Abstract:
The invention relates to a loudspeaker assembly including a housing having a central driver mounting plate upon which a driver is mounted. The central driver mounting plate and the driver divide the housing into an upper compartment and a lower compartment, wherein the lower compartment includes at least one slot providing fluid communication between an interior of the lower compartment and an external environment.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. Patent Application is based upon U.S. Provisional Patent Application Serial No. 60/137,793, filed Jun. 3, 1999, and entitled “SUBWOOFER ASSEMBLY”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a subwoofer assembly. More particularly, the present invention relates to a low profile subwoofer assembly shaped and dimensioned for mounting adjacent the floor under an aircraft seat, behind a divan, below a drink rail or between adjacent windows. 
     2. Description of the Prior Art 
     The current global community has made it possible for people from around the country, and around the world, to interact for both business and personal reasons. For many people, this requires that they spend considerable time traveling from one location to another location. More often than not, these people travel in aircrafts. 
     Whether these people travel in private or commercial aircrafts, they desire high quality entertainment during the many hours they spend within the confines of an aircraft. However, while high quality entertainment, for example, digital video with CD quality sound, is readily available for theater and home use, the weight and size requirements for use in aircrafts make it very difficult to incorporate high fidelity systems within an aircraft. This problem is especially pronounced for audio speaker assemblies when one attempts to meet the size, weight and shape requirements for use in aircrafts. 
     In the aircraft industry great priority is placed upon component weight and size reduction. In addition, spacing and positioning of the speaker assemblies is a great priority to those optimizing the operation of aircrafts. The size, weight and shape of conventional terrestrial speaker assembly designs adversely affect range and payload. These concerns are notable when one attempts to make changes within smaller private jets. For example, a small increase in the weight carried by an aircraft results in a substantial increase in the fuel consumption of the aircraft. In addition, the limited space available within an aircraft dictates the use of any space within the aircraft be carefully considered by those responsible for ensuring the comfort of passengers. 
     Lightweight and compact audio speakers are currently available. These speakers, however, substantially compromise sound quality for reductions in size and weight. An individual wishing to add an audio system to an aircraft must make a choice between high fidelity speakers not suiting the size and weight requirements of the aircraft and lower quality speakers providing desirable size and weight characteristics. 
     The weight and size problems associated with the use of loudspeaker systems within aircraft is very evident when one attempts to incorporate woofers into an aircraft design. Conventional woofers employ substantial housings designed to control the manner in which sound is transmitted from the woofer. The controlled porting of sound employed in conventional woofers necessitates the construction of rather substantial housings. These housings, while controlling the transmission of sound as desired, are commonly beyond the size and weight constraints required for use within an aircraft. 
     A need, therefore, exists for a speaker assembly providing high fidelity sound, while also meeting the size and weight requirements of an aircraft. The present invention provides such a speaker assembly. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a loudspeaker assembly including a housing having a central driver mounting plate upon which a driver is mounted. The central driver mounting plate and the driver divide the housing into an upper compartment and a lower compartment, wherein the lower compartment includes at least one slot providing fluid communication between an interior of the lower compartment and an external environment. 
     It is also an object of the present invention to provide a loudspeaker assembly wherein the housing is made of a material which will resonate to transmit sound from within the housing. 
     It is another object of the present invention to provide a loudspeaker assembly wherein the housing is made of aluminum. 
     It is a further object of the present invention to provide a loudspeaker assembly wherein the housing is made of aluminum honeycomb sheet material. 
     It is yet another object of the present invention to provide a loudspeaker assembly wherein the aluminum honeycomb sheet material has a thickness of approximately ¼ inch. 
     It is still a further object of the present invention to provide a loudspeaker assembly wherein the housing is composed of a cover plate with a plurality of side walls extending therefrom to form an enclosure with an open end. The central driver mounting plate and the driver are secured within the enclosure to divide the housing into an upper compartment and a lower compartment wherein the lower compartment is defined by the plurality of side walls and the open end of the enclosure. 
