacent layers being oriented with the axes of elongation of the strands in one layer normal to the axes of elongation of the strands in the adjacent layer. The enclosure has an axis of elongation and a transverse axis, and the strands in layers adjacent to the surfaces of the walls are generally parallel to the axis of elongation.

Abstract: A loudspeaker structural arrangement enhancing frequency range and flatness of frequency response. The speaker enclosure has an aperture wall defining an aperture at a front portion of the enclosure. The aperture wall has an inclined inside surface sot that the aperture size varies as function of distance along an axis of the aperture. The speaker's transducer unit includes a frame having an outside surface that is inclined to generally match the inclinator of the aperture wall. So that the transducer can be force fit into the enclosure and pressed against it to firmly secure it without attachment to a flange of the transducer.

Abstract: In an acoustical speaker having a movable diaphragm responsive over a range of frequencies, an air duct having a cross-sectional area less than that of the diaphragm substantially surrounding the diaphragm and in communication with one side thereof for acoustically isolating the diaphragm, dampening low-frequency ringing and acoustically loading the diaphragm for extending the frequency range to lower frequencies to enhance the performance of the speaker with small speaker enclosures. One embodiment provides for similar ducting for passive radiator diaphragms.

Abstract: An improved speaker system includes an open tube arrangement operated in conjunction with one or more closed tube components. The system includes a speaker having a frontal side which is positioned proximate an inlet end of an open primary tube. The tube may be provided with a plurality of apertures therethrough along the length thereof for the creation of even harmonic overtones. These apertures may be equally or unequally spaced as desired. Slits are provided at opposite ends of the primary tube and first and second additional tubes each close at one end surround opposite ends of the primary tube including the intensify base notes and enhance the fundamental wave lengths and odd harmonic overtones.

Abstract: A multi-chamber loudspeaker enclosure comprises a primary chamber having a principle interior volume and a secondary chamber having a minor interior volume substantially smaller than the principal interior volume. The secondary chamber comprises an elongated housing mounted to a front wall of the primary chamber. The secondary chamber has a speaker mounting opening from the enclosure and an interior opening that opens simply and directly from the secondary chamber into the primary chamber. The two openings are substantially coaxially aligned. The speaker mounting opening is the only opening from the inside of the enclosure to its exterior. The secondary chamber projects from one of the faces of the front wall of the primary chamber. The length of the secondary chamber between the two openings is substantially greater than the length of a loudspeaker mountable in the speaker mounting opening. This multichamber loudspeaker enclosure has enhanced freedom from resonance.

Abstract: An acoustic device in the form of a loudspeaker is described. An envelope consisting of many discrete parts is driven by an internal driven element so that the parts of the envelope move alternately in unison in an outwards direction and in unison in an inwards direction. Inside the envelope is arranged a framework comprising struts and tensile members, and the envelope parts are mounted on these struts and tensile members. Operation of the driven element varies the distance between two parallel struts of the framework. The framework is thus caused to distort and so cause the desired movement of the envelope parts. The single internal driven element can be replaced with two or more such elements in a modified arrangement.

Abstract: An audible device of the vibrating diaphragm type which has improved acoustical performance by reducing the open area of the acoustical wave egress port. Through use of a masked grille having a small percentage of open grille space it is possible to improve the performance of a vibrating diaphragm type audible device such as a vibratory horn by increasing its energy transfer or acoustical output.

Abstract: A multi-chamber loudspeaker enclosure comprises a primary chamber having a principal interior volume and a secondary chamber having a minor interior volume substantially smaller than the principal interior volume. The secondary chamber comprises an elongated housing mounted to a front wall of the primary chamber. The secondary chamber has a speaker mounting opening exterior of the primary chamber and an interior opening that opens directly from the interior of the secondary chamber into the interior of the primary chamber. The speaker mounting opening is open essentially directly from the interior of the secondary chamber to the exterior of the enclosure. The length of the secondary chamber housing is substantially greater than the wall thickness of the primary chamber front wall, so that the secondary chamber housing projects beyond at least one face of the primary chamber front wall. This multi-chamber loudspeaker enclosure has enhanced freedom from resonance.

Abstract: A molded pressure ring adapted primarily for holding the peripheral marginal portion of a diaphragm in a tone generator under uniform light pressure so that the tone does not change significantly under normal changes in ambient conditions of temperature and pressure; more particularly the ring comprises an outer annular body having circumferentially equi-spaced, radially inwardly extending, generally U-shaped, independently movable, flexible and resilient cantilevers provided at the free ends thereof with pressure applicators arranged to engage and hold the diaphragm under pressure exerted by torsion-stressed portions of the cantilevers.

Abstract: A loudspeaker enclosure comprises a housing defining therein a principal volume having a front wall and a substantially smaller minor volume. The minor volume has a rear wall common to the front wall of the principal volume. The common wall defines a port which communicates the minor volume to the principal volume. A speaker mounting opening is defined in a front wall of the minor volume. The speaker mounting opening defines the only opening from the exterior of the housing to the interior thereof.