Loudspeaker system

Abstract

The loudspeaker system has a main axis of sound propagation, a first enclosure receiving a first driver; a second enclosure receiving a second driver, the second enclosure being separated from the first enclosure in a transverse orientation relative to the main axis; and a bracket having a structural web extending between the first enclosure and the second enclosure, the bracket having a first enclosure attachment secured to the first enclosure, and a second enclosure attachment secured to the second enclosure.

Description

LOUDSPEAKER SYSTEMFIELD

[0001] This specification concerns the field of sound reproduction, and more specifically describes a loudspeaker system.BACKGROUND

[0002] Loudspeaker systems have evolved from an animal horn used as a warning device into speech projection and musical instruments. The metal horn of a Victrola then established acoustic gain and the reproduction of recorded sounds. A desire for more and better sound resulted in the invention of the electroacoustic transducer to convert electrical audio signals into corresponding sound, thus increasing available sound power. In this specification, electroacoustic transducers will be referred to, in short, as transducers or drivers. T ransducers or drivers may also be referred to as loudspeakers or speakers.

[0003] Early transducers were either a direct radiator having a cone shaped diaphragm for the reproduction of low and mid frequencies or a high frequency compression driver having a small, lightweight diaphragm that required an acoustic source device such as an acoustic transformer in the form of a horn to be coupled to it.

[0004] Further development resulted in the audio signal being divided electrically into defined bandwidths, each to be reproduced by a separate transducer, operating within a common assembly referred to as a loudspeaker system. Depending on the number of reproduced bandwidths, loudspeaker systems may be referred to as two-way or three-way loudspeaker systems. The frequency range of these varied bandwidths are arbitrary and subject to the various considerations of loudspeaker design. For example, the bandwidth of high, mid, and low frequency transducers will differ between a design applied to a dance music system and a sound bar designed for home theatre.

[0005] Many different transducers have been developed, such as electro-dynamic, electrostatic, piezo-electric or plasma transducers. This broad range of development includes woofers, tweeters, ribbon tweeters, compression drivers, electrostatic panels, piezo-electric tweeters, and many other forms of transducers. Drivers configured for lower frequency bandsare known as low frequency drivers or LF drivers (woofers), drivers configured for intermediary frequency bands are known as mid-range drivers or MF drivers, and drivers configured for higher frequency bands are known as high frequency drivers or HF drivers (tweeters).

[0006] The output of any single loudspeaker system is limited by the non-linearity of air at high sound pressure levels, but this is generally acceptable for smaller venues such as living rooms, home theaters or recording studios, with a limited numbers of listeners. In larger venues, multiple closely spaced loudspeaker systems operating in parallel, referred to as a loudspeaker array, are the norm. Individual loudspeaker systems forming part of such loudspeaker arrays can alternately be referred to as line array elements. For applications where deploying an array of loudspeakers is not required, the loudspeaker systems that are used alone or in small quantities can alternately be referred to as point source systems.

[0007] Arrays of loudspeaker systems are conventionally rectangular in orientation with multiple rows and / or columns, provide the required sound power in larger venues. While acceptable for closely spaced low and mid frequencies, nearing the approximation of a point or line source when the wavelengths are larger than the driver. However, since high frequency wavelengths are smaller than the HF drivers and their associated waveguides, they cannot be arrayed to approximate a common point source, thus limiting achievable power and sonic coherence.

[0008] Reproduction of sound at higher power levels has subsequently been achieved by the addition of multiple HF, MF and LF drivers within a single loudspeaker system. This gave rise to the challenge of arranging transducers in a manner that does not negatively interfere with other transducers of the same bandwidth or at the overlapping summation of adjacent transducers of different bandwidths. For this reason, the potential wavelength-dependent interference patterns associated with different geometries within a single loudspeaker system must be considered, as well as interference patterns which may occur when placing multiple systems in an array.

[0009] Careful consideration of interference between HF drivers revealed the weakness of using acoustic source devices having exponential horn geometries in addressing this issue. As a result, a family of acoustic source devices including more specialized horns, waveguidesand wave-shaping sound chambers have been developed, which allow multiple HF drivers to radiate sound from an array with greatly reduced interference. Typically, these geometries included narrow vertical slots that behave in the established manner of a diffraction horn, but many acoustic source devices also included internal shapes that flattened the wavefront along the vertical axis. Such acoustic source devices are typically configured in a manner which is adapted to an intended end use. Accordingly, acoustic source devices integrated to loudspeaker systems which are designed to be used in loudspeaker line arrays, such as line array elements for instance, can have a geometry adapted to approximating a line source in the intended context of use and may be referred to as line source elements. Alternately, acoustic source devices integrated to loudspeaker systems which are designed to be used as point source systems (e.g., intended to be used alone or in a geometry other than a line array), can have a geometry adapted to approximating a point source in the intended context of use and may be referred to as point source devices. In this specification, the combination of a single driver coupled to at least one associated line source device will also be referred to as a loudspeaker system.

