Abstract:
A method for controlling an audio amplifier unit having an audio input, an amplifier, a volume regulation unit and an audio output. An audio signal is received via the audio input and is amplified by the amplifier, and an adjustment procedure modifies an operating curve of the volume regulation unit for the received audio signal. From a modified setting of the volume regulation unit, a modified amplification value is calculated according to a first volume operating curve. The amplifier&#39;s amplification is modified to match the modified amplification value, and a second volume operating curve is determined and assigned to the calculation of modified amplification values of the amplifier. The modified amplification value is substantially at the center of the second volume operating curve. Further, the volume regulation unit is adjusted mechanically or electrically to a predefined position.

Description:
[0001]    The present application claims priority from German Patent Application No. 10 2016 112 503.2 on Jul. 7, 2016. 
       FIELD OF THE INVENTION 
       [0002]    It is noted that citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention. 
         [0003]    The invention relates to an audio amplifier unit and a method for controlling an audio amplifier unit. 
         [0004]    Audio amplifier units such as pre-amplifiers, audio-video (AV) receivers, full amplifiers or headphone amplifiers can be connected to different audio sources, such as e.g. a smart phone, a stationary CD player or the like. 
         [0005]    However, these audio sources typically provide different input signal levels. 
         [0006]    For compensating the different input signal levels of the audio sources connected to the audio amplifier unit, an external actuator can be used that lowers or raises the input signal level, such that the level range of the volume regulating button can be utilized better. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an object of the present invention to provide an audio amplifier unit and a method for controlling an audio amplifier unit, which allows an improved adaptation to the connected audio source. Further, the operating unit for volume control shall be improved. 
         [0008]    Thus, a method for controlling an audio amplifier unit is provided. The audio amplifier unit has an audio input, an amplifier, a volume regulation unit and an audio output. An audio signal received via the audio input is amplified by the amplifier. By operating a control member, an adjustment process is started. A medium volume can be selected by operating the volume regulation unit. The volume regulation unit is adjusted mechanically and/or electrically such that a given volume setting is at a predefined position. 
         [0009]    According to a further aspect of the present invention, the volume regulation unit has a control knob or slide control with a first position, a second position and a third position as well as an actuator for mechanical and/or electrical adjustment of the control knob or slide control, such that the first position is in a middle position (e.g. 12 o&#39;clock position). 
         [0010]    According to a further aspect of the present invention, the adjustment process can be performed for different audio sources connected to the audio input and/or for different output devices connected to the audio output, and the resulting settings can be stored. 
         [0011]    The invention also relates to an audio amplifier unit with at least one audio input to which an external audio source can be connected. The audio amplifier unit further has an amplifier for amplifying an audio signal received via the audio input. Furthermore, the audio amplifier unit has a volume regulation unit for adjusting an amplification level of the amplifier. The audio amplifier unit has also an audio output to which an output device can be connected. The volume regulation unit is adapted for storing, for at least one connectable external audio source and/or at least one connectable audio output device, a setting at which a volume control knob of the volume regulation unit is in a 12 o&#39;clock position which corresponds to a medium volume at the audio output or the audio output device. 
         [0012]    An audio amplifier unit has typically at least one input for an external audio source, an amplifier stage for amplifying the received audio signals and a volume regulation unit for adjusting the volume. 
         [0013]    The audio amplifier unit according to the invention enables a user-friendly adjustment of the listening volume. 
         [0014]    With the audio amplifier unit according to the invention and the method for controlling an audio amplifier unit according to the invention, an audio amplifier unit is provided that enables a simple and effective adjustment of a volume control range to different input levels of the connected audio sources. Further, according to the invention a personal listening volume range preference can be considered. Thus, the listener becomes part of the regulation, so that an optimal adaptation to the listener&#39;s preference is possible. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  shows a schematic block diagram of an audio amplifier unit according to the invention. 
           [0016]      FIG. 2  shows two different logarithmic volume operating curves. 
           [0017]      FIG. 3  shows a first individually adapted volume operating curve. 
           [0018]      FIG. 4  shows a second individually adapted volume operating curve. 
           [0019]      FIG. 5  shows a third individually adapted volume operating curve. 
           [0020]      FIG. 6  shows a transition from a first to a second individually adapted volume operating curve. 
           [0021]      FIG. 7  shows an individually adapted volume operating curve with smoothed transitions between portions. 
