Patent Publication Number: US-11044551-B2

Title: Acoustic horn for an acoustic assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. national phase of International Application No. PCT/US2017/068936 filed Dec. 29, 2017, which claims the benefit of U.S. provisional application Ser. No. 62/440,872 filed Dec. 30, 2016, the disclosures of which are hereby incorporated in their entireties by reference herein. 
    
    
     TECHNICAL FIELD 
     Embodiments herein generally relate to an acoustic horn for an acoustic assembly. 
     BACKGROUND 
     An example of a conventional acoustic system includes a first transducer and a second transducer in an enclosure. The first transducer operates over a first frequency range, and the second transducer operates over a second frequency range. While the two frequency ranges are not identical, the first frequency range includes an overlap region with the second frequency range. The overlap region is referred to as a crossover region. In the crossover region, a directivity anomaly occurs. The directivity anomaly is due to a first coverage angle of the first transducer and a second coverage angle of the second transducer in the crossover region. More specifically, the first coverage angle differs from the second coverage angle in the crossover region. The differing coverage angles result in a non-uniform dispersion of sound in a listening area. Because of the non-uniform dispersion, a first person in one location of the listening area may have a drastically different listening experience than a second person in another location of the listening area. Moreover, in the conventional acoustic system, the beamwidths of the first transducer and the second transducers may detract from the listening experience. This may be particularly noticeable in the crossover region. 
     SUMMARY 
     In one embodiment, an acoustic assembly includes an enclosure. The enclosure contains at least one acoustic emitting device. Additionally, the acoustic assembly includes an acoustic horn. The acoustic horn is positioned between a removable cover of the acoustic assembly and the at least one acoustic emitting device. Moreover, the acoustic horn includes at least one waveguide, at least one lens, at least one plug, and at least one integrator. The at least one waveguide, the at least one lens, and the at least one plug attach to the at least one integrator. 
     In another embodiment, an acoustic assembly includes an enclosure. The enclosure includes a plurality of acoustic emitting devices. The acoustic emitting devices are attached to the enclosure. The enclosure further includes an acoustic horn. The acoustic horn is attached to the enclosure. The acoustic horn is configured to improve a beamwidth in a crossover region of the plurality of acoustic emitting devices. The acoustic horn includes a waveguide, a first integrator, and a second integrator. The first integrator and the second integrator are attached to the waveguide. The second integrator is spaced apart from the first integrator. 
     In another embodiment, an acoustic assembly includes an enclosure. The enclosure includes a plurality of acoustic emitting devices. The acoustic emitting devices are attached to the enclosure. The enclosure further includes an acoustic horn. The acoustic horn is attached to the enclosure. The acoustic horn is configured to improve a beamwidth in a crossover region of the plurality of acoustic emitting devices. The acoustic horn is aligned along a bisecting plane and a mirror plane. The bisecting plane is perpendicular to the mirror plane. The acoustic horn includes a waveguide, a first integrator, and a second integrator. The waveguide is aligned along the mirror plane. The first integrator is aligned along the bisecting plane. The second integrator is aligned along the bisecting plane and spaced apart from the first integrator. The first integrator includes a plug and at least one lens. The plug of the first integrator is aligned along the bisecting plane. The at least one lens of the first integrator is offset from the bisecting plane and the mirror plane. The second integrator includes a plug and at least one lens. The plug of the second integrator is aligned along the bisecting plane and spaced apart from the plug of the first integrator. The at least one lens of the second integrator is offset from the bisecting plane and the mirror plane. Further, the at least one lens of the second integrator is spaced apart from the at least one lens of the first integrator. 
     In another embodiment, an acoustic assembly includes a plurality of acoustic emitting devices. The acoustic assembly further includes an acoustic horn. The acoustic horn improves a beamwidth in a crossover region of the acoustic emitting devices. A first acoustic emitting device outputs sound over a first frequency range. A second acoustic emitting device outputs sound over a second frequency range. The first frequency range partially overlaps with the second frequency range. Because of that, the first frequency range includes a first crossover region with the second frequency range. The acoustic horn alters the sound from the first acoustic emitting device. For example, the alteration of the sound may occur via a plug and an integrator of the acoustic horn. The plug may be attached to the integrator. The alteration of the sound from the first acoustic emitting device occurs in the first crossover region. Moreover, this alteration of the sound from the first acoustic emitting device changes a first beamwidth in the crossover region from a non-linear-curve for sound coverage angle versus frequency to a substantially linear, decreasing line for sound coverage angle versus frequency. This change improves the first beamwidth. This is because the change creates a more linearized, decreasing line than before for the first beamwidth. This is a desirable change, which is due to the acoustic horn&#39;s influence on the sound from the first acoustic emitting device. 
     Additionally, the acoustic horn alters the sound from the second acoustic emitting device. For example, this alteration may occur via a lens and the integrator. The lens may be attached to the integrator. The alteration of the sound from the second acoustic emitting device occurs in the first crossover region. Moreover, this alteration changes a second beamwidth in the crossover region from a non-linear curve for sound coverage angle versus frequency to a substantially linear, decreasing line for sound coverage angle versus frequency. Similarly, this change improves the second beamwidth. This is because the change creates a more linearized, decreasing line than before for the second beamwidth. This is a desirable change, which is due to the acoustic horn&#39;s influence on the sound from the second acoustic emitting device. The substantially linear, decreasing line of the improved first beamwidth may be parallel to the substantially linear, decreasing line of the improved second beamwidth. 