[0010] A property of line source devices is their directional characteristic, typically a very narrow vertical pattern is accompanied by a very wide horizontal pattern. Many of these devices achieve this behavior by first flattening the wavefront by causing the sound waves to pass through purposefully unique passageways, and then causing the sound to exit through a slot that is narrow horizontally with respect to the wavelength. Other line source devices, such as a ribbon tweeter achieve this effect by having the inherent properties of a narrow rectangular exit aperture and a flat wavefront.

[0011] A particular loudspeaker system configuration adapted for use in a loudspeaker line array and utilizing this particular geometric solution is based on a single rectangular enclosure oriented horizontally wherein the HF drivers and their associated line source devices are placed along a central, vertical plane, flanked symmetrically about this plane by pairs of MF drivers which are in turn flanked by LF drivers. This design approach was initially popularized by L’Acoustics and is now an industry standard among manufacturers and users of large-scale loudspeaker systems.

[0012] Adamson expanded these concepts to include mid-range reproduction resulting in inventive waveguides, sound chambers and phase plugs (any of which, and any combination of which may be referred to generally as an acoustic source device, and more specifically line source device when specifically configured for use in the context of a loudspeaker line array) achieving a complete integration of the mid- and high-frequency wavefronts. Clarification of these terminologies is important since they have been subject to somewhat fluid interpretation.

[0013] The use of waveguide is derived from the work of Geddes, [Acoustic Waveguide Theory J. Audio Eng. Soc., 1989], recognizing the need to allow a waveguide to allow a wave to propagate naturally according to the wave equation, an immutable law of physics. Waveguides are sometimes incorrectly referred to as devices which does not guide the wavefront according to the wave equation but directs the acoustic energy through narrow passageways presenting a resistive and modal acoustic load to the driver (Heil's Guide d’Onde). In this specification, "waveguide" means a device that allows a wavefront to propagate according to the wave equation, wherein the movement of air at the wavefront is normal to the shape of the wavefront.

[0014] The words "sound chamber" and "wave-shaping sound chamber" (used by Adamson in US Patent Nos. 6,343,133 and 6,581 ,719) mean passageways that modify the shape or curvature of a wavefront according to arbitrary objectives.

[0015] A "phase plug" is a device having at least one passageway, forming an acoustical transformer between a diaphragm and an acoustic load, and is devised to be attached to the entrance of a horn, waveguide or sound chamber.

[0016] A popular multi-driver arrangement has two enclosures (e.g. for LF drivers) which are laterally separated from one another and fixed in that position by a structure which may also be responsible for holding MF and / or HF drivers, associated line source devices, and potentially additional equipment (e.g. electronic equipment), such as the arrangement described in US Patent No. 9,344,800 to Adamson.

[0017] While such configurations have been popular and commercially effective, there remains room for improvement, including how two driver enclosures can be structurally heldin a fixed spatial relationship to one another while allowing the attachment of intermediary components, respecting all structural and wave-propagation considerations, and achieving this in a manner that improves manufacturability while limiting costs and weight of the final assembly.SUMMARY

[0018] In one aspect, a loudspeaker enclosure system is described which comprises a structural element positioned and configured to hold two enclosures in a fixed spatial relationship to one another, where said structural element is formed as a monolithic component. The monolithic component can be formed as folded and shaped sheet metal, or molded or cast of any material with suitable structural properties.

[0019] In another aspect, described herein is a loudspeaker enclosure system comprising a central structural element comprising flanges protruding both forwardly and rearwardly from a central web, at least one of which is further transversely bent, to get a greater longitudinal footprint with the single part. A longitudinal spacing can be present between enclosure attachments provided at the forwardly protruding flanges and enclosure attachments provided at the rearwardly protruding flanges.

[0020] In another aspect, described herein is a loudspeaker enclosure comprising at least one structurally stiff acoustic source device fastened to or otherwise made integral to inward facing walls of the enclosure, as part of the structure which holds enclosures in a fixed spatial relationship with one another. Preferably, the structurally stiff acoustic source device comprises at least one waveguide and / or at least one sound chamber.

