Abstract:
A multimode audio reproduction device is disclosed that comprises first and second audio reproduction modules coupled by a support structure. The first and second audio reproduction modules are movable between two configurations. In the first configuration the audio reproduction device serves as a loudspeaker while in the second configuration the audio reproduction device serves as a headphone.

Description:
FIELD OF THE INVENTION 
     This invention relates to a multimode audio reproduction device and refers particularly, though not exclusively to an audio reproduction device that can be used both as a headphone and a loudspeaker. 
     BACKGROUND OF THE INVENTION 
     The reproduction of audio requires a reproduction device such as, for example, earphones, headphones or one or more loud speakers. 
     Many people now have one or more of: portable music players, portable media players, portable game consoles and players; portable computers with games, multimedia players including movies, and audio; and the like. This often requires the use of external, attachable speakers for audio reproduction and/or headphones for audio reproduction. Many have both headphones for use when traveling, and speakers for use in offices, hotel rooms, and the like. 
     SUMMARY OF THE INVENTION 
     In accordance with a first preferred aspect there is provided an audio reproduction device. The audio reproduction device comprises a first audio driver module and a second audio driver module, as well as a support structure coupling the first and second audio driver modules. The first and second audio driver modules are movable relative to one another between a first configuration in which they are positioned to be used as headphones and a second configuration in which they are positioned to be used as loudspeakers. 
     The first and second audio driver modules may each include a headphone audio driver and a loudspeaker audio driver. The headphone audio drivers may face generally towards each other and the loudspeaker audio drivers may face generally away from each other when the audio reproduction device is in the first configuration. The first and second audio driver modules may be movable towards each other to assume the second configuration. 
     The loudspeaker audio drivers of the first and second audio modules may be positioned to project sound in the same general direction when the first and second audio modules are in the second configuration. The loudspeaker audio drivers of the first and second audio modules may be positioned to project sound in the same general direction when the first and second audio modules are in the second configuration. 
     The audio reproduction device may further comprise a switch to disable the loudspeaker audio drivers when the audio reproduction device is in the first configuration and to disable the headphone audio drivers when the audio reproduction device is in the second configuration. The switch may operate automatically as the first and second audio modules are moved between configurations. 
     The first and second audio modules may engage each other in the second configuration so that they maintain their relative position. The support structure may serve to prop up the first and second audio modules when in the second configuration and as a headband for the first and second audio driver modules when in the first configuration. 
     The audio reproduction device may further comprise circuitry for wireless reception of audio. The circuitry may include a processor for decompressing compressed audio data. 
     The first and second audio driver modules may each comprise an enclosure. Each enclosure may comprise a front face and a rear face. The loudspeaker audio drivers may be mounted in the front faces, and the headphone audio drivers may be mounted in the rear faces. 
     The loudspeaker audio drivers may be operative when the first and second audio driver modules are in the second configuration but may not be operative when the first and second audio driver modules are in the first configuration. The headphone audio drivers may be operative when the first and second audio driver modules are in the first configuration. Preferably, the headphone audio drivers are not operative when the first and second audio driver modules are in the second configuration. 
     At least one of the enclosures may further comprise a detector for detecting whether the first and second audio driver modules are in the first configuration or the second configuration. The support structure may be pivotally connected to the enclosure of both the first and second audio driver modules. 
     Each enclosure may further comprise an end, and each end may comprise a retainer for releasably retaining the end of the first audio driver module with the end of the second audio driver module when the first and second audio driver modules are in the second configuration. The retainer may be a tongue and a complementary groove, or a pin and a complementary hole. Also, there may be an ear pad mounted to the rear face co-axial with the headphone audio driver. 
     There may be at least one internal baffle within each enclosure located between the headphone audio driver and the loudspeaker audio driver. The at least one baffle may divide each enclosure into two sub-enclosures: a first sub-enclosure for the headphone audio driver, and a second sub-enclosure for the loudspeaker audio driver. 
     According to a second preferred aspect there is provided an audio reproduction device comprising a first audio driver module and a second audio driver module with the first and second audio driver modules being movable relative to one another between a first configuration and a second configuration. At least one of the first and second audio driver modules comprises audio processing circuitry for processing audio supplied to the device. The audio processing circuitry comprising an amplifier, the amplifier being for responding to an input to automatically limit an output of the amplifier when the device is in the first configuration. 
     Each of the first and second audio driver modules may comprise an enclosure with each enclosure having an end. The input may be from a detector mounted on the end of at least one of the enclosures. The audio processing circuitry may further comprise a switch for receiving an output from the detector and providing the input. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be fully understood and readily put into practical effect, there shall now be described by way of non-limitative example only a preferred embodiment of the present invention, the description being with reference to the accompanying illustrative drawings. 
       In the drawings: 
         FIG. 1  is a front perspective view of a first embodiment of the audio reproduction device in a first mode; 
         FIG. 2  is a front perspective view of the first embodiment in a second mode; 
         FIG. 3  is a view corresponding to  FIG. 1 ; 
         FIG. 4  is a side view of the first embodiment in a third mode; 
         FIG. 5  is a side view corresponding to  FIG. 2 ; 
         FIG. 6  is a partial cross-sectional view along the lines and in the direction of arrows  6 - 6  in  FIG. 3 ; 
         FIG. 6(   a ) is a view corresponding to  FIG. 6  but of an alternative embodiment; 
         FIG. 7  is an illustration of a preferred form of circuit; 
         FIG. 8  is a top perspective rear view of a second embodiment when in the first mode; 
         FIG. 9  is an underneath perspective corresponding to  FIG. 6 ; 
         FIG. 10  is an underneath view corresponding to  FIGS. 6 and 7 ; 
         FIG. 11  is a front view corresponding to  FIGS. 6 to 8 ; 
         FIG. 12  is a side view corresponding to  FIGS. 6 to 9 ; 
         FIG. 13  is a front perspective view of the second embodiment in the second mode; and 
         FIG. 14  is a rear perspective view corresponding to  FIG. 11 ; 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     To refer to  FIGS. 1 and 3 , there is shown a multimode audio reproduction device able to be used in two modes: a first mode or configuration in which it is usable as a headphone, and a second mode or configuration in which it is usable as a loudspeaker. 
       FIG. 1  shows the audio reproduction device in a first configuration in which it functions as a headphone. The audio reproduction device  10  includes a head band  12  extending between and pivotally connected to a first audio reproduction module  14  and a second audio reproduction module  16 . At each end  18  of the head band  12  there is a pivotal or hinged connection  20  between the head band  12  and the respective audio reproduction module  14 ,  16 . 
     The head band  12  has a first portion  22  and a second portion  24  that are slidable relative to each other to enable the effective length of the head band  12  to be varied. This enables the head band  12  to be adjusted to suit a user&#39;s head. The first portion  22  and second portion  24  may engage each other telescopically. 
     Each audio reproduction module  14 ,  16  comprises an enclosure  30  having a front face  32 , a rear face  34 , an end face  36  and a top  38 . The pivotal connection  20  is preferably on rear face  34  at or adjacent the top  38 . 
     Mounted in and/or to front face  32  is at least one loudspeaker driver  40 . Although a single driver  40  is shown, there may be more than one driver  40  in front face  32 . 
     To protect the driver  40 , a removable cover  42  is provided to cover at least that part of front face  32  in which the driver  40  is located. The cover  42  may be removably attached using any known, suitable retainer such as, for example, Velcro™, bayonet fittings, clips, snap fittings, or the like. As shown, the cover  42  has a rim  44  that is a snap fit over peripheral edge  46  of front face  32 . 
     Mounted to rear face  34  is an ear pad  50 . The ear pad  50  may be of the “rest on the ear” style (as shown) or may be of the type than encompasses the ear. Ear pad  50  may be releasably attached to rear face  34  by a mount  52 . The mount  52  may be in a form of a short hollow cylinder to which ear pad  50  is attached. Mounted in and/or to rear face  34  and substantially co-axial with ear pad  50  as well as mount  52  is a headphone driver  54 . Audio as reproduced by headphone driver  54  can pass through mount  52  and ear pad  50  and be heard by a user. Headphone driver  54  may be mounted in or to the enclosure  30  so that the enclosed volume of enclosure  30  provides an improved acoustic response, for example in lower frequencies. 
     The end  36  of each audio reproduction module  14 ,  16  has a retainer  56 . As shown in  FIGS. 4 and 6 , this comprises complementary tongues  58  and grooves  60  engaging in the manner of a snap or sliding fit. In this way the two ends  36  can be brought together and the tongues  58  engaged in grooves  60  for the two audio reproducing modules  14 ,  16  to be releasably secured together with rear faces  34  being generally co-planar, and ends  36  being adjacent each other or even in contact with each other. 
     In this situation, the audio reproduction device  10  is in now in the second mode or configuration in which it serves as a loudspeaker. This is shown in  FIGS. 2 and 5 . Here, the headband  12  acts as a support or prop so that the audio reproducing modules  14 ,  16  can be placed on a surface  62  at an angle relative to surface  62  that provides for projection of sound from the drivers  40 . 
     In  FIG. 4 , the support  12  is used as a carry handle. 
     Either or both of the ends  36  may have a detector  64  for determining when the ends  36  are engaged and disengaged so that the audio reproduction modules  14 ,  16  will switch automatically between headphone mode and speaker mode. The detector  64  may be a pressure switch, proximity switch, cams, contacts or the like that automatically connect or disconnect the relevant audio drivers when the audio reproduction modules pivot between the headphone and speaker configurations. 
     The drivers  40 ,  54  are shown in more detail in  FIG. 6 . They may be opposite each other or may be vertically or laterally spaced apart. If desired, a divider or baffle  82  [ FIG. 6(   a )] may be provided between the drivers  40 ,  54  to improve the acoustic response, and/or to separate or isolate drivers  40 ,  54  into separate compartments by dividing the enclosure into two sub-enclosures - one for the first driver  40  and one for the headphone driver  54 . The baffle or divider  82  may be perforated if desired. 
     The audio reproduction modules  14 ,  16  are joined by a cable  76  ( FIG. 7 ) located within headband support  12  in the usual manner. The audio reproduction device  10  receives the audio from an external source, or from an inbuilt MP3, FM radio or like player. If from an external source, it may be by:
         (i) a direct connection using relevant connections such as, for example, an USB connection, IEEE 1394 connection, or using RCA or like connections;   (ii) a cable connection using a suitable connector at a remote end, such as a conventional or mini headphone plug. The cable connection may be permanently connected to the audio reproduction device  10  or may be removable by use of an appropriate connector; or   (iii) wirelessly using, for example, Bluetooth, Wi-Fi, infrared or magnetic induction. If Bluetooth it may be the A2DP profile for audio.       

     The audio reproduction device  10  may have appropriate audio processing circuitry  66 , as illustrated in  FIG. 7 . The circuitry is usually provided in one of the audio reproduction modules  14 ,  16 . Included is an antenna  70  for receiving the audio wirelessly and a decoder  71  for decoding the received audio if in an encoded format such as, for example, MP3. A processor  72  controls controls the overall functionality. A spatializer  73  or other audio processor may be used to enhance the user experience. A clipper  74  may be used to prevent overload of the audio drivers. The audio reproduction modules  14 ,  16  may be powered using an external or internal amplifier, or an internal amplifier. When onboard circuitry is used for wireless audio reception and/or decoding, an onboard amplifier  75  is used to amplify the audio. 
     The detector(s)  64  is operatively connected to a switch  77  that may be separate to or integral with processor  72 . The switch  77  is to enable the processor  72  to determine whether the audio reproduction modules  14 ,  16  are separate and thus in headphone mode, or are joined and thus in speaker mode. If in headphone mode, the output from amplifier  75  may be limited to protect the hearing of a user. Also, with driver  54  is use as headphones the loudspeaker drivers  40  may be disabled to prevent audio from being reproduced by drivers  40 . When in the speaker mode and thus loudspeaker drivers  40  are operative, the headphone drivers  54  may be disabled. Alternatively, when in the speaker mode, the headphone drivers  54  may remain enabled to provide an improved acoustic response from the audio reproduction module  14 ,  16 . 
     The loudspeaker driver  40  and the headphone driver  54  may be the same but, as their functions are different, they typically have different audio reproduction characteristics. It is normal for the loudspeaker driver  40  to be physically larger, to have a larger power rating, and a relatively wider frequency response than the headphone driver  54 . However, the loudspeaker driver  40  may be small physically, and have a frequency response that is better in the higher frequencies than the headphone driver, but may have a lesser frequency response in the lower frequencies. In this way the headphone driver  54  may be also used when in the speaker mode so that the rear-facing headphone driver can reproduce the audio with a better lower frequency response. The reflection of such reproduced audio may have an enhanced low frequency response. 
     A battery  78  is used to provide the necessary power if required. In one embodiment, the audio reproduction device  10  receives an amplified analog signal directly via a cable (i.e. in conventional headphone manner), and no further power is required. If additional power is required for wireless audio reception, decoding of audio data, or amplification, this may be provided by an external power source (e.g. a battery pack or AC power supply) or an onboard power source such as the battery  78 . 
     Controls  79  for volume and/or balance and/or tone and/or treble and/or bass response may also be provided, if required or desired. Alternatively or additionally, the control of the external source of audio may be used. A noise cancellation feature  80  may also be included. 
       FIGS. 9 to 14  illustrate a second embodiment that is the same as the first embodiment except that the pivotal connection  20  is of a slightly different form, and the enclosures  30  are of a different shape. Also, the mount  52  is a hollow cylinder of relatively small diameter. In all other respects it is the same as the embodiment of  FIGS. 1 to 8 . 
     Whilst there has been described in the foregoing description preferred embodiments of the present invention, it will be understood by those skilled in the technology that many variations or modifications in details of design or construction or operation may be made without departing from the present invention.