     Further, the acoustic horn may alter and improve one or more additional beamwidths, which may be in one or more additional crossover regions. For example, the acoustic horn may alter and improve a third beamwidth and a four beamwidth in a second crossover region between the second acoustic emitting device and a third acoustic emitting device. For example, this alteration may occur via the lens and the integrator, as well as a waveguide. The waveguide may be attached to the integrator. Similarly, the alteration and improvement of the third and fourth beamwidths may change from non-linear curves to yielding substantially linear, decreasing lines for sound coverage angle versus frequency. The changes may create more linearized, decreasing lines than before—i.e., without the acoustic horn. Moreover, the substantially linear, decreasing line of the improved third beamwidth may be parallel to the substantially linear, decreasing line of the improved fourth beamwidth. 
     In another embodiment, an acoustic assembly includes an enclosure. A first transducer is attached to the enclosure. The first transducer may emit sound along a first path over a first frequency range. A second transducer is attached to the enclosure. The second transducer may emit sound along a second path over a second frequency range. An acoustic horn is attached to the enclosure. The acoustic horn may be positioned to at least partially extend into the first path and the second path. The acoustic horn may adjust at least one beamwidth in a crossover region of the first frequency range and the second frequency range. For example, the acoustic horn may adjust the beamwidth of the first transducer in the crossover region of the first frequency range and the second frequency range. As another example, the acoustic horn may adjust the beamwidth of the second transducer in the crossover region of the first frequency range and the second frequency range. The acoustic horn includes a waveguide. The waveguide may be positioned to at least partially extend into the first path. The acoustic horn further includes an integrator. The integrator is attached to the waveguide. The integrator may be positioned to at least partially extend into the second path. 
     In another embodiment, an acoustic assembly includes an enclosure. The acoustic assembly further includes a plurality of transducers that are supported by the enclosure. The plurality of transducers includes a first transducer and a second transducer. The first transducer may emit sound along a first path over a first frequency range. The second transducer may emit sound along a second path over a second frequency range. The acoustic assembly further includes an acoustic horn attached to the enclosure. The acoustic horn may be positioned to at least partially extend into the first path of the first transducer and the second path of the second transducer. The acoustic horn may adjust at least one beamwidth in a crossover region of the first frequency range and the second frequency range. The acoustic horn is aligned along a first plane that bisects the enclosure and a second plane that is arranged perpendicular to the first plane. The acoustic horn includes a waveguide aligned along the second plane. The acoustic horn further includes a first integrator aligned along the first plane. The acoustic horn further includes a second integrator aligned along the first plane and spaced from the first integrator. 
     In another embodiment, an acoustic assembly includes an enclosure. The acoustic assembly further includes a first plurality of transducers attached to the enclosure. The first plurality of transducers may emit sound over a first frequency range. The acoustic assembly further includes a second plurality of transducers attached to the enclosure. The second plurality of transducers may emit sound over a second frequency range. The acoustic assembly further includes a third plurality of transducers attached to the enclosure. The third plurality of transducers may emit sound over a third frequency range. The acoustic assembly further includes an acoustic horn positioned on the enclosure. The acoustic horn may adjust at least one beamwidth in a crossover region of the first frequency range and the second frequency range. The acoustic horn may adjust at least one beamwidth in a crossover region of the second frequency range and the third frequency range. The acoustic horn includes a waveguide, a first integrator attached to the waveguide, and a second integrator attached to the waveguide and spaced from the first integrator. 
     As such, the inclusion of the acoustic horn is desirable because of its influence on sound from the acoustic emitting devices in the acoustic assembly. The acoustic horn in one or more embodiments may be used to improve a beamwidth of the acoustic assembly. This may be by adjusting one or more beamwidths in a crossover region. This may be by altering the path(s) of sound emitted by one or more of the acoustic emitting devices. The acoustic horn may therefore correct the path(s) to achieve a desired beamwidth, such as in a crossover region. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a perspective view of an acoustic assembly according to one or more embodiments. 
         FIG. 2  illustrates a perspective view of an enclosure of the acoustic assembly of  FIG. 1 . 
         FIG. 3  illustrates an exploded view of an acoustic horn of the acoustic assembly from  FIG. 1 . 
         FIGS. 4-5  illustrate rear views of the acoustic horn of  FIG. 3 . 
         FIG. 6-10  illustrate front views of an acoustic assembly according to one or more embodiments. 
         FIG. 11  illustrates a top view of the enclosure of  FIGS. 6-10  in a partially assembled state. 
         FIG. 12  illustrates a virtual simulation of an acoustic assembly according to one or more embodiments. 
         FIG. 13  illustrates results of a mid-frequency test of a modified acoustic assembly, which is at least in part based on one or more embodiments. 
         FIG. 14  illustrates results of a mid-frequency test of an acoustic assembly according to one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
       FIG. 1  illustrates a perspective view of an acoustic assembly  100 , which is in accordance with one or more embodiments of the present invention. The acoustic assembly  100  includes an enclosure  101 . The enclosure  101  may include a modular construction, an integral construction, such as from a molding process, or a combination thereof. Furthermore, the enclosure  101  may include an exterior shape, which may appear cubic, rectangular, trapezoidal, spherical, conical, cylindrical, ellipsoidal, triangular, pentagonal, hexagonal, pyramidal, or another multi-sided three-dimensional shape. 