[0021] In some embodiments, the at least one structurally stiff acoustic source device may offer a grid-like structure between the enclosures of the loudspeaker system and provide structural stiffness at least in the Y plane, and preferably also in the X plane and / or Z plane. Preferably, the structurally stiff acoustic device provides structural stiffness in 3 mutually orthoganal planes, thereby providing resistance to bending from torsional forces.

[0022] In some embodiments, top, rear, and / or bottom cover plates can collaborate with the at least one structurally stiff acoustic source devices in addition to other structural elementssuch as the central structural element and / or one or more walls of the enclosure to form a boxlike structure. Depending on the embodiment, the at least one structurally stiff acoustic source device can include at least one line source device and / or at least one point source device.

[0023] In another aspect, a loudspeaker enclosure comprises a centrally positioned structural element comprising at least one stiffener bar. In an embodiment, a plurality of stiffener bars are configured to engage both the top walls and the bottom walls of the transversely spaced-apart enclosures, preferably behind enclosure attachments of the bracket, to collaborate with the structure while minimizing any acoustic interference with the line source devices of the loudspeaker system.

[0024] The configuration of a loudspeaker system described herein can be applied to embodiments of a line array as described in US patent 9,344,800, the entire contents of which are incorporated herein by reference where permitted, wherein the rigging attachments are configured to enable the connections associated to use as part of a loudspeaker line array to be formed and the centrally located drivers energize line source devices. In alternative embodiments, the configuration can also be applied to use as a point source system deploying suitable rigging geometry, wherein line source devices are not used, and substituted in their place are point source devices such as a HF driver and horn or a tweeter, as well as any optional electronic components.

[0025] In accordance with one aspect, there is provided a loudspeaker system having a main axis of sound propagation, the loudspeaker system comprising: a first enclosure receiving a first driver; a second enclosure receiving a second driver, the second enclosure being spaced-apart from the first enclosure in a transverse orientation relative to the main axis; and a bracket having a structural web extending between the first enclosure and the second enclosure, the bracket having a first enclosure attachment secured to the first enclosure, and a second enclosure attachment secured to the second enclosure, the second enclosure attachment and the first enclosure attachment being monolithic to one another and to the structural web.

[0026] In preferred embodiments, the first and second enclosure attachments are borne on a first pair of flanges protruding forwardly along the main axis and transversely from thestructural web and a second pair of flanges protruding rearwardly along the main axis and transversely from the structural web and bearing rear enclosure attachments secured to the first enclosure and to the second enclosure.

[0027] In preferred embodiments, there is provided a loudspeaker system having a main axis of sound propagation, the loudspeaker system comprising : a first enclosure receiving a first driver; a second enclosure receiving a second driver, the second enclosure being spacedapart from the first enclosure in a transverse orientation relative to the main axis; a structural component having a structural web extending between the first enclosure and the second enclosure, the bracket having a first transverse enclosure attachment secured to the first enclosure, and a second transverse enclosure attachment secured to the second enclosure; and at least one acoustic source device secured to the structural component and acoustically coupled to a driver, the at least one acoustic source device being structurally stiff in a plane normal to the main axis and secured to a transversely internal wall of at least one of the first enclosure and of the second enclosure.

[0028] In accordance with another aspect, there is provided a loudspeaker system having a main axis of sound propagation, the loudspeaker system comprising : a first enclosure receiving a first driver; a second enclosure receiving a second driver, the second enclosure being spaced-apart from the first enclosure in a transverse orientation relative to the main axis; a structural component having a structural web extending transversely between the first enclosure and the second enclosure, the bracket having a first transverse enclosure attachment secured to the first enclosure, and a second transverse enclosure attachment secured to the second enclosure; and a pair of stiffener bars each extending transversely between the first enclosure and the second enclosure, the pair of stiffener bars including an upper stiffener bar secured to a top wall of the first enclosure and to a top wall of the second enclosure, and a lower stiffener bar secured to a bottom wall of the first enclosure and to a bottom wall of the second enclosure, the pair of stiffener bars positioned rearwardly of the structural component relative the main axis.

[0029] In accordance with another aspect, there is provided a loudspeaker system having a main axis of sound propagation, the loudspeaker system comprising: a first enclosure receiving a first driver; a second enclosure receiving a second driver, the second enclosurebeing spaced-apart from the first enclosure in a transverse orientation relative to the main axis; a structural component having a structural web extending transversely between the first enclosure and the second enclosure, and comprising a first pair of flanges which protrude rearwardly in the X plane and attach to an inward facing wall of each of the first and second enclosures. In preferred embodiments, the structural component comprise a second pair of flanges which protrude forwardly in the Z plane and each second pair flange attaches to a crossplate spanning between and attached to the first and second enclosures. In preferred embodiments, each crossplate attaches to each flange at an attachment portion, and comprises a forward portion positioned forward of the attachment portion and a reward portion positioned rearward of the attachment portion.

