Patent Publication Number: US-8995696-B2

Title: Speaker

Description:
BACKGROUND 
     A speaker with acoustic drivers and passive radiators can be vibrated if the drivers and passive radiators are not arranged so that their mechanical vibrations cancel out. This speaker vibration can cause the speaker to “walk” or move along a surface on which the speaker has been placed. In addition, a speaker with a multiplicity of drivers and a multiplicity of passive radiators can end up being relatively large in all dimensions. 
     SUMMARY 
     In one aspect, a speaker includes a housing and four substantially similar electro-acoustic drivers secured inside the housing. The drivers are driven by substantially the same audio signal and are arranged such that the net mechanical vibrational force between the drivers and the housing is substantially zero. Four substantially similar passive radiators are secured inside the housing and driven by acoustic energy from the four drivers. The passive radiators are arranged such that the net mechanical vibrational force between the passive radiators and the housing is substantially zero. 
     Embodiments may include one or more of the following features. The intended directions of travel of the four drivers and the four passive radiators are substantially parallel with each other. The intended directions of travel of the four drivers and the four passive radiators are substantially parallel with a shortest dimension of the housing. A longest dimension of each of the drivers and each of the passive radiators lies substantially in a common plane. One of the drivers has a diaphragm with a first surface and a second surface. The diaphragm is vibrated during operation of the driver such that the first surface creates acoustic energy in a first acoustic volume inside the housing. The acoustic energy exits the speaker through an opening in the housing located along a first portion of the housing. One of the passive radiators has a first surface and a second surface. The diaphragm is vibrated during operation of the driver such that the second surface of the diaphragm creates acoustic energy in a second acoustic volume inside the housing. The acoustic energy in the second acoustic volume impinges on the first surface of the passive radiator which causes the passive radiator to vibrate. A second surface of the passive radiator thereby creates acoustic energy which exits the speaker through a second opening in the housing located along a second portion of the housing which is oriented at substantially a right angle to the first portion of the housing. The four drivers are arranged substantially side-by-side with each other in a substantially straight line. The four passive radiators are arranged substantially side-by-side with each other in a substantially straight line. Each driver is mounted on a respective passive radiator. 
     In another aspect, a speaker includes a housing and an electro-acoustic driver secured inside the housing having a diaphragm with a first surface and a second surface. The diaphragm is vibrated during operation of the driver such that the first surface creates acoustic energy in a first acoustic volume inside the housing. The acoustic energy exits the speaker through an opening in the housing located along a first portion of the housing. A passive radiator is secured inside the housing and hays a first surface and a second surface. The diaphragm is vibrated during operation of the driver such that the second surface of the diaphragm creates acoustic energy in a second acoustic volume inside the housing. The acoustic energy in the second acoustic volume impinges on the first surface of the passive radiator which causes the passive radiator to vibrate. A second surface of the passive radiator thereby creates acoustic energy which exits the speaker through a second opening in the housing located along a second portion of the housing which is oriented at substantially a right angle to the first portion of the housing. Embodiments may include any of the above features and/or the following. The intended directions of travel of the driver and the passive radiator are substantially parallel with each other. The intended directions of travel of the driver and the passive radiator are substantially parallel with a shortest dimension of the housing. A longest dimension of the driver and the passive radiator lies substantially in a common plane. 
     In yet another aspect, a speaker includes a housing having a first internal surface and a second internal surface that is substantially parallel with the first surface. The housing defines at least a portion of a common acoustic volume inside the housing. First and second electro-acoustic drivers secured inside the housing each have a diaphragm with a first surface and a second surface. The first surface of the first driver faces the first internal surface of the housing. The second surface of the first driver faces the second internal surface of the housing and the common acoustic volume. The first surface of the second driver faces the second internal surface of the housing. The second surface of the second driver faces the first internal surface of the housing and the common acoustic volume. 
     Embodiments may include any of the above features and/or the following. The speaker includes first and second passive radiators secured inside the housing that each have a first surface and a second surface. The first surface of the first passive radiator faces the first internal surface of the housing. The second surface of the first passive radiator faces the second internal surface of the housing and the common acoustic volume. The first surface of the second passive radiator faces the second internal surface of the housing. The second surface of the second passive radiator faces the first internal surface of the housing and the common acoustic volume. In still another aspect, a speaker includes a housing having a first internal surface and a second internal surface that is substantially parallel with the first surface. The housing defines at least a portion of a common acoustic volume inside the housing. First and second passive radiators are secured inside the housing, and each have a first surface and a second surface. The first surface of the first passive radiator faces the first internal surface of the housing. The second surface of the first passive radiator faces the second internal surface of the housing and the common acoustic volume. The first surface of the second passive radiator faces the second internal surface of the housing. The second surface of the second passive radiator faces the first internal surface of the housing and the common acoustic volume. 
     Embodiments may include any of the above features and/or the following. The speaker further includes an electro-acoustic driver secured inside the housing and having a diaphragm with a first surface and a second surface. The diaphragm is vibrated during operation of the driver such that the first surface creates acoustic energy in an additional acoustic volume inside the housing. The acoustic energy exits the speaker through an opening in the housing located along a portion of the housing. 
     In still another aspect, a speaker includes a housing and three passive radiators supported by the housing for movement. One of the passive radiators has a moving portion which weighs substantially the same as the combined weights of the moving portions of the other two passive radiators. 
     Embodiments may include any of the above features and/or the following. A surface area of the moving portion of the one of the passive radiators is substantially the same as the combined surface areas of the moving portions of the other two passive radiators. The passive radiators do not overlap each other in a direction parallel to a direction of motion of a moving portion of the passive radiators. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a speaker as seen from the top, front and left sides; 
         FIG. 2  is a perspective view of the speaker of  FIG. 1  as seen from the bottom, rear and right sides; 
         FIG. 3  is similar to  FIG. 1  except that a top portion of a speaker housing has been removed to facilitate viewing of the inside of the speaker; 
         FIG. 4  is another example of a speaker as seen from the top, front and left sides; 
         FIG. 5  is a view of the speaker of  FIG. 4  as seen from the bottom, rear and right sides; 
         FIG. 6  is yet another example of a speaker as seen from the top, front and left sides; 
         FIG. 7  is a view of the speaker of  FIG. 6  as seen from the bottom, rear and right sides; 
         FIG. 8  is a further example of a speaker as seen from the top, front and left sides; 
         FIG. 9  is a view of the speaker of  FIG. 8  as seen from the bottom, rear and right sides. 
         FIG. 10  is a still further example of a speaker as seen from the top, front and left sides; and 
         FIG. 11  is a view of the speaker of  FIG. 10  as seen from the bottom, rear and right sides. 
     
    
    
     DETAILED DESCRIPTION 
     The description below discloses a speaker that includes four electro-acoustic drivers and four passive radiators. The drivers and passive radiators are arranged so that (a) the mechanical vibrations from all of the drivers and passive radiators substantially cancel out, and (b) a height of the speaker is substantially less than a width and a length of the speaker. As such, the speaker can be secured to the back of a flat panel video display to provide enhanced acoustic performance without appreciably increasing the depth of the display. 
     With reference to  FIG. 1 , a speaker  10  includes a housing  12  with a top portion  14 , a front portion  16  and a left portion  18 . The front housing portion  16  includes two openings  20  and  22  which allow acoustic energy from inside the speaker  10  to propagate to an environment external to the speaker. The left housing portion  16  includes two openings  24  and  26  which allow acoustic energy from inside the speaker  10  to propagate to the environment. The size of the housing  12  in the Z dimension of the coordinate axes  28  is substantially smaller than the size of the housing in the X and Y dimensions. 
     Turning to  FIG. 2 , the housing  12  of the speaker  10  has a bottom portion  30 , a rear portion  32  and a right portion  34 . The right housing portion  34  includes two openings  36  and  38  which allow acoustic energy from inside the speaker  10  to propagate to the environment. The rear housing portion  32  includes an opening  40  which allows acoustic energy from inside the speaker  10  to propagate to the environment. The bottom housing portion  34  includes two openings  42  and  44  which allow acoustic energy from inside the speaker  10  to propagate to the environment. Four feet (not shown) are preferably placed on the housing portion  30  to stand off the speaker  10  from a horizontal surface on which the speaker is placed. This arrangement allows acoustic energy emanating from openings  42  and  44  to more effectively reach the environment in which the speaker  10  resides. 
     Referring now to  FIG. 3 , the speaker  10  includes four substantially similar electro-acoustic drivers  46 ,  48 ,  50  and  52  which are secured inside the housing  12  and driven by substantially the same audio signal. Electrical power cables and audio signal cables are not shown in the drawings in order to not over-clutter the drawings. Other elements such as a power supply, amplifier and digital signal processor are likewise not shown, and may be included in an audio device (e.g. an amplifier) separate from the speaker  10 . The drivers  46  and  52  are inverted relative to the drivers  48  and  50 . When diaphragms  54  and  60  of the drivers  46  and  52  are moving in one direction, diaphragms  56  and  58  of the drivers  48  and  50  will be moving in the opposite direction. This arrangement of the drivers results in substantially zero net mechanical vibrational energy being induced by the drivers on the housing  12 . 
     The speaker  10  also includes four substantially similar passive radiators  62 ,  64 ,  66  and  68  which are secured inside the housing  12 . Each of these passive radiators preferably uses a surround described in U.S. patent application Ser. No. 12/977,484 (publication 20120160598) which is incorporated herein by reference. This type of surround provides a more symmetrical force and motion in the intended direction of travel of the passive radiator, and reduces undesired rocking motion of the radiator. There is a common acoustic volume  70  inside the housing  12  that is defined at least in part by the housing which is sealed from the environment external to the housing  12 . As viewed in  FIG. 3 , the volume  70  extends above the radiator  66 , driver  50 , radiator  64  and driver  48 . The volume  70  also extends below the radiator  68 , driver  52 , radiator  62  and driver  46 . With this arrangement, when the diaphragms  54  and  60  move down as viewed in  FIG. 3  and the diaphragms  56  and  58  move up, this will cause a pressure increase in the volume  70 . This pressure increase will cause the radiators  64  and  66  to move down at the same time the radiators  62  and  68  move up (the four radiators are driven by acoustic energy from the four drivers). When the diaphragms  54  and  60  move up and the diaphragms  56  and  58  move down, this will cause a pressure decrease in the volume  70 . This pressure decrease will cause the radiators  64  and  66  to move up at the same time the radiators  62  and  68  move down (the four radiators are driven by acoustic energy from the four drivers). This arrangement of the passive radiators results in a substantially zero net mechanical vibrational force between the passive radiators and the housing. 
     In this example, the intended directions of travel of the four drivers  46 ,  48 ,  52  and  54  and the four passive radiators  62 ,  64 ,  66  and  68  are substantially parallel with each other and the shortest dimension of the housing  12  along the Z axis ( FIG. 1 ). In addition, as shown in  FIG. 3 , a longest dimension of each of the drivers  46 ,  48 ,  50  and  52 , and each of the passive radiators  62 ,  64 ,  66  and  68  lies substantially in a common plane which is substantially parallel to the bottom portion  30  of the housing  12 . However, it is not necessary that the passive radiators all lie in the same plane. The radiators may lie in two or more parallel planes and/or may be skewed relative to each other. What matters is that the net mechanical vibration from the four radiators on the housing  12  cancels out and is substantially zero. The same thing goes for the four drivers. This arrangement of drivers and passive radiators allows for a relatively thin speaker (e.g. in the Z direction) because two passive radiators do not need to be stacked on top of each other (e.g. in the Z direction). Instead, the passive radiators are substantially side-by-side. In this example the speaker  10  can be tuned to about 55 hz. 
     The driver diaphragms  54 ,  56 ,  58  and  60  each have a surface that is visible in  FIG. 3  and a surface on the opposite side of the diaphragm that is not visible. Diaphragm  54  is vibrated during operation of driver  46  such that the diaphragm surface visible in  FIG. 3  creates acoustic energy in an acoustic volume  72  inside the housing  12 . This acoustic energy exits the speaker  10  through the opening  24  in the housing  12 . Diaphragm  60  is vibrated during operation of driver  46  such that the diaphragm surface visible in  FIG. 3  creates acoustic energy in an acoustic volume  74  inside the housing  12 . This acoustic energy exits the speaker  10  through the openings  36  and  22  in the housing  12 . Diaphragm  58  is vibrated during operation of driver  46  such that the diaphragm surface which is not visible in  FIG. 3  creates acoustic energy in an acoustic volume  76  inside the housing  12 . This acoustic energy exits the speaker  10  through the opening  26  in the housing  12 . Diaphragm  56  is vibrated during operation of driver  50  such that the diaphragm surface which is not visible in  FIG. 3  creates acoustic energy in an acoustic volume  78  ( FIG. 2 ) inside the housing  12 . This acoustic energy exits the speaker  10  through the opening  38  in the housing  12 . 
     Each of the passive radiators  62 ,  64 ,  66 , and  68  has a respective surface  78 ,  80 ,  82  and  84  that is visible in  FIG. 3 , and a second surface on the respective opposite sides of the radiators that is not visible in  FIG. 3 . As discussed above, the driver diaphragms  54 ,  56 ,  58  and  60  are moved/vibrated during operation of the drivers  46 ,  48 ,  50  and  52  such that a surface of each diaphragm creates acoustic energy (pressure increases and decreases) in the acoustic volume  70  inside the housing  12 . This acoustic energy in the acoustic volume  70  impinges on (a) the surfaces  80  and  82  of the passive radiators  64  and  66 , and (b) the surfaces of radiators  62  and  68  which are not visible in  FIG. 3 . As a result, the passive radiators  62 ,  64 ,  66  and  68  move/vibrate. This causes (a) the surfaces  78  and  84  of the passive radiators  62  and  68 , and (b) the surfaces of radiators  64  and  66  which are not visible in  FIG. 3  to create acoustic energy. 
     Acoustic energy from surface  78  exits the speaker  10  through the opening  40  ( FIG. 2 ) in the housing  12  located along portion  32  of the housing which is oriented at substantially a right angle to the portion  18  of the housing. Acoustic energy from surface  84  exits the speaker  10  through the openings  22  and  36  ( FIGS. 1 and 2 ) in the housing  12 . Acoustic energy from the surface of the radiator  64  which is not visible in  FIG. 3  exits the speaker  10  through the openings  20  and  44  ( FIGS. 1 and 2 ) in the housing  12 . Acoustic energy from the surface of the radiator  66  which is not visible in  FIG. 3  exits the speaker  10  through the opening  42  ( FIG. 2 ) in the housing  12 . 
     An internal surface  86  of the housing portion  30  ( FIG. 2 ) and an internal surface (not shown) of the housing portion  14  ( FIG. 1 ) are substantially parallel with each other. The surfaces of the diaphragms  54  and  60  that are visible in  FIG. 3  face the internal surface of housing portion  14 . The surfaces of the diaphragms  54  and  60  that are not visible in  FIG. 3  face the internal surface  86  of the housing portion  30  and the common acoustic volume  70 . The surfaces of the diaphragms  56  and  58  that are visible in  FIG. 3  face the internal surface of housing portion  14  and the common acoustic volume  70 . The surfaces of the diaphragms  56  and  58  that are not visible in  FIG. 3  face the internal surface  86  of the housing portion  30 . 
     The surfaces  78  and  84  of the passive radiators  62  and  68  that are visible in  FIG. 3  face the internal surface of housing portion  14 . The surfaces of the passive radiators  62  and  68  that are not visible in  FIG. 3  face the internal surface  86  of the housing portion  30  and the common acoustic volume  70 . The surfaces  80  and  82  of the passive radiators  64  and  66  that are visible in  FIG. 3  face the internal surface of housing portion  14  and the common acoustic volume  70 . The surfaces of the passive radiators  64  and  66  that are not visible in  FIG. 3  face the openings  44  and  42  in the housing portion  30 . 
       FIGS. 4 and 5  disclose another example of a speaker  90 . The four drivers  46 ,  48 ,  50  and  52  have the same structure and operate in the same manner as the four drivers described above in  FIG. 3 . The drivers  46 ,  48 ,  50  and  52  each radiate acoustic energy which exits the speaker through respective openings  92 ,  94 ,  96  and  98  in the housing in a manner similar to that described above with reference to  FIG. 3 . The drivers  46 ,  48 ,  50  and  52  each also radiate acoustic energy into a common acoustic volume  100  which functions in a similar way to the acoustic volume  76  described above. 
     The speaker  90  has three passive radiators  102 ,  104  and  106  as compared with the speaker  10  described above which has four substantially identical passive radiators. The radiators  102 ,  104  and  106  radiate acoustic energy which exits the speaker through respective openings  108 ,  110  and  112  in the housing in a manner similar to that described above with reference to  FIG. 3 . The radiators  102 ,  104  and  106  each also have a surface exposed to the common acoustic volume  100  in a manner similar to that described above with reference to  FIG. 3 . The moving portion of radiator  104  weighs twice as much and has twice the surface area as the combined moving portions of the radiators  102  and  106 . As such, the radiators  102 ,  104  and  106  are force balanced when the speaker  90  is operating resulting in substantially zero net force being imparted to the speaker  90 . As in  FIG. 3 , the passive radiators  102 ,  104  and  106  do not overlap each other in a direction parallel to a direction of motion of a moving portion of the passive radiators. 
       FIGS. 6 and 7  disclose another example of a speaker  120 . The four drivers  46 ,  48 ,  50  and  52  have substantially the same structure and operate in substantially the same manner as the four drivers described above in  FIG. 3 . The driver  48  is in substantially the same location in  FIG. 6  as it was in  FIG. 3 . However, when comparing  FIG. 6  to  FIG. 3 , the driver  46  has swapped places with the radiator  64 , the driver  52  has been moved to the location of the radiator  68 , the radiator  68  has been moved to the location of the driver  50 , and the driver  50  has been moved to the location of the driver  52 . The radiators  62  and  66  are in similar positions to those shown in  FIG. 3 . The drivers  46 ,  48 ,  50  and  52  are side-by-side in a substantially straight line. The radiators  62 ,  64 ,  66  and  69  are also side-by-side in a substantially straight line. 
     The driver/radiator pairs  46 / 62 ,  48 / 64 ,  50 / 68  and  52 / 66  each radiate acoustic energy which exits the speaker through respective openings  122 ,  124 ,  126  and  128  in the housing in a manner similar to that described above with reference to  FIG. 3 . The drivers  46 ,  48 ,  50  and  52  each also radiate acoustic energy into a common acoustic volume  130  which functions in a similar way to the acoustic volume  76  described above. The driver  48  radiates acoustic energy into a main portion of the common volume  130  via a slot  132 . There is a similarly arranged slot through which the driver  50  radiates acoustic energy into the main portion of the common volume  130 , but this slot is not visible in  FIGS. 6 and 7 . The radiators  62 ,  64 ,  66  and  68  each also have a surface exposed to the common acoustic volume  130  in a manner similar to that described above with reference to  FIG. 3 . As in FIG.  3 , the passive radiators  62 ,  64 ,  66  and  68  do not overlap each other in a direction parallel to a direction of motion of a moving portion of the passive radiators. An optional wall  132  may be provided to divide the common acoustic volume  130  into two portions having substantially equal volume. This wall substantially acoustically isolates the driver/radiator pairs  46 / 62  and  48 / 64  from the pairs  50 / 68  and  52 / 66 . 
       FIGS. 8 and 9  disclose another example of a speaker  120 . Four drivers  142 ,  144 ,  146  and  148  are respectively mounted on four passive radiators  150 ,  152 ,  154  and  156 . This arrangement of a driver/passive radiator pair is disclosed in U.S. Pat. No. 8,189,841 which is incorporated herein by reference. The driver/passive radiator pairs  142 / 150 ,  144 / 152 ,  146 / 154  and  148 / 156  are arranged side-by-side in a substantially straight line. The driver/radiator pairs  142 / 150 ,  144 / 152 ,  146 / 154  and  148 / 156  each radiate acoustic energy which exits the speaker through respective openings  158 ,  160 ,  162  and  164  in the housing in a manner similar to that described above with reference to  FIG. 3 . The driver/radiator pairs  142 / 150 ,  144 / 152 ,  146 / 154  and  148 / 156  each also radiate acoustic energy into a common acoustic volume  166  which functions in a similar way to the acoustic volume  76  described above. As such, the driver/radiator pairs  142 / 150 ,  144 / 152 ,  146 / 154  and  148 / 156  each have a surface exposed to the common acoustic volume  166  in a manner similar to that described above with reference to  FIG. 3 . As in  FIG. 3 , the passive radiators  62 ,  64 ,  66  and  68  do not overlap each other in a direction parallel to a direction of motion of a moving portion of the passive radiators. The driver/radiator pairs  142 / 150 ,  144 / 152 ,  146 / 154  and  148 / 156  are side-by-side in a substantially straight line. 
       FIGS. 10 and 11  disclose another example of a speaker  170 . Four drivers  172 ,  174 ,  176  and  178  are respectively mounted on four passive radiators  180 ,  182 ,  184  and  186 . The driver/radiator pairs  172 / 180 ,  174 / 182 ,  176 / 184  and  178 / 186  each radiate acoustic energy which exits the speaker through respective openings  188 ,  190 ,  192  and  194  in the housing in a manner similar to that described above with reference to  FIG. 3 . The driver/radiator pairs  172 / 180 ,  174 / 182 ,  176 / 184  and  178 / 186  each also radiate acoustic energy into a common acoustic volume  196  which functions in a similar way to the acoustic volume  76  described above. As such, the driver/radiator pairs  172 / 180 ,  174 / 182 ,  176 / 184  and  178 / 186  each have a surface exposed to the common acoustic volume  196  in a manner similar to that described above with reference to  FIG. 3 . As in  FIG. 3 , the driver/radiator pairs  172 / 180 ,  174 / 182 ,  176 / 184  and  178 / 186  do not overlap each other in a direction parallel to a direction of motion of a moving portion of the passive radiators. 
     It will be understood that additional modifications may be made without departing from the spirit and scope of the examples described herein, and, accordingly, other embodiments are within the scope of the following claims. For example, a speaker can be made that includes a greater even number (e.g. 6, 8) of passive radiators.