Patent Publication Number: US-8526655-B2

Title: Loudspeaker enclosures for mounting in an aperture in a cavity wall

Description:
This invention related to loudspeaker enclosures for mounting in an aperture in a cavity wall. 
     In order to obtain good bass response, the effective internal volume of a loudspeaker enclosure should be adequately large. For aesthetic reasons, it is desirable, when a cavity wall-mounted loudspeaker enclosure is large, to conceal part of the enclosure within the wall cavity. That, however, represents an installation difficulty because there is only limited space within the wall cavity and it is undesirable to make an over-size hole in the wall for the sake of being able to install the enclosure. 
     U.S. Pat. No. 6,741,720 discloses an enclosure having a tapered shape for a lower part of the enclosure so that the enclosure can be angularly inserted into the wall with the tapered part passing through the aperture and into the wall cavity. The provision of an adequately large taper to allow entry into the wall cavity of the tapered portion without the rest of the enclosure fouling the edges of the aperture means, however, that the enclosure in many cases cannot be as large as would be acoustically desirable, given that cavity walls impose limitations because of the spacing of studs and the depth of the cavity. 
     It is an object of the invention to provide a loudspeaker enclosure for mounting in an aperture in a cavity wall with a part of the enclosure being located within the wall cavity adjacent the aperture, which is able to combine ease of installation with a large internal volume for good acoustic performance. 
     The present invention provides a loudspeaker enclosure for mounting in an aperture in a cavity wall with a part of the enclosure being located within the wall cavity adjacent the aperture, wherein the enclosure comprises:
         a main enclosure unit for mounting in the aperture and housing one or more loudspeaker drive units, and   a supplementary enclosure unit for location within the wall cavity and being acoustically connected in use to the main unit to increase the effective internal volume of the enclosure beyond that of the main unit, and wherein:   the supplementary unit is connected to the main unit by an articulated connection enabling the main unit to be angled relative to the supplementary unit while the supplementary unit is being inserted through the aperture and into the wall cavity, and enabling the main unit to be aligned with and acoustically coupled to the supplementary unit when the main unit is positioned in the wall aperture. Because the enclosure is formed by two units and the main unit can be angled relative to the supplementary unit, a larger supplementary unit can be got into the wall cavity than would be possible if the enclosure were a single rigid whole. The use of a larger supplementary unit enables the acoustic properties of the enclosure to be improved.       

     Advantageously, securing means are provided to fix the supplementary unit in position relative to the main unit when the two units are installed and aligned. The securing means ensures the integrity of the mechanical and acoustic connection between the two units, stops one unit from rattling against the other, and prevents the installed enclosure from coming out of the installed location. 
     Preferably, the securing means comprises screw-threaded securing means. Such a fastening is simple to use and very secure. 
     Advantageously, the securing means comprises two or more threaded studs projecting from the supplementary unit, and associated nuts to secure the ends of the studs within the main unit. Such a fastening is simple for the installer. 
     Preferably, the associated nuts are wing nuts. Wings nuts have the advantage of easy tightening without a special tool. 
     Advantageously, the articulated connection comprises a hinge. A hinge is a particularly simple form of articulate connection although some type of concertina-like connection could be used instead. 
     The hinge may comprise a living hinge comprising a first hinge wing attached, in use, to the main unit, a second hinge wing attached, in use, to the supplementary unit, and a web of material connecting the first and second hinge wings. Such a hinge is simple and cheap and to use. Alternatively, an ordinary hinge with a hinge pin may be used. 
     Advantageously, the supplementary unit is shallower than the main unit, and the articulated connection is located at the front of the supplementary unit but is spaced from the front of the main unit by a spacing such as to cause the backs of the units to be in alignment in use, the terms “front” and “back” referring to the installed orientation of the units. By this means, the enclosure can be used with various thicknesses of wall in front of the wall cavity. 
     Preferably, the supplementary unit has a depth substantially half that of the main unit. Such a dimension is suitable for most cavity wall constructions likely to be encountered in practice. 
     Advantageously, the back, in the in use orientation, of the supplementary unit has a bevel running from the end of the supplementary unit remote from the main unit for part only of the length of the supplementary unit. The bevel further facilitates the installation of the enclosure in the cavity wall. 
     Preferably, the bevel runs between one quarter and two thirds the lengths of the supplementary unit. These lengths of bevel are advantageous in facilitating installation without substantially impairing acoustic properties. 
     Preferably, an acoustic sealing gasket is provided between the adjacent ends of the main and supplementary units. The use of a gasket ensures a good acoustic seal between the two units. If desired, a resilient gasket may be used. 
     Preferably, respective oblong boxes arranged lengthwise in use with respect to each other constitute the main and supplementary units. This is an advantageous geometric arrangement both as regards insertion in a cavity wall and acoustically. 
     Preferably, an aperture for acoustic communication with the other unit is provided at one longitudinal end of the supplementary unit and at each longitudinal end of the main unit, and a blanking plate is provided for closing a selected one of the apertures of the main unit. By this means, the user is able to choose at which end to attach the supplementary unit according to available space in the cavity wall. 
     Preferably, the main unit comprises a crate-like body portion of moulded plastics material, and a baffle plate mounting the one or more loudspeaker drive units and being releasably mounted on the mouth of the crate-like body portion. This construction allows easy access into the interior of the main unit for making mechanical connections. 
     Push and turn quick-release fastenings may be provided to secure the baffle plate to the crate-like body portion. Such fastenings are particularly simple for the installer to use. 
     Advantageously, the supplementary enclosure unit can be sub-divided into a plurality of sub-parts, an articulated connection being provided between adjacent sub-parts, and the articulated connection of the sub-parts enabling the sub-parts to be angled relative to each other while the supplementary unit is being inserted through the aperture and into the wall cavity, and enabling the sub-parts to be aligned with and acoustically coupled to each other when the supplementary unit is positioned in the wall cavity. Such an arrangement further facilitates the installation of the enclosure in a cavity wall and permits the use of a supplementary unit of greater length. 
     The supplementary enclosure unit may be sub-divided into just two sub-parts. 
     The invention also provides a supplementary unit and articulated connection having the features defined in any preceding claim for retro-fitting to an existing main unit. The purchase of a supplementary unit on its own enables a user to upgrade the acoustic properties of an existing enclosure installed in a cavity wall. 
    