[0030] In some embodiments, there is provided a loudspeaker system which comprises any combination or sub-combination of features or elements described herein.DESCRIPTION OF THE FIGURES

[0031] Fig. 1 is an oblique view of one embodiment of a loudspeaker system.

[0032] Fig. 2 is an oblique view of the embodiment of Fig. 1 with some components removed.

[0033] Fig. 3 is an oblique view of a central structural component of the loudspeaker system of Fig. 1 , shown enlarged and from a different angle.

[0034] Fig. 4 is an oblique view of the loudspeaker system of Fig. 1 with additional components.

[0035] Fig. 5 is an oblique view of an alternative embodiment of a loudspeaker system.

[0036] Fig. 6 is an oblique view of an alternative embodiment of a loudspeaker system.

[0037] Fig. 7 is an oblique view of the embodiment of Fig. 6 with some components removed.

[0038] Fig. 8 is an oblique view of an alternative embodiment of a central structural component of the loudspeaker system of Fig. 6, shown enlarged and from a different angle.DETAILED DESCRIPTION

[0039] Loudspeaker systems are often referred to ambiguously as a loudspeaker enclosure, because of the contained volume of air required for the LF driver usually found in such loudspeaker systems. As used herein, an "enclosure" means the structure comprising any suitable material that fully or partially encloses a volume of air and provides a mounting location for a driver.

[0040] The expression “monolithic”, as used herein, refers to a part which is formed or composed continuously of material without joints or seams, such as a component resulting from the folding of a previously flat sheet metal component, or resulting from molding or casting of material directly into a single part. A monolithic part is not an assembly or component which is made of a number of initially separate parts which are welded, brazed, fastened or otherwise assembled or joined to one another. Additional elements may nonetheless be assembled, attached or joined to a monolithic part, in any suitable manner.

[0041] An exemplary loudspeaker system 10 shown in Fig. 1 has a plurality of drivers which approximate a single audio source that directs sound generally along the main sound propagation axis 12. In this description, certain geometrical references are defined as follows. For instance, the Y plane can be defined as being normal to the main axis 12. A lateral axis or orientation 30 can be defined as being lateral relative to the main axis, with up and down, or top and bottom, being defined normal to both the lateral orientation 30 and to the main axis 12. The expression “transverse” is used herein to refer to an orientation which is nonparallel to the main axis 12. Accordingly, the lateral axis 30 and the vertical axis 32 are both transverse. A Z plane can be defined as parallel to both the main axis 12 and to the lateral axis 30, and an X plane can be defined as being parallel to both the main axis 12 and to the up axis 32.

[0042] In this example, the loudspeaker system 10 includes two enclosures 14a, 14b each comprising a box structure formed of a number of panels. The enclosures 14a, 14b each hold at least one driver, such as a LF driver 16a, 16b (present in Fig. 4). Each LF driver (or woofer)has a diaphragm with a relatively large diameter commensurate to the relatively long wavelength of low frequency sound. As known in the art, the enclosures 14a, 14b can offer the function of preventing sound waves generated by the rearward facing surface of the associated diaphragm from interacting / interfering with the sound waves generated by the forward-facing surface of the diaphragm.

[0043] The two enclosures 14a, 14b are held in a spaced apart relationship by a central assembly 18 including structural element 20. In a typical installation, a flat bottom surface of the loudspeaker system 10 shown in Fig. 1 can be roughly aligned with the horizontal orientation, such as may be the case when the loudspeaker system used as a point source system or as part of a loudspeaker line array. Thus, the major bottom and upper surfaces of the enclosures 14a and 14b are in a substantially horizontal plane.

[0044] Alternately, the flat bottom surface of the loudspeaker system 10 may be somewhat inclined relative to the horizontal orientation during use, typically around the lateral axis 30, as may be the case when the loudspeaker system 10 is used as a linear array element of a loudspeaker system array including a number of loudspeaker systems linearly arrayed relative one another, typically in the vertical array orientation.

