Patent Publication Number: US-6712177-B2

Title: Cross-fired multiple horn loudspeaker system

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/207,811, filed May 30, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to horn loudspeakers, and in particular, to a system of vertically offset horn loudspeakers with a common throat section and cross-fired aiming angles. 
     2. Background of the Related Art 
     Horn loudspeakers are used for sound reinforcement, public address, paging, announcement, warning systems and the like. Typical venues include stadiums, arenas, parks, beaches, schools, public buildings, factories, distribution centers, shopping malls, hotels, airports, and mass transit areas. 
     In many situations it is desirable to provide wide horizontal polar response, substantially constant with frequency, to cover a broad target such as seating areas within a stadium. Similarly, it is desirable to provide narrow vertical polar response, substantially constant with frequency, to focus the sound energy into the audience area. Also, in certain highly reverberant venues such as cathedrals and train stations, narrow vertical polar response can mitigate or reduce undesirable sound reflections off hard floors and ceilings, thereby improving the sound quality. 
     One typical horn loudspeaker, as known in the art, utilizes a pair of horn elements horizontally positioned next to each other. This conventional side-by-side horn loudspeaker produces narrow horizontal polar response and wide vertical polar response, particularly at low and mid frequencies. Moreover, the polar response of the side-by-side horn loudspeaker can exhibit interference patterns. The interference can be particularly severe in the horizontal direction and at mid and high frequencies. 
     SUMMARY OF THE INVENTION 
     The invention relates to a horn loudspeaker system. The horn loudspeaker system includes a pair of vertically displaced horns with cross-fired aiming angles. A common throat section couples the horns to a driver. A substantially asymmetrical baffling is incorporated into the horn loudspeaker system to further improve the acoustic performance. In one embodiment, the baffling is integrally formed with the sound expansion chambers of the horns to provide an integral unit. 
     The invention demonstrates certain advantages and benefits over conventional horn systems. One advantage of the novel cross-fired horn loudspeaker system is that it provides improved polar response. The horizontal polar response is desirably wide, substantially smooth, substantially symmetric, and substantially constant with frequency. The wide horizontal polar response covers broad target areas. Additionally, the vertical polar response is desirably narrow, substantially constant with frequency and results in increased gain, or energy focusing, and reduced undesirable reflections. 
     The utilization of a single driver in certain embodiments saves on costs. The drivers are typically one of the more expensive components of a horn system. The drivers are also heavy, and the use of a single driver lowers the system weight. This desirably reduces the structural requirements of the mounting system resulting in cost savings. 
     Other advantages are provided in certain embodiments by the integral construction of the cross-fired horn elements and the baffling. The integral construction further aids in ease of installation, improves aiming accuracy, and saves installation time, as opposed to mounting and orienting multiple horn and driver components. The timesavings desirably translate into additional cost savings. 
     The ease of system installation also addresses safety issues. In many cases, loudspeaker systems have to be mounted on poles, roofs, ceilings, and the like. The invention, by providing a low system weight and an integral horn-baffling unit reduces the chances of accidents during installation and in subsequent use. 
     The flexibility in the selection of the throat configuration adds to the versatility and utility of the invention. The throats of the cross-fired horn loudspeaker can be optimized for a particular application to achieve certain benefits and advantages. For example, the throats can be configured to provide a generally compact design, an extended high frequency response, and an extended low frequency response, among others, as required or desired. 
     The horn mouth sizes and shapes, the number of horn elements, the horn element coverage, and the horn element aiming can be selected, as required or desired, for a particular application. This flexibility in choice further adds to the versatility and utility of the invention. 
     For purposes of summarizing the invention, certain aspects, advantages and novel features of the invention have been described herein above. Of course, it is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     These and other embodiments of the present invention will also become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular embodiment(s) disclosed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a graphical representation of the experimentally measured horizontal polar response curves of a cross-fired horn loudspeaker. 
     FIG. 2 is a graphical representation of the experimentally measured vertical polar response curves of a cross-fired horn loudspeaker. 
     FIG. 3 is a graph based on experimentally measured data illustrating the directivity response of a cross-fired horn loudspeaker of the invention. 
     FIG. 4 is a schematic perspective view of a cross-fired horn loudspeaker having features in accordance with one embodiment of the invention. 
     FIG. 5 is a schematic front elevation view of the cross-fired horn loudspeaker of FIG.  4 . 
     FIG. 6 is a schematic top plan view of the cross-fired horn loudspeaker of FIG.  4 . 
     FIG. 7 is a schematic side elevation view of the cross-fired horn loudspeaker of FIG.  4 . 
     FIG. 8 is a schematic side elevation view of a cross-fired horn loudspeaker illustrating horn throats in accordance with one embodiment of the invention. 
     FIG. 9 is a schematic side elevation view of a cross-fired horn loudspeaker illustrating horn throats in accordance with another embodiment of the invention. 
     FIG. 10 is a schematic side elevation view of a cross-fired horn loudspeaker illustrating horn throats in accordance with a further embodiment of the invention. 
     FIG. 11 is a schematic perspective view of a cross-fired horn loudspeaker illustrating a baffling configuration in accordance with one embodiment of the invention. 
     FIG. 12 is a schematic perspective view of a multi-way speaker system with a cross-fired horn system in accordance with one embodiment of the invention. 
     FIG. 13 is a schematic perspective view of a multi-way speaker system with a cross-fired horn system in accordance with another embodiment of the invention. 
     FIG. 14 is a schematic perspective view of a multi-way speaker system with a cross-fired horn system in accordance with yet another embodiment of the invention. 
     FIG. 15 is a schematic perspective view of an asymmetric horn element in accordance with one embodiment of the invention. 
     FIG. 16 is a schematic top plan view of the asymmetric horn element of FIG. 15 illustrating the orientation of the horn element longitudinal plane with respect to the reference plane. 
     FIG. 17 is a schematic side elevation view of the asymmetric horn element of FIG.  15 . 
     FIG. 18 is a schematic perspective view of a stack of asymmetric horn elements in accordance with one embodiment of the invention. 
     FIG. 19 is a schematic top plan view of the stack of asymmetric horn elements of FIG.  18 . 
     FIG. 20 is a schematic side elevation view of the stack of asymmetric horn elements of FIG.  18 . 
     FIG. 21 is a schematic front perspective view of an asymmetric multi-way speaker system with an asymmetric horn element in accordance with one embodiment of the invention. 
     FIG. 22 is a schematic top plan view of the asymmetric multi-way speaker system of FIG. 21 illustrating the orientation of the horn element longitudinal plane with respect to the reference plane. 
     FIG. 23 is a schematic perspective view of a stack of multi-way speaker systems with each including an asymmetric horn element in accordance with one embodiment of the invention. 
     FIG. 24 is a schematic top plan view of the stack of multi-way speaker systems of FIG.  23 . 
     FIG. 25 is a schematic side elevation view of the stack of multi-way speaker systems of FIG.  23 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a graphical representation of the horizontal polar responses  92 , over a range of frequencies, of a cross-fired horn loudspeaker in accordance with one embodiment of the invention. As discussed in greater detail later herein, in one embodiment, the cross-fired horn loudspeaker comprises a pair of vertically displaced or offset horns, horn sections, or horn elements with “cross-fired” aiming angles and a common throat section. 
     These polar response charts  92  were generated utilizing known experimental and theoretical techniques. The horizontal polar response plots  92  indicate that the cross-fired horn loudspeaker desirably provides a generally wide, substantially smooth, substantially symmetric and substantially constant with frequency horizontal polar response. This smooth and symmetric response is attributable at least partially to the cross-fired horn elements, the asymmetric baffling and/or the common throat section of the cross-fired horn loudspeaker system. 
     FIG. 2 is a graphical representation of the vertical polar responses  94 , over a range of frequencies, of a cross-fired horn loudspeaker in accordance with one embodiment of the invention. These polar response charts  94  were generated utilizing known experimental and theoretical techniques. The vertical polar response plots  94  indicate that the cross-fired horn loudspeaker desirably provides a generally narrow vertical polar response, substantially constant frequency. This generally narrow response is attributable at least partially to the vertically displaced horn sections. 
     FIG. 3 is a directivity response graph  20  illustrating the directivity response of a cross-fired horn loudspeaker in accordance with one embodiment of the invention. The directivity response graph  20  includes an x-axis  22  representing the frequency in units of Hertz (Hz) and a y-axis  24  representing the beamwidth angle in degrees (°). As is known in the art, the beamwidth is defined as the included angle between the −6 dB points on the corresponding polar response curves and the directivity response is the beamwidth over the frequency range of interest. 
     Line  26  depicts the empirically determined horizontal directivity response of a cross-fired horn loudspeaker of the invention. The horizontal directivity response  26  shows that the beamwidth angle is between about 100° and 120° over a frequency range from about 1000 Hz to greater than 6 kHz. This illustrates that the cross-fired system of the invention desirably achieves a wide and substantially constant horizontal directivity response. 
     Line  28  depicts the empirically determined vertical directivity response of a cross-fired horn loudspeaker of the invention. The vertical directivity response  28  shows that the beamwidth angle is between about 15° and 30° over a frequency range from about 1000 Hz to greater than 6 kHz. This illustrates that the cross-fired system of the invention desirably achieves a narrow and substantially constant vertical directivity response. 
     Cross-Fired Horn Loudspeaker System 
     FIGS. 4 to  7  show respective schematic perspective, front, top and side views of a cross-fired multiple horn loudspeaker sound system, assembly, combination, or apparatus  30  having features in accordance with one embodiment of the invention. The cross-fired horn loudspeaker system  30  generally comprises a pair of vertically displaced or offset horns, or horn elements/modules/sections  32 ,  34  with cross-fired aiming angles. In one embodiment, the horns  32 ,  34  are in acoustical communication with a common throat section or divider  36  connected to a compression driver unit or assembly  38 . 
     In one embodiment, and as discussed in greater detail later herein, a baffle system or structure  40  is integrally formed or molded with the horns  32 ,  34 . This further improves the acoustic performance of the cross-fired horn loudspeaker system  30 . In other embodiments, the horns  32 ,  34  can be mounted or housed in the baffling  40 . 
     The upper first horn  32  comprises a sound expansion chamber  42  in acoustical communication with a throat  44  which in turn is in acoustical communication with the common throat section  36 . The sound expansion chamber  42  includes a bell portion or section  46  and a flange portion or section  48  which forms a mouth  50  at the sound radiating end of the first horn  32 . 
     The bell section  46  is positioned intermediate the throat  44  and the flange section  48 . In one embodiment, the bell section  46  forms a generally flared sound transmitting passage and includes a plurality of flared internal surfaces. The direction of the flare is towards the horn mouth  50 . 
     In one embodiment, the flange section  48  forms a generally flared sound transmitting passage and includes a plurality of flared internal surfaces. The direction of the flare is towards the horn mouth  50 . In one embodiment, the mouth  50  has substantially radial top and bottom edges  52 ,  54  in the horizontal plane, with generally straight side edges  56 ,  58  in the vertical plane, and a substantially rectangular cross-sectional shape in a projection on a plane normal to the outbound longitudinal axis  80  (defined later herein). In other embodiments, the horn mouth edges  52 ,  54 ,  56 , and  58  may be shaped in a wide variety of manners, for example, curved, straight or irregular, among others, in both the horizontal and/or vertical planes, and the mouth cross-section may be shaped in a wide variety of manners, for example, rectangular, square, oval, round or irregular, among others, in a projection on a plane normal to the outbound longitudinal axis  80  (defined later herein). 