    
     
       A loudspeaker enclosure for mounting in an aperture in a cavity wall will now be described by way of example only with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of a supplementary unit of the enclosure; 
         FIG. 2  shows a hinge used in the enclosure; 
         FIG. 3  is a perspective view of a main unit of the enclosure; 
         FIG. 4  shows the location at which the hinge is placed; 
         FIG. 5  shows securing means fixing the supplementary unit to the main unit, the side of the main being cut away in the drawing to reveal the interior of the main unit; 
         FIG. 6  is a perspective view of the main and supplementary units showing an alternative communicating aperture provided in the main unit; 
         FIG. 7  is a perspective view of a blanking plate for closing the alternative aperture; 
         FIG. 8  is a diagrammatic side view showing the installation of the enclosure in a cavity wall; and 
         FIG. 9  is a side view in perspective of an enclosure in which the supplementary unit is divided into two parts. 
     
    
    
     Referring to the accompanying drawings, a loudspeaker enclosure  1  is shown for mounting in an aperture  4  in a cavity wall  3  with a part of the enclosure being located within the wall cavity  5  adjacent the aperture. The enclosure comprises a main enclosure unit  6  for mounting in the aperture  4  and housing loudspeaker drive units  8  and an acoustic port  9 , and a supplementary enclosure unit  10  for location within the wall cavity and being acoustically connected in use to the main unit  6  to increase the effective internal volume of the enclosure beyond that of the main unit. Respective oblong boxes arranged lengthwise in use with respect to each other constitute the main and supplementary units  6 ,  10 . The supplementary unit  10  is connected to the main unit  6  by an articulated connection  12  enabling the main unit  6  to be angled relative to the supplementary unit  10  while the supplementary unit is being inserted through the aperture  4  and into the wall cavity  5 , and enabling the main unit to be aligned with and acoustically coupled to the supplementary unit when the main unit is positioned in the wall aperture. 
     Securing means  14  are provided to fix the supplementary unit  10  in position relative to the main unit  6  when the two units are installed and aligned. The securing means  14  comprises screw-threaded securing means specifically two threaded studs  16  projecting from the supplementary unit  10 , and associated wing nuts  18  to secure the ends of the studs within the main unit  6 . 
     The articulated connection  12  comprises a so-called “living” hinge  20  of flexible polymeric material comprising a first hinge wing  22  attached, in use, to the main unit  6 , a second hinge wing  26  attached, in use, to the supplementary unit  10 , and a web of material  28  connecting the first and second hinge wings  22 , 26 . The first hinge wing  22  is in the form of three tabs  23 ,  24  and  25 . 
     As shown in  FIG. 1 , the supplementary unit  10  is of box-like form with a cover plate  11  retained by screws  13 . The hinge wing  26  is secured to the supplementary unit  10  by means of four endmost ones of the screws  13  and corresponding apertures  13 A in the hinge wing. The supplementary unit  10  has a large rectangular aperture  42  communicating with the interior of the supplementary unit for connection to the main unit  6 . 
     The three tabs  23 ,  24  and  25  of the first hinge wing  22  are secured to the main unit  6  by means of three screws  27  passing through apertures  27 A in the tabs  23 ,  24 ,  25  into fixing holes  27 B in the main unit  6 . It should be noted that  FIG. 4  shows where the hinge  20  is to go but does not actually show the hinge in position. 
     The supplementary unit  10  is shallower than the main unit  6  (see  FIG. 6 ), and the articulated connection is located at the front of the supplementary unit but is spaced from the front of the main unit by a spacing  30  such as to cause the backs of the units to be in alignment in use, the terms “front” and “back” referring to the installed orientation of the units. 
     As shown in the drawings, the supplementary unit  10  has a depth substantially half that of the main unit  6  and the back, in the in use orientation, of the supplementary unit has a bevel  32  running from the end of the supplementary unit remote from the main unit for part only of the length of the supplementary unit, the partial length for which the bevel runs being marked  34  in  FIG. 6 . 
     Preferably, the bevel runs between one quarter and two thirds the lengths of the supplementary unit  10 . 
