Abstract:
A portable system capable of receiving audio signals from one or more sources and reproducing the signals via speakers contained therein. The portable audio reproduction system can include a docking station or similar means for communicatively coupling an audio device to the portable audio reproduction system, thereby reducing desktop clutter and simplifying connecting the portable audio reproduction system with the audio device. The speakers of the portable audio reproduction system can preferably be received within a base portion of the system, thereby protecting the speakers during transport and reducing the overall size of the system for improved portability. External connections may also be provided, thereby enabling the portable audio reproduction system to receive audio signals from additional sources, and a mixer allows the system to reproduce signals from a portable audio device and an auxiliary source, such as a computer.

Description:
PRIORITY CLAIM  
       [0001]     This application is a divisional of U.S. patent application Ser. No. 10/836,113 filed Apr. 30, 2004, which claims priority from U.S. Design Patent Application Ser. No. 29/191,799, filed Oct. 15, 2003, both of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to the field of portable audio equipment, and more particularly to a portable device for reproducing audio signals.  
       BACKGROUND OF THE INVENTION  
       [0003]     The past several decades have seen remarkable advances in audio reproduction equipment, particularly equipment that allows a variety of audio tracks to be carried or transported with a user from one location to another. Such equipment includes, e.g., equipment for digitally recording, editing, mixing, producing, storing and reproducing audio tracks. Digital files are advantageous for several reasons, including the fact that error correction algorithms can be run on the files to guarantee that the audio track data in the files is properly stored, which means that the audio can be faithfully reproduced even where an underlying recording medium induces errors or where errors are induced in the copy process. Another advantage of digital files is that reproduction equipment can precisely control the speed at which the audio track is played, thereby effectively guaranteeing consistent playback. However, because of the limited processing speed of computers and digital signal processors at the time, the digital versions of the audio tracks were relatively large files, and a new means for storing large amounts of data on a relatively small media was necessitated. This lead to the development of the Audio Compact Disc, or CD.  
         [0004]     Early CD&#39;s were designed to hold seventy-two minutes of music, almost as much as the larger cassette tapes that were in popular use at the time. By putting the CD in an appropriate reproduction device, or player, the CD could consistently reproduce audio from the audio track data stored thereon. The recording techniques used to generate the digital files also tended to sample a wider frequency range than could be stored on and reproduced from traditional magnetic media, making the reproduction more faithful than was experienced with cassette and 8-track tape players, and frequently rivaled or exceeded that of even high-end reel-to-reel systems.  
         [0005]     Because of the many advantages of CD&#39;s over magnetic media and phonographic records, CD&#39;s quickly gained popularity. This lead to an ever-increasing number of digital audio tracks being available to individual users. As computer processing speeds and technology has continued to increase, new algorithms for storing audio tracks have emerged. One of the more popular of these new audio track storage algorithms is the Motion Picture Entertainment Group level 3 algorithm, commonly referred to as the MP3 algorithm. The MP3 algorithm uses a variety of techniques, including allowing users to vary the audio track sampling rate as the audio track is recorded, varying the number of bits used to represent a given frequency range, and the like, to generate digital audio track files that are significantly smaller than those used on CD&#39;s. This means that users can carry more audio data files on a given medium than they could in the past. For example, a typical seventy-two minute audio CD holds approximately 650 MB of data. Depending on the compression methods chosen, a 650 MB CD-ROM can easily hold several hours&#39; worth of compressed music.  
         [0006]     As digital storage capacity continues to increase and compression algorithms continue to advance, users are able to carry more and more of the music they like with them. This has resulted in the incorporation of audio track reproduction capabilities in an ever-increasing array of audio-capable devices, including, but not limited to, digital cameras, portable digital assistants (commonly referred to as PDA&#39;s), wireless telephones, and the like. Several other devices have been introduced into the market that are predominately used for reproduction of compressed audio tracks. These devices are generally referred to as portable music players, or PMP&#39;s. One of the most popular PMP&#39;s is the iPod, sold by Apple Computer, Inc. of Cupertino, Calif. The iPod has become popular because it has a relatively small form factor but can store many tens of gigabytes of audio files and other information on a hard disk drive stored within the PMP.  
