Abstract:
A multi-channel audio speaker system is provided for use with a desktop personal computer. This system includes a cabinet having a bottom surface for placement upon a desktop and having a top surface for supporting a computer monitor. Left front, center front and right front speakers are housed in the cabinet along with two sub-woofer speakers. Left rear and right rear speakers are provided in separate remote cabinets. The primary cabinet includes an amplifier having seven channels of amplification. The system is provided for use with a multi-channel audio source such as Dolby® 5.1 format, which provides five channels of full range audio data which are directed to the first five channels of amplification and then to the front and rear speakers. The sixth channel of low frequency audio data is split and directed to the sixth and seventh amplification channels which are in turn directed to the two sub-woofer systems. A by-pass inlet signal conductor may also be provided so that the speaker system can be utilized with alternative sound sources such as a conventional high fidelity receiver.  
     Be it known that Henry E. Juszkiewicz residing at  1818  Elm Hill Pike, Nashville, Tenn.  37210,  a citizen of the United States and Andy J. Ewen residing at  1 -B Primrose Hill, Chelmsford, Essex, United Kingdom CM 1 2 RQ, a citizen of the United Kingdom have invented a new and useful “Audio Speaker System for Personal Computer.”

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to high fidelity audio speaker systems, and more particularly, to such a system designed for use with a personal computer.  
           [0003]    2. Description of the Prior Art  
           [0004]    Over the years, various formats of multiple channel audio have been developed to provide ever increasing realism in sound reproduction.  
           [0005]    The earliest systems were monophonic having only a single channel of sound. The next development was stereophonic sound having two channels.  
           [0006]    Then various surround sound systems, such as quadraphonic systems having four channels were developed. One of the most recently developed multi-channel sound formats is that often referred to as Dolby® AC- 3  or as Dolby® 5.1, which terms both refer to the same system. The Dolby® 5.1 system delivers six completely separate channels of sound. It includes left, center and right front channels for the front of the room. It includes left and right rear channels. It includes a sixth channel which has low frequency audio data.  
           [0007]    The Dolby® 5.1 system was originally developed to provide high quality sound in movie theaters or the like. It has more recently become available in the home from several sources.  
           [0008]    Digital video discs, commonly referred to as DVD&#39;s, now include a Dolby® 5.1 sound track.  
           [0009]    Currently, probably 30 to 40 percent of the personal computers which are being sold include DVD players and provide a means for decoding the Dolby® 5.1 signal.  
           [0010]    Another currently available source for the Dolby® 5.1 signal in the home environment is a Hi-Fi receiver for a home audio system. Most Hi-Fi receivers being sold today include a Dolby® 5.1 decoding circuit.  
           [0011]    In spite of the fact that some of the personal computers presently being sold provide a Dolby® 5.1 sound source, there has not yet been available any suitable speaker system for use with a personal computer which can reproduce all six channels of sound information which are available from the Dolby® 5.1 format.  
           [0012]    The typical audio system available for a personal computer simply includes a pair of stereo speakers which only effectively utilize two channels of data.  
           [0013]    There is therefore, a need in the art for an audio speaker system capable of reproducing multi-channel sound and particularly sophisticated multi-channel sound such as the Dolby® 5.1 format in connection with the home personal computer environment.  
         SUMMARY OF THE INVENTION  
         [0014]    The present invention provides a multi-channel audio speaker system for use with a desktop personal computer. The system includes a cabinet having a bottom surface for placement upon a desk and having a top surface for supporting a computer monitor. At least first, second and third speakers are housed in the cabinet. Fourth and fifth speakers are located remote from the cabinet. An amplifier includes at least first, second, third, fourth and fifth channels of amplification connected to the first, second, third, fourth and fifth speakers, respectively. A primary inlet signal conductor carries at least five channels of audio data to the amplifier.  