           [0022]      FIG. 8  shows individually adapted volume operating curves according to another embodiment of the invention. 
           [0023]      FIG. 9  shows a block diagram of a volume regulator. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0024]    It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, many other elements which are conventional in this art. Those of ordinary skill in the art will recognize that other elements are desirable for implementing the present invention. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein. 
         [0025]    The present invention will now be described in detail on the basis of exemplary embodiments. 
         [0026]      FIG. 1  shows a schematic block diagram of an audio amplifier unit according to the invention. In  FIG. 1 , an audio amplifier unit  100  with at least one audio input  110 , an audio amplifier  120 , a volume regulation unit  130  and an audio output  140  is provided. An external audio source  300  can be connected to the audio input  110 . Optionally, an earpiece  200  can be connected to the audio output  140 , e.g. headphones or earphones. Alternatively, loudspeakers or other audio output devices can be connected to the audio output  140 . 
         [0027]    The volume regulation unit  130  is for adjusting the amplification level of the amplifier  120 . The volume regulation unit  130  can comprise e.g. a control knob. Optionally, the control knob can have a first position  132  (e.g. 7 o&#39;clock position), a second substantially middle position  131  (e.g. 12 o&#39;clock position) and a third position  133  (e.g. 5 o&#39;clock position). The first position  132  can represent the minimum volume, the third position  133  can represent the maximum volume, and the second position  131  can represent a medium volume. Other positions than the 12 o&#39;clock, 5 o&#39;clock or 7 o&#39;clock positions are also possible. E.g. the first position  132  can be near a 6 o&#39;clock position and the second position  131  near a 3 o&#39;clock position. The complete slewing range may also be more than 270° or less than 270°. The volume regulation unit  130  may comprise a control member  150  for adjustment, with which the control range of the volume regulation unit can be adjusted. The control member  150  may be implemented as a knob or a button. Alternatively, the volume control knob may also be a push button. Moreover, alternatively or additionally, a corresponding control member  150 ′ may be provided on a remote control  400 . In one embodiment, it can be automatically detected that the volume regulation unit  130 , after being set to any particular position, remained for a given time in that position. Based on that, a re-adjustment or tracking may be performed automatically, wherein the current volume is selected automatically as the new medium volume and the volume regulation unit  130  is driven to the predefined position. Optionally, this automatic tracking may be switched on and off. 
         [0028]    Before operating the control member  150 , the user may connect an audio source  300  to the audio input  110  and, using the volume regulator, set the volume as desired or comfortable for the user. Depending on the connected audio source  300  and the audio output level provided by the audio source (e.g. smartphone 250 mV, stationary CD player 2V), the volume desired by or comfortable for the user will differ very much. For audio sources providing a high output level, the user will turn the volume control knob towards the 7 o&#39;clock position  132 , and for signal sources providing a low output level towards the 5 o&#39;clock position  133 . A medium volume as desired or pleasant for the user is thus assigned to a position of the volume control knob that, as a start, needs not necessarily be the middle or 12 o&#39;clock position  131 . 
         [0029]    By operating the control member  150  the input adjustment function is launched, and the volume control knob is rotated by an actuator  135  such that the medium volume (setting) is in the 12 o&#39;clock position  131 . In the case of a slide control, the slide control is driven to a middle position. The actuator  135  may be e.g. a motor. This adjustment, or setting respectively, of the control member does not modify the current volume, but only modifies the relative position of the volume control knob and the knob&#39;s effect in usage, particularly the volume operating curve. For other kinds of volume regulators, e.g. a slide control, the adjustment works correspondingly. If the user now wants to modify the volume, or audio output level respectively, of the audio signal at the audio output  140 , the volume regulator needs to be operated again. However, the volume regulator now follows a new volume operating curve. Thus, according to the invention, a new relationship between the middle position of the volume regulator and the amplification factor, or curve of the regulator, is defined and stored. Generally, the volume regulator is the regulator of the volume control and can be implemented as a mechanical regulator, a virtual regulator (e.g. on a display or touch screen) or any other regulator with a minimum position  132  and a maximum position  133 . In the case of a virtual regulator, also the actuator is virtual. 
         [0030]    Optionally, this procedure may be performed for various different audio sources  300  that may be connected to the audio input  110 . Optionally, the audio amplifier unit may automatically recognize the audio source  300  connected to the audio input  110 , store or retrieve the middle position of the volume regulator or the relationship between the middle position of the volume regulator and the factor or curve of the regulator respectively, and set the regulator correspondingly. 