[0045] In some embodiments, the central structural element 20 is a bracket 36. Preferably, bracket 36 comprises a structural web 34 extending substantially in the Y plane between the first enclosure 14a and the second enclosure 14b. In some embodiments, web 34 may not be exactly parallel to the Y plane. The shape and configuration of the structural web 34 can vary in alternate embodiments, and it may have at least one sections which may be more strongly inclined than in the embodiment shown in Fig. 3. The bracket 36 comprises a plurality of enclosure attachment tabs, such as those illustrated as 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b via which it can be secured to each one of the enclosures 14a, 14b. In this specific embodiment, the enclosure attachment tabs 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b are each secured to a top and to a bottom of the first enclosure and of the second enclosure, with four enclosure attachments on each lateral side. The securing means may comprise any suitable fastener, such as a screw or a bolt as is well known in the art.

[0046] In some embodiments, the structural element 20 including web 34 and enclosure attachment tabs 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b is monolithic. The structural element 20 may be formed of a single sheet-metal component which is cut (e.g. by a simple and cost- effective means such as for example laser cutting, punch or plasma cutting, or a combination of such or similar technologies) and folded into shape. Alternatively, a monolithic structural element 20 may be molded or cast as a single part and could thus be formed of a mouldable material such as plastic, fiberboard or composite. In another alternative, the structural element 20 may be manufactured using additive manufacturing, such as 3D printing.

[0047] Sheet-metal of high tensile strength steel, for instance, may be particularly suitable for an embodiment where the enclosures 14a, 14b are relatively large and heavy (e.g. above 150 lbs), whereas in an embodiment where the enclosures 14a, 14b are relatively small and light (e.g. below 120 lbs), a high tensile strength plastic may be suitable.

[0048] In the illustrated embodiment, the bracket 36 has a plurality of flanges 46a, 46b, 48a, 48b which bear the enclosure attachment tabs 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b. Preferably, a first pair of flanges 46a, 46b protrude from the structural web 34, and bear the forward enclosure attachment tabs 38a, 38b, 42a, 42b, and a second pair of flanges 48a, 48b rearwardly from the structural web 34 and bear the rear enclosure attachment tabs 40a, 40b, 44a, 44b. Preferably, one pair of flanges protrude in the opposite direction of the other pair. Preferably, one pair of flanges have an orientation that is perpendicular to the other pair. Thus, in a preferred embodiment, the first pair of flanges 46a, 46b, protrude forwardly and in the Z plane, while the second pair of flanges 48a, 48b protrude rearwardly and in the X plane.

[0049] The enclosure attachment tabs 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b are extensions of the flanges 46a, 46b, 48a, 48b in this embodiment. For instance, in this embodiment, front upper tabs protrude transversely from and in-plane with a main portion of the front top flange 46a and front bottom tabs protrude transversely from and in-plane with a main portion of the front bottom flange 46b. Moreover, in this embodiment, rear upper tabs protrude transversely from an upper edge of a main portion of the transverse flanges 48a, 48b and rear bottom tabs protrude transversely from a lower edge of a main portion of the transverse flanges 48a, 48b. The tabs can be configured to engage a corresponding portion of the top and bottom of the enclosures 14a, 14b, respectively. More specifically, the tabs canhave at least one aperture configured to receive a fastener therethrough, for instance. In the illustrated embodiment, and especially if made of folded sheet metal, the central web, main portions, and tabs can all be made of the same metal of the same thickness.

[0050] In the illustrated embodiment, the tabs forming the front enclosure attachments 38a, 38b, 42a, 42b are spaced-apart from the tabs forming the rear enclosure attachments 40a, 40b, 44a, 44b by a spacing distance. In the illustrated embodiments, the tabs forming the front enclosure attachments 38a, 38b, 42a, 42b are spaced-apart form the central structural web 34. Such spacing distances can be useful in increasing the footprint of the bracket’s enclosure attachments parallel to the main axis 12 while limiting weight. In an alternate embodiment, the tabs forming the rear enclosure attachments 40a, 40b, 44a, 44b may be spaced-apart from the central structural web 34.

[0051] In some embodiments, acoustic source device locating features 50 are embodied in the form of notches in the flanges 46a, 46b of the first pair, allowing for the location of at least one acoustic source device between the two enclosures. In such embodiments, the at least one acoustic source device can be provided with a corresponding locating feature, such as a pin which engages the notch 50. As a result, the at least one acoustic source device can be correctly positioned relative the bracket during assembly and / or during use.

