Patent Publication Number: US-6222929-B1

Title: Speaker having middle-high sound speakers

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Application No. 97-57637, filed Nov. 3, 1997, in the Korean Patent Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a speaker and, more particularly, to a speaker in which a middle-high frequency speaker is disposed in front of a low frequency speaker and a sound guiding member is disposed behind the low frequency speaker and in front of the middle-high sound speaker improving low frequency sound while lowering noise and distortion. 
     2. Description of the Related Art 
     Generally, a speaker converts an electrical signal into a sound wave signal and radiates a sound wave through free space. That is, an electric current flows through a voice coil disposed in a strong magnetic field, generally a magnet, so as to generate a force causing a vibrating plate to vibrate radiating the sound wave. 
     FIG. 1 is a cross-sectional diagram of a conventional speaker. In general, a conventional speaker includes a vibrating plate  11  (also known as a “cone  11 ) attached to a frame  10 , a bobbin  12 , a voice coil  13  inside the frame  10 , a damper  14  disposed between the frame  10  and the bobbin  12 , an upper plate  15 , a magnet  16 , and a polepiece  17  disposed behind the frame  10 . The voice coil  13  is wound on the outer side of the cylindrical-shaped bobbin  12  and moves integrally with the bobbin  12 . The bobbin  12 , is connected at a front end thereof, with a lower side of the vibrating plate  11  and is supported by the elastic damper  14 . The polepiece  17  is disposed at a predetermined distance from the inner side of the bobbin  12 . The region between the polepiece  17  and the upper plate  15  receives the magnetic field from the magnet  16 . 
     The bobbin  12  vibrates axially, by the Fleming&#39;s left hand law, when current passes through the voice coil  13 . The vibration of the bobbin causes the vibrating plate  11 , disposed forward of the bobbin  12 , to vibrate thereby radiating sound waves through free space. Since a speaker can not reproduce all ranges of sound, it is necessary to provide a tweeter for high sound, a squawker for middle sound, and a woofer for low sound to obtain the highest quality sound. However, the size of a cabinet to accommodate all three speakers, must, by necessity, be quite large, increasing the costs of the speaker. 
     SUMMARY OF THE INVENTION 
     The present invention has as an object to provide a speaker apparatus which can reproduce all ranges of sound such as low, middle, and high frequency sound in a small cabinet. 
     It is another object of the present invention to provide a speaker apparatus which can make sound more clear and stereophonic by reducing the distortion or noise due to the collision of sound. 
     In order to achieve the objects of the invention, a speaker apparatus according to the present invention includes: a yoke having a path arranged at the rear side of a woofer for low sound; a sound guiding member disposed in the yoke for guiding sound discharged through the path; a tweeter for reproducing middle to high frequency sound disposed at the front end of the sound guiding member; a partition wall disposed at the edge of the tweeter for separating the middle-high frequency sound from the low frequency sound radiated from the woofer; and a sound guiding member disposed at the central portion of the tweeter. 
     As described above, in a speaker apparatus according to the present invention, the tweeter is disposed at the front side of the woofer. To improve low frequency sound, the low frequency sound radiated toward the rear direction of the woofer is passed through the sound guiding member disposed within the yoke minimizing the collision with the turbulent flow generated from the rear sound and reducing noise and the distortion of sound. Middle-high frequency sound radiated from the tweeter is radiated and separated from the low frequency sound radiated from the woofer by a partition wall and at the same time guided by a sound guiding member disposed in front of the woofer to improve ambience and stereophonic quality. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the invention will become more apparent and more readily appreciated from the following detailed description taken in conjunction with the accompanying drawings of which: 
     FIG. 1 is a cross sectional diagram of a conventional speaker; and 
     FIG. 2 is a cross sectional diagram of a speaker according to a preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now made in detail to a preferred embodiment of the present invention, an example of which is illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. 
     FIG. 2 is a cross sectional diagram of a speaker according to a preferred embodiment of the present invention. A speaker in accordance with a preferred embodiment of the present invention is constructed by placing a tweeter  31  within a woofer  20 . A frame  21  has a lower side attached to an upper plate  22 . The frame  21  has an upper side attached with an upper side of a vibrating plate  23  via an edge  23   a . The vibrating plate  23  has a lower side connected to a bobbin  25  about which is wound a voice coil  24 . The bobbin  25  is movably supported by the frame  21  via a damper  26  secured to the frame  21 . 
     A yoke  28  is held at a distance from to a lower side of the upper plate  22  by way of a magnet  27 . The yoke  28  is disposed within the bobbin  25  and extends rearward from the bobbin  25 . The outer edge of the yoke  28  is a predetermined distance from the inner edge of the bobbin  25 . The yoke  28  forms a path  29  for radiating the rear sound. A sound guiding member  30 , formed within the yoke  28 , guides the rearward radiated sound to the rear of the woofer  20 . The sound guiding member  30  is preferably of a solid construction, but may be hollow. 
     The sound guiding member  30  includes a column  30   a  disposed in the path  29 , at a predetermined distance from the walls of the yoke  28 , and a guiding plate  30   b , formed at the front end of the column  30   a . The guiding plate  30   b  protrudes from the yoke  28  and is supported by the yoke  28  via a boss portion  30   c  connected between the yoke  28  and the guiding plate  30   b . It is preferable that the guiding plate  30   b  is cylindrical in shape. The column  30   a  of the sound guiding member  30  has upper end extending into the space defined by the vibrating plate  23 . The column  30   a  is connected to the vibrating plate  23  by a membrane  23   b , preferably glued to the column  30   a . The column  30   a  supports the tweeter  31 . 
     The tweeter  31  reproduces high frequency sound and preferably reproduces middle to high frequency sound. The edge of the tweeter  31  is provided with a partition wall  32  partitioning the forward radiated sound from the tweeter  31  from the forward radiating sound from the vibrating plate  23 . A sound guiding member  33 , for guiding sound to be radiated in the front direction, is formed within the partition wall  32 . The sound guiding member  33  is preferably of a solid construction, but may be hollow. The sound guiding member  33  includes a column  33   a  with a guiding plate  33   b  formed at the front end of the column  33   a . A boss portion  33   c  connects an inner side of the partition wall  32  with the guiding plate  33   b.    
     The frame  21  is provided with a cloth  34  covering the speaker opening for filtering noise and distorted sound included in the sound radiated from the frame  21 . The frame  21  also has an input terminal  35  to supply power to the voice coil  24 . When a current passes through the voice coil  24 , from the input terminal  35 , the bobbin  25  begins to vibrate axially, by way of the Fleming&#39;s left hand law, thereby radiating low frequency sound waves. 
     The low frequency sound waves radiate forward and rearward from the vibrating plate  23 . The low frequency sound waves radiated toward the rear pass through the path  29  formed by the yoke  28 , and are guided by the sound guiding member  30 . This structure causes the sound waves to be radiated toward the rear direction. The high frequency sound waves radiated from the tweeter  31 , disposed at the front end of the sound guiding member  30 , are guided by the sound guiding member  33 , disposed within the partition wall  32 , causing the sound waves to be radiated toward the front of the sound guiding member  33 . 
     The high frequency sound waves radiated from the tweeter  31  are separated from the forward radiating low frequency sound waves radiated from the vibrating plate  23  so that noise from the turbulent flow or distortion of sound waves is reduced. Forward radiating sound waves from the woofer  20  and the tweeter  31  are filtered by the cloth  34  further reducing noise or distortion, producing clearer sound with a high stereophonic quality. 
     While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. For example, the specific frequencies reproduced by the woofer  20  and the tweeter  31  can be selected based upon external factors, such as cabinet volume, presence of other speakers and costs.