           [0015]    The system may also include one or more sub-woofer speakers contained in the cabinet and associated with a sixth channel of amplification which is included in the amplifier. The amplifier may include both a sixth and a seventh channel of amplification, each one of which is connected to one of the two sub-woofers if two sub-woofers are included in the system. In this system, the primary inlet signal conductor carries a sixth channel of low frequency audio data, which sixth channel is split and connected to each of the sixth and seventh amplifiers.  
           [0016]    The system may also include a by-pass inlet signal conductor for by-passing the amplifier and carrying the first five channels of audio data direct to the first through fifth speakers. The sixth channel of audio data continues to be directed to the sixth channel of amplification. The by-pass inlet signal conductor is provided so that the system of the present invention may be utilized within an auxiliary Dolby® 5.1 sound source such as a conventional Hi-Fi receiver. Such a receiver conventionally only includes five channels of amplification, because most commonly used sub-woofer systems are self-amplified. Thus, the sixth channel of data from the Dolby® 5.1 system leaves the Hi-Fi receiver unamplified and must be amplified prior to being directed to the sub-woofer speakers.  
           [0017]    The cabinet in which the speaker system is contained is particularly designed to be a relatively wide and shallow cabinet which conveniently fits on a conventional desktop and provides space for placement of a computer monitor on top of the cabinet. Thus, the cabinet will include the left front, center front and right front speakers along with the sub-woofer speakers, all of which will have outlets from the cabinet directed toward a person using the computer. The left and right rear speakers are remote speakers and will preferably be mounted on conventional microphone stands or the like placed in the room behind the user of the computer.  
           [0018]    Thus, a very convenient, economical, effective and attractive system is provided for utilizing and reproducing all of the data available from a Dolby® 5.1 sound source, or other multi-channel source while using a personal computer. This system is particularly well suited for reproducing sound associated with computer games provided on a DVD player in the computer. Thus, the computer user, while playing the computer games can enjoy a state of the art sound experience associated with the playing of the computer game.  
           [0019]    The system can, of course, also be utilized for reproducing sounds other than those associated with the computer games, such as music recordings and the like.  
           [0020]    Accordingly, it is an object of the present invention to provide an improved audio sound system for use with a personal computer.  
           [0021]    Another object of the present invention is the provision of an attractive and conveniently shaped cabinetry containing a sound system, which may be utilized to support a computer monitor on top of the cabinet.  
           [0022]    Another object of the present invention is the provision of an audio sound system for use with a multi-channel audio source, of which the Dolby® 5.1 system is only an example.  
           [0023]    Still another object of the present invention is the provision of a speaker system which may be alternatively utilized with a multi-channel sound source from a Hi-Fi audio receiver which already provides amplification for some or all of the channels of audio data.  
           [0024]    Other objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the following disclosure when taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    [0025]FIG. 1 is a perspective view of the speaker system of the present invention assembled with a personal computer and monitor on a conventional desk with the remote speakers being shown located in front of the desk on conventional microphone stands.  
         [0026]    [0026]FIG. 2 is an enlarged perspective view of the cabinet of the speaker system with a computer monitor sitting on top of the cabinet.  
         [0027]    [0027]FIG. 3 is an enlarged front view of the control panel of the speaker system of FIG. 2.  
         [0028]    [0028]FIG. 4 is a plan view of the cabinet of the system of FIG. 2.  
         [0029]    [0029]FIG. 5 is a front elevation view of the cabinet of FIG. 4.  
         [0030]    [0030]FIG. 6 is a plan cross-section view taken along line  6 - 6  of FIG. 5 showing the internal construction of the cabinet including location of the electronics board and location of the various baffling and the like associated with the speakers contained in the cabinet.  
         [0031]    [0031]FIG. 7 is an electrical schematic illustration of the amplifier system contained in the cabinet of FIG. 2 and its connections to a Dolby® 5.1 signal from the computer or alternatively from a hi fidelity receiver.  
         [0032]    [0032]FIG. 8 is a schematic cross-section view taken along line  8 - 8  of FIG. 4, showing the manner in which the sub-bass speakers are mounted in the cabinet and showing the porting of the cabinet.  