     Further in  FIG. 1 , a cover  102  may removably attach to the enclosure  101 . The cover  102  may be removably attached to the enclosure  101  by fasteners, adhesives, and/or other ways known in the art. Moreover, the cover  102  may be shaped similarly or identical to one or more sides of the enclosure  101 . Furthermore, the cover  102  may be a solid panel or an acoustically transparent grille. Using the solid panel as the cover  102  may be desirable for use during set-up, tear-down, transportation, and/or storage of the acoustic assembly  100 . When the solid panel is attached to the enclosure  101 , sensitive and/or critical components, such as a loudspeaker diaphragm, that would otherwise be exposed to the surroundings may be completely covered and protected. The protection from the surroundings may be due to the solid panel&#39;s robust design, which is able to withstand forces commonly experienced with set-up, tear-down, transportation, and/or storage of the acoustic assembly  100 . Under such forces, the solid panel will not fail. Conversely without the solid panel, such forces could impact the sensitive and/or critical components directly, which could cause those components to fail. Alternatively, to the solid panel, using the acoustically transparent grille as the cover  102  may be desirable during operation of the acoustic assembly  100 . During operation, the acoustically transparent grille does not interfere with sound waves produced from the acoustic assembly  100 . As another alternative, the cover  102  may be removed completely before operating the acoustic assembly  100 . 
     The acoustic assembly  100  may be removably attached to one or more additional acoustic assemblies. For example, one or more additional acoustic assemblies may be removably attached to the acoustic assembly  100  to create a line-array. The line-array may be hung, such as to a rafter or scaffolding, above a ground floor. 
     In  FIG. 2 , the enclosure  101  of the acoustic assembly  100  is illustrated without the cover  102 . As an example of removal, the cover  102  may have been detached, such as by unscrewing threaded fasteners, from a first side  103  and a second side  104  of the enclosure  101 . After detaching, the cover  102  may have been removed from the enclosure  101 . 
     In the enclosure  101 , the first side  103  may be laterally spaced from the second side  104  along an X axis. The first side  103  may generally be parallel to the second side  104 , and the first side  103  may generally mirror the shape of the second side  104 . Further on shape, the first side  103  and the second side  104  may include tapered portions, as shown in the illustrated embodiment. Additionally, the first side  103  and the second side  104  may attach to a top side  105 , a bottom side  106 , and a back side  107 . The top side  105  may be laterally spaced from the bottom side  106  along a Y axis. The Y axis may be oriented 90 degrees to the X axis. Additionally, the back side  107  may attach to the top side  105  and the bottom side  106 . The first side  103 , the second side  104 , the top side  105 , the bottom side  106 , and the back side  107  may define a cavity  108  for receiving at least one acoustic emitting device  109 , such as a loudspeaker or a compression driver. To receive the at least one acoustic emitting device  109 , the cavity may include a frame  110 . The frame  110  may attach to the first side  103 , the second side  104 , the top side  105 , the bottom side  106 , and/or the back side  107 . Alternatively, the frame  110  may be integrally formed with the first side  103 , the second side  104 , the top side  105 , the bottom side  106 , and/or the back side  107 . 
     Additionally, the acoustic assembly  100  may include at least one acoustic horn  111 . The at least one acoustic horn  111  at least partially covers the at least one acoustic emitting device  109 . The at least one acoustic horn  111  may improve one or more acoustical parameters of the acoustic assembly. For example, the at least one acoustic horn  111  may be designed to achieve a desired directivity of the acoustic assembly  100 . As another example, the acoustic horn  111  may be designed to achieve a smooth, uninterrupted transition across frequency bands, which at least range from a low frequency (20 Hz) to a high frequency (20 KHz). Furthermore, the at least one acoustic horn  111  may attach to the first side  103 , the second side  104 , the top side  105 , the bottom side  106 , the back side  107 , the at least one acoustic emitting device  109 , and/or the frame  110 . The attachments between the first side  103 , the second side  104 , the top side  105 , the bottom side  106 , the back side  107 , the at least one acoustic emitting device  109 , the frame  110 , and/or the acoustic horn  111  may be serviceable or non-serviceable and may occur by fasteners, adhesive, and/or other ways known in the art. 
       FIG. 3  illustrates an exploded view of the acoustic horn  111  for the acoustic assembly  100 . The acoustic assembly  100  may include at least one waveguide  112 , at least one lens  113 , at least one plug  114 , and/or at least one integrator  115 . The at least one waveguide  112 , the at least one lens  113 , and the at least one plug  114  may attach to the at least one integrator  115 . The attachments may be permanent or non-permanent and may occur by fasteners, adhesive, and or/or other ways known in the art. Additionally, as part of the attachments, a vibration absorbing layer (not shown) may be placed between the at least one integrator  115  and the at least one waveguide  112 , the at least one lens  113 , and/or the at least one plug  114 . Alternatively, the at least one waveguide  112 , the at least one lens  113 , and/or the at least one plug  114  may be integrally formed with the at least one integrator  115 . 
     As an example of the acoustic horn  111  in the acoustic assembly  100 , when the at least one acoustic emitting device  109  in the acoustic assembly  100  includes at least one high-frequency compression driver, the at least one waveguide  112  may be positioned in front of an output opening of the at least one high-frequency compression driver. Positioning the at least one waveguide  112  in that manner allows the at least one waveguide  112  to receive and influence a sound wave—such as directivity—from the at least one high-frequency compression driver. In addition to positioning, the at least one waveguide  112  may attach to the at least one high-frequency compression driver. 