     The throat  44  is part of a sound transmitting passage originating at the common throat section  36  and terminating at the mouth  50 . The throat  44  can be coupled to the sound expansion chamber  42  in a wide variety of manners, for example, by utilizing suitable mounting flanges, connectors, couplings, and the like, giving due consideration to the goal of providing acoustical communication between the throat  44  and the sound expansion chamber  42 . In other embodiments, the throat  44  is in a continuous transition with the sound expansion chamber  42  to form an integral unit. 
     In one embodiment, the inner diameter, cross-section, or other appropriate area scale of the throat  44  generally increases in the direction commencing from the common throat section  36  and leading towards the sound expansion chamber  42 . This increase in throat size can be generally steady, linear, exponential, irregular, stepped or non-linear, among other configurations. 
     The lower second horn  34  comprises a sound expansion chamber  62  in acoustical communication with a throat  64  which in turn is in acoustical communication with the common throat section  36 . The sound expansion chamber  62  includes a bell portion or section  66  and a flange portion or section  68  which forms a mouth  70  at the sound radiating end of the second horn  34 . 
     The bell section  66  is positioned intermediate the throat  64  and the flange section  68 . In one embodiment, the bell section  66  forms a generally flared sound transmitting passage and includes a plurality of flared internal surfaces. The direction of the flare is towards the horn mouth  70 . 
     In one embodiment, the flange section  68  forms a generally flared sound transmitting passage and includes a plurality of flared internal surfaces. The direction of the flare is towards the horn mouth  70 . In one embodiment, the mouth  70  has substantially radial top and bottom edges  72 ,  74  in the horizontal plane, with generally straight side edges  76 ,  78  in the vertical plane, and a substantially rectangular cross-sectional shape in a projection on a plane normal to the outbound longitudinal axis  90  (defined later herein). In other embodiments, the horn mouth edges  72 ,  74 ,  76 , and  78  may be shaped in a wide variety of manners, for example, curved, straight or irregular, among others, in both the horizontal and/or vertical planes, and the mouth cross-section may be shaped in a wide variety of manners, for example, rectangular, square, oval, round or irregular, among others, in a projection on a plane normal to the outbound longitudinal axis  90  (defined later herein). 
     The throat  64  is part of a sound transmitting passage originating at the common throat section  36  and terminating at the mouth  70 . The throat  64  can be coupled to the sound expansion chamber  62  in a wide variety of manners, for example, by utilizing suitable mounting flanges, connectors, couplings, and the like, giving due consideration to the goal of providing acoustical communication between the throat  64  and the sound expansion chamber  62 . In other embodiments, the throat  64  is in a continuous transition with the sound expansion chamber  62  to form an integral unit. 
     In one embodiment, the inner diameter, cross-section, or other appropriate area scale of the throat  64  generally increases in the direction commencing from the common throat section  36  and leading towards the sound expansion chamber  62 . This increase in throat size can be generally steady, linear, exponential, irregular, stepped or non-linear, among other configurations. 
     In one embodiment, the sound expansion chambers  42 ,  62  and throats  44 ,  64  of the respective horns  32 ,  34  are configured and/or dimensioned substantially identically. In another embodiment, the sound expansion chambers  42 ,  62  and throats  44 ,  64  comprise different dimensions. Furthermore, in other embodiments, more than two horns, or horn elements, may be used. 
     The common throat section  36  essentially serves as a sound divider for distributing the sound energy from the compression driver  38  between the top first horn  32  and the bottom second horn  34  of the cross-fired horn loudspeaker system  30 . The divider  36  can be coupled to the driver  38  and the first and second throats  44 ,  64  in a wide variety of manners, for example, by utilizing suitable mounting flanges, connectors, couplings, and the like, giving due consideration to the goal of providing acoustical communication between the driver  38  and the throats  44 ,  64 . In one embodiment, the common throat section  36  is integrally formed or molded with the throats  44 ,  64 . 
     The driver unit  38  comprises one or more compression drivers and is coupled to the common throat section  36 . The driver  38  serves as a transducer to convert and/or transform electrical signals or energy into sound waves, signals or energy. Any one of a number of commercially available compression drivers may be utilized with the cross-fired horn loudspeaker system  30  of the invention, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. 
     FIG. 6 (top view) shows the longitudinal axes or centerlines  80 ′,  90 ′ of each of the respective horns  32 ,  34 . The upper horn longitudinal axis or centerline  80 ′ originates at the common throat section  36 , travels through, continues or spans the throat  44  and sound expansion chamber  42 , and extends outbound through the mouth  50 . The lower horn longitudinal axis or centerline  90 ′ originates at the common throat section  36 , travels through, continues or spans the throat  64  and sound expansion chamber  62 , and extends outbound through the mouth  70 . The horn longitudinal axes  80 ′,  90 ′ also define sound paths through the respective horns  32 ,  34 . 
     The upper horn “outbound” longitudinal axis or centerline  80  comprises a segment of the upper horn axis  80 ′ originating at or near the junction of the upper horn sound expansion chamber  42  and throat  44  and extending outbound through the upper horn mouth  50 , or a substantially straight segment of the upper horn axis  80 ′ extending outbound through the upper horn mouth  50 . The lower horn “outbound” longitudinal axis or centerline  90  comprises a segment of the lower horn axis  90 ′ originating at or near the junction of the lower horn sound expansion chamber  62  and throat  64  and extending outbound through the lower horn mouth  70 , or a substantially straight segment of the lower horn axis  90 ′ extending outbound through the lower horn mouth  70 . The bisecting vertical plane  96  is a vertical plane along a line that bisects the projections of the outbound longitudinal axes  80 ,  90  on a common horizontal plane. 
     Referring in particular to FIG. 6, the horns  32 ,  34  are defined to be “cross-fired” when the projections of the horn longitudinal axes or centerlines  80 ′,  90 ′ on a common horizontal plane intersect or cross one another at a point downstream from the driver  38  or common throat section  36  in the direction of the flow of the acoustic signal. The cross-fire angle (CFA) is defined as the angle of intersection between the projections of the outbound longitudinal axes  80 ,  90  on a common horizontal plane. In certain embodiments, there can be more than one point of intersection of the projections of the horn longitudinal axes or centerlines  80 ′,  90 ′ on a common horizontal plane. 
     In one embodiment, as seen in FIG. 6, the top horn  32  and the bottom horn  34  vertically overlap. That is, there is an overlap area or region between the projections of the horns  32 ,  34  (or sound expansion chambers  42 ,  62 ) on a common horizontal plane. 
     It is also convenient to define an “overlap area” as the area of overlap between the projections of the sound chambers of a pair of horns onto a common horizontal plane. Thus, when there is a finite “overlap area” the horns can be referred to as having “vertically overlapping sound chambers.” 
     FIG. 7 (side view) also illustrates the longitudinal axes or centerlines  80 ′,  90 ′ of each of the respective horns  32 ,  34 . The horns  32 ,  34  are defined to be “vertically divergent/convergent” when the projections of the outbound horn longitudinal axes or centerlines  80 ,  90  on the bisecting plane  96  intersect or cross one another. The vertical divergence/convergence angle (VDA) is defined as this angle of intersection. Note that for the embodiment illustrated in FIGS. 4-7, there is no intersection between the projections of the outbound horn longitudinal axes or centerlines  80 ,  90  on the bisecting vertical plane  96 , hence VDA=0° and the horns are referred to as “vertically parallel.” In certain embodiments, there can be more than one point of intersection of the projections of the horn longitudinal axes or centerlines  80 ′,  90 ′ on the bisecting vertical plane  96 . 
     Referring to FIGS. 4-7, a substantially asymmetric baffle system or structure  40  is integrally formed or molded with the horns  32 ,  34  to further improve the acoustic performance of the cross-fired horn loudspeaker system  30 . The baffling  40  functions to substantially prevent or mitigate undesirable diffraction and interaction between the sound waves or signals broadcasted from the top horn  32  and the bottom horn  34  and the cavities formed between the top horn  32  and the bottom horn  34 . 
     In one embodiment, the baffle system  40  is generally associated with the sides of the top sound expansion chamber  42  near the mouth  50  and the bottom sound expansion chamber  62  near the mouth  70 . In one embodiment, the baffling  40  is in mechanical communication with the sound expansion chambers  42 ,  62 . The baffling  40  generally comprises baffle elements  82 ,  84 ,  86 ,  88 . The baffle elements  82 ,  84  are associated with the top sound expansion chamber  42  with the baffle element  82  being substantially wider than the baffle element  84 . Similarly, the baffle elements  86 ,  88  are associated with the bottom sound expansion chamber  62  with the baffle element  86  being substantially wider than the baffle element  88 . 
     The substantially wide top baffle element  82  is positioned generally above and in mechanical communication with the substantially narrow bottom baffle element  88 . The substantially narrow top baffle element  84  is positioned generally above and in mechanical communication with the substantially wide bottom baffle element  86 . This configuration and dimensional contrast between the baffle elements  82 ,  84 ,  86 ,  88  gives rise to the desirable asymmetry of the baffling  40 . In turn, this causes a further improvement in the acoustical performance of the cross-fired horn loudspeaker system  30  of the invention. 
     In other embodiments, the baffle system  40  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. Baffle elements can also be provided along the top and/or bottom edges of sound expansion chamber  42  near the mouth  50  and/or the top and/or bottom edges of sound expansion chamber  62  near the mouth  70 , giving due consideration to the goal of further enhancing the acoustical performance of the cross-fired horn loudspeaker system  30  of the invention. 
     In another embodiment, the baffle system  40  is autonomous from the sound expansion chambers  42 ,  62 . As the skilled artisan will realize, the baffling  40  can be coupled to the sound expansion chambers  42 ,  62  utilizing a wide variety of techniques, for example, screws, nut-bolt combinations, rivets, clamps, adhesives, or combinations thereof, among others. 
     In one embodiment, the top sound expansion chamber  42 , the bottom sound expansion chamber  62  and the baffling  40  are formed by an injection molding process. This results in an integral unit comprising the sound expansion chambers  42 ,  62  and the baffling  40 . 
     In another embodiment, the top sound expansion chamber  42 , the bottom sound expansion chamber  62 , the throats  44 ,  64 , and the baffling  40  are formed by an injection molding process to form an integral unit. In other embodiments, as the skilled artisan will realize, the cross-fired horn loudspeaker system  30  of the invention can be fabricated in a wide variety of manners, for example, utilizing machining, forging, casting, or combinations thereof, among others. 
     The throats  44 ,  64  are coupled to the respective sound expansion chambers  42 ,  62  and to the divider or common throat section  36 . In turn, the divider  36  is connected to the driver unit  38 . This completes the assembly and formation of the cross-fired horn loudspeaker system  30 . The particular sequence in which the above connections, involving the throats  44 ,  64 , the sound expansion chambers  42 ,  62 , the divider  36 , and the driver  38 , are carried out is usually not of critical importance. Thus, the order in which these connection steps are performed can be chosen, as required or desired. 
     The sound expansion chambers  42 ,  62  are preferably fabricated from a substantially non-resonant, structural material. For example, in one embodiment, the sound expansion chambers  42 ,  62  are fabricated from a fiberglass material. In another embodiment, the sound expansion chambers  42 ,  62  are fabricated from a polyester material. In other embodiments, the sound expansion chambers  42 ,  62  can be fabricated from a wide variety of materials. 
     The baffling  40  is preferably fabricated from a substantially non-resonant, structural material. For example, in one embodiment, the baffling  40  is fabricated from a fiberglass material. In another embodiment, the baffling  40  is fabricated from a polyester material. In other embodiments, the baffling  40  can be fabricated from a wide variety of materials. 
     The throats  44 ,  64  are preferably fabricated from a substantially non-resonant, structural material. For example, in one embodiment, the throats  44 ,  64  are fabricated from a fiberglass material. In another embodiment, the throats  44 ,  64  are fabricated from a polyester material. In a further embodiment, the throats  44 ,  64  are fabricated from a metal, for example, by metal casting. In other embodiments, the throats  44 ,  64  can be fabricated from a wide variety of materials. 