[0052] In some embodiments, the central assembly 18 further comprises at least one acoustic source device 24, which preferably is made of a structurally stiff material and secured to the inward facing walls of the first enclosure 14a and of the second enclosure 14b. The at least one acoustic source device 24 may be coupled to drivers which are positioned between the first enclosure 14a and the second enclosure 14b. In the specific example illustrated, there are four additional drivers between the first enclosure 14a and the second enclosure 14b, including two HF drivers and two MF drivers, and each one of the four additional drivers has a corresponding acoustic source device 24. Acoustic source devices 24 are preferably made of a relatively stiff or rigid material such as high stiffness plastic or composite. Each one of the acoustic source devices 24 can include at least one of a phase plug, a sound chamber, and a waveguide for instance.

[0053] In some embodiments, a plurality of acoustic source devices 24 are housed between the enclosures 14a, 14b. The acoustic source devices 24 can be secured to the central web 34 of the central structural component 20, for instance, and can further be secured to the inward facing walls of either one or both enclosures 14a, 14b. The additional drivers can include MF drivers and / or HF drivers. The exits of the acoustic source devices 24 can have rectangular cross-sectional shapes in the Y plane and can offer a certain degree of structure in that plane, particularly if they are at least one of i) all integral to one another, ii) secured to the inward facing walls 23 of the enclosures, and / or iii) secured to top and bottom cover plates (shown in Fig. 4).

[0054] In preferred embodiments, the additional drivers comprise two high frequency drivers mounted coaxially to medium frequency drivers. The acoustic source devices 24 of the additional drivers can include geometrical wave-guiding and sound projecting (e.g. sound chamber) features. More specifically, in the particular embodiment illustrated, the loudspeaker system 10 is embodied as a line array element configured for assembly, with other identical loudspeaker systems, in a vertically-oriented loudspeaker line array. In this context, the acoustic source devices 24 are embodied as line source devices. The line source devices of the high frequency drivers can broaden in the top-bottom orientation between two legs of the line source devices of the medium frequency drivers, and the high aspect-ratio outlet section of the line source devices of the high frequency drivers can be structurally connected between the lower aspect-ratio outlet sections of the legs of the line source devices of the medium frequency drivers. Overall, the acoustic source devices 24 have exit which are arranged to form a structural grid having stiffness in various planes, including the Y plane. For example, four rectangular exits are arranged to form a grid-like structure as shown in Figs. 1 and 7.

[0055] It will be understood that in the embodiment presented in Fig. 4, optional rigging (not shown) is further included in the loudspeaker system 10, secured to the enclosures 14a, 14b. The rigging adapts the loudspeaker system 10 for use in a linear array. A linear array may be suitable to project sound to large audiences for instance, though such a linear array is but one example of many possible embodiments.

[0056] Returning to Fig. 1 , the central assembly 18 may further include optional stiffener bars 22, which offer additional structural strength and rigidity to that provided by the centralstructural element 20. In particular, in the illustrated embodiment, a pair of stiffener bars 22 are used including a top stiffener bar and a bottom stiffener bar are used. The top stiffener bar has enclosure attachments at both transversely opposite ends which are secured to the top of the enclosures, respectively. Similarly, the bottom stiffener bar has enclosure attachments at both transversely opposite ends which are secured to the bottom of the enclosures, respectively. The stiffener bars 22 may both be flat in the Z plane. In an embodiment having a central structural element 20 with a structural web 34 extending between the enclosures 14a, 14b, the stiffener bars 22 may be positioned rearwardly of the central structural element 20.

[0057] As shown in Fig. 4, in some embodiments, the central assembly 18 may further include at least one of a top cover plate 26, a bottom cover plate, and a rear cover plate 27. More specifically, at least one of the top cover plates 26, bottom cover plate and rear cover plate 27 may contribute to form a box-like structure between the two enclosures 14a, 14b. In the illustrated embodiment, the top cover plate 26, bottom cover plate and rear cover plate 27 collaborate with the structural array of structurally stiff acoustic source devices 24 and with the inward facing walls 23 of the enclosures 14a, 14b in forming a central box-like structure. Depending on the embodiment, the central box-like structure may be further strengthened or segmented into two box-like structures by the presence of a bracket 36 or other form of central structural element 20 having a structural web 34 extending between the enclosures 14a, 14b.

[0058] Fig. 5 presents another example loudspeaker system. In this example, the loudspeaker system has a structural element 20 configured for holding two enclosures spaced apart from one another, and the structural element is similar in many ways to the structural element of the example loudspeaker system shown in Figs. 1-4. However, in this example, the loudspeaker system is embodied as a two-way system rather than as a three-way system. Woofers can be provided in the enclosures, and high frequency transducers, coupled to a line source device, are provided between the enclosures, secured to a central structural element 20.