     As a further example, when the at least one acoustic emitting device  109  in the acoustic assembly  100  includes at least one mid-frequency loudspeaker, the at least one lens  113  may be positioned in front of an output side of the at least one mid-frequency loudspeaker. Positioning the at least one lens  113  in that manner allows the at least one lens  113  to receive and influence a sound wave—such as directivity—from the at least one mid-frequency loudspeaker. In addition to positioning, the at least one lens  113  may attach to the at least one mid-frequency loudspeaker. 
     As another example, when the at least one acoustic emitting device  109  in the acoustic assembly  100  includes at least one low-frequency loudspeaker, the at least one plug  114  may be positioned in front of an output side of the at least one low-frequency loudspeaker. Positioning the at least one plug  114  in that manner allows the at least one plug  114  to receive and influence a sound wave—such as directivity—from the at least one low-frequency loudspeaker. Furthermore, one or more of the at least one waveguide  112 , the at least one lens  113 , the at least one plug  114 , and the at least one integrator  115  may include at least one through-hole aperture  116 , such as a slotted opening, for directing sound waves there-through. 
       FIG. 4  illustrates an example of the acoustic horn  111  for the acoustic assembly  100 . In the example, the acoustic horn  111  aligns along an X′ plane containing the X axis. Additionally, the acoustic horn  111  aligns along a Y′ plane containing the Y axis. Like the X and Y axes, the X′ plane is oriented 90 degrees to the Y′ plane. The acoustic horn  111  includes a center point  117  that is positioned along a line at the intersection of the X′ plane and the Y′ plane. The center point  117  may correspond to the intersection of the X axis and the Y axis. Based on the design of the acoustic horn  111 , the acoustic horn  111  may include a desired directivity in the X′ plane. Additionally, based on the design of the acoustic horn  111 , the acoustic horn  111  may include a desired directivity in the Y′ plane. 
     Along the X′ plane, the acoustic horn  111  includes a horizontal length H, which runs in the direction of the X axis. And along the Y′ plane, the acoustic horn includes a vertical length V, which runs in the direction of the Y axis. The horizontal length H is greater than the vertical length V. Furthermore, the Y′ plane may act as a first mirror such that a first portion of the acoustic horn  111  mirrors a second portion of the acoustic horn  111 . Additionally, the X′ plane may act as a second mirror such that a third portion of the acoustic horn  111  mirrors a fourth portion of the acoustic horn  111 . 
     In the example of  FIG. 4 , the acoustic horn  111  includes one waveguide  112 . The one waveguide  112  extends along the Y′ plane. The one waveguide  112  may do so in the direction of the Y axis. The one waveguide  112  includes at least one through-hole aperture  116 . In addition to the one waveguide  112 , the acoustic horn includes four lenses  113 . The four lenses  113  may be evenly distributed around the X′ plane and Y′ plane. Additionally, the four lenses  113  may be adjacent to the one waveguide  112 . Each of the four lenses  113  includes at least one through-hole aperture  116 . In addition to the four lenses  113 , the acoustic horn  111  includes two plugs  114 . The two plugs  114  are laterally spaced from one another along the X′ plane. The lateral spacing of the two plugs  114  may be done in the direction of the X axis. In addition to the two plugs  114 , the acoustic horn  111  includes two integrators  115 . The two integrators  115  may be adjacent to the one waveguide  112 . Each of the two integrators  115  includes at least one through-hole aperture  116 , which may be in fluid communication with one or more of the through-hole apertures  116  of the lenses  113 . The one waveguide  112 , the four lenses  113 , and the two plugs  114  may attach to the two integrators  115 . When attached, the two plugs  114  and the two integrators  115  form two sealed chambers  118 . The two sealed chambers  118  may be hollow or filled with a material. The two chambers  118  may act as resonators when used in the acoustic assembly  100 . 
     The two plugs  114  include overall horizontal lengths L along the X′ plane, which run in the direction of the X axis. Additionally, the two plugs include overall vertical lengths D, which are in directions parallel to the Y axis on the Y′ plane. The overall horizontal lengths L are greater than the vertical lengths D. The perimeters of the two plugs  114  are non-circular and include arcuate tapered segments  119 . On the two plugs  114 , with reference to the Y axis on the Y′ plane, the arcuate tapered segments  119  begin at starting points  120  furthest from the X axis on the X′ plane. And, again with reference to the Y axis on the Y′ plane, the arcuate tapered segments  119  taper to end points  121  that are closer to the X axis on the X′ plane than their respective starting points  120 . From the arcuate tapered segments  119 , radial segments  122  may complete the perimeters of the two plugs  114 . Like the two plugs  114 , the two integrators  115  include arcuate tapered segments  123  and radial segments  124 , which correspond to the arcuate tapered segments  119  and the radial segments of the two plugs  114 . The surfaces of the two plugs  114  may be smooth. Alternatively, the surfaces of the two plugs  114  may include one or more protrusions  125  and/or indentations  126 . 
       FIGS. 6 through 11  illustrate an acoustic assembly  200 , which is in accordance with one or more embodiments of the present invention. The acoustic assembly  200  includes an enclosure  201 . A cover  202  removably attaches to the enclosure  201 . In particular, the cover  202  removably attaches to a first side  203  and a second side  204  of the enclosure  201 . Additionally, the first side  203  and the second side  204  of the enclosure  201  attach to a top side  205 , a bottom side  206 , and a back side  207 . The first side  203 , the second side  204 , the top side  205 , the bottom side  206 , and the back side  207  define a cavity  208  for receiving a first low-frequency loudspeaker  209 , a second low-frequency loudspeaker  210 , a first mid-frequency loudspeaker  211 , a second mid-frequency loudspeaker  212 , a third mid-frequency loudspeaker  213 , a fourth mid-frequency loudspeaker  214 , a first high-frequency compression driver  215 , a second high-frequency compression driver  216 , and a third high-frequency compression driver  217 . To receive the two low-frequency loudspeakers  209 ,  210 , the four mid-frequency loudspeakers  211 ,  212 ,  213 ,  214 , and the three high-frequency compression drivers  215 ,  216 ,  217 , the cavity includes a frame  218 . The frame  218  at least attaches to the bottom side  206 . 