     The common throat section or divider  36  is preferably fabricated from a substantially non-resonant, structural material. For example, in one embodiment, the divider  36  is fabricated from a fiberglass material. In another embodiment, the divider  36  is fabricated from a polyester material. In a further embodiment, the divider  36  is fabricated from a metal, for example, by metal casting. In other embodiments, the divider  36  can be fabricated from a wide variety of materials. 
     Cross-Fired Horn Overlap Configurations 
     The invention can be embodied with a plurality of cross-fired horn configurations. As defined above, the cross-fire angle CFA is the angle of intersection between the projections of the outbound horn longitudinal axes or centerlines  80 ,  90  on a common horizontal plane, and hence is a measure of the angular offset or angulation (in a generally horizontal plane) between the vertically offset cross-fired horns  32 ,  34  and/or the respective sound expansion chambers  42 ,  62 . It is also convenient to define an “overlap area” as the area of overlap between the projections of the sound chambers of a pair of horns onto a common horizontal plane. Thus, when there is a finite “overlap area” the horns can be referred to as having “vertically overlapping sound chambers.” 
     In accordance with one embodiment of the invention, the vertically displaced cross-fired horns are configured so that there is no “overlap area” between the horn sound chambers. Hence, the horns do not have “vertically overlapping sound chambers.” In this embodiment, the projections of the horn outbound longitudinal axes or centerlines on a common horizontal plane intersect behind the projections on a common horizontal plane of one or both of the horn sound chambers. 
     In accordance with one embodiment of the invention, the vertically displaced cross-fired horns are configured so that there is a small “overlap area” between the horn sound chambers. Hence, the horns have “vertically overlapping sound chambers.” In this embodiment, the projections of the outbound horn longitudinal axes or centerlines on a common horizontal plane intersect substantially at or near the projections on a common horizontal plane of the junctions of one or both of the horn sound chambers and respective throats. 
     Referring to FIG. 6, in accordance with one embodiment of the invention, the vertically displaced cross-fired horns are configured so that there is an “overlap area” between the horn sound chambers. Hence, the horns have “vertically overlapping sound chambers.” In this embodiment, the projections of the outbound horn longitudinal axes or centerlines on a common horizontal plane intersect within the overlap area of the projections on a common horizontal plane of the horn sound chambers. 
     In accordance with one embodiment of the invention, the vertically displaced cross-fired horns are configured so that there is an “overlap area” between the horn sound chambers. Hence, the horns have “vertically overlapping sound chambers.” In this embodiment, the projections of the outbound horn longitudinal axes or centerlines on a common horizontal plane intersect substantially at or near the projections on a common horizontal plane of one or both of the horn mouths. 
     In accordance with one embodiment of the invention, the vertically displaced cross-fired horns are configured so that there is substantially no “overlap area” between the horn sound chambers. Hence, the horns do not have “vertically overlapping sound chambers.” In this embodiment, the projections of the outbound horn longitudinal axes or centerlines on a common horizontal plane intersect ahead or in front of the projections on a common horizontal plane of one or both of the horn mouths. 
     In accordance with one embodiment of the invention, the vertically displaced cross-fired horns are configured so that there is no “overlap area” between the horn sound chambers. Hence, the horns do not have “vertically overlapping sound chambers.” In this embodiment, the projections of the outbound horn longitudinal axes or centerlines on a common horizontal plane intersect ahead or in front of the projections on a common horizontal plane of one or both of the horn mouths. 
     Vertically Divergent/Convergent Horn Configurations 
     The invention can be embodied with a plurality of cross-fired vertically divergent/convergent horn configurations. As defined above, the vertical divergence/convergence angle VDA is the angle of intersection between the projections of the outbound horn longitudinal axes or centerlines  80 ,  90  on the bisecting vertical plane  96 , and hence is a measure of the angular offset or angulation (in a generally vertical plane) between the horns  32 ,  34  and/or the respective sound expansion chambers  42 ,  62 . 
     In one embodiment, and referring to FIG. 7, the horn sound expansion chambers  42 ,  62  are positioned so that there is no intersection or crossover between the projections of the outbound horn longitudinal axes or centerlines  80 ,  90  on the bisecting vertical plane  96 . That is, VDA=0°, and the horns  32 ,  34  are vertically parallel. The horns  32 ,  34  (or sound expansion chambers  42 ,  62 ) can also be shifted longitudinally, or laterally, or both while maintaining their vertical parallelness (VDA=0°). 
     In another embodiment, the vertically offset horn sound chambers are positioned to provide a vertically divergent cross-fired system. For a vertically divergent system, in one embodiment, the horn mouths point vertically outwardly away from one another and the projections of the outbound horn longitudinal axes or centerlines on the bisecting vertical plane  96 , intersect or crossover at a point generally behind the horn mouths. The angle at this point of intersection is the vertical divergence angle of the cross-fired system. The lower horn outbound longitudinal axis is chosen as a “reference axis” to indicate a vertical divergence angle VDA&gt;0°. 
     In yet another embodiment, the vertically offset horn sound chambers are positioned to provide a vertically convergent cross-fired system. For a vertically convergent system, in one embodiment, the horn mouths point vertically inwards towards one another and the projections of the outbound horn longitudinal axes or centerlines on the bisecting vertical plane  96 , intersect or crossover at a point generally ahead or in front of the horn mouths. The angle at this point of intersection is the vertical convergence angle of the cross-fired system. The lower horn outbound longitudinal axis is chosen as a “reference axis” to indicate a vertical convergence angle VDA&lt;0°. 
     Cross-Fire Angles (CFA) and Vertical Divergence/Convergence Angles (VDA) 
     For a given horn section, the “nominal dispersion angles” (NDA) are industry standard terms that refer to the angles between the 6 dB down points both in a horizontal and vertical direction across a wide frequency range and generally above the break frequency F b , that is, the included angles between the −6 dB points on the corresponding polar response curves. The break frequency F b  is typically defined by the relation:                F   b     =       10   6       θ                 x               (   1   )                         
     where, θ is the physical flare angle formed by sides or top and bottom of the horn through the sound expansion chamber in either the horizontal or vertical plane and x is the nominal width of the horn mouth (for the horizontal break frequency) or the nominal height of the horn mouth (for the vertical break frequency). Hence a horn will have independent break frequencies for its horizontal directivity response and its vertical directivity response. The horizontal break frequency is established using the break frequency equation and the horn mouth width and physical horizontal flare angle. The vertical break frequency is established using the break frequency equation and the horn mouth height and the physical vertical flare angle. For a given industry horn the nominal dispersion angles are listed by the manufacturer, for example, 60°×40° refers to a nominal horizontal dispersion angle of 60° and a nominal vertical dispersion angle of 40°. 
     In one embodiment of the invention, the cross-fire angle (CFA) is selected based on the following relation:              CFA   =         NDA     H   -   1       +     NDA     H   -   2         K             (   2   )                         
     where, NDA H−2  is the nominal horizontal dispersion angle of the first horn (for example, the horn  32 ), NDA H−2  is the nominal horizontal dispersion angle of the second horn (for example, the horn  34 ), and K is a parameter that defines the degree of cross-firing. Equation or expression (2) permits the two horns to be oriented at a predetermined cross-fire angle CFA. 
     In one embodiment, K=2, and the cross-fire angle CFA is the average of the nominal horizontal dispersion angles of the two horns  32 ,  34 . In another embodiment, 1≦K≦4. In a further embodiment, 1.5≦K≦3. In other embodiments, K can be selected, as required or desired, to achieve a cross-fire angle in the range from greater than 0° to less than 180°, that is, 0°&lt;CFA&lt;1800. 
     In one embodiment of the invention, the vertical divergence/convergence angle (VDA) is selected based on the following relation:              VDA   =         NDA     V   -   1       +     NDA     V   -   2         C             (   3   )                         
     where, NDA V−1 , is the nominal vertical dispersion angle of the first horn (for example, the horn  32 ), NDA V−2  is the nominal vertical dispersion angle of the second horn (for example, the horn  34 ), and C is a parameter that defines the degree of vertical divergence/convergence. Equation or expression (3) permits the two horns to be oriented at a predetermined vertical divergence/convergence angle VDA. 
     In one embodiment, C=±∞, and hence VDA=0° so that the horns  32 ,  34  are vertically parallel. Note that divergence is indicated by VDA&gt;0° and convergence is indicated by VDA&lt;0°, as discussed above. In one vertically divergent embodiment, 3&lt;C&lt;∞. In another vertically divergent embodiment, 1.3&lt;C&lt;3. In yet another vertically divergent embodiment, 0.10&lt;C&lt;1.3. In one vertically convergent embodiment, −∞&lt;C≦−3. In another vertically convergent embodiment, −3&lt;C≦−1.3. In yet another vertically convergent embodiment, −1.3&lt;C≦−0.10. In other embodiments, C can be selected, as required or desired, to achieve a vertical divergence/convergence angle in the range from −180° to 180°, that is, −180°≦VDA≦180°. 
     The cross-fire angles (CFA) and/or the vertical divergence/convergence angles (VDA) can be selected in a wide variety of manners with efficacy, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. This adds to the versatility of the invention, for example, in the choice of coverage angles, among others. Also, the horns and other components of the cross-fired system can be dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to the particular application. 
     Throat Configurations 
     FIGS. 8 to  10  are schematic side elevation views illustrating a plurality of throat configurations for the cross-fired horn loudspeaker system  30  of the invention. The common throat section or divider  36  couples the throats  44 ,  64  with the driver unit or assembly  38 . As illustrated in FIG. 8, in one embodiment, the throats  44 ,  64  are generally straight (in the projection on a vertical plane.) In another embodiment, shown in FIG. 9, the throats  44 ,  64  bend to provide a more compact assembly. In yet another embodiment, and referring to FIG. 10, the throats  44 ,  64  have double bends to provide longer throats  44 ,  64 . 
     In other embodiments, the throats  44 ,  64  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to achieving one or more of the benefits and advantages as taught or suggested herein. In general, the throat configuration typically takes into consideration such factors as the desired or required frequency response and/or other operational parameters or physical constraints. 
     Baffle System Configurations 
     FIG. 11 is a schematic perspective view of a cross-fired horn loudspeaker  30  illustrating a baffling or baffle system  40  in accordance with one embodiment of the invention. The baffling  40  is substantially asymmetric and generally comprises top baffle elements  82 ,  84 ,  83 ,  85  and bottom baffle elements  86 ,  88 ,  87 ,  89 . 
     The baffle elements  82 ,  84  are associated with the side edges of the top sound expansion chamber  42  near the mouth  50  with the baffle element  82  being substantially wider than the baffle element  84 . The baffle elements  85 ,  83  are associated with respective upper and lower edges of the upper sound expansion chamber  42  near the mouth  50 . Similarly, the baffle elements  86 ,  88  are associated with the side edges of the bottom sound expansion chamber  62  near the mouth  70  with the baffle element  86  being substantially wider than the baffle element  88 . The baffle elements  87 ,  89  are associated with respective upper and lower edges of the lower sound expansion chamber  62  near the mouth  70 . 
     In one embodiment, baffle elements  82  to  89  can be provided, as required or desired, giving due consideration to the goals of preventing or mitigating undesirable diffraction and interaction between the sound waves or signals broadcasted from the top horn  32  and the bottom horn  34  and the cavities formed between the top horn  32  and the bottom horn  34 . 
     In one embodiment, as shown in FIG. 11, the baffle elements  82  to  89  curve in the horizontal direction. In other embodiments, one or more of the baffle elements  82  to  89  can also curve in the horizontal and vertical directions or only in the vertical direction. In other embodiments, one or more baffle elements  82  to  89  can be straight, stepped, irregular, among others, in the horizontal direction and/or vertical direction. 