         [0033]    [0033]FIG. 9 is an enlarged view of FIG. 6 showing internal baffling and speaker mounting within the cabinet. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0034]    Referring now to the drawings, and particularly to FIG. 1, the speaker system of the present invention is shown and generally designated by the numeral  10 . The speaker system  10  is shown in place upon a desktop  12 . The speaker system  10  includes a main cabinet  14  and includes left and right remote speaker cabinets  16  and  18 .  
         [0035]    The remote cabinets  16  and  18  will be 195 mm cubes, with the front and back walls constructed from 25 mm thick medium density fiberboard (MDF), and with the sides constructed of 15 mm thick MDF. These units have infinite baffles, removable foam grills and mic stand mounting plates. The mounting plates are fitted internally so they do not protrude through the bottom of the cabinets. This allows the cabinets to be shelf mounted if necessary.  
         [0036]    A personal computer  20  is shown adjacent the desk. A computer monitor  22  is shown in place upon the cabinet  14 .  
         [0037]    The cabinet  14  is best seen in FIGS. 2, 4 and  5 . The cabinet  14  has a bottom surface  24  for placement upon the desktop  12 , and has a top surface  26  for supporting the computer monitor  22 . The cabinet has a height  28 , a depth  30 , and a width  32  as shown in FIGS. 4 and 5. In one preferred embodiment, the height  28  is approximately 7 ⅝″ (195 mm), the depth 30 is approximately 12″ (300 mm) and the width 32 is approximately 48″ (1,225 mm).  
         [0038]    In general, the relative dimensions of the cabinet are such as to create a cabinet which is shallow in height and which expands its width across most of the width of a conventional desktop  12 , and has a depth which occupies a rear portion of the desktop  12  while still allowing substantial unobstructed workspace on the desktop  12  in front of the cabinet  10 . In general, the representative dimensions set forth above can be described as a cabinet having a width 32, a depth 30 and a height 28, the depth 30 being greater than the height 28, and the width 32 being at least four times as great as the height 28. The height of the cabinet can be described as being at least 7″. The width 32 may also be described as being at least three times as great as the depth 30.  
         [0039]    As seen in the plan view of FIG. 4, the cabinet  14  includes a front wall  34  which is irregular in plan view so that the depth  30  of the cabinet varies along the width  32  of the cabinet. The front wall  34  is profiled to look similar to a car dashboard with the left and right speakers  42  and  46  angled in at approximately 15°.  
         [0040]    The cabinet  14  can be described as including a central portion  36  and left and right end portions  38  and  40 , with the central portion  36  including the top surface  26  for supporting the computer monitor.  
         [0041]    The cabinet  14  is preferably constructed from medium density fiberboard (MDF) which is an acoustically superior material for construction of speaker cabinets.  
         [0042]    As is schematically illustrated in FIG. 6, the cabinet  14  includes first, second and third speakers  42 ,  44  and  46  housed in the cabinet. Speakers  42 ,  44  and  46  function as the left front, center front and right front speakers, respectively, when utilized with a Dolby® 5.1 format audio source.  
         [0043]    The system  10  also includes fourth and fifth speakers  48  and  50  housed in the remote cabinets  16  and  18  which function as the left rear and right rear speakers, respectively, when utilized with a Dolby® 5.1 format audio source.  
         [0044]    The system  10  further includes two sub-woofer speakers  52  and  54  located within a chamber  55  in the cabinet  14 .  
         [0045]    The front wall  34  of cabinet  14  will include first, second and third speaker openings  56 ,  58  and  60  within which the speakers  42 ,  44  and  46 , respectively, are received. As seen in FIG. 2, the speaker openings  56 ,  58  and  60  are covered with suitable grills  66 ,  68  and  70 , respectively.  