         [0031]    According to a further aspect of the present invention, different sound reproduction devices or output devices  200  may be connected to the audio output  140 . 
         [0032]    According to a further aspect of the present invention, the adjustment process may be performed not only for different audio input sources, but also for different audio output devices. 
         [0033]    According to a further aspect of the invention, when an audio source  300  or an audio output device  200  is changed, then the audio amplifier unit may read the previously stored settings to adjust the volume regulator&#39;s operating curve, and drive the regulator to its respective position by using the actuator  135 . E.g. if before the audio source  300  or the audio output device  200  being changed the amplifier was set to an above-average high volume, then this setting—considering the modified volume curve corresponding to the new audio source/output device—may be kept, and the volume regulator may be driven to its respective position by the actuator  135 . 
         [0034]    Thus, according to the invention, a separate relationship between the medium volume and the middle position of the volume control knob  130  may be stored, and may be retrieved and used if required, for different audio sources  300 . The same applies for different output devices  200  that can be connected to the audio output  140 . 
         [0035]      FIG. 2  shows two different logarithmic volume operating curves. Due to the scale, which is in Decibels and thus logarithmic, the curves appear straight. A first volume operating curve K T  represents the complete range of possible volume settings. If this range is very large, a conventional volume regulator will react very sensitive to actuation. Even a small adjustment can have a large impact, which will be perceived as uncomfortable. Thus, for a small volume adjustment, the user would be forced to handle the volume regulator very carefully. A second volume operating curve K R  has a lower slope, which makes its operation more comfortable, but it cannot cover the complete range of possible volume levels. According to the invention, an adapted operating curve is generated by operating the control member  150 . The adapted operating curve has in its middle portion a slope according to the second volume operating curve K R . In an embodiment, the adapted volume operating curve has in its outer portions slopes that allow coverage of the complete range of possible volume levels. Therefore, this adapted volume operating curve covers the same range of possible volume levels as the first volume operating curve K T . In a different embodiment, the adapted volume operating curve has in its outer portions slopes that enable a coverage of a major portion of the range of possible volume levels, instead of the complete range. The position of the middle portion of the adapted volume operating curve depends on the volume that is set while operating the control member  150 . 
         [0036]      FIG. 3  shows a first individually adapted volume operating curve K 1 . It consists of three sections or portions: a middle portion B C  has a lower slope than the first volume operating curve K T , e.g. corresponding to the second volume operating curve K R  shown in  FIG. 1 . It may also be a different slope that is lower than the first volume operating curve K T . The middle portion B C  is positioned such that a desired volume, i.e. a particular point S 1  of the operating curve, corresponds to a middle position (x=0,5) of the regulator. When operating the regulator, it has a reduced sensitivity within the middle portion B C , corresponding to the lower slope of the curve K 1  in this range. A lower portion B L  of the operating curve K 1  connects the lower end of the middle portion B C  with a minimum volume value, which in this example is at −120 dB. A higher portion B U  of the operating curve K 1  connects the upper end of the middle portion B C  with a maximum volume value, which in this example is at 0 dB (not attenuated). Therefore, due to the reduced sensitivity in the middle portion B C , small to medium volume adjustments can easier be made, while still a very large (or in this example, the complete) range of volume control remains. In the example depicted in  FIG. 3 , both the lower portion B L  as well as the higher portion B U  of the operating curve K 1  have a higher slope than the middle portion B C , and thus a higher sensitivity. 
         [0037]      FIG. 4  shows a second individually adapted volume operating curve K 2 , where the upper portion B U  of the curve K 2  has a lower slope and thus a lower sensitivity than the middle portion B C . In this case, the user has set a medium volume according to an operating point S 2 ′ on the first volume operating curve K T . For this, the user has selected on any arbitrary volume operating curve that was previously set, a volume level corresponding to S 2 ′ and then re-adjusted the volume regulator, e.g. by using the control member  150 , 150 ′. This generates a new adapted volume operating curve K 2  that has the center S 2  of its middle portion B C  shifted to a volume equal to that of S 2 ′. However, the slope and thus the sensitivity of the middle portion B C  is not changed, and in this example is still that of the second volume operating curve K R  in  FIG. 1 . Moreover, during the re-adjustment the volume regulator is moved to the middle position without changing the volume, as described above. 