     In one embodiment, the cross-fired horn system  30  comprises a pair of side mounting flange portions or sections  98 ,  100  (FIG.  11 ). The mounting flange sections  98 ,  100  facilitate the mounting of the cross-fired system  30 . In other embodiments, mounting flanges can be provided above and below the cross-fired horn system  30 , as required or desired, giving due consideration to the goal of facilitating the mounting of the cross-fired system  30 . 
     In one embodiment, the baffling  40  is configured without one or both of the baffle elements  84 ,  88 . In another embodiment, the baffling  40  is configured without one or more of the baffle elements  83 ,  85 ,  87 ,  89 . In yet another embodiment, respective top and bottom caps or cap elements  85   a ,  89   a  are provided above and below respective sound expansion chambers  42 ,  62 . In a further embodiment, the cross-fired horn loudspeaker  30  of the invention is configured without any baffling, caps and/or mounting flanges. 
     In other embodiments, baffle elements, cap elements, and/or mounting flanges can be provided in a desired or required combination and/or configuration to the sides, above, below or between the sound expansion chambers  42 ,  62  with efficacy, giving due consideration to the goals of preventing or mitigating undesirable diffraction and interaction between the sound waves or signals broadcasted from the top horn  32  and the bottom horn  34  and the cavities formed between the top horn  32  and the bottom horn  34  and/or facilitating the mounting of the cross-fired horn loudspeaker system  30 . 
     Sound Chamber Configurations 
     FIG. 11 illustrates sound expansion chambers  42 ,  62  with respective bell sections  46 ,  66  and flange sections  48 ,  68  in accordance with one embodiment of the invention. The bell sections  46 ,  66  form generally flared sound transmitting passages and include a plurality of internal flared surfaces. In one embodiment, the sound expansion chambers  42 ,  62  are configured with bell sections  46 ,  66  only and no flange sections  48 ,  68 . In another embodiment, one or both of the bell sections  46 ,  66  form sound transmitting passages with a single flared internal surface, for example, substantially conical or frusto-conical. 
     Referring again to FIG. 11, the flange sections  48 ,  68  form generally flared sound transmitting passages and include a plurality of internal flared surfaces. In one embodiment, the sound expansion chambers  42 ,  62  are configured with flange sections  48 ,  68  only and no bell sections. In another embodiment, one or both of the flange sections  48 ,  68  form sound transmitting passages with a single flared internal surface, for example, substantially conical or frusto-conical. 
     In other embodiments, the sound expansion chambers  42 ,  62  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to achieving one or more of the benefits and advantages as taught or suggested herein. In general, the sound chamber configuration typically takes into account such factors as the desired or required directivity response, frequency response, and/or other operational parameters. 
     Multi-Way System 
     FIG. 12 is a schematic drawing of a multi-way speaker sound system  110  with a small format cross-fired horn system, assembly, combination or apparatus  130  and having features in accordance with one embodiment of the invention. The multi-way assembly  110  generally comprises the cross-fired horn system  130  and a woofer or low frequency sound source  112  housed or mounted in a speaker body, enclosure, support structure or frame  114 . One advantage of the multi-way combination  110  is that it provides a mid and/or high frequency directivity response that is desirably wide in the horizontal direction and narrow in the vertical direction and an extended low frequency response. 
     The cross-fired horn system  130  generally comprises a pair of vertically displaced or offset horns, or horn elements/modules/sections  132 ,  134  with cross-fired aiming angles. In one embodiment, the horns  132 ,  134  are in acoustical communication with a common throat section or divider  136  connected to a compression driver unit or assembly  138 . 
     In one embodiment, a baffle system or structure  140  is integrally formed or molded with the horns  132 ,  134 . In other embodiments, the horns  132 ,  134  can be mounted or housed in the baffling  140 . As the skilled artisan will realize, the enclosure  114 , the baffling  140 , and the horns  132 ,  134  can be coupled to one another utilizing a wide variety of techniques, for example, screws, nut-bolt combinations, rivets, clamps, adhesives, or combinations thereof, among others. 
     The upper first horn  132  comprises a sound expansion chamber  142  in acoustical communication with a throat  144  which in turn is in acoustical communication with the common throat section  136 . The sound expansion chamber  142  includes a generally flared bell portion or section  146  and a generally flared flange portion or section  148  which forms a mouth  150  at the sound radiating end of the first horn  132 . In one embodiment, the mouth  150  has substantially radial top and bottom edges  152 ,  154  in the horizontal plane, with generally straight side edges  156 ,  158  in the vertical plane, and a substantially rectangular cross-sectional shape in a projection on a plane normal to the outbound longitudinal axis (as defined above). In other embodiments, the horn mouth edges  152 ,  154 ,  156 , and  158  may be shaped in a wide variety of manners, for example, curved, straight or irregular, among others, in both the horizontal and/or vertical planes, and the mouth cross-section may be shaped in a wide variety of manners, for example, rectangular, square, oval, round or irregular, among others, in a projection on a plane normal to the outbound longitudinal axis (as defined above). 
     The throat  144  is part of a sound transmitting passage originating at the common throat section  136  and terminating at the mouth  150 . In one embodiment, the inner diameter, cross-section, or other appropriate area scale of the throat  144  generally increases in the direction commencing from the common throat section  136  and leading towards the sound expansion chamber  142 . This increase in throat size can be generally steady, linear, exponential, irregular, stepped or non-linear, among other configurations. 
     The lower second horn  134  comprises a sound expansion chamber  162  in acoustical communication with a throat  164  which in turn is in acoustical communication with the common throat section  136 . The sound expansion chamber  162  includes a generally flared bell portion or section  166  and a generally flared flange portion or section  168  which forms a mouth  170  at the sound radiating end of the second horn  134 . In one embodiment, the mouth  170  has substantially radial top and bottom edges  172 ,  174  in the horizontal plane, with generally straight side edges  176 ,  178  in the vertical plane, and a substantially rectangular cross-sectional shape in a projection on a plane normal to the outbound longitudinal axis (as defined above). In other embodiments, the horn mouth edges  172 ,  174 ,  176 , and  178  may be shaped in a wide variety of manners, for example, curved, straight or irregular, among others, in both the horizontal and/or vertical planes, and the mouth cross-section may be shaped in a wide variety of manners, for example, rectangular, square, oval, round or irregular, among others, in a projection on a plane normal to the outbound longitudinal axis (as defined above). 
     The throat  164  is part of a sound transmitting passage originating at the common throat section  136  and terminating at the mouth  170 . In one embodiment, the inner diameter, cross-section, or other appropriate area scale of the throat  164  generally increases in the direction commencing from the common throat section  136  and leading towards the sound expansion chamber  162 . This increase in throat size can be generally steady, linear, exponential, irregular, stepped or non-linear, among other configurations. 
     The horn sections  132  and  134  can be oriented in a wide variety of manners to provide a wide range of cross-fire angles (CFA) and vertical divergence/convergence angles (VDA), as required or desired, giving due consideration to the goals of achieving one or more of the benefits and advantages as taught or suggested herein. 
     In one embodiment, and as indicated above, a substantially asymmetric baffle system or structure  140  is integrally formed or molded with the horns sections  132 ,  134  to further improve the acoustic performance of the multi-way speaker system  110 . This results in an integral unit comprising the sound expansion chambers  142 ,  162  and the baffling  140 . The baffling  140  functions to substantially prevent or mitigate undesirable diffraction and interaction between the sound waves or signals broadcasted from the top horn  132  and the bottom horn  134  and the cavities formed between the top horn  132  and the bottom horn  134  and/or reflected or reradiated from the speaker body/enclosure or frame  114 . 
     In one embodiment, the baffle system  140  is generally associated with the side edges of the top sound expansion chamber  142  near the mouth  150  and the bottom sound expansion chamber  162 . In one embodiment, the baffling  140  is in mechanical communication with the sound expansion chambers  142 ,  162 . The baffling  140  generally comprises baffle elements  182 ,  184 ,  186 ,  188 . The baffle elements  182 ,  184  are associated with the top sound expansion chamber  142  with the baffle element  182  being substantially wider than the baffle element  184 . Similarly, the baffle elements  186 ,  188  are associated with the bottom sound expansion chamber  162  with the baffle element  186  being substantially wider than the baffle element  188 . 
     The substantially wide top baffle element  182  is positioned generally above and in mechanical communication with the substantially narrow bottom baffle element  188 . The substantially narrow top baffle element  184  is positioned generally above and in mechanical communication with the substantially wide bottom baffle element  186 . This configuration and dimensional contrast between the baffle elements  182 ,  184 ,  186 ,  188  gives rise to the desirable asymmetry of the baffling  140 . In turn, this causes a further improvement in the acoustical performance of the multi-way speaker system  110  of the invention. 
     In one embodiment the baffle elements  182 ,  184 ,  186  and  188  curve in the horizontal direction. In other embodiments, one or more of the baffle elements can also curve in the horizontal and vertical directions or only in the vertical direction. In further embodiments, one or more baffle elements  182  to  188  can be straight, stepped, irregular, among others, in the horizontal direction and/or vertical direction. 
     In one embodiment, the cross-fired horn system  130  comprises a pair of side mounting flange portions or sections  198 ,  200  (FIG.  12 ). The mounting flange sections  198 ,  200  facilitate the mounting of the cross-fired system  130  to the speaker body, enclosure, support structure, or frame  114 . In other embodiments, mounting flange sections can be provided above and below the cross-fired horn system  130 , as required or desired, giving due consideration to the goal of facilitating the mounting of the cross-fired system  130 . 
     In one embodiment, respective top and bottom caps or cap elements  185   a ,  189   a  are provided above and below respective sound expansion chambers  142 ,  162 . In another embodiment, the cross-fired loudspeaker  130  of the invention is configured without any cap elements. 
     In other embodiments, baffle elements, cap elements, and/or mounting flange sections can be provided in a desired or required combination and/or configuration to the sides, above, below or between the sound expansion chambers  142 ,  162  with efficacy, giving due consideration to the goals of preventing or mitigating undesired diffraction and interaction between the sound waves or signals broadcasted from the top horn  132  and the bottom horn  134  and the cavities formed between the top horn  132  and bottom horn  134  and/or reflected or reradiated by the speaker body/enclosure  114  and/or facilitating the mounting of the cross-fired horn loudspeaker system  130 . 
     FIG. 13 is a schematic perspective view of a multi-way speaker system  110  with a large format cross-fired horn system, assembly, combination or apparatus  130  having features in accordance with one embodiment of the invention. The multi-way speaker system  110  generally comprises the cross-fired horn system  130  with a substantially asymmetric baffling  140  and a woofer  112  with a generally matching baffling  141  substantially circumscribing the woofer  112 . The cross-fired horn system  130  generally comprises cross-fired horn sections  132 ,  134 . The cross-fired horn system  130  and the woofer  112  are housed or mounted in a speaker enclosure or body  114 . In one embodiment, the multi-way speaker system  110  comprises more than one or a plurality of woofers or low frequency sound sources. 
     Referring to FIG. 13, in one embodiment, the horn baffling  140  is substantially curved or radial in the horizontal direction and the woofer baffling  141  is substantially curved or radial in the horizontal direction. An internal surface  143  of the woofer baffling  141  generally fans out, flares, or provides for acoustical expansion. This further accentuates the performance of the woofer  112 , and hence that of the multi-way speaker system  110 . In one embodiment, the horn baffling  140  and the woofer baffling  141  are separate units. 
     The generally matching woofer baffling  141  functions to substantially prevent or mitigate undesirable diffraction and interaction between the sound waves or signals broadcasted from the cross-fired horn system  130  and those reflected by the speaker body  114  and/or broadcasted from the woofer  112 . In other embodiments, the woofer baffling  141  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. 
     FIG. 14 is a schematic perspective view of a multi-way speaker system  110  having a cross-fired horn system  130  and a woofer  112  in accordance with yet another embodiment of the invention. The cross-fired horn system  130  generally comprises cross-fired horn sections  132 ,  134 . In this embodiment, a fully integrated multi-way system  110  is provided with the horn sound expansion chambers  142 ,  162 , the horn baffling  140 , and the woofer baffling  141  being formed as an integral unit, for example, by injection molding. In one embodiment, a speaker enclosure  114  is integrally formed into the multi-way system  110 . 
     Referring to FIG. 14, in one embodiment, the horn baffling  140  is substantially curved or radial in the horizontal direction and the woofer baffling  141  is substantially curved or radial in the horizontal direction. An internal surface  143  of the woofer baffling  141  generally fans out, flares, or provides for acoustical expansion and substantially circumscribes the woofer  112 . This further accentuates the performance of the woofer  112 , and hence that of the multi-way speaker system  110 . In one embodiment, the integrated multi-way speaker system  110  comprises more than one or a plurality of woofers. 
     The embodiment of FIG. 14 also illustrates generally round or oval shaped horn mouths  150 ,  170 . Additionally, the bell sections  146 ,  166  of the respective sound expansion chambers  142 ,  162  each comprise a single generally flared internal surface. Further, sound expansion chambers  142 ,  162  have no flange sections. In other embodiments, and as discussed above, the mouths  150 ,  170  and/or the sound expansion chambers  142 ,  162  can be configured in a wide variety of manners. 
     Asymmetric Horn Element 
     FIGS. 15 to  17  show perspective, top and side views of an asymmetric horn element, section or module  310  and having features in accordance with one embodiment of the invention. The asymmetric horn element  310  generally comprises a sound expansion chamber  342  with an asymmetric aiming angle and a means for aligning/mounting/combining a second vertically displaced asymmetric horn element in a manner to provide a cross-fire angle between them. In one embodiment, as discussed in greater detail later herein, a reference plane  410  (FIG. 16) is specified at a predetermined angle with regard to the nominal dispersion angle of the asymmetric horn element  310  and the required or desired degree of crossfire of a vertical stack of asymmetric horn elements. FIG. 18 shows a perspective view of an asymmetric horn element stack generally comprising two asymmetric horn elements, with coincident reference planes, one inverted and vertically displaced, and providing a cross-fire angle between them. Two or more asymmetric horn elements arranged, for example, in a vertical stack with a cross-fired orientation provide a desirably wide horizontal directivity response and a narrow vertical directivity response. 
     In one embodiment, as discussed in greater detail later herein, mounting flange sections  398 ,  400  are integrally formed or molded with the asymmetric horn element  310  and are coincident with the reference plane  410 . This provides for the alignment/mounting/combining of two asymmetric horn elements, one inverted and vertically displaced, and achieves the desired crossfire angle between them. In a further embodiment, the mounting flange sections  398 ,  400  are parallel to and displaced from the reference plane  410 . 
     In another embodiment, the asymmetric horn element  310  is housed in an enclosure, box, support structure or frame  314  (FIG. 18) whose mounting surface  365  is coincident with the reference plane  410 . This provides for the aligning/mounting/arranging of two asymmetric horn elements, one inverted and vertically displaced, and achieves the desired crossfire angle between them. In yet a further embodiment, the mounting surface  365  of the enclosure/box/support structure or frame  314  is parallel to and displaced from the reference plane  410 . 
     In a further embodiment, as discussed in greater detail later herein, a baffle system or structure  340  is integrally formed or molded with the asymmetric horn element  310 . This further improves the acoustical performance. In other embodiments, the asymmetric horn element  310  can be mounted or housed in the baffling  340 . 
     The asymmetric horn element  310  comprises the sound expansion chamber  342  in acoustical communication with a throat  344  which in turn is connected to a compression driver unit or assembly  338 . The sound expansion chamber  342  includes a bell portion or section  346  and a flange portion or section  348  which forms a mouth  350  at the sound radiating end of the horn element  310 . 
     The bell section  346  is positioned intermediate the throat  344  and the flange section  348 . In one embodiment, the bell section  346  forms a generally flared sound transmitting passage and includes a plurality of flared internal surfaces. The direction of the flare is towards the horn mouth  350 . In one embodiment, the flange section  348  forms a generally flared sound transmitting passage and includes a plurality of flared internal surfaces. The direction of the flare is towards the horn mouth  350 . 
     In one embodiment, the mouth  350  has substantially radial top and bottom edges  352 ,  354  in the horizontal plane, with generally straight side edges  356 ,  358  in the vertical plane, and a substantially rectangular cross-sectional shape in a projection on a plane normal to the outbound longitudinal axis  380  (defined again later herein). In other embodiments, the horn element mouth edges  352 ,  354 ,  356 ,  358  may be shaped in a wide variety of manners, for example, curved, straight or irregular, among others, in both the horizontal and/or vertical planes, and the mouth cross-section may be shaped in a wide variety of manners, for example, rectangular, square, oval, round or irregular, among others, in a projection on a plane normal to the outbound longitudinal axis  380  (defined again later herein). 
     The throat  344  is part of a sound transmitting passage originating at the driver  338  and terminating at the mouth  350 . The throat  344  can be coupled to the sound expansion chamber  342  in a wide variety of manners, for example, by utilizing suitable mounting flanges, fittings, connectors, couplings, and the like, giving due consideration to the goal of providing acoustical communication between the throat  344  and the sound expansion chamber  342 . In other embodiments, the throat  344  is in a continuous transition with the sound expansion chamber  342  to form an integral unit. 
     In one embodiment, the inner diameter, cross-section, or other appropriate area scale of the throat  344  generally increases in the direction commencing from the driver  338  and leading towards the sound expansion chamber  342 . This increase in throat size can be generally steady, linear, exponential, irregular, stepped or non-linear, among other configurations. 
     The driver unit  338  comprises one or more compression drivers and is coupled to the throat  344 . The driver  338  serves as a transducer to convert and/or transform electrical signals or energy into sound waves, signals, or energy. Any one of a number of commercially available compression drivers may be utilized with the asymmetric horn element  310  of the invention, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. 
     FIG. 16 (top view) shows the longitudinal axis or centerline  380 ′ of the asymmetric horn element  310 . The longitudinal axis or centerline  380 ′ originates at the driver  338 , travels through, continues or spans the throat  344  and sound expansion chamber  342 , and extends outbound through the mouth  350 . 
     The “outbound” longitudinal axis or centerline  380  comprises a segment of the longitudinal axis  380 ′ originating at or near the junction of the sound expansion chamber  342  and throat  344  and extending outbound through the horn mouth  350 , or a substantially straight segment of the longitudinal axis  380 ′ extending outbound through the horn mouth  350 . The vertical longitudinal plane  420  is a vertical plane through the outbound longitudinal axis or centerline  380 . 
     In one embodiment, the reference plane  410  is oriented with respect to the vertical longitudinal plane  420  by a predetermined horizontal asymmetry angle α (in degrees) given by the expression:              α   =     90   -       NDA   H     K               (   4   )                         
     where NDA H  is the nominal dispersion angle in the horizontal plane as defined above herein and K is a parameter that defines the degree of horizontal asymmetry. The horn element  310  is said to be “horizontally asymmetric” when the reference plane  410  is not orthogonal to the vertical longitudinal plane  420 . Stated differently, the horn element  310  is said to be “horizontally asymmetric” when the angle between the reference plane  410  and the vertical longitudinal plane  420  is not equal to 90°. 
     FIG. 17 (side view), also illustrates the longitudinal axis or centerline  380 ′ of the asymmetric horn element  310 . The vertical reference axis  430  is a vertical axis at or through the intersection of the vertical longitudinal plane  420  and the reference plane  410 . In one embodiment, the vertical reference axis  430  and hence the reference plane  410  is oriented with respect to the outbound longitudinal axis  380  by a predetermined vertical asymmetry angle β (in degrees) given by the expression:              β   =     90   -       NDA   V     C               (   5   )                         
     where NDA V  is the nominal dispersion angle in the vertical plane as defined above herein and C is a parameter that defines the degree of vertical asymmetry. The horn element  310  is said to be “vertically asymmetric” when the vertical reference axis  430  is not orthogonal to the outbound longitudinal axis  380 . Stated differently, the horn element  310  is said to be “vertically asymmetric” when the angle between the vertical reference axis  430  and the outbound longitudinal axis  380  is not equal to 90°. In another embodiment, β=90°, and the horn element  310  can be said to be “vertically normal or orthogonal” as shown in FIG.  17 . 
     Referring to FIGS. 15 to  17 , in one embodiment, a substantially asymmetric baffle system or structure  340  is integrally formed or molded with the asymmetric horn element  310  to further improve the acoustical performance. The baffling  340  functions to substantially prevent or mitigate undesirable diffraction of the sound waves broadcasted from the asymmetric horn element mouth  350 . 
     In one embodiment, the baffle system  340  is generally associated with the side edges of the sound expansion chamber  342  near the mouth  350 . In one embodiment, the baffling  340  is in mechanical communication with the sound expansion chamber  342 . The baffling  340  generally comprises baffle elements  382 ,  384 . The baffle elements  382 ,  384  are associated with the side edges of the sound expansion chamber  342  near the mouth  350  with the baffle element  382  being substantially wider than the baffle element  384 . 
     In other embodiments, the baffle system  340  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. Respective baffle elements can also be provided above and below the top and/or bottom edges of the sound expansion chamber  342  near the mouth  350 , giving due consideration to the goal of further enhancing the acoustical performance of the asymmetric horn element  310  of the invention. 
     In one embodiment, the baffle system  340  is in mechanical communication with the sound expansion chamber  340 . In another embodiment, the baffle system  340  is autonomous from the sound expansion chamber  342 . As the skilled artisan will realize, the baffling  340  can be coupled to the sound expansion chamber  342  utilizing a wide variety of techniques, for example, screws, nut-bolt combinations, rivets, clamps, adhesives, or combinations thereof, among others. 
     In one embodiment, the sound expansion chamber  342  and the baffling  340  are formed by an injection molding process. This results in an integral unit comprising the sound expansion chamber  342  and baffling  340 . 
     In another embodiment, the sound expansion chamber  342 , the throat  344 , and the baffling  340  are formed by an injection molding process to form an integral unit. In other embodiments, as the skilled artisan will realize, the asymmetric horn element  310  of the invention can be fabricated in a wide variety of manners, for example, utilizing machining, forging, casting, or combinations thereof, among others. 
     The throat  344  is coupled to sound expansion chamber  342  and the compression driver or unit  338 . This completes the assembly and formation of the asymmetric horn element  310 . 
     The sound expansion chamber  342  is preferably fabricated from a substantially non-resonant, structural material. For example, in one embodiment, the sound expansion chamber  342  is fabricated from a fiberglass material. In another embodiment, the sound expansion chamber  342  is fabricated from a polyester material. In other embodiments, the sound expansion chamber  342  can be fabricated from a wide variety of materials. 
     The baffling  340  is preferably fabricated from a substantially non-resonant, structural material. For example, in one embodiment, the baffling  340  is fabricated from a fiberglass material. In another embodiment, the baffling  340  is fabricated from a polyester material. In other embodiments, the baffling  340  can be fabricated from a wide variety of materials. 
     The throat  344  is preferably fabricated from a substantially non-resonant, structural material. For example, in one embodiment, the throat  344  is fabricated from a fiberglass material. In another embodiment, the throat  344  is fabricated from a polyester material. In a further embodiment, the throat  344  is fabricated from a metal, for example, by metal casting. In other embodiments, the throat  344  can be fabricated from a wide variety of materials. 