[0059] An alternative embodiment is shown in Figs. 6-8. A monolithic central structural element 200 has a structural web 202 and a first set of attachment flanges 204, which preferably protrude rearwardly in the X plane. The attachment flanges 204 compriseattachment tabs 206 which accept fasteners to connect to the inward facing walls of the first and second enclosures. The central structural element 200 also comprises a second set of attachment flanges 208 which preferably protrude forwardly in the Z plane. The second set of attachment flanges have attachment tabs 210 which accept fasteners to attach top and bottom crossplates 212 and 214.

[0060] In preferred embodiments, the top and bottom crossplates 212, 214 each have a plurality of attachment tabs 220 for connecting to the first and second enclosures. A forward portion extends forward of the mounting points where the crossplate is attached to the central structural element 200 and comprises a central web 216. Rearward portions 218a, 218b are wing-like members which extend rearwardly. The attachment tabs 220 are provided in a spaced apart manner along each side edge of the crossplates 212, 214.

[0061] In any embodiment, where a central structural element is positioned transversely across the main axis of sound propagation, the central web (34 or 202) preferably defines at least opening which aligns with the sound propagation path of the third driver. In both examples shown in Fig. 3 and 6, the central web (34 or 202) defines both curvilinear openings which align with a phase plug sound path for a MF driver, and central openings for the sound paths of HF drivers. One skilled in the art will understand that the openings correspond to the installation of upper and lower pairs of co-axially mounted HF and MF drivers. Mounting holes for the HF and MF drivers may be seen.

[0062] As can be understood, the examples described above and illustrated are intended to be exemplary only. For instance, while in the embodiment presented in Fig. 1 , a first enclosure receives only one transducer referred to as the first transducer, and a second enclosure receives only one transducer referred to as the second transducer, other embodiments are possible, including embodiments where the first enclosure includes at least one additional transducer to the first transducer, where the second enclosure includes at least one additional transducer to the second transducer, and where at least one additional enclosure forms part of the loudspeaker system. It will also be noted that while, the illustrated embodiment includes two enclosures separated from one another laterally, alternate embodiments can include two or more enclosures separated from one another vertically, or in another orientation transverse to the main axis of sound propagation. Moreover, while in theillustrated embodiment, four additional drivers are located between the first enclosure and the second enclosure, in an alternate embodiment, a different number of additional drivers can be located between the first enclosure and the second enclosure, with or without acoustic source devices. It will be noted that in an alternate embodiment, the enclosure could be provided as a monolithic component, such as by being molded, rather than being made of a number of initially separate panels assembled to one another. In an alternate embodiment, a portion, or the entirety, of the bracket can be monolithic with one or two enclosures, and if monolithic to one enclosure, can be configured in a manner to be attached to the other enclosure, or to another portion of the bracket monolithic to the other enclosure. In an alternate embodiment, a portion, or the entirety, of a waveguide can be monolithic to at least one enclosure, such as by being moulded with it in a single part. In an embodiment, a first half of a waveguide arrangement can be made integral to a first enclosure, and a second half of a waveguide arrangement can be made integral to the second enclosure. The scope is indicated by the appended claims.

[0063] The forgoing description supplies specific details in order to provide a thorough understanding. Nevertheless, the skilled artisan would understand that the apparatuses, systems, and associated methods of using the apparatuses and systems can be implemented and used without employing these specific details. Indeed, the apparatuses, systems, and associated methods can be placed into practice by modifying the illustrated apparatus and associated methods and can be used in conjunction with any other apparatus and techniques conventionally used in the industry.

[0064] The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims appended to this specification are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed.

[0065] References in the specification to "one embodiment", "an embodiment", etc., indicate that the embodiment described may include a particular claim, feature, structure, or characteristic, but not every embodiment necessarily includes that claim, feature, structure, orcharacteristic. Moreover, such phrases may, but do not necessarily, refer to the same embodiment referred to in other portions of the specification. Further, when a particular claim, feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of one skilled in the art to affect or connect such module, claim, feature, structure, or characteristic with other embodiments, whether or not explicitly described. In other words, any module, element or feature may be combined with any other element or feature in different embodiments, unless there is an obvious or inherent incompatibility, or it is specifically excluded.

[0066] It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for the use of exclusive terminology, such as "solely," "only," and the like, in connection with the recitation of claim elements or use of a "negative" limitation. The terms "preferably," "preferred," "prefer," "optionally," "may," and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.