     It is also another object of the present invention to provide a loudspeaker assembly wherein the at least one slot is formed in the plurality of side walls providing fluid communication between an interior of the lower compartment and an external environment when the loudspeaker is mounted to cover the open end of the enclosure. 
     It is a further object of the present invention to provide a loudspeaker assembly wherein the driver is a low frequency driver. 
     It is also an object of the present invention to provide a loudspeaker assembly wherein the driver is positioned to fire into the lower compartment of the housing with a convex portion of the driver extending into the upper compartment of the housing. 
     Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the present subwoofer module showing the internal components. 
     FIG. 2 is a partial cross section view of the present subwoofer module mounted beneath an aircraft seat. 
     FIG. 3 is a perspective view of the present subwoofer module configured for mounting in a vertical orientation. 
     FIG. 4 is a partial cross sectional view of the present subwoofer module mounted within the fuselage wall. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limited, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. 
     With reference to FIG. 1, a subwoofer module  10  in accordance with the present invention is disclosed. The subwoofer module  10  is particularly designed for use within an aircraft  12 , although the subwoofer module  10  may be used in various other environments without departing from the spirit of the present invention. The present subwoofer module  10  is particularly designed for horizontal positioning on the floor  14  under an aircraft seat  16 . The subwoofer module  10  is also designed for vertical mounting within an aircraft  12 . For example, the present subwoofer module  10  may be mounted behind a divan, below a drink rail or between adjacent windows of an aircraft. 
     The present subwoofer module  10  includes a substantially rectangular housing  18 . The housing  18  is preferably manufactured from aluminum. More specifically, the housing is preferably manufactured from a ¼″ inch thick aluminum honeycomb sheet material. While preferred materials are disclosed in accordance with a preferred embodiment of the present invention, other materials may be used without departing from the spirit of the present invention. Regardless of the material used in the construction of the housing  18 , the chosen material should resonate in a manner transmitting sound from the interior of the housing. The mechanism by which the housing  18  functions as a transducer in the transmission of sound is discussed below in greater detail. 
     The housing  18  is composed of lateral side walls  20 ,  22 , a front side wall  24  and a rear side wall  26 . A central driver mounting plate  28  is secured to the side walls of the housing  18  and divides the housing  18  into an upper compartment  30  and a lower compartment  32 . Specifically, the upper compartment  30  is defined by the upper surface  34  of the driver mounting plate  28 , the side walls  20 - 26  and a cover plate  36 . The lower compartment  32  is defined by the lower surface  38  of the driver mounting plate  28  and side walls  20 - 26 , while the bottom  40  of the housing  18  remains open to be ultimately closed off when the subwoofer module  10  is mounted to the floor  14  in the manner discussed below in greater detail. 
     The lower compartment  32  of the front side wall  24  is provided with two slots  42 ,  44  positioned on opposite sides of the front side wall  24 . The slots  42 ,  44  provide fluid communication between the interior  46  of the lower compartment  32  and the external environment when the subwoofer module  10  is mounted to the floor  14  beneath an aircraft seat  16 . 
     A low frequency driver  48  is mounted to the driver mounting plate  28 . The driver  48  is positioned to fire into the lower compartment  32  of the housing  18  with the convex portion  50  of the driver  48  extending into the upper compartment  30  of the housing  18 . 
     In use, and with reference to FIG. 2, the present subwoofer module  10  is ideally designed for mounting to the floor  14  beneath an aircraft seat  16 . Specifically, brackets  52  bolt the subwoofer module  10  to the floor  14  beneath an aircraft seat  16  with the lower compartment  32  facing downwardly and the bottom  40  of the housing  18  contacting the floor  14  of the aircraft  12  to substantially seal the lower compartment  32  (with the exception of the two slots  42 ,  44 ). In this way, the lower compartment  32  of the housing  18  becomes a sealed enclosure with a pair of slots  42 ,  44  permitting the passage of forced air and waves from within the lower compartment  32  of the housing  18 . Additional sound is transmitted from the housing  18  which resonates in the manner discussed above to generate sound as desired. 