     In the acoustic assembly  200 , the first and the second low-frequency loudspeakers  209 ,  210  are in the cavity  208  of the enclosure  201 . The first and the second low-frequency loudspeakers  209 ,  210  are attached to the frame  218 . Moreover, the first and the second low-frequency loudspeakers  209 ,  210  align along a first plane  219 . The first plane  219  bisects the first low-frequency loudspeaker  209 . Additionally, the first plane  219  bisects the second low-frequency loudspeaker  210 . Along the first plane  219 , the first low-frequency loudspeaker  209  is laterally spaced from the second low-frequency loudspeaker  210 . 
     Further in the acoustic assembly  200 , the first, the second, and the third high-frequency compression drivers  215 ,  216 ,  217  are aligned along a second plane  220 . The first, the second, and the third high-frequency compression drivers  215 ,  216 ,  217  are attached to the frame  218 . The second plane  220  is oriented 90 degrees to the first plane  219 . The second plane  220  bisects the first high-frequency compression driver  215 , as well as the second high-frequency compression driver  216  and the third high-frequency compression driver  217 . Unlike the first high-frequency compression driver  215  and third high-frequency compression driver  217 , the second high-frequency compression driver  216  is also aligned along the first plane  219 . Because of that, the first plane  219  also bisects the second compression driver  216 . 
     Further in the acoustic assembly  200 , the first, the second, the third, and the fourth mid-frequency loudspeakers  211 ,  212 ,  213 ,  214  are distributed around the first plane  219  and the second plane  220 . Because the first plane  219  and the second plane  220  intersect, the first plane  219  and the second plane  220  form four quadrants: I, II, III, and IV. In quadrant I, the first mid-frequency loudspeaker  211  is positioned and attached to the frame  218 . In quadrant II, the third mid-frequency loudspeaker  213  is positioned and attached to the frame  218 . In quadrant III, the fourth mid-frequency loudspeaker  214  is positioned and attached to the frame  218 . In quadrant IV, the second mid-frequency loudspeaker  212  is positioned and attached to the frame  218 . 
     The first low-frequency loudspeaker  209  includes a rear face  221  that faces the back side  207 . Additionally, the second low-frequency loudspeaker  210  includes a rear face  222  that also faces the back side  207 . Opposite the rear face  221 , the first low-frequency loudspeaker  209  includes a front output side  223 . The front output side  223  of the first low-frequency loudspeaker  209  is at least defined by a diaphragm  224 . When the cover  202  is attached, the front output side  223  faces the cover  202 . Additionally, opposite the rear face  222 , the second low-frequency loudspeaker  210  includes a front output side  225 . The front output side  225  of the second low-frequency loudspeaker  210  is at least defined by a diaphragm  226 . Like the first low-frequency loudspeaker  209 , the front output side  225  of the second low-frequency loudspeaker  210  also faces the cover  202 , when the cover  202  is attached. 
     The first, the second, and the third high-frequency compression drivers  215 ,  216 ,  217  include a first output opening  227 , a second output opening  228 , and a third output opening  229 , respectively. When the cover  202  is attached, the first output opening  227 , the second output opening  228 , and the third output opening  229  face the cover  202 . 
     Similar to the first and the second low-frequency loudspeaker  209 ,  210 , the first, the second, the third, and the fourth mid-frequency loudspeakers  211 ,  212 ,  213 ,  214  include front output sides  230 ,  231 ,  232 ,  233 , respectively. When the cover  202  is attached, the front output sides  230 ,  231 ,  232 ,  233  of the four mid-frequency loudspeakers  211 ,  212 ,  213 ,  214  generally face the cover  202 . Unlike the first and the second low-frequency loudspeakers  209 ,  210 , though, the front output sides  230 ,  231 ,  232 ,  233  of the four mid-frequency loudspeakers are angled toward the second plane  220 . 
     Furthermore, the acoustic assembly  200  includes an acoustic horn  234 . The acoustic horn includes a waveguide  235 . The waveguide  235  is aligned along the second plane  220 . The second plane  220  bisects the waveguide  235 . The waveguide  235  is positioned in front of the first output opening  227 , the second output opening  228 , and the third output opening  229  of the first, the second, and the third high-frequency compression drivers  215 ,  216 ,  217 . Because of the positioning, the waveguide  235  receives and influences sound waves from the first, the second, and the third high-frequency compression drivers  215 ,  216 ,  217 . When the cover  202  is attached, the waveguide  235  is between the cover  202  and the first, the second, and the third high-frequency compression drivers  215 ,  216 ,  217 . 
     In addition to the waveguide  235 , the acoustic horn  234  includes a first lens  236 , a second lens  237 , a third lens  238 , and a fourth lens  239 . With respect to the first mid-frequency loudspeaker  211 , the first lens  236  is positioned in front of the front output side  230 . With respect to the second mid-frequency loudspeaker  212 , the second lens  237  is positioned in front of the front output side  231 . With respect to the third mid-frequency loudspeaker  213 , the third lens  238  is positioned in front of the front output side  232 . And with respect to the fourth mid-frequency loudspeaker  214 , the fourth lens  239  is positioned in front of the front output side  233 . Because of the positioning, the first, the second, the third, and the fourth lenses  236 ,  237 ,  238 ,  239  receive and influence sound waves from the first, the second, the third, and the fourth mid-frequency loudspeakers  211 ,  212 ,  213 ,  214 . When the cover  202  is attached, the first, the second, the third, and the fourth lenses  236 ,  237 ,  238 ,  239  are positioned between the cover  202  and the first, the second, the third, and the fourth mid-frequency loudspeakers  211 ,  212 ,  213 ,  214 . 
     In addition, the acoustic horn  234  includes a first plug  240  and a second plug  241 . With respect to the first low-frequency loudspeaker  209 , the first plug  240  is positioned in front of the front output side  223 . With respect to the second low-frequency loudspeaker  210 , the second plug  241  is positioned in front of the front output side  225 . Because of the positioning, the first and the second plugs  240 ,  241  receive and influence sound waves from the first and the second low-frequency loudspeakers  209 ,  210 . When the cover  202  is attached, the first and the second plugs  240 ,  241  are positioned between the cover  202  and the first and the second low-frequency loudspeakers  209 ,  210 . 
     Further, the acoustic horn  234  includes a first integrator  242  and a second integrator  243 . The waveguide  235 , the first lens  236 , the second lens  237 , and the first plug  240  are attached to the first integrator  242 . The waveguide  235 , the third lens  238 , and the fourth lens  239 , and the second plug  241  are attached to the second integrator  243 . The first integrator  242  at least covers the first mid-frequency loudspeaker  211 , the second mid-frequency loudspeaker  212 , and the first plug  240 . The second integrator  243  at least covers the third mid-frequency loudspeaker  213 , the fourth mid-frequency loudspeaker  214 , and the second plug  241 . When the cover  202  is attached, the cover  202  covers the first integrator  242  and the second integrator  243 . 
     The first plug  240  may have a convex side  244 , and the second plug  241  may have a convex side  245 . With respect to the first plug  240 , the convex side  244  may face the diaphragm  224  of the first low-frequency loudspeaker  209 . The diaphragm  224  may have a conical shape, which may be a frustoconical shape. The first low-frequency loudspeaker  209  may have a cone volume  246  defined by the diaphragm  224 . The convex side  244  of the first plug  240  may be positioned into a portion of the cone volume  246 . During operation of the first low-frequency loudspeaker  209 , the diaphragm  224 , however, does not contact the first plug  240 . Therefore, the convex side  244  of the first plug is spaced from the diaphragm  224  of the first low-frequency loudspeaker  209 , such that the diaphragm  224  does not contact the first plug  240  during operation of the first low-frequency loudspeaker  209 . Furthermore, during operation, sound waves from the first low-frequency loudspeaker  209  may travel around the first plug  240 . 
     With respect to the second plug  241 , the convex side  245  may face the diaphragm  226  of the second low-frequency loudspeaker  210 . The diaphragm  226  may have a conical shape, which may be a frustoconical shape. The second low-frequency loudspeaker  210  may have a cone volume  247  defined by the diaphragm  226 . The cone volume  247  of the second low-frequency loudspeaker  210  may equal the cone volume  246  of the first low-frequency loudspeaker  209 . The convex side  245  of the second plug  241  may be positioned into a portion of the cone volume  247  of the second low-frequency loudspeaker  210 . Like the first low-frequency loudspeaker  209 , during operation of the second low-frequency loudspeaker  210 , the diaphragm  226  does not contact the second plug  241 , because the convex side  245  is spaced from the diaphragm  226 . Furthermore, during operation, sound waves from the second low-frequency loudspeaker  210  may travel around the second plug  241 . 
     As illustrated in  FIG. 7 , when the first integrator  242  and the first plug  240  are positioned in front of the first low-frequency loudspeaker  209 , the first low-frequency loudspeaker includes a first unobstructed area  248  and a second unobstructed area  249 . This is because the first integrator  242  and the first plug  240  only cover a portion of the front output side  223  of the first low-frequency loudspeaker  209 . Like the first integrator  242  and the first plug  240 , when the second integrator  243  and the second plug  241  are positioned in front of the second low-frequency loudspeaker  210 , the second low-frequency loudspeaker  210  includes a first unobstructed area  250  and a second unobstructed area  251 . This is also because the second integrator  243  and the second plug  241  only cover a portion of the front output side  225  of the second low-frequency loudspeaker  210 . 
     During operation, the acoustic assembly  200  may include a first crossover region and a second crossover region. The first crossover region may be the overlap in frequency ranges between the low-frequency loudspeakers  209 ,  210  and at least the mid-frequency loudspeakers  211 ,  212 ,  213 ,  214 . The second crossover region may be the overlap in frequency ranges between the high-frequency compression drivers  215 ,  216 ,  217  and at least the mid-frequency loudspeakers  211 ,  212 ,  213 ,  214 . 
     In the first crossover region, the low-frequency loudspeakers  209 ,  210  may include sound coverage patterns that may be identical to at least the mid-frequency loudspeakers&#39;  211 ,  212 ,  213 ,  214  sound coverage patterns. For example, in the first crossover region, the first and the second low-frequency loudspeakers  209 ,  210  may include a first sound coverage angle in the first plane  219  and a second sound coverage angle in the second plane  220 . Additionally, in the crossover region, at least the first, the second, the third, and the fourth mid-frequency loudspeakers  211 ,  212 ,  213 ,  214  may include a third sound coverage angle in the first plane  219  and a fourth sound coverage angle in the second plane  220 . The first sound coverage angle may be equal to the third sound coverage angle, and the second sound coverage angle may be equal to the fourth sound coverage angle. This may be achieved by the acoustic horn  234  in the acoustic assembly  200 . 
     In the second crossover region, the high-frequency compression drivers  215 ,  216 ,  217  may include sound coverage patterns that may be identical to at least the mid-frequency loudspeakers&#39;  211 ,  212 ,  213 ,  214  sound coverage patterns. For example, in the second crossover region, the high-frequency compression drivers  215 ,  216 ,  217  may include a first sound coverage angle in the first plane  219  and a second sound coverage angle in the second plane  220 . Additionally, in the second crossover region, at least the first, the second, the third, and the fourth mid-frequency loudspeakers  211 ,  212 ,  213 ,  214  may include a third sound coverage angle in the first plane  219  and a fourth sound coverage angle in the second plane  220 . The first sound coverage angle may be equal to the third sound coverage angle, and the second sound coverage angle may be equal to the fourth sound coverage angle. This may be achieved by the acoustic horn  234  in the acoustic assembly  200 . 
     Additionally or alternatively, the acoustic assembly  200  may include a third crossover region. The third crossover region may be the overlap in frequency ranges between the low-frequency loudspeakers  209 ,  210  and the high-frequency compression drivers  215 ,  216 ,  217 . In the third crossover region, the low-frequency loudspeakers  209 ,  210  may include sound coverage patterns that may be identical to the high-frequency compression drivers  215 ,  216 ,  217 . For example, in the third crossover region, the low-frequency loudspeakers  209 ,  210  may include a first sound coverage angle in the first plane  219  and a second sound coverage angle in the second plane  220 . Additionally, in the third crossover region, the high-frequency compression drivers  215 ,  216 ,  217  include a third sound coverage angle in the first plane  219  and a fourth sound coverage angle in the second plane  220 . The first sound coverage angle may be equal to the third sound coverage angle, and the second sound coverage angle may be equal to the fourth sound coverage angle. This may be achieved by the acoustic horn  234  in the acoustic assembly  200 . 
     Therefore during operation, the acoustic horn  234  in the acoustic assembly  200  may result in a uniform coverage pattern over a listening area in the first plane  219  and/or the second plane  220 . The uniform coverage pattern may result in an improved listening experience for persons located in the listening area. That is because the coverage pattern may not differ at various locations inside of the listening area. 
     As such, and among other things, embodiments herein may improve directivity for acoustic assemblies that include at least one acoustic emitting device and operate over the audible hearing range (20 Hz to 20 KHz). 
       FIG. 12  illustrates a virtual-simulation  300  of an acoustic assembly according to one or more embodiments. The virtual-simulation  300  illustrates ideal horizontal beamwidths for the acoustic assembly (i.e., sound coverage angle in a horizontal plane versus frequency). As such, the virtual-simulation  300  illustrates a horizontal beamwidth  301  for at least one low-frequency acoustic emitting device, a horizontal beamwidth  302  for at least one mid-frequency acoustic emitting device, and a horizontal beamwidth  303  for at least one high-frequency acoustic emitting device. 
     The virtual-simulation  300  further illustrates a first crossover region  304  between the at least one low-frequency acoustic emitting device and the at least one mid-frequency acoustic emitting device. Further, the virtual-simulation illustrates a second crossover region  305  between the at least one mid-frequency acoustic emitting device and the at least one high-frequency acoustic emitting device. In the virtual simulation  300 , the first crossover region  304  extends from around 200 Hz to around 600 Hz, and the second crossover region  305  extends from around 600 Hz to 2,000 Hz. 
     In the virtual-simulation  300 , in the first crossover region  304 , the at least one low-frequency acoustic emitting device decreases in sound coverage angle as frequency increases. That decrease may be linear. Thus, the decrease in sound coverage angle as frequency increases for the at least one low-frequency acoustic emitting device in the first crossover region  304  may have a constant slope. Similarly, in the first crossover region  304 , the at least one mid-frequency acoustic emitting device decreases in sound coverage angle as frequency increases. That decrease may similarly be linear. Thus, the decrease in sound coverage angle as frequency increases for the at least one mid-frequency acoustic emitting device in the first crossover region  304  may have a constant slope. The slope of decrease for the at least one low-frequency acoustic emitting device may be equal to the slope of decrease for the at least one mid-frequency acoustic emitting device. Alternatively, in the first crossover region  304 , the curve of decrease for the at least one low-frequency acoustic emitting device may be parallel to the curve of decrease for the at least one mid-frequency acoustic emitting device. The equal slope and/or parallel curves may be a byproduct of the acoustic horn in the acoustic assembly. This may be due to the interaction between the at least one low-frequency acoustic emitting device, the at least one mid-frequency acoustic emitting device, the at least one high-frequency acoustic emitting device, and the acoustic horn in the acoustic assembly. 
     In the virtual simulation  300 , in the first crossover region  304 , the sound coverage angle for the at least one mid-frequency acoustic emitting device may be greater than the sound coverage angle for the at least one low-frequency acoustic emitting device at a given frequency. The net result, however, may yield a constant coverage angle. For example, as the virtual-simulation  300  illustrates, in the first crossover region  304 , the net result yields or substantially yields a sound coverage angle of 100 degrees. The net result may be a byproduct of the acoustic horn in the acoustic assembly. This may be due to the interaction between the at least one low-frequency acoustic emitting device, the at least one mid-frequency acoustic emitting device, and the acoustic horn in the acoustic assembly. 
     In the virtual-simulation  300 , in the second crossover region  305 , the at least one mid-frequency acoustic emitting device decreases in sound coverage angle as frequency increases. That decrease may be linear. Thus, the decrease in sound coverage angle as frequency increases for the at least one mid-frequency acoustic emitting device in the second crossover region  305  may have a constant slope. Similarly, in the second crossover region  305 , the at least one high-frequency acoustic emitting device decreases in sound coverage angle as frequency increases. That decrease may similarly be linear. Thus, the decrease in sound coverage angle as frequency increases for the at least one high-frequency acoustic emitting device in the second crossover region  305  may have a constant slope. The slope of decrease for the at least one mid-frequency acoustic emitting device may be equal to the slope of decrease for the at least one high-frequency acoustic emitting device. Alternatively, in the first crossover region  304 , the curve of decrease for the at least one mid-frequency acoustic emitting device may be parallel or substantially parallel to the curve of decrease for the at least one high-frequency acoustic emitting device. 
     In the virtual simulation  300 , in the second crossover region  305 , the sound coverage angle for the at least one mid-frequency acoustic emitting device may be less than the sound coverage angle for the at least one high-frequency acoustic emitting device at a given frequency. The net result, however, may yield a constant coverage angle. For example, as the virtual-simulation  300  illustrates, in the second crossover region  305 , the net result yields or substantially yields a sound coverage angle of 100 degrees. The net result may be a byproduct of the acoustic horn in the acoustic assembly. This may be due to the interaction between the at least one mid-frequency acoustic emitting device, the at least one high-frequency acoustic emitting device, and the acoustic horn in the acoustic assembly. 
     Thus the acoustic horn in the acoustic assembly improves the beamwidths in a given plane, such as the horizontal plane or vertical plane. This improvement may be particularly evident in the crossover regions of the acoustic assembly. In the crossover regions, the acoustic horn may achieve desirable beamwidths. 
       FIG. 13  illustrates results of a mid-frequency test of a modified acoustic assembly  400 , which is primarily based on the acoustic assembly  200  of  FIGS. 6-11 . Unlike the acoustic assembly  200 , though, the modified acoustic assembly  400  does not include a first plug or a second plug, nor does the modified acoustic assembly  400  include a first integrator that extends over a first low-frequency loudspeaker or a second integrator that extends over a second low-frequency loudspeaker. Instead, the first and the second integrators in the modified acoustic assembly  400  stop short of the first and the second low-frequency loudspeakers. Besides that, though, the modified acoustic assembly is based on the acoustic assembly  200  of  FIGS. 6-11 . The mid-frequency test of the modified acoustic assembly  400  illustrates a horizontal beamwidth  401 . 
       FIG. 14  illustrates results of a mid-frequency test of an acoustic assembly  500 , which is based on the acoustic assembly  200  of  FIGS. 6-11 . Unlike the modified acoustic assembly  400 , the acoustic assembly  500  does include a first plug and a second plug, which are positioned in front of a first and a second low-frequency loudspeaker, like in the acoustic assembly  200 . Moreover, unlike the modified acoustic assembly  400 , the acoustic assembly  500  includes a first integrator and a second integrator that does extend over portions of the first and the second low-frequency loudspeakers, like in the acoustic assembly  200 . With the exceptions regarding the first plug, the second plug, the first integrator, and the second integrator, the modified acoustic assembly  400  and the acoustic assembly  500  are identical. The mid-frequency test of the acoustic assembly  500  illustrates a horizontal beamwidth  501 . 
     Comparing  FIG. 13  to  FIG. 14  reveals that in a first critical passband between 500 Hz to 1,000 Hz, the horizontal beamwidth  401  of the modified acoustic assembly  400  is generally much wider than the horizontal beamwidth  501  of the acoustic assembly  500 . Additionally, in a second critical passband between 1,000 Hz and 2,000 Hz, the horizontal beamwidth  401  of the modified acoustic assembly  400  becomes much narrower than the horizontal beamwidth  501  of the acoustic assembly  500 . For the first critical passband and the second critical passband, when a target horizontal beamwidth of 90 degrees is set, based on the tests in  FIGS. 16-17 , the acoustic assembly  500  outperforms the modified acoustic assembly  400 . This is because the horizontal beamwidth  501  of the acoustic assembly  500  is closer to the target horizontal beamwidth than the horizontal beamwidth  401  of the modified acoustic assembly  400 . 
     Moreover, the acoustic assembly  500  outperforms the modified acoustic assembly  400  because the horizontal beamwidth  501  of the acoustic assembly  500  includes a nearly linear decrease in sound coverage angle over frequency between around 100 Hz to around 2,000 Hz. Conversely, the modified acoustic assembly  400  yields a significantly non-linear curve over that range. The nearly linear decrease for the horizontal beamwidth  501  of the acoustic assembly  500  is preferable than the significantly non-linear curve for the horizontal beamwidth of the modified acoustic assembly  400 . The nearly linear decrease for the horizontal beamwidth  501  of the acoustic assembly  500  is closer to the corresponding ideal beamwidth  302  that is depicted in the virtual-simulation  300  than the significantly non-linear curve for the horizontal beamwidth  401  of the modified acoustic assembly  400 . 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.