[0067] The singular forms "a," "an," and "the" include the plural reference unless the context clearly dictates otherwise. The term "and / or" means any one of the items, any combination of the items, or all of the items with which this term is associated. The phrase "one or more" is readily understood by one of skill in the art, particularly when read in context of its usage.

[0068] As will also be understood by one skilled in the art, all language such as "up to", "at least", "greater than", "less than", "more than", "or more", and the like, include the number recited and such terms refer to ranges that can be subsequently broken down into sub-ranges as discussed above. In the same manner, all ratios recited herein also include all sub-ratios falling within the broader ratio.

Claims

WHAT IS CLAIMED IS:

1. A loudspeaker system having a main axis of sound propagation, comprising: a first enclosure having a first driver; a second enclosure having a second driver, the second enclosure being separated from the first; a monolithic bracket comprising a structural web and connecting the first enclosure and the second enclosure in a spaced apart relationship; and at least one additional driver located between the first enclosure and the second enclosure, the third driver having a different frequency bandwidth than the first driver and than the second driver.

2. The loudspeaker system of claim 1 wherein the bracket is formed of a single piece of one of plastic, fiberboard, metal, and composite material.

3. The loudspeaker system of any one of claims 1 to 2 wherein the bracket comprises a first pair of flanges and a second pair of flanges, where at least one pair of flanges comprises an attachment tab for attaching to the first or second enclosure, and each pair of flanges:(a) protrude in opposite directions along the main axis; and / or(b) are planar in non-parallel planes to each other.

4. The loudspeaker system of claim 3 wherein the first pair of flanges extend horizontally in a forward direction and the second pair of flanges extend in a rearward direction.

5. The loudspeaker system of claim 3 or 4 wherein the second pair of flanges extend vertically.

6. The loudspeaker system of claim 5 wherein the vertical pair of flanges each extend rearwardly from a respective one of transversely opposite edges of the structural web, and each comprise enclosure attachment tabs along its length for attaching to an inward facing wall of each of the first and second enclosures.

7. The loudspeaker system of claim 6 wherein each vertical flange comprises an enclosure attachment tab extending transversely in the horizontal plane.

8. The loudspeaker system of any one of claims 4 to 7, wherein each horizontal flange extends forwardly in the horizontal plane and comprises attachment tabs for attaching to (a) the first and second enclosures, and / or (b) a crossplate spanning between and attached to the first and second enclosures.

9. The loudspeaker system of claim 8 wherein the crossplate comprises a flange attachment portion disposed between a forward portion positioned forward of the attachment portion and a reward portion positioned rearward of the attachment portion.

10. The loudspeaker system of any one of claims 1 - 9 wherein either one horizontal flange or one crossplate defines an acoustic source device locating feature, such as a notch that receives a pin.

11. The loudspeaker system of any one of claims 1 to 10 wherein the third driver acoustically is coupled to an acoustic source device, the acoustic source device being structurally stiff in a plane normal to the main axis and secured to an inward facing wall of either or both of the first enclosure and the second enclosure.

12. The loudspeaker system of any one of claims 1 to 11 further comprising at least one stiffener bar extending transversely between the first enclosure and the second enclosure.

13. The loudspeaker system of claim 12 comprising a pair of stiffener bars including an upper stiffener bar secured to a top wall of the first enclosure and to a top wall of the second enclosure, and a lower stiffener bar secured to a bottom wall of the first enclosure and to a bottom wall of the second enclosure.

14. The loudspeaker system of any one of claims 1 to 13, wherein the at least one additional driver comprises at least a MF driver and a HF driver, and preferably a pair of MF drivers and a pair of HF drivers.

15. The loudspeaker system of any one of claims 1-14, wherein the structural web comprises at least one opening defining part of a sound propagation path of the at least one additional driver.

16. The loudspeaker system of claim 14 or 15 wherein the at least one acoustic source device includes a sequence of a phase plug, a sound chamber and a waveguide, and at least the waveguide is structurally stiff in a plane normal to the main axis and secured to the inward facing wall of at least one of the first enclosure and of the second enclosure and / or an adjacent waveguide.

17. The loudspeaker system of any one of claims 1-16 further comprising at least one of a top cover plate, a bottom cover plate and a rear cover plate, secured to the first enclosure and the second enclosure.

18. The loudspeaker system of claim 17 comprising a top cover plate, a bottom cover plate and a rear cover plate, forming a box structure with the inward facing walls of the first enclosure and of the second enclosure and with the at least one acoustic source device of the third drive.

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