       SUMMARY OF THE INVENTION  
       [0007]     Most of the currently available audio devices are designed to be highly portable and to allow an individual to carry a relatively large number of audio tracks. However, because design of these devices has centered on portability, the manufacturers tend to limit them so as to present the reproduced audio to a user only through monaural or stereo headphones that are plugged into the audio device. This means that, at best, these audio devices can only be used to reproduce audio tracks for a limited number of users, such as where one or more splitters are used to allow multiple users to plug headphones into the device. However, because the audio devices are typically battery powered, they are not capable of generating enough energy to power several pairs of headphones. Furthermore, increasing the number of users connected to a single device beyond one or two limits the device&#39;s portability.  
         [0008]     One method alternative employed by some in the prior art is to allow users to attach speakers to an audio device. This allows multiple users to experience audio tracks at the same time. Because the power output of audio devices is typically relatively low, it is frequently advantageous for the speakers to include an amplifier which is powered by an external power source. By way of example, without intending to limit the present invention, some in the prior art have created relatively small, battery powered or alternating current (AC) powered speakers for use with portable audio reproduction equipment. One limitation of such powered speakers is that they are frequently sold as stand-alone units, without a carrying case or other means for simplifying their transportation. The speakers also tended to take a lot of physical abuse during transportation, and frequently the cables and adaptors used to connect the speakers to the audio device are not capable of withstanding such abuse.  
         [0009]     The present invention is directed to a portable audio reproduction system that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0010]     The present invention is a portable audio reproduction system preferably consisting of a plurality of powered speakers housed in a protective case, wherein the protective case also preferably functions as part of a stand for the speakers. This stand is preferably designed to facilitate positioning the speakers at an optimum angle to enhance enjoyment of reproduced audio tracks. The speaker amplifier can preferably be powered by batteries or an AC power source, although it should be apparent to one skilled in the art that purely battery powered and purely AC powered speaker amplifiers can be substituted therefor without departing from the spirit or the scope of the invention.  
         [0011]     The portable audio reproduction system of the present invention is preferably designed to be communicatively coupled with one or more audio devices. In one embodiment, the present invention preferably includes an adaptor by which the portable audio reproduction system can be connected to one or more PMP&#39;s. By way of example, without intending to limit the present invention, the portable audio reproduction system may include a docking cradle for attaching an iPod to the portable audio reproduction system, thereby allowing the portable audio reproduction system to reproduce audio signals from the iPod. In an alternative embodiment, the docking cradle provided by the present invention may support multiple, interchangeable connection means, thus allowing a plurality of PMP&#39;s, satellite radio receivers, digital radio receivers, standard radio receivers, CD players, or other audio devices to be communicatively coupled with the portable audio reproduction system. The signal received by the system from the audio device may be either digital or analog, and the audio device may be detachable from the system or permanently connected.  
         [0012]     In addition to communicatively coupling through a docking port or the like, a preferred embodiment of the present invention also allows external devices, such as, but not limited to, audio signals from a computer, secondary audio device, or the like, to be communicatively coupled to the portable audio reproduction system through a standard audio connector. Electronic mixing circuitry preferably allows audio signals from the external device to be input to, and reproduced by, the portable audio reproduction system in conjunction with an audio signal from an attached PMP or other device.  
         [0013]     An adapter may also be provided by which the present invention can be mated with higher fidelity audio equipment. Such higher fidelity audio equipment may include, but is not limited to, a subwoofer or a home theater system. This can further enhance the audio fidelity and reproduced frequency range of the system.  
         [0014]     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of at least one embodiment of the invention.  
         [0016]     In the drawings:  
         [0017]      FIG. 1  is a rear planar view of a preferred embodiment of the invention when closed.  
         [0018]      FIG. 2  is a front planar view of a preferred embodiment of the invention when closed.  
         [0019]      FIG. 3  is a left planar view of a preferred embodiment of the invention when closed.  
         [0020]      FIG. 4  is a right planar view of a preferred embodiment of the invention when closed.  
         [0021]      FIG. 5  is a top planar view of a preferred embodiment of the invention when closed.  
         [0022]      FIG. 6  is a rear isometric view of a preferred embodiment of the invention when closed.  
         [0023]      FIG. 7  is a front isometric view of a preferred embodiment of the invention when closed.  
         [0024]      FIG. 8  is a left planar view of a preferred embodiment of the invention when open.  
         [0025]      FIG. 9  is a right planar view of a preferred embodiment of the invention when open.  
         [0026]      FIG. 10  is a rear planar view of a preferred embodiment of the invention when open.  
         [0027]      FIG. 11  is a front planar view of a preferred embodiment of the invention when open.  
         [0028]      FIG. 12  is a bottom planar view of a preferred embodiment of the invention when open.  
         [0029]      FIG. 13  is a top planar view of a preferred embodiment of the invention when open.  
         [0030]      FIG. 14  is a front isometric view of a preferred embodiment of the invention when open.  
         [0031]      FIG. 15  is a rear isometric view of a preferred embodiment of the invention when open.  
         [0032]      FIG. 16  is a rear planar view of a preferred embodiment of the invention when open, wherein a portable audio device has been attached to the invention.  
         [0033]      FIG. 17  is a front planar view of a preferred embodiment of the invention when open, wherein a portable audio device has been attached to the invention.  
         [0034]      FIG. 18  is a top planar view of a preferred embodiment of the invention when open, wherein a portable audio device has been attached to the invention.  
         [0035]      FIG. 19  is a rear isometric view of a preferred embodiment of the invention when open, wherein a portable audio device has been attached to the invention.  
         [0036]      FIG. 20  is a front isometric view of a preferred embodiment of the invention when open, wherein a portable audio device has been attached to the invention.  
         [0037]      FIG. 21  is a front planar view of an embodiment of the invention when open, wherein a portable audio device and a subwoofer have been attached to the invention 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0038]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. For clarity, corresponding features are consistently labeled across the various views of the invention provided in the figures.  
         [0039]      FIGS. 1 through 21  illustrate various views of a preferred portable audio reproduction system embodiment of the present invention. As  FIG. 1  illustrates, a preferred embodiment of the present invention includes power adapter  110 , external audio input jack  115 , headphone jack  120 , and cable port  125 .  
         [0040]     Power adapter  110  preferably allows the portable audio reproduction system of the present invention to be powered from an external power source, such as, but not limited to, an AC to DC converter or external battery pack. In addition to receiving power from an external power source, the portable audio reproduction system can also preferably be powered by one or more batteries, which are preferably stored within the portable audio reproduction system, such as, but not limited to, in compartment  185  and/or compartment  190 . Access to such compartments can be provided through removable covers, such as, but not limited to, covers  200 . Although rechargeable batteries, such as, but not limited to, lithium ion batteries, are presently preferred, it should be apparent to one skilled in the art that disposable batteries can be substituted therefor without departing from the spirit or the scope of the invention.  
         [0041]     In an embodiment in which rechargeable batteries are used, the rechargeable batteries are preferably recharged any time the portable audio reproduction system is connected to an external power source via power adapter  110 . The portable audio reproduction system may also charge the batteries, and receive power, if a device implementing the Universal Serial Bus (USB), FireWire, or other such interface standards are connected thereto via cable port  125 . In an embodiment in which rechargeable batteries are used, the batteries should preferably be of a capacity such that, if the portable audio reproduction system is disconnected from the external power source when the batteries are fully charged, the portable audio reproduction system can be powered and reproduce audio signals for several consecutive hours without needing to be recharged.  
         [0042]     Power from power adapter  110 , an externally connected device, and/or the batteries is preferably used to power a Class D or other audio amplifier housed within the portable audio reproduction system, as well as other aspects of the invention. A Class D amplifier is presently preferred because of the relatively high efficiencies associated with such amplifiers. Such efficiencies provide reduced power consumption over conventional amplifiers, thereby improving the system&#39;s battery life. The amplifier is preferably used to convert the audio signals from audio device  170  (illustrated in phantom in  FIGS. 16 through 20  for clarity), preferably received via docking cradle  155  and/or from an external audio source connected to the present invention through external audio input jack  115 , into a signal capable of driving speakers  160  and  165 .  
         [0043]     A preferred embodiment of the present invention also includes a differential-input mixer, which is capable of combining audio signals from audio device  170  with audio signals from an external audio source. A differential-input mixer is preferred as this can reduce the amount of noise propagated through the portable audio reproduction system. Examples of noise which can be reduced by a differential-input mixer include, but are not limited to, noise generated by the power supply in audio device  170 , noise generated by an external audio device&#39;s power supply, noise generated by the power supply within the portable audio reproduction system, noise from an AC to DC converter, and the like.  
         [0044]     Mixer control  135  preferably allows a user to adjust the relative strength with which each of the audio signals will be reproduced. By way of example, without intending to limit the present invention, a user can elect to listen solely to an audio signal from audio device  170 , solely to an audio signal from the external audio source, or to a combination of the two audio signals, with, by way of example, twenty-five percent of the overall reproduced audio coming from audio device  170  and the remaining seventy-five percent coming from the external audio source. Although the previous example includes specific percentages, it should be apparent to one skilled in the art that mixer control  135  can allow a user to select from an effectively infinite set of input ratios. If the user has elected to have audio reproduced by the present invention include audio signals from multiple inputs, and if the portable audio reproduction system does not detect a device attached to one of the inputs, the present invention may automatically adjust the reproduced audio to be exclusively from the input on which an audio signal is detected. In addition to setting the relative volume of the inputs through mixer control  135 , a user can also set the overall output level, or volume, by adjusting volume control  130 .  
         [0045]     In an alternative embodiment, controls  130  and  135  may operate as volume controls. In such an embodiment, by pressing control  130 , a user can cause the volume of the audio reproduced by the portable audio reproduction system to decrease. Similarly, by pressing control  135 , the volume of the audio reproduced by the portable audio reproduction system can be increased.  
         [0046]     Regardless of whether implemented as controls  130  and  135  or mixer control  135  and volume control  130 , the controls also preferably control audio signals sent to headphone jack  120 . Locating headphone jack  120 , cable port  125 , power adapter  110 , and audio input jack  115  near each other is presently preferred because it simplifies connecting the portable audio reproduction system to, and disconnecting the portable audio reproduction system from, the attached devices. Although locating headphone jack  120  near cable port  125 , power adapter  110 , and audio input jack  115  is presently preferred, it should be apparent to one skilled in the art that the physical location of headphone jack  120 , cable port  125 , power adapter  110 , and audio input jack  115  can be varied without departing from the spirit or the scope of the invention. By way of example, without intending to limit the present invention, headphone jack  120  may be located on the front of one of speakers  160  and  165 .  
         [0047]     When audio device  170  is communicatively coupled with the portable audio reproduction system, audio device  170  may also receive power from the portable audio reproduction system. In one embodiment, the portable audio reproduction system may only supply power to audio device  170  when the portable audio reproduction system is receiving power from an external power source, such as, but not limited to, an AC to DC converter, or to an external device capable of providing power to the portable audio reproduction system. In an alternative embodiment, the portable audio reproduction system may supply power to audio device  170  regardless of whether the portable audio reproduction system is operating on power from an external power source or from internal batteries. In addition to allowing audio device  170  to function, power supplied by the portable audio reproduction system to audio device  170  may also allow audio device  170  to charge any rechargeable batteries stored therein.  
         [0048]     Bar  205 , which is preferably formed of the rear portion of speakers  160  and  165 , preferably includes rubber pad  145 . Rubber pad  145  can provide additional isolation between audio device  170  and the portable audio reproduction system. Bar  205  also preferably prevents the portable audio reproduction system from accidentally closing while the portable audio reproduction system is open and audio device  170  is attached thereto.  
         [0049]     As  FIGS. 1 through 7  illustrate, the present invention preferably includes protective surface  175 , which protects speakers  160  and  165  from damage when the portable audio reproduction system is closed. In one embodiment, by depressing latch  140 , a user can preferably unlock speakers  160  and  165  and articulate the speakers around hinge  180 , thereby exposing speakers  160  and  165 . Detents may be provided for controlling the angle of the speakers with respect to the protective surface. In another embodiment, speakers  160  and  165  can be held closed against protective surface  175  via friction or a passive latch. Because hinge  180  is preferably only nominally visible from the exterior of the portable audio reproduction system, hinge  180  is illustrated in phantom in the figures. Hinge  180  is preferably a hollow, barrel-type hinge, with cables for speakers  160  and/or  165  running therethrough. One or more rubber grommets are preferably used to isolate the vibrations from speakers  160  and  165  from the rest of the portable audio reproduction system. Rubber pad  145  and rubber feet  147  can further isolate the portable audio system, speakers  160  and  165 , and audio device  170  from any vibrations.  
         [0050]     As illustrated in  FIGS. 9 and 10 , when a user opens the portable audio reproduction system (i.e. transforms the portable audio reproduction system from a closed state to an open state), the user preferably rotates speakers  160  and  165  approximately  285  degrees around hinge  180  until speakers  160  and  165  come to rest against a hinge stop (not shown). This allows speakers  160  and  165  to be positioned at an angle that best aligns speakers  160  and  165  with an anticipated user position when the portable audio reproduction system is used on a desk or other surface and positioned within arm&#39;s reach of the user. Although an approximately  285  degree rotation is preferred, it should be apparent to one skilled in the art that the hinge stop position can be made adjustable, and that alternative rotation angles may be substituted therefor without departing from the spirit or the scope of the invention.  
         [0051]     Although the illustrated invention permits speakers  160  and  165  to be positioned by way of hinge  180 , alternative speaker positioning means are also envisioned. In one embodiment, the portable audio reproduction system may be of a “clamshell” design. In such an embodiment, protective surface  175  may sit against the desk or other surface on which the portable audio reproduction system rests, and speakers  160  and  165  may be hinged such that they fold down and are covered by protective surface  175  when the portable audio reproduction system is closed.  
         [0052]     As illustrated in  FIGS. 1 through 21 , the portable audio reproduction system is preferably equipped with power switch  105 , which allows a user to easily turn the system on and off. Light emitting diode (LED)  100  is preferably capable of displaying a plurality of colors and thereby conveying information to a user. By way of example, without intending to limit the present invention, LED  100  may be powered off, or dark, when the portable audio reproduction system is turned off, may glow green when the portable audio reproduction system is connected to an external power source, may glow yellow when the portable audio reproduction system is being powered by batteries, and may glow red when the portable audio reproduction system is being powered by batteries and the estimated remaining battery power drops below a given threshold.  
         [0053]     Although power switch  105  can preferably be used to turn the portable audio reproduction system on and off, the portable audio reproduction system may ignore attempts to turn the portable audio reproduction system on when the portable audio reproduction system is closed. The portable audio reproduction system may also automatically power off when closed. These features can help prevent draining the batteries when the portable audio reproduction system is not in use.  
         [0054]     As illustrated in  FIG. 21 , cable port  125  can allow the portable audio reproduction system to be easily connected to a wide range of high fidelity audio equipment, such as, but not limited to, subwoofer  195  or a home theater system. Cable port  125  can also allow the portable audio reproduction system to receive power and audio signals from the high fidelity audio equipment. Cable port  125  can thereby allow audio signals from audio device  170  and audio input jack  115  to be routed through an amplifier in subwoofer  195  prior to being reproduced by speakers  160  and  165 . Still further, cable port  125  can allow audio device  170  to interface with a computer or other such device via docking cradle  155 .  
         [0055]     In an alternative embodiment, audio adapter  125  may be located on the bottom of the portable audio reproduction system, thereby allowing the portable audio reproduction system to connect with the high fidelity audio equipment by way of a docking cradle or other such attachment means. Such an arrangement may reduce the number of cables and other connectors a user must deal with when connecting and disconnecting the portable audio reproduction system.  
         [0056]      FIGS. 16 through 21  illustrate the docking of audio device  170  with the portable audio reproduction system via docking port  155 . Although the illustrated embodiment of the present invention does not permit audio device  170  to be stored within the portable audio reproduction system when closed, as illustrated in  FIG. 5 , docking port  155  is preferably accessible even with the portable audio reproduction system is closed. This can allow the portable audio reproduction system to charge audio device  170  regardless of whether the portable audio reproduction system is open or closed.  
         [0057]     In an alternative embodiment, the portable audio reproduction system may be configured to permit audio device  170  to be stored therein as the portable audio reproduction system is being transported. In such an embodiment, the portable audio reproduction system may recharge audio device  170  as needed.  
         [0058]     Additional connectors, such as those supporting the Universal Serial Bus, Fire Wire, or other such standards, may also be added to the portable audio reproduction system, either individually or as part of cable port  125 . Such connectors may allow the portable audio reproduction system to replace a docking station traditionally associated with an audio device, thus enabling audio device  170  to synchronize files with a computer.  
         [0059]     The portable audio reproduction system may also be equipped with one or more handles or carrying straps. This can facilitate easily transporting the portable audio reproduction system.  
         [0060]     While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.