         [0046]    Preferably, all seven speakers  42 - 54  utilize the same type of speaker elements to achieve a fully balanced system. The left and right front speakers  42  and  46  are each full range direct radiating speakers. The center front speaker  44  is a high pass filtered speaker. The sub-bass speakers  52  and  54  are mono-band pass sub-bass drivers. All of the loudspeakers will be fully magnetically shielded for CRT proximity and all units except the sub-base speakers  52  and  54  will have center mounted, filtered, high frequency devices for space saving and phase-coherent point source sound. Each of the five direct radiating speakers  42 ,  44 ,  46 ,  48  and  50  will be covered with removable, 20 mm thick, acoustically transparent foam, fitted to the baffles with long Velcro® discs.  
         [0047]    [0047]FIG. 8 and FIG. 9 show the manner in which the interior of the cabinet  14  is divided by various baffles into chambers, and it also shows the manner in which the speakers are mounted and shows the location of the various electronics.  
         [0048]    The cabinet  14  has an interior chamber generally designated by the numeral  55 . The chamber  55  is divided into a series of sub-chambers associated with the various speakers.  
         [0049]    A longitudinal baffle  154  extends across the width of the cabinet  14 . A cross-baffle  156  separates the rearward portion of chamber  55  into first and second rear chambers  158  and  160 .  
         [0050]    First, second, third and fourth forward cross-baffles  162 ,  164 ,  166 , and  168  isolate the front speakers  42 ,  44 , and  46  and define first and second front chamber portions  170  and  172 , respectively.  
         [0051]    The first sub-woofer  52  is mounted on the longitudinal baffle  154  adjacent the center of first front chamber portion  170  so that the first speaker  52  radiates both forward into first front chamber  170  and rearward into first rear chamber  158 . Similarly, the second sub-woofer  54  is mounted on the longitudinal baffle  154  adjacent second forward chamber portion  172  so that the second sub-woofer  54  radiates forward into second forward chamber portion  172  and rearward into second rear chamber portion  160 .  
         [0052]    Then, as best seen in FIG. 8, the front chamber portion  170  is communicated with the exterior of cabinet  14  through a first vertical slotted port  62 , and the first rear chamber portion  158  is communicated with the exterior of cabinet  14  through a first horizontal slotted port  63 . The slotted ports  62  and  63  are further shown in the front view of FIG. 5.  
         [0053]    The second sub-woofer  54  is communicated with the exterior of cabinet  14  similarly by second vertical slot  64  and second horizontal slot of port  65  as seen in FIG. 5.  
         [0054]    This type of mounting of the sub-bass speakers is referred to as a dual vented bandpass enclosure. Bandpass refers to a band of frequencies that this speaker configuration will reproduce, frequencies either side of this will be rejected. This type of arrangement has the advantage that it has its own natural crossover frequency and will attenuate higher frequencies at roughly 12dB per octave. As applied to the present invention, this arrangement is particularly efficient because higher frequency signals are electronically filtered before they reach the sub-bass speakers  52  and  54 , and thus the resonance problems at the ported vents which are sometimes associated with such construction at higher audible frequencies is not a problem.  
         [0055]    The principle behind the dual vented bandpass enclosure is as follows. A partition is placed somewhere is near the center of the enclosure and the bass speaker is mounted on this. The longitudinal baffle  154  is such a partition. This longitudinal baffle  154  serves as the speaker baffle. The front chamber  170  is then vented or slot ported to tune the cabinet. In this way, the audio output is from the vent  62  and no direct output comes from the speaker driver  52  itself. The horizontal vent  63  in turn, vents the first rear chamber portion  158 . The audio output therefore comes from this second horizontal vent  63 , as well as the vertical vent  62 . This extends the low bass response of the combined enclosure of first sub-woofer  52  down below those frequencies at which a conventional “direct radiating” bass cabinet would produce, because the present arrangement allows for maximum controlled excursion of the speaker. If the rear speaker chamber  158  were sealed, then the sub-bass speaker  52  is held much tighter because of the enclosed air contained in rear chamber  158  and the bass response of the speaker  52  would roll off at a higher frequency. The arrangement illustrated results in an extended bass response, as compared to a “direct radiating” bass arrangement which would normally require a larger speaker cone area to achieve a comparable response.  