         [0038]      FIG. 5  shows a third individually adapted volume operating curve K 3 . Here, the user has set a lower medium volume than in  FIG. 2-4 . The reason may be e.g. that a connected audio source provides a signal at a very high signal level. For this the user has selected, on any volume operating curve that was previously set, a volume level corresponding to S 3 ′ and then re-adjusted the volume regulator. As part of the re-adjustment, a new adapted volume operating curve K 3  is generated (e.g. calculated or retrieved from a storage) that has the center S 3  of its middle portion B C  shifted to a volume equal to that of S 3 ′, and the volume regulator is moved to the middle position again. 
         [0039]      FIG. 6  exemplarily shows a transition from a first individually adapted volume operating curve K 3  to a second individually adapted volume operating curve Based on the previously set individually adapted volume operating curve K 3 , the user has selected a volume according to S 4 ′. For this, the volume regulator was rotated or shifted so far that the operating point S 4 ′ has left the middle portion B C  of the operating curve and is located in the upper portion B U , where the slope of the first individually adapted volume operating curve K 3  is higher. After the re-adjustment, e.g. using the control member  150 , 150 ′, the second operating curve K 4  is generated, whose middle portion B C  is centered at the selected volume S 4 . The volume regulator now follows the second individually adapted volume operating curve K 4 . 
         [0040]    The transitions between the different portions need not necessarily be abrupt, as above.  FIG. 7  shows an individually adapted volume operating curve with smoothed transitions between the different portions. Also, the various portions B C , B L , B U  of the adapted operating curve need not necessarily be exactly logarithmic (or depicted as a straight line in a diagram with logarithmic scale), but may deviate slightly. However, the slope of the middle portion is always lower than that of the first volume operating curve K T  that connects the values for minimum and maximum volume directly. 
         [0041]    In an embodiment, not the complete volume range is covered by the currently set volume operating curve, but it is possible to switch between different volume operating curves that all together cover the complete volume range.  FIG. 8  shows an example where a first minimum volume operating curve K 61  exemplarily covers a volume range from −120 dB to −15 dB. A second maximum volume operating curve K 62  covers a volume range from −105 dB to 0 dB. The two curves run parallel, i.e. the distance D between the curves is constant. Other possible operating curves are between them and also run parallel to them. The middle portion B C  of each curve has a lower slope than the first volume operating curve K T . Selecting a desired volume level based on a current volume operating curve and re-adjusting the volume regulator switches to a new volume operating curve, which has a center value corresponding to the current volume level if it is within an adjustment window E. Otherwise it may be switched to an adjacent volume operating curve, i.e. to K 61  or K 62 . E.g. in the depicted example, with a currently valid volume operating curve K 61  and a desired volume level at the right-hand edge of the curve (maximum volume level selectable with K 61 ), it is possible by re-adjustment to switch to the maximum volume operating curve K 62  that has a center value (x=0,5) exactly at this volume level. With a currently valid volume operating curve K 62  and a desired volume level at the left-hand edge of the curve (minimum volume level selectable with K 62 ), it is possible to switch to the minimum volume operating curve K 61  by re-adjustment. 
         [0042]      FIG. 9  shows a block diagram of a volume regulator  900 . It comprises a volume operating member  920  that may be operated by a user and that has a particular, fixed raw operating curve K R . It outputs a control value C R  according to the user-defined setting and according to the raw operating curve K R . An operating curve adaptation unit  940  converts the control value C R  according to the raw operating curve K R  into a control value C A  according to an adapted operating curve K A . The operating curve adaptation unit  940  may receive the adapted operating curve K A , or an adaptation rule respectively, from outside, or create and store it on its own. 
         [0043]    For example, the volume operating member  920  may be an analog potentiometer with a logarithmic operating curve. Then, the raw operating curve K R  corresponds to the first operating curve K T , for example. In another example, the volume operating member  920  is a digital rotary pulse encoder that provides only “up” or “down” pulses, so that the raw operating curve K R  comprises only the discrete values “up”, “inactive” and “down”. The control value C A  converted according to the adapted operating curve K A  by the operating curve adaptation unit  940  may be used e.g. for controlling the amplification of an amplifier circuit. The operating curve adaptation unit  940  may be implemented as a computing unit, a control unit or a processor, and may be configured by a software program. 
         [0044]    The invention may be used in particular for regulators that cover a very large control range while still allowing an improved fine adjustment around a currently selected value. This is particularly advantageous for volume control. 
         [0045]    While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the inventions as defined in the following claims.