     An acoustic sealing gasket  36  surrounding the aperture  42  is provided between the adjacent ends of the main and supplementary units  6 ,  10 . 
     An aperture for acoustic communication with the other unit is provided at one longitudinal end of the supplementary unit (this is the aperture  42  already mentioned) and at each longitudinal end of the main unit, namely apertures  43  and  44  and a blanking plate  45  is provided for closing a selected one of the apertures  43 ,  44  of the main unit  6 . 
     The main unit  6  comprises a crate-like body portion  46  of moulded plastics material, and a baffle plate  47  mounting the loudspeaker drive units  8  and being releasably mounted on the mouth of the crate-like body portion. 
     Push and turn quick-release fastenings  48 , for example, the type known as Dzus, are provided to secure the baffle plate  47  to the crate-like body portion  46 . 
     To install the enclosure  1 , the main unit  6  is opened by removal of the baffle plate  47  and an articulated connection between the supplementary unit  10  to a chosen end of the main unit  6  is made using the hinge  20  and corresponding screws. The unwanted aperture  44  is closed off using the blanking plate  45  which has two threaded studs  45 A for securing it in position. 
     The main unit  6  is now angled away from the supplementary unit  10  as shown in  FIG. 8  and the supplementary unit is passed through the aperture  4  into the wall cavity  5 , the bevel  32  facilitating entry. The supplementary unit  10  is passed so far into the cavity  5  as to allow the main unit  6  to be swung into the aperture  4  and into longitudinal alignment with the supplementary unit (as in  FIG. 6 ). The main unit  6  is secured to the wall  3  by suitable fixing screws (not shown) and the supplementary unit  10  is rigidly connected to the main unit by applying the wing nuts  18  to the ends of the threaded studs  16  and tightening up the wing nuts. The threaded studs  16  of the supplementary unit  6  pass through struts  17  spanning the aperture  43  as seen in  FIG. 3 . The installation is completed by putting the baffle plate  47  back in place using the fastenings  48 . 
     It is not essential that the articulated connection should be in the form of a living hinge, a hinge of the ordinary form with a hinge pin could be used or an arrangement using tensioned wires passing through a multiplicity of plates. 
     The supplementary unit  10  can be retro-fitted by means of the articulated connection  12  to an existing main unit  6 . 
     A straight line bevel has been shown but alternatively a bevel consisting of many steps can be used, or a single step or just a few steps or a curved section. 
       FIG. 9  shows an embodiment of the invention in which the supplementary unit  10  is sub-divided into two sub-parts  10 A and  10 B. An articulated connection  50  (not shown in detail) is provided between the sub-parts  10 A and  10 B. The articulated connection  50  enables the sub-parts  10 A,  10 B to be angled relative to each other while the supplementary unit  10  is being inserted through the aperture and into the wall cavity, and enables the sub-parts to be aligned with and acoustically coupled to each other when the supplementary unit is positioned in the wall cavity. 
     Although the supplementary unit is shown sub-divided into just two sub-parts, it is possible to divide the unit into three or more sub-parts with a respective articulated connection between the adjacent sub-parts. 
     LIST OF REFERENCE NUMERALS 
     
         
           1 —loudspeaker enclosure 
           2 —cavity wall 
           4 —cavity wall aperture 
           5 —wall cavity 
           6 —main enclosure unit 
           8 —loudspeaker drive units 
           9 —acoustic port 
           10 —supplementary enclosure unit 
           10 A,  10 B—supplementary enclosure sub-parts 
           11 —cover plate 
           12 —articulated connection 
           13 —cover plate screws 
           13 A—apertures 
           14 —securing means 
           16 —threaded studs 
           17 —struts 
           18 —wing nuts 
           20 —hinge 
           22 —first hinge wing 
           23 ,  24 ,  25 —tabs of the first hinge wing 
           26 —second hinge wing 
           27 —screws 
           27 A—apertures 
           27 B—fixing holes 
           28 —web of material 
           30 —spacing 
           32 —bevel 
           34 —partial length 
           36 —acoustic sealing gasket 
           42 ,  43 ,  44 —apertures for acoustic communication 
           45 —blanking plate 
           45 A—blanking plate threaded studs 
           46 —crate-like body portion 
           47 —baffle plate 
           48 —push and turn quick-release fastenings 
           50 —articulated connection of sub-units