         [0056]    The irregular plan shape of front wall  34  as seen in FIG. 4 results in the first, second and third speakers  42 ,  44  and  46  being directed non-parallel to each other. In the specific embodiment illustrated, the center speaker  44  faces directly forward. The left and right front speakers  42  and  46  are aimed about 15° toward the center and forward.  
         [0057]    The slotted port acoustical outlets  62  and  63  associated with first sub-woofer  52  may be described as first sub-woofer openings  62  and  63  defined in the front wall  34  between the first and second speaker openings  56  and  58 . Similarly, the slotted port acoustic outlets  64  and  65  associated with second sub-woofer  54  may be described as a sub-woofer openings  64  and  65  defined in the front wall  34  between the second and third speaker openings  58  and  60 .  
         [0058]    The system  10  also includes self adhesive feet (not shown) for all units, the two microphone stands  19 , and lengths of suitable speaker cable to connect the remote speakers  48  and  50  to the amplifier  72 . The wiring connecting amplifier  72  to the rear speakers  48  and  50  may be flat tape adhesive wiring. One advantage of the system  10  is that all of the wiring between the amplifiers and speakers is contained within the cabinet  14  which eliminates the typical wiring “nest” associated with multiple speaker systems utilized with personal computers.  
         [0059]    Referring now to FIG. 7, a schematic illustration is there shown of the amplifier system included in the speaker system  10  and the various connections to the speakers  42 - 54 .  
         [0060]    The amplifier  72  preferably includes first through seventh channels of amplification designated as  74 ,  76 ,  78 ,  80 ,  82 ,  84  and  86 . The preferred location of the amplifier components in best shown in FIG. 9. A main transformer  87  provides electrical power to the amplifiers.  
         [0061]    As is apparent in FIG. 7, the first through seventh channels of amplification  74 - 86  are associated with the first through seventh speakers  42 - 54 , respectively.  
         [0062]    The amplification channels  74 - 86  will each provide approximately 35-40 watts of power, and increased power may be provided to the sub-bass speakers  52  and  54  if necessary.  
         [0063]    The amplifier components  74 - 86  may, for example, be model ILP HY2001 Power Amplifiers available from ILP Direct Ltd. of Sponge Lane, Elmsted, Ashford, Kent UK TN 25 5JU. This amplifier is passively cooled with an aluminum heat sink (not shown).  
         [0064]    The cabinet  14  has a primary signal inlet port  88  by means of which a signal source such as the computer  20  is connected to a primary inlet signal conductor  90  which carries six channels of audio data  92 ,  94 ,  96 ,  98 ,  100  and  102 . The first through fifth channels  92 - 100  are associated with the first through fifth amplifier channels  74 - 82 , respectively, as shown in FIG. 7.  
         [0065]    The sixth channel of audio data  102  carries the low frequency data from the Dolby® 5.1 format. This sixth channel  102  is split into two identical signals  102 A and  102 B which are carried to the sixth and seventh amplifier channels  84  and  86  associated with the two sub-woofer units  52  and  54 . The sixth low frequency data channel  102  contains additional bass information to maximize the effect of events such as explosions, crashes, etc. In the Dolby® 5.1 format, this sixth channel has a limited frequency response from 3Hz to 120Hz, and it is sometimes referred to as the “0.1″ channel of the Dolby® 5.1 system.  
         [0066]    The primary signal input port  88  is located on a circuit board  89  shown in FIG. 9, which carries the various inputs and outputs for cabinet  14 .  
         [0067]    The primary input signal received at the primary signal input port  88  comprises six channels of analog audio data. This primary input signal can be created in several ways.  
         [0068]    One such source is the use of a modern personal computer  20 , many of which now include DVD players which play DVD&#39;s which have a Dolby® 5.1 formatted soundtrack. The computer  20  when so equipped, will typically have a sound card that has an outlet port which is either a single co-axial RCA type connector or a fiber-optic output connector, either of which can carry multiple channels of digital audio data in a SP/DIF format.  