     Throat Configurations 
     Referring again to FIGS. 15 to  17 , the throat  344  couples the sound expansion chamber  342  with the compression driver or unit  338 . In one embodiment, the throat  344  is generally straight. In other embodiments, the throat  344  may bend in the horizontal direction and/or the vertical direction. In yet other embodiments, the throat  344  may have a plurality of bends in the horizontal and/or vertical directions. In other embodiments, the throat  344  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to achieving one or more of the benefits and advantages as taught or suggested herein. In general, the throat configuration typically takes into account such factors as the desired or required frequency response and/or other operational parameters or physical constraints. 
     Baffle Configurations 
     Referring again to FIG. 15, the baffle system  340  is generally associated with the side edges of the sound expansion chamber  342  near the mouth  350 . The baffling  340  is substantially asymmetric and comprises baffle elements  382  and  384 . In one embodiment, the baffle elements  382 ,  384  curve in the horizontal direction. In other embodiments, one or both of the baffle elements  382 ,  384  can curve in the horizontal and vertical directions or only in the vertical direction. In further embodiments, one or more baffle elements can be straight, stepped, or irregular, among others, in the horizontal direction and/or vertical direction. 
     The baffle elements  382 ,  384  are associated with the side edges of the sound expansion chamber  342  near the mouth  350  with the baffle element  382  being substantially wider than baffle element  384 . In one embodiment, the baffling  340  is configured without one or both of the baffle elements  382 ,  384 . In another embodiment, respective baffle elements are provided above and below the top and/or bottom edges of the sound expansion chamber  342  near the mouth  350 . 
     In one embodiment, and referring in particular to FIG. 15, respective top and bottom caps or cap elements  385   a ,  389   a  are provided above and below the sound expansion chamber  342 . 
     In other embodiments, the baffle elements and/or cap elements can be provided in a desired or required combination and/or configuration to the sides, top and bottom of the sound expansion chamber  342  with efficacy, giving due consideration to the goals of preventing or mitigating undesirable diffraction of the sound waves broadcasted from the asymmetric horn element mouth  350 . 
     Mounting Flange Configurations 
     Referring again to FIGS. 15 to  16 , in one embodiment, the asymmetric horn element comprises a pair of side mounting flange sections  398 ,  400 . The flange sections  398 ,  400  provide for the aligning/mounting/combining of the asymmetric horn element  310 . In other embodiments, mounting flanges can be provided above and below the asymmetric horn element  310 , as required or desired, giving due consideration to the goal of providing for the aligning/mounting/combining of the asymmetric horn element  310 . 
     In one embodiment, the side mounting flange sections  398 ,  400  are coincident with the reference plane  410 . In another embodiment, the side mounting flange section  398 ,  400  are coincident with a plane parallel to the reference plane  410 , giving due consideration to the goal of aligning/mounting/combining two asymmetric horn elements, one inverted and vertically displaced, to provide a cross-fire angle between them. Two or more asymmetric horn elements arranged, for example, in a vertical stack and with a crossfired orientation provide a desirably wide horizontal directivity response and a narrow vertical directivity response. 
     Sound Chamber Configurations 
     Referring again to FIGS. 15 to  17 , the sound expansion chamber  342  is comprised of a bell section  346  and a flange section  348 , in accordance with one embodiment of the invention. The bell section  346  forms a generally flared sound transmitting passage and includes a plurality of internal flared surfaces. The flange section  348  forms a generally flared sound transmitting passage and includes a plurality of internal flared surfaces. In one embodiment, the sound expansion chamber  342  is configured with a bell section  346  only and no flange section. In another embodiment, the sound chamber is configured with a flange section  348  only and no bell section. In yet another embodiment, one or both of the bell and flange sections  346 ,  348  form sound transmitting passages with a single flared internal surface, for example, substantially conical or frusto-conical shaped. 
     In other embodiments, the sound expansion chamber  342  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to achieving one or more of the benefits and advantages as taught or suggested herein. In general, the sound chamber configuration typically takes into account such factors as the desired or required directivity response and/or other operational parameters. 
     Asymmetric Horn Element Stack 
     FIGS. 18 through 20 show perspective, top, and side views of a stack, system, assembly or combination  320  comprising two asymmetric horn elements  310 ,  310 ′ housed in an enclosure, box, support structure or frame  314  and having features in accordance with one embodiment of the invention. The stack  320  includes respective asymmetric horn elements  310 ,  310 ′ aligned/mounted/combined with coincident reference planes  410 ,  410 ′, one inverted and vertically displaced, and providing a crossfire angle between them. The asymmetry refers to the off-axis orientation of the sound expansion chambers  342 ,  362  with respect to their respective reference planes  410 ,  410 ′. One advantage of the asymmetric horn element stack  320  is that it provides a desirably wide horizontal directivity response and a narrow vertical directivity response. 
     Two or more asymmetric horn elements can be stacked, vertically displaced and providing a crossfire angle, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. The structure of the asymmetric horn element  310  has been described above, and the basic structure of the second asymmetric horn element  310 ′ is of a generally similar nature. The asymmetric horn elements  310 ,  310 ′ include respective sound expansion chambers  342 ,  362  in acoustical communication with respective throats  344 ,  364  which in turn are connected to respective compression drivers  338 ,  338 ′. 
     In one embodiment, the sound expansion chambers  342 ,  362  and throats  344 ,  364  of the respective asymmetric horn elements  310 ,  310 ′ are configured and/or dimensioned substantially identically. In another embodiment, the sound expansion chambers  342 ,  362  and throats  344 ,  364  comprise different dimensions. 
     As shown in FIG. 19, the horn elements  310 ,  310 ′ have respective longitudinal axes or centerlines  380 ′,  380   a ′ and respective outbound longitudinal axes  380 ,  380   a . The cross-fire angle (CFA) between the two asymmetric horn elements  310 ,  310 ′ and/or sound expansion chambers  342 ,  362  is the angle between the projections of the outbound longitudinal axes  380 ,  380   a  on a common horizontal plane and hence is a measure of angular offset or angulation. The bisecting vertical plane  396  is a vertical plane along a line that bisects the projections of the outbound longitudinal axes  380  on a common horizontal plane. 
     The vertical divergence/convergence angle (VDA) is the angle between the projections of the outbound longitudinal axes  380 ,  380   a  on the vertical bisecting plane  396 , and hence is a measure of angular offset or angulation. The asymmetric horn elements  310 ,  310 ′ can be oriented in a wide variety of manners to provide a wide range of cross-fire angles (CFA) and vertical divergence/convergence angles (VDA), as required or desired, giving due consideration to the goals of achieving one or more of the benefits and advantages as taught or suggested herein. 
     FIG. 18 is a perspective view of an asymmetric horn element stack  320  generally comprising two asymmetric horn elements  310 ,  310 ′ and having features in accordance with one embodiment of the invention. The stack  320  is formed with autonomous respective upper and lower asymmetric horn elements  310 ,  310 ′. In another embodiment, the upper and lower asymmetric horn elements  310 ,  310 ′ can be integrally formed to provide an integral unit or stack  320 . 
     In one embodiment, a baffle system  340  or structure is integrally formed or molded with the upper asymmetric horn element  310 . This further improves the acoustic performance of the asymmetric horn element stack  320 . In other embodiments, the asymmetric horn element  310  can be mounted or housed in the baffling  340 . As the skilled artisan will realize, the asymmetric horn element  310  can be coupled to the baffling  340  utilizing a wide variety of techniques, for example, screws, nut-bolt combinations, rivets, clamps, adhesives, or combinations thereof, among others. 
     In one embodiment, a baffle system or structure  340 ′ is integrally formed or molded with the lower asymmetric horn element  310 ′. This further improves the acoustic performance of the asymmetric horn element stack  320 . In other embodiments, the asymmetric horn element  310 ′ can be mounted or housed in the baffling  340 ′. As the skilled artisan will realize, the asymmetric horn element  310 ′ can be coupled to the baffling  340 ′ utilizing a wide variety of techniques, for example, screws, nut-bolt combinations, rivets, clamps, adhesives, or combinations thereof, among others. 
     As illustrated in FIG. 19 (top view), the vertical longitudinal plane  420  of the upper asymmetric horn element  310  is a vertical plane through the outbound longitudinal axis  380 . The vertical longitudinal plane  420  intersects a continuous reference plane  410  at an angle not equal to 90°. The upper horn element asymmetry is a consequence of the vertical longitudinal plane  420  not being orthogonal to the reference plane  410 , that is, at an angle not equal to 90°. 
     Referring again to FIG. 19, the vertical longitudinal plane  420   a  of the lower asymmetric horn element  310 ′ is a vertical plane through the outbound longitudinal axis  380   a . The vertical longitudinal plane  420   a  intersects a second continuous reference plane  410 ′ at an angle not equal to 90°. The lower horn element asymmetry is a consequence of the vertical longitudinal plane  420   a  not being orthogonal to the reference plane  410 ′, that is, at an angle not equal to 90°. In one embodiment, the reference planes  410 ,  410 ′ associated with the upper and lower asymmetric horn elements  310 ,  310 ′ are coincident. In another embodiment, the reference planes  410 ,  410 ′ are displaced from each other and parallel. 
     As illustrated in FIG. 19, the reference plane  410  of the upper asymmetric horn element  310  intersects the vertical longitudinal plane  420  at an angle given by the following relation:                α     H   -   1       =     90   -       NDA     H   -   1       K               (   6   )                         
     where, α H−1  is the horizontal asymmetry angle of the upper asymmetric horn element  310 , NDA H−1  is the nominal horizontal dispersion angle and K is a parameter that defines the degree of cross-fire of the asymmetric horn element stack  320 . 
     As further illustrated in FIG. 19, the reference plane  410 ′ of the lower asymmetric horn element  310 ′ intersects the vertical longitudinal plane  420   a  at an angle given by the following relation:                α     H   -   2       =     90   -       NDA     H   -   2       K               (   7   )                         
     where, α H−2  is the horizontal asymmetry angle of the lower asymmetric horn element  310 ′, NDA H−2  is the nominal horizontal dispersion angle and K is a parameter that defines the degree of cross-fire of the asymmetric horn element stack  320 . 
     Equation or expression (8) permits two asymmetric horn elements  310 ,  310 ′, vertically displaced and with parallel reference planes  410 ,  410 ′, one inverted with respect to the other, to provide a predetermined cross-fire angle CFA given by: 
     
       
           CFA= 180−α H−1 −α H−2   (8)  
       
     
     where α H−1  refers to the angle between the reference plane  410  of the upper asymmetric horn element  310  and the vertical longitudinal plane  420  and α H−2  refers to the angle between the reference plane  410 ′ of the lower asymmetric horn element  310 ′ and the vertical longitudinal plane  420   a.    
     In one embodiment, K=2, and the cross-fire angle CFA is the average of the nominal horizontal dispersion angles of the two asymmetric horn elements  310 ,  310 ′. In another embodiment, 1&lt;K≦4. In a further embodiment 1.5≦K≦3. In other embodiments, K can be selected, as required or desired, to achieve a cross-fire angle in the range from 0° &lt;CFA &lt;180°. 
     As illustrated in FIGS. 19 and 20, the vertical reference axis  430  of the upper horn element  310  is a vertical axis located coincident with the intersection of the vertical longitudinal plane  420  and the reference plane  410 . The vertical reference axis  430 ′ of the lower horn element  310 ′ is a vertical axis located along the intersection of the vertical longitudinal plane  420 ′ and the reference plane  410 ′. 
     As illustrated by FIG. 20 (side view), the vertical reference axis  430  and hence the reference plane  410  is oriented with respect to the outbound longitudinal axis  380  by a predetermined vertical asymmetry angle β V−1  (in degrees) given by the expression:                β     V   -   1       =     90   -       NDA     V   -   1       C               (   9   )                         
     where, β V−1  is the vertical asymmetry angle of the upper asymmetric horn element  310 , NDA V−1  is the nominal vertical dispersion angle of the upper asymmetric horn element  310 , and C is a parameter that defines the degree of vertical divergence/convergence of the asymmetrical horn element stack  320 . 
     As further illustrated by FIG. 20, the vertical reference axis  430 ′ and hence the reference plane  410 ′ is oriented with respect to the outbound longitudinal axis  380   a  by a predetermined vertical asymmetry angle β V−2  (in degrees) given by the expression:                β     V   -   2       =     90   -       NDA     V   -   2       C               (   10   )                         
     where, β V−2  is the vertical asymmetry angle of the lower asymmetric horn element  310 ′, NDA V−2  is the nominal vertical dispersion angle of the lower asymmetric horn element  310 ′, and C is a parameter that defines the degree of vertical divergence/convergence of the asymmetrical horn element stack  320 . 
     Equation (11) permits two asymmetric horn elements  310 ,  310 ′, vertically displaced and with parallel reference planes  410 ,  410 ′, one inverted and displaced with respect to the other, to provide a predetermined vertical divergence/convergence angle given by: 
     
       
           VDA= 180−β V−1 −β V−2   (11)  
       
     
     where β V−1  refers to the angle between the vertical reference axis  430  of the upper asymmetric horn element  310  and the outbound longitudinal axis  380  and β V−2  refers to the angle between the vertical reference axis  430 ′ of the lower asymmetric horn element  310 ′ and the outbound longitudinal axis  380   a.    
     In one embodiment, C=±∞, and hence VDA=0° so that the horn elements  310 ,  310 ′ are vertically parallel as shown in FIG.  20 . Note that divergence is indicated by VDA&gt;0° and convergence is indicated by VDA&lt;0°, as discussed above. In one vertically divergent embodiment, 3≦C&lt;∞. In another vertically divergent embodiment, 1.3≦C&lt;3. In yet another vertically divergent embodiment, 0.10≦C&lt;1.3. In one vertically convergent embodiment, −∞&lt;C≦−3. In another vertically convergent embodiment, −3&lt;C≦−1.3. In yet another vertically convergent embodiment, −1.3&lt;C≦−0.10. In other embodiments, C can be selected, as required or desired, to achieve a vertical divergence/convergence angle in the range from −180° to 180°, that is, −180°≦VDA≦180°. 
     The horizontal asymmetry angles, the cross-fire angles, the vertical asymmetry angles, and/or the vertical divergence/convergence angles can be selected in a wide variety of manners with efficacy, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. This adds to the versatility of the invention, for example in the choice of coverage angles, among others. 
     Asymmetric Horn Element Stack Overlap Configurations 
     The asymmetric horn element stack  320  can be embodied with a plurality of cross-fired configurations. As defined above, the cross-fire angle (CFA) is the angle between the projections of the outbound longitudinal axes  380 ,  380   a  on a common horizontal plane and hence is a measure of angular offset or angulation. It is also convenient to define an “overlap area” as the area of overlap between the projections of the sound chambers of a pair of asymmetric horn elements, one inverted and vertically displaced onto a common horizontal plane. Thus, when there is a finite “overlap area” the asymmetric horn elements can be referred to as having “vertically overlapping sound chambers.” 
     In accordance with one embodiment of the invention, the vertically displaced asymmetric horn elements are configured so that there is no “overlap area” between the horn sound chambers. Hence, the horn elements do not have “vertically overlapping sound chambers.” In this embodiment, the vertical longitudinal planes intersect behind the projections on a common horizontal plane of one or both of the sound expansion chambers. 
     In accordance with one embodiment of the invention, the vertically displaced asymmetric horn elements are configured so that there is a small “overlap area” between the horn sound chambers. Hence, the horn elements have “vertically overlapping sound chambers.” In this embodiment, the vertical longitudinal planes intersect substantially at or near the projections on a common horizontal plane of the junctions of one or both of the sound expansion chambers and throats. 
     Referring to FIG. 19, in accordance with one embodiment of the invention, the vertically displaced asymmetric horn elements are configured so that there is an “overlap area” between the horn sound chambers. Hence, the horn elements have “vertically overlapping sound chambers.” In this embodiment, the vertical longitudinal planes intersect within the projections on a common horizontal plane of the sound expansion chambers. 
     In accordance with one embodiment of the invention, the vertically displaced asymmetric horn elements are configured so that there is an “overlap area” between the horn sound chambers. Hence, the horn elements have “vertically overlapping sound chambers.” In this embodiment, the vertical longitudinal planes intersect substantially at or near the projections on a common horizontal plane of one or both of the horn mouths. 
     In accordance with one embodiment of the invention, the vertically displaced asymmetric horn elements are configured so that there is substantially no “overlap area” between the horn sound chambers. Hence, the horn elements do not have “vertically overlapping sound chambers.” In this embodiment, the vertical longitudinal planes intersect ahead or in front of the projections on a common horizontal plane of one or both of the horn mouths. 
     In accordance with one embodiment of the invention, the vertically displaced asymmetric horn elements are configured so that there is no “overlap area” between the horn sound chambers. Hence, the horn elements do not have “vertically overlapping sound chambers.” In this embodiment, the vertical longitudinal planes intersect ahead or in front of the projections on a common horizontal plane of one or both of the horn element mouths. 
     The invention can be embodied with a plurality of cross-fired vertically divergent/convergent configurations. As defined above, the vertical divergence/convergence angle VDA is the angle between the projections of the outbound longitudinal axes  380 ,  380   a  on the bisecting vertical plane  396 , and hence is a measure of the angular offset or angulation between the asymmetric horn elements  310 ,  310 ′ and/or their respective sound expansion chambers  342 ,  362 . 
     In one embodiment, and referring to FIG. 20, the vertically offset asymmetrical horn elements are oriented so that there is no intersection or crossover between the projections of the outbound longitudinal axes  380 ,  380   a  on the bisecting vertical plane  396 . That is, VDA=0°, and the asymmetric horn elements can be said to be “vertically parallel.” The horn elements can be shifted longitudinally or laterally, or both while maintaining their vertical parallelness (VDA=0°). 
     In another embodiment, the vertically offset asymmetrical horn elements are oriented to provide a vertically divergent asymmetric horn element stack. For a vertically divergent stack, in one embodiment, the horn element mouths point vertically outward away from one another and the projections of the outbound longitudinal axes on the bisecting vertical plane  396  intersect or crossover at a point behind the asymmetric horn element mouths. The angle between the projections of the outbound longitudinal axes on the bisecting vertical plane  396  is the vertical divergence angle of the asymmetric horn element stack. The lower asymmetric horn element outbound longitudinal axis is chosen as a “reference axis” to indicate a vertical divergence angle VDA&gt;0°. 
     In yet another embodiment, the vertically offset asymmetric horn elements are oriented to provide a vertically convergent stack. For a vertically convergent stack, in one embodiment, the asymmetric horn element mouths point vertically inward towards one another and the projections of the outbound longitudinal axes on the bisecting vertical plane  396 , intersect or crossover at a point ahead or in front of the asymmetric horn element stack. The lower asymmetric horn element outbound longitudinal axis is chosen as a “reference axis” to indicate a vertical convergence angle VDA&lt;0°. 
     Asymmetric Multi-Way System 
     FIGS. 21 and 22 show frontal and top views of an asymmetric multi-way speaker sound system  210  with one asymmetric horn element, section or module  232  and having features in accordance with one embodiment of the invention. The speaker assembly  210  generally comprises an asymmetric horn element/module/section  232  and a woofer or low frequency sound source  212  housed or mounted in a speaker enclosure, body, support structure or frame  214  and a means for aligning/mounting/combining a second asymmetric multi-way system, inverted and vertically displaced, in a manner to provide a crossfire angle between the asymmetric horn elements. 
     In one embodiment, as discussed in greater detail later herein, a reference plane  510  is specified at a predetermined angle with regard to the nominal dispersion angle of the asymmetric horn element  232  and the required or desired degree of crossfire of a vertical stack of asymmetric multi-way systems. FIG. 23 shows a perspective view of an asymmetric multi-way system stack generally comprising two asymmetric multi-way systems, with coincident reference planes, one inverted and vertically displaced, and providing a cross-fire angle between the asymmetric horn elements. Two or more asymmetric multi-way speaker sound systems arranged, for example, in a vertical stack with a cross-fired orientation provide a desirably wide horizontal directivity response, a narrow vertical directivity response, and an extended low frequency response. 
     In one embodiment, mounting flange sections  598  are integrally formed or molded with the asymmetric horn element  232  and are coincident with the reference plane  510 . The horn element  232  is mounted to the speaker enclosure, body, support structure or frame  214 , whose mounting surface  265  is coincident with the reference plane  510 . The woofer or low frequency sound source  212  is mounted to the enclosure  214  in a manner parallel to the reference plane  510 . 
     In one embodiment, the mounting flange sections  598  of the asymmetric horn element  232  are parallel to and displaced from the reference plane  510 . In another embodiment, the mounting surface  265  of the enclosure  214  is parallel to and displaced from the reference plane  510 . In a further embodiment, the woofer  212  is mounted parallel to and displaced from the reference plane  510 . In yet a further embodiment, the woofer  212  is mounted in a manner not parallel to the reference plane. 
     The asymmetric horn element  232  comprises a sound expansion chamber  242  in acoustical communication with a throat  244  which in turn is connected to a compression driver unit or assembly  238 . In one embodiment, the throat  244  and driver  238  are enclosed within the speaker body  214 . The sound expansion chamber  242  includes a generally flared bell  246  portion or section and a generally flared flange portion or section  248  which forms a mouth  250  at the sound radiating end of the horn  232 . 
     In one embodiment, the mouth  250  has substantially radial top and bottom edges  252 ,  254  in the horizontal plane, with generally straight side edges  256 ,  258  in the vertical plane, and a substantially rectangular cross-sectional shape in a projection on a plane normal to the outbound longitudinal axis  580  (as defined above; note that the horn element longitudinal axis is labeled by the reference numeral  580 ′ in FIG.  22 ). In other embodiments, the horn element mouth edges  252 ,  254 ,  256 ,  258  may be shaped in a wide variety of manners, for example, curved, straight or irregular, among others, in both the horizontal and/or vertical planes, and the mouth cross-section may be shaped in a wide variety of manners, for example, rectangular, square, oval, round or irregular, among others, in a projection on a plane normal to the outbound longitudinal axis  580 . 
     In one embodiment, a baffle system or structure is integrally formed or molded with the asymmetric horn element  232 . This further improves the acoustical performance. The baffling  240  functions to substantially prevent or mitigate undesirable diffraction and interaction between sound waves broadcasted from the asymmetric horn element mouth  250  and sound waves reflected or reradiated by the enclosure  214  and/or radiated or “broadcasted” by the woofer  212 . In other embodiments, the asymmetric horn element  232  can be mounted or housed in the baffling  240 . As the skilled artisan will realize, the horn  232  and the baffling  240  can be coupled to one another utilizing a wide variety of techniques, for example, screws, nut-bolt combinations, rivets, clamps, adhesives, or combinations thereof, among others. 
     In one embodiment, the baffle system  240  is generally associated with the sides of the sound expansion chamber  242  near the mouth  250 . In one embodiment, the baffling  240  is in mechanical communication with the sound expansion chamber  242 . The baffling  240  generally comprises baffle elements  282 ,  284 . The baffle elements  282 ,  284  are associated with the sound expansion chamber  242  near the mouth  250  with the baffle element  282  being substantially wider than the baffle element  284 . 
     In one embodiment, the baffle elements  282 ,  284  curve in the horizontal direction. In other embodiments, one or both of the baffle elements  282 ,  284  can curve in the horizontal and vertical directions or only in the vertical direction. In yet other embodiments, one or more baffle elements can be straight, curved, or irregular, among others, in the horizontal direction and/or vertical direction. 
     In other embodiments, the baffle system  240  can be configured and dimensioned in a wide variety of manners with efficacy, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. Baffle elements and/or cap elements can also be provided above and below the sound expansion chamber  242 , giving due consideration to the goal of further enhancing the acoustical performance of the asymmetric horn element  232  of the invention. 
     Referring again to FIG. 21, the asymmetric multi-way speaker system  210  includes a woofer baffling  241 . In one embodiment, the woofer baffling  241  generally matches the horn baffling  240  and is generally associated with the sides of the woofer  212  or substantially circumscribes the woofer  212 . In another embodiment, the horn baffling  240  and the woofer baffling  241  are separate units. In yet another embodiment, a fully integrated asymmetric multi-way speaker system  210  is provided with the horn sound expansion chamber  242 , the horn baffling  240 , and the woofer baffling  241  being formed as an integral unit, for example, by injection molding. In a further embodiment, the speaker enclosure  214  is integrally formed into the asymmetric multi-way system  210 . 
     In one embodiment, the horn baffling  240  is substantially curved or radial in the horizontal direction and the woofer baffling  241  is curved or radial in the horizontal direction. An internal surface  243  of the woofer baffling  241  generally fans out, flares, or provides for an acoustical expansion. This further accentuates the performance of the woofer  212  and hence that of the asymmetric multi-way speaker system  210 . In further embodiments, the horn and/or woofer baffle elements can curve in the vertical direction or in both the horizontal and vertical directions. In further embodiments, the woofer baffling  241  is flat, stepped or irregular. In another embodiment, the multi-way asymmetric system  210  comprises more than one or a plurality of woofers  212 . 
     Asymmetric Multi-Way System Stack 
     FIGS. 23 through 25 show perspective, top, and side views of a stack, system, assembly or combination  220  comprising two asymmetric multi-way systems  210 ,  210 ′ and having features in accordance with one embodiment of the invention. The stack  220  includes respective asymmetric multi-way system elements  210 ,  210 ′ aligned/mounted/combined with coincident reference planes  510 ,  510 ′, one inverted and vertically displaced, and providing a crossfire angle between the asymmetric horn elements  232 ,  234 . The asymmetry refers to the off-axis orientation of the asymmetric sound expansion chambers  242 ,  262  with respect to their respective reference planes  510 ,  510 ′. One advantage of the asymmetric multi-way system stack  220  is that it provides a desirably wide horizontal directivity response, a narrow vertical directivity response, and an extended low frequency response. 
     Two or more asymmetric multi-way systems can be stacked, vertically displaced and providing a crossfire angle between the horns, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. The structure of the asymmetric multi-way system  210  has been described above, and the basic structure of the second asymmetric multi-way system  210 ′ is of a generally similar nature. The asymmetric horn elements  232 ,  234  include respective sound expansion chambers  242 ,  262  in acoustical communication with respective throats  244 ,  264  which in turn are connected to respective compression drivers  238 ,  238 ′. In one embodiment, the throats  244 ,  264  and drivers  238 ,  238 ′ are enclosed within the speaker bodies  214 ,  214 ′. 
     In one embodiment, the asymmetric horn elements  232 ,  234 , woofers  212 ,  212 ′, enclosures  214 ,  214 ′, horn bafflings  240 ,  240 ′and woofer bafflings  241 ,  241 ′ are configured and/or dimensioned substantially identically. In another embodiment, the asymmetric horn elements  232 ,  234 , woofers  212 ,  212 ′, enclosures  214 ,  214 ′, horn bafflings  240 ,  240 ′ and woofer bafflings  241 ,  241 ′ comprise different dimensions. The mounting flanges of the asymmetric horn element  234  are labeled as  598 ′ in FIGS. 23-24 and the mounting surface of the enclosure  214 ′ is labeled as  265 ′ in FIG.  24 . 
     The asymmetric horn elements  232 ,  234  can be oriented in a wide variety of manners to provide a wide range of cross-fire angles (CFA) and vertical divergence/convergence angles (VDA), as required or desired, giving due consideration to the goals of achieving one or more of the benefits and advantages as taught or suggested herein. 
     Referring to FIG. 23, the stack  220  is formed with autonomous respective upper and lower asymmetric multi-way systems  210 ,  210 ′. In another embodiment, the upper and lower asymmetric multi-way systems  210 ,  210 ′ can be integrally formed to provide an integral unit or stack  220 . 
     Referring to FIG. 24 (top view), the vertical longitudinal plane  520  of the upper asymmetric multi-way system  210  is a vertical plane through the outbound longitudinal axis  580  of the upper asymmetric horn element  232 . The upper horn longitudinal axis is labeled by the reference numeral  580 ′. The vertical longitudinal plane  520  intersects a reference plane  510  at an angle not equal to 90°. The upper multi-way system asymmetry is a consequence of the vertical longitudinal plane  520  not being orthogonal to the reference plane  510 , that is, at an angle not equal to 90°. 
     Referring again to FIG. 24, the vertical longitudinal plane  520   a  of the lower asymmetric multi-way system  210 ′ is a vertical plane through the outbound longitudinal axis  580   a  of the lower asymmetric horn element  234 . The lower horn longitudinal axis is labeled by the reference numeral  580   a ′. The vertical longitudinal plane  520   a  intersects a reference plane  510 ′ at an angle not equal to 90°. The lower multi-way system asymmetry is a consequence of the vertical longitudinal plane  520   a  not being orthogonal to the reference plane  510 ′, that is, at an angle not equal to 90°. 
     As illustrated in FIG. 24, the reference plane  510  of the upper asymmetric multi-way system  210  intersects the vertical longitudinal plane  520  at an angle given by the following relation:                α     H   -   1       =     90   -       NDA     H   -   1       K               (   12   )                         
     where, α H−1  is the horizontal asymmetry angle of the upper asymmetric multi-way system  210 , NDA H−1  is the nominal horizontal dispersion angle of the upper asymmetric horn element  232  and K is a parameter that defines the degree of cross-fire of the horn elements  232 ,  234  of the asymmetric multi-way system stack  220 . 
     As further illustrated in FIG. 24, the reference plane  510 ′ of the lower asymmetric multi-way system  210 ′ intersects the vertical longitudinal plane  520   a  at an angle given by the following relation:                α     H   -   2       =     90   -       NDA     H   -   2       K               (   13   )                         
     where, α H−2  is the horizontal asymmetry angle of the lower asymmetric multi-way system  210 ′, NDA H−2  is the nominal horizontal dispersion angle of the lower asymmetric horn element  234  and K is a parameter that defines the degree of cross-fire of the horn elements  232 ,  234  of the asymmetric multi-way system stack  220 . 
     Equation or expression (14) permits two asymmetric multi-way systems  210 ,  210 ′, vertically displaced and with parallel reference planes  510 ,  510 ′, one inverted with respect to the other, to provide a predetermined cross-fire angle CFA given by: 
     
       
           CFA= 180−α H−1 −α H−2   (14)  
       
     
     where α H−1  refers to the angle between the reference plane  510  of the upper asymmetric multi-way system  210  and the vertical longitudinal plane  520  and α H−2  refers to the angle between the reference plane  510 ′ of the lower asymmetric system  210 ′ and the vertical longitudinal plane  520   a.    
     In one embodiment, K=2, and the cross-fire angle CFA is the average of the nominal horizontal dispersion angles of the two asymmetric horn elements  232 ,  234  of the asymmetric multi-way system stack  220 . In another embodiment, 1&lt;K≦4. In a further embodiment 1.5≦K≦3. In other embodiments, K can be selected, as required or desired, to achieve a cross-fired angle in the range from 0°&lt;CFA&lt;180°. 
     As illustrated in FIGS. 24 and 25, the vertical reference axis  530  of the upper horn element  232  is a vertical axis located at or through the intersection of the vertical longitudinal plane  520  and the reference plane  510 . The vertical reference axis  530 ′ of the lower horn element  234  is a vertical axis located at or through the intersection of the vertical longitudinal plane  520   a  and the reference plane  510 ′. 
     As illustrated by FIG. 25 (side view), the vertical reference axis  530  and hence the reference plane  510  is oriented with respect to the outbound longitudinal axis  580  by a predetermined vertical asymmetry angle β V−1  (in degrees) given by the expression:                β     V   -   1       =     90   -       NDA     V   -   1       C               (   15   )                         
     where, β V−1  is the vertical asymmetry angle of the upper asymmetric multi-way system  210 , NDA V−1  is the nominal vertical dispersion angle of the upper asymmetric horn element  232  and C is a parameter that defines the degree of vertical divergence/convergence of the horn elements  232 ,  234  of the asymmetric multiway system stack  220 . 
     As further illustrated by FIG. 25, the vertical reference axis  530 ′ and hence the reference plane  510 ′ is oriented with respect to the outbound longitudinal axis  580   a  by a predetermined vertical asymmetry angle β V−2  (in degrees) given by the expression:                β     V   -   2       =     90   -       NDA     V   -   2       C               (   16   )                         
     where, β V−2  is the vertical asymmetry angle of the lower asymmetric multi-way system  210 ′, NDA V−2  is the nominal vertical dispersion angle of the lower asymmetric horn element  234  and C is a parameter that defines the degree of vertical divergence/convergence of the horn elements  232 ,  234  of the asymmetric multiway system stack  220 . 
     Equation (17) permits two asymmetric multi-way systems  210 ,  210 ′, one inverted and vertically displaced and with parallel reference planes  510 ,  510 ′, to provide a predetermined vertical divergence/convergence angle given by: 
     
       
           VDA= 180−β V−1 −β V−2   (17)  
       
     
     where β V−1  refers to the angle between the vertical reference axis  530  of the upper asymmetric multi-way system  210  and the outbound longitudinal axis  580  and β V−2  refers to the angle between the vertical reference axis  530 ′ of the lower asymmetric multi-way system  210 ′ and the outbound longitudinal plane  580   a.    
     In one embodiment, C=±∞, and hence VDA=0° so that the two asymmetric multi-way systems  210 ,  210 ′ are vertically parallel. Note that divergence is indicated by VDA&gt;0° and convergence is indicated by VDA&lt;0°, as discussed above. In one vertically divergent embodiment, 3≦C&lt;∞. In another vertically divergent embodiment, 1.3≦C&lt;3. In yet another vertically divergent embodiment, 0.10≦C&lt;1.3. In one vertically convergent embodiment, −∞&lt;C≦−3. In another vertically convergent embodiment, −3&lt;C≦−1.3. In yet another vertically convergent embodiment, −1.3&lt;C≦−0.10. In other embodiments, C can be selected, as required or desired, to achieve a vertical divergence/convergence angle in the range from −180° to 180°, that is, −180°≦VDA≦180°. 
     The horizontal asymmetry angles, the cross-fire angles, the vertical asymmetry angles, and/or the vertical divergence/convergence angles can be selected in a wide variety of manners with efficacy, as required or desired, giving due consideration to the goal of achieving one or more of the benefits and advantages as taught or suggested herein. This adds to the versatility of the invention, for example in the choice of coverage angles, among others. 
     While the components and techniques of the present invention have been described with a certain degree of particularity, it is manifest that many changes may be made in the specific designs, constructions and methodology hereinabove described without departing from the spirit and scope of this disclosure. It should be understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification, but is to be defined only by a fair reading of the appended claims, including the full range of equivalency to which each element thereof is entitled.