     Mounting the present subwoofer module  10  in this manner presents further advantages improving the sound generated by the properly mounted subwoofer module  10 . For example, the creation of a partially enclosed-lower compartment  32 , including two slots  42 ,  44  along the front side wall  24  of the housing  18 , reduces possible excursions (X max ) of the driver  48  by physically damping the movement of the driver cone  54  with progressively greater pressure on the driver cone  54 . That is, because the driver cone  54  moves within the confined space defined by the lower compartment  32 , pressure is generated as the driver cone  54  moves closer to the surface upon which the subwoofer module  10  is mounted. The pressure increases in such a way that the generated pressure prevents further movement of the driver cone  54 . 
     The reduction and control of the possible excursion of the driver  48  eliminate cone chirp which results when the driver cone  54  moves beyond X max . With this in mind, the slots  42 ,  44  and the relative position of the driver  48  with respect to the floor  14  may be tuned to enhance the efficiency of the present subwoofer design, thus essentially resulting in a “ground effect”. 
     In addition, the controlled excursion of the driver cone  54  enhances the sound resonating from the housing itself to produce a full low frequency sound from an enclosure substantially smaller and lighter than woofers found in the prior art. 
     By using the floor  14  of the aircraft  12  to form a wall of the lower compartment  32  of the housing  18 , substantial weight savings are realized. In accordance with the preferred embodiment of the present invention, use of the floor  14  in completing the lower compartment  32  results in a substantial weight savings. While a simple plate in a housing may appear to represent only a small amount of weight, any weight reduction within an aircraft is considered to be a substantial benefit. 
     As previously discussed, and with reference to FIGS. 3 and 4, the present subwoofer module  10  may also be vertically mounted behind a divan, below a drink rail or between adjacent windows of the aircraft. When the subwoofer is mounted in this manner, the two slots  42 ,  44  located in the front side wall  24  are not necessary and it is more desirable that the lower compartment  32  include four fully closed side walls. 
     With this in mind, and particularly with reference to FIG. 3, the present subwoofer module  10  is provided with an auxiliary side plate  56  shaped and dimensioned to cover the two slots  42 ,  44  formed along the front side wall  24 . The side plate  56  is secured to the exterior of the front side wall  24  using standard bonding techniques known to those skilled in the art. For example, adhesive may be used, although other bonding techniques known to those skilled in the art may be employed without departing from the spirit of the invention. 
     Once the auxiliary side plate  56  is properly secured to cover the two slots  42 ,  44 , the subwoofer module  10  may be vertically mounted as desired. For example, and with reference to FIG. 4, the subwoofer module  10  is mounted between adjacent windows and the interior of the wall  58  defining the fuselage  60 . The subwoofer module  10  is secured to the fuselage  60  by a plurality of mounting brackets  62  secured between the subwoofer housing  18  and the fuselage  60 . The subwoofer module  10  is supported such that the lower compartment  32  faces the fuselage wall  58 , while the upper compartment  30  faces the passenger compartment  64 . In this way, forced air and waves radiate between the space separating the bottom  40  of the housing  18  from the wall  58  of the fuselage  60 , and out a speaker grill or vent  66  formed in the passenger compartment wall  68 . 
     The resulting subwoofer module  10  is wired in a conventional manner, which those skilled in the art will readily appreciate. As such, variations in wiring are contemplated in accordance with the spirit of the present invention. 
     It should be appreciated that the concepts surrounding the present invention may be applied in various applications without departing from the spirit of the present invention. As such, the dimensions of the subwoofer module may be varied to suit specific applications in accordance with the spirit of the present invention. 
     In practice, multiple subwoofers are commonly mounted within an aircraft. The number of subwoofers employed is determined by the size of the aircraft and the needs of the aircraft owners. Those of ordinary skill in the art will certainly appreciate the need for specific positioning of the subwoofers within the aircraft to optimize the generated sound. 
     While the preferred embodiments have been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, it is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention.