Abstract:
The disclosed embodiments relate to an audio system ( 100 ) and an associate method. An exemplary embodiment of the system ( 100 ) comprises a user interface ( 104 ) that enables adjustment of a volume level of an audio signal being reproduced on at least a portion of the audio system to a desired maximum volume level. The user interface further enabling the desired maximum volume level to be selected as a set maximum volume level. A processor ( 102 ) electrically interconnected with the user interface is adapted to limit the volume at which audio programs are reproduced on at least a portion of the audio system to said set maximum volume level. An exemplary method comprises generating an audio signal, adjusting a volume level of the audio signal to a desired maximum volume level in response to a user input, and establishing the desired maximum volume level as a set maximum volume level for audio programs played on at least a portion of the audio system ( 100 ).

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention generally relates to audio systems. In particular, the present invention relates to a system and method for setting a maximum volume level for headphones that are used in a confined space, such as a vehicle interior.  
       BACKGROUND OF THE INVENTION  
       [0002]     Many conventional vehicle audio systems allow occupants of one or more rear seats to listen to audio programs, such as music or the audio portion of a movie, via headphones. Such systems typically also give the listener the ability to adjust the volume of the audio signal being reproduced by the headphones. Because a vehicle is a rather confined space, other occupants of the vehicle may be annoyed if a rear seat occupant, such as a child, is listening to an audio program at an elevated volume level. Additionally, audio systems may permit volume levels sufficiently loud to cause discomfort to a user. An audio system and associated method that facilitates listening in a confined space without annoying others in addition to contributing to improved user comfort is therefore desirable.  
       SUMMARY OF THE INVENTION  
       [0003]     The disclosed embodiments relate to an audio system, as well as an associated method. An exemplary embodiment of the system comprises a user interface that is adapted to allow adjustment of a volume level, and a processor that is adapted to allow a maximum volume level to be set for audio programs played on at least a portion of the audio system, such as one or more headphones. When the maximum volume level has been set, subsequent attempts to raise the volume level at which audio programming is played to a level above the set maximum volume level will be ignored by the system. An exemplary method comprises generating an audio signal, adjusting a volume level of the audio signal in response to a user input to a desired maximum volume level, and setting a maximum volume level for an audio program played on at least a portion of the audio system based on the desired maximum volume level of the audio signal. Subsequent attempts by a listener of the system to exceed the set maximum volume level are ignored. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]     The above-mentioned and other features and advantages of the present invention, and the manner of attaining them, will become apparent and be better understood by reference to the following description of one embodiment of the invention in conjunction with the accompanying drawings, wherein:  
         [0005]      FIG. 1  is a block diagram of an audio system in accordance with an exemplary embodiment of the present invention;  
         [0006]      FIG. 2  is a block diagram of a system setup menu in accordance with an exemplary embodiment of the present invention;  
         [0007]      FIG. 3  is a block diagram of an audio setup menu in accordance with an exemplary embodiment of the present invention;  
         [0008]      FIG. 4  is a diagram of a display screen in accordance with an exemplary embodiment of the present invention; and  
         [0009]      FIG. 5  is a flow diagram of a process in accordance with an exemplary embodiment of the present invention. 
     
    
       [0010]     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate a preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting in any manner the scope of the invention.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0011]     This section is intended to introduce the reader to various aspects of art which may be related to various aspects of the present invention which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.  
         [0012]     Exemplary embodiments of the present invention allow a parent or other authorized user of an audio system, such as a vehicle audio system, to set a maximum volume level for the playing of audio programs. For example, an authorized user may set the maximum volume level for wired or wireless rear seat headphones. The maximum volume level may be set or established at a level that minimizes or reduces annoyance to other vehicle occupants. Specifically, the maximum volume level may be set or established so as to reduce the likelihood of discomfort or surprise to a subsequent listener. Also, the maximum volume level may be set or established so as to eliminate or reduce unpleasant surprise and discomfort experienced when subsequent listeners put on the headphones without realizing they were previously set to play programs at a louder volume level than they desire.  
         [0013]      FIG. 1  is a block diagram of an audio system in accordance with an exemplary embodiment of the present invention. The system is generally referred to by the reference number  100 . The audio system  100  is controlled by a microprocessor  102 , which may be programmed to provide a wide variety of system functions. A user interface  104  is connected to the microprocessor  102  to allow the entry of control information by a user of the system. The user interface may comprise a keypad, a remote control or the like.  
         [0014]     In an exemplary embodiment of the present invention, the user interface  104  comprises a rear seat audio control mounted in the general vicinity of the rear seat of the vehicle or within reach of rear seat occupants. Such a rear seat audio control may be used, for example, to select a desired audio or video program and to adjust the volume of the audio program being reproduced in headphones worn by a rear seat occupant. Alternatively, the user interface  104  may comprise a portion of a front seat control or “head” unit accessible to a front seat occupant of the vehicle. In addition, those of ordinary skill in the art will appreciate that exemplary embodiments of the present invention may be employed in connection with other audio and video systems as well, such as, for example, those not in vehicles. As set forth below, the user interface  104  is used to set a maximum volume level in accordance with an exemplary embodiment of the present invention. When a maximum volume level is set, subsequent attempts to exceed the set maximum volume level when playing audio programs will be ignored.  
         [0015]     A display  106  is connected to the microprocessor  102 . The display  106  may be adapted to provide a visual representation of various control functions of the audio system  100 . For example, the display  106  may be used to provide a visual indication of a set maximum volume level that is programmable by a user of the system. Examples of implementations of the display  106  in exemplary embodiments of the present invention include use of the display  106  as a control panel disposed for access by either a front or rear seat occupant of a vehicle or the like. Additionally, the display  106  may also serve as the primary display screen of a video device such as a television or DVD player.  
         [0016]     The reference generator  108  is connected to a signal source  110 , which is adapted to provide a variety of programming options to users of the audio system  100 . For example, the signal source  110  may be adapted to allow a user to select a program input from a variety of program input choices. Examples of program inputs in a typical system include input from a DVD player, a CD player, an auxiliary input such as a video game, AM radio, FM radio or the like. Programming may be provided by the signal source  110  via a plurality of program inputs  112 ,  114 . In an exemplary embodiment of the present invention, the user interface  104  is adapted to allow the selection of a program to be played by the signal source  110 .  
         [0017]     A reference generator  108  is connected to the microprocessor  102  and the signal source  110 . In an exemplary embodiment of the present invention, the reference generator  108  produces a test tone of predetermined frequency or combination of frequencies that is used to set the maximum volume level for the system as further described below. In an alternative embodiment, the reference generator  108  is omitted from the system and the user employs an audio program selected via the signal source  110  to set the maximum volume level. A user of the system adjusts the volume level to a desired maximum volume level and then establishes or sets the maximum volume level at which audio programming may be played. When the maximum volume level is set for the system, the volume of audio programs may be subsequently adjusted up to but not in excess of the set maximum volume level.  
         [0018]     The output of the signal source  110  is delivered to a digital signal processor (DSP)  116 . The DSP  116  comprises a level detect and compare circuit  118  and a voltage controlled amplifier circuit  120 , which is identified as “VCA” in  FIG. 1 .  
         [0019]     Output from the DSP  116  is delivered to an infrared headphone driver  122  and a wired headphone driver  134 . The infrared headphone driver  122  comprises a driver circuit  124 , which delivers output to a plurality of infrared transmitters  126 ,  128 ,  130  and  132 . The infrared transmitters  126 ,  128 ,  130  and  132  are adapted to deliver an audio signal to a corresponding wireless set of headphones (not shown).  
         [0020]     The wired headphone driver  134  comprises a driver circuit  136 , which delivers a signal to a plurality of headphone jacks  138 ,  140 . A set of headphones, represented as a speaker  142  in  FIG. 1 , is connected to the headphone jack  138 . In an exemplary embodiment of the present invention, the headphones  142  comprise multiple speakers.  
         [0021]     As set forth above, a listener may listen to an audio program provided by the signal source  110  via the headphones  142 . In addition, a user may listen to a reference audio signal generated by the reference generator  108  through the headphones  142 . The user then adjusts the volume level to a desired maximum volume level and sets or establishes the desired maximum volume level as the set maximum volume level for a portion of the audio system via the user interface  104 . The system will ignore subsequent attempts to adjust the volume of the headphones to a volume level that is higher than the set maximum volume level established by the authorized user.  
         [0022]     In an exemplary embodiment of the present invention, setting or establishing the maximum volume level requires entry of a predetermined authorization code. For example, setting or establishing the maximum volume level is accomplished by inputting a predetermined authorization code via user interface  104 . In this manner, the set maximum volume level is enforced on users of the system not in possession of the authorization code. For example, a parent may enforce the set maximum volume level on children who listen to audio programs on the system. The process of setting or establishing the maximum volume level using a menu control system in conjunction with video feedback via the display  106  is described below with reference to  FIGS. 2-4 .  
         [0023]      FIG. 2  is a block diagram of a system setup menu in accordance with an exemplary embodiment of the present invention. The system setup menu is generally referred to by the reference number  200 . In an exemplary embodiment of the present invention, the system setup menu  200  is displayed on the display  106  ( FIG. 1 ) upon entry of a command by the user. The system setup menu  200  includes a video icon  202 , which allows the user to choose submenus to control functionality related to a video display. An audio icon  204  allows the user to access submenus to control functionality related to an audio system. A selection indicator  206  is movable between the video icon  202  and the audio icon  204 . Upon selecting the audio icon  204 , the user is provided with a list of submenus relating to audio functionality of the system.  
         [0024]      FIG. 3  is a block diagram of an audio setup menu in accordance with an exemplary embodiment of the present invention. The audio setup menu is generally identified by the reference number  300 . The audio setup menu  300  includes a variety of choices relating to system audio functionality. In the exemplary embodiment shown in  FIG. 3 , an SRS surround icon  302  allows the user to select further submenus relative to surround sound parameters of the system. A parental volume control icon  304  is used to allow the user to set the maximum volume level of the system in accordance with an exemplary embodiment of the present invention. The user may position a selection indicator  306  adjacent to the parental volume control icon  304  and select that icon to initiate the process of setting or establishing the maximum volume.  
         [0025]      FIG. 4  is a diagram of a display screen in accordance with an exemplary embodiment of the present invention. The parental volume control screen is generally referred to by the reference number  400 . In an exemplary embodiment of the present invention, the set maximum volume level applies to listeners using headphones connected to an access point such as a headphone jack  138  ( FIG. 1 ) or one or more wireless or infrared headphones for use in the rear of the vehicle. Alternatively, the set maximum volume setting may be enforced on other speakers such as front speakers in a vehicle, or on all speakers associated with the system.  
         [0026]     In operation, the parental volume control screen  400  prompts the user to initiate a test audio signal generated by the reference generator  108  ( FIG. 1 ). The user adjusts the volume of the test audio signal in the headphones  142  ( FIG. 1 ) via the user interface  104  ( FIG. 1 ) to a desired maximum volume level. As set forth above, the user interface may be disposed for access in the rear of the vehicle. Alternatively, the user interface  104  may comprise touch screen controls on a display accessible from the front seat of the vehicle. The touch screen controls may include a “reduce volume” control  402  and/or an “increase volume” control  404 .  
         [0027]     A visual indication of the volume level is given via the display of a plurality of loudness bars  406 . The current volume level is indicated by coloring or shading of a particular volume bar, as represented by the volume bar  408  in  FIG. 4 . Additionally, a volume scale  410  is employed to give a visual indication of the relative current volume of the test audio signal. When the maximum desired volume is reached, the user selects or sets that volume level as the maximum allowable volume level for subsequent audio programming. For example, the user presses the enter key when the desired maximum volume level is obtained to thereby establish or set that volume level as the set maximum volume level. In an exemplary embodiment of the present invention, the maximum volume level may only be set or established by a user who enters a predetermined authorization code such as a parental lock code. Once set, the maximum volume level is enforced through at least a portion of the audio system until reset by a user with the proper authorization code. An exemplary embodiment of the present invention provides a default maximum volume level, such as, for example, in the midrange of the capabilities of the audio system  100  ( FIG. 1 ).  
         [0028]      FIG. 5  is a flow diagram of a process in accordance with an exemplary embodiment of the present invention. The diagram is generally referred to by the reference number  500 . At block  502 , the process begins. At block  504 , a parental volume control menu is produced by a system such as the system  100  ( FIG. 1 ). In response to a user input, a test audio signal is generated, as shown at block  506 , through one or more predetermined or user-selected speakers or headphones. As set forth above, the test audio signal may be a typical audio program of which the system is capable of playing or an application-specific audio program, such as a test tone generated by the reference generator  108  ( FIG. 1 ).  
         [0029]     At block  508 , a maximum volume level is set within the system responsive to a user input. In an exemplary embodiment of the present invention, the user is prompted for entry of an authorization code in order to set or establish the maximum volume level. In this manner, the set maximum volume level is able to be set or established only by an authorized user and is enforced on all other users of the system not having access to the authorization code. After the maximum volume level is established, subsequent attempts to exceed that level are ignored by the system for one or more speakers, zones of speakers, or headphones associated with the system, as shown at block  510 . It will be understood by those of ordinary skill in the art that the speakers, zones of speakers, or headphones to which the set maximum volume level shall be applied are selectable by a user. At block  512 , the process ends.  
         [0030]     While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.