         [0069]    In FIG. 7, the output port from the sound card of computer  20  is schematically illustrated as  104 . The computer  20  is equipped internally with suitable electronics for decoding the compressed Dolby® 5.1 signal to create six channels of expanded, but still digital audio data.  
         [0070]    At some point between the audio signal output port  104  of computer  20  and the primary signal input port  88  of the system  10 , there must be a digital to analog converter  106 . The output port  104  of computer  20  will be connected to digital to analog converter  106  by suitable co-axial cables, optical fiber or the like which is designated by the numeral  108 .  
         [0071]    The digital to analog converter  106  may either be a separate stand alone component which is connected to the inlet port  88  of cabinet  14 , or it may optionally be located within the cabinet  14  itself. The digital to analog converter  106  may, for example, be an “Audio Storm Digital Decoder Box” available from Minton Optic Industry Co., Ltd. of Chung Ho City, Taipei, Taiwan. This particular digital to analog converter  106  provides the capability of handling all commonly available audio sources including the Dolby® digital 5.1 format and many others. Other formats which are in common use and can be handled by the digital audio converter  106  include the Dolby® Surround Pro Logic system which provides four channels of analog data. Digital to analog converter  106  may also be utilized with conventional two channel analog stereo inputs carried by two RCA connectors. The digital to analog converter  106  may also be utilized or adapted to accept other multi-channel digital formats similar to the Dolby® 5.1 system, such, for example, the DTS system.  
         [0072]    It will be appreciated that once a computer user has the system  10  associated with his personal computer  20 , he may desire to utilize other sound sources with the speaker system  10 .  
         [0073]    Such an alternative sound source may be found in a conventional high fidelity receiver  110 . Modern day high fidelity receivers typically include Dolby® 5.1 capability, and they include five channels of amplification resulting in six channels of analog audio data available at an output port  112  of the receiver  110 . Five of those channels of audio data are amplified, and are ready to be directed to a mechanical speaker, and the sixth channel of low frequency data is unamplified. The sixth channel is unamplified because typical sub-woofer speaker systems as they are presently available are active systems which include their own amplification.  
         [0074]    Thus, to utilize the Hi-Fi receiver  110  as a sound source, its outlet  112  will be connected to a by-pass input port  116  of the cabinet  14  by a suitable cable  114 .  
         [0075]    It will be appreciated that the outlet  112  and the inlet port  116  may, in fact, be comprised of six individual stereo jack connections and the cable  114  may be comprised of six individual cables.  
         [0076]    The six channels of analog audio data carried over cable  114  to by-pass inlet port  116  are then carried by a by-pass inlet conductor  118 . The first five channels  120 ,  122 ,  124 ,  126  and  128  by-pass the first five stages of amplification of amplifier  72  and go directly to the speakers  42 ,  44 ,  46 ,  48  and  50 , respectively. There is no need for further amplification of those signals because they have been amplified in the Hi-Fi receiver  110 . The unamplified sixth channel  130  of low frequency audio data is carried to the sixth and seventh amplification channels  84  and  86  of amplifier  72  where they may be amplified prior to being carried to the two sub-woofers  52  and  54 .  
         [0077]    Thus, the by-pass inlet port  116  and by-pass conductor  118  function to by-pass the first five channels of analog audio data directly to the first five speakers, while carrying the sixth channel of low frequency data to the amplifiers associated with the sub-woofers of the system  10 .  
         [0078]    The front wall  34  carries a control panel  132  which is shown in detail in FIG. 3. Control panel  132  includes four separate volume controls. The first volume control  134  controls the left and right front speakers  42  and  46 . The second volume control  136  controls left and right rear speakers  48  and  50 . The third volume control  138  controls center front speaker  44 . The fourth volume control  140  controls the two sub-woofers  52  and  54 .  
         [0079]    Control panel  132  also includes a power on/off button  142  with associated indicator light  144 . There is also a test button  146  with associated indicator light  148 . Finally, there is a Dolby® on/off  150  with associated indicator light  152 .  
         [0080]    Thus, it is seen that the apparatus of the present invention readily achieves the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the invention have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims.