Abstract:
An audio signal processor performs a signal processing on the first audio signal and the second audio signal in correspondence with an operation to produce an output. The processor comprises and operation device, a signal processing device and a control device. The operation device is operatively movable between one end and the other end. The one end is associated with the first audio signal and the other end is associated with the second audio signal. The signal processing device performs a signal processing on any one of the first audio signal and the second audio signal to provide at least one kind of predetermined effect. The control device controls the signal processing device so that the effect is provided for any one of the first audio signal and the second audio signal at a predetermined timing based on a position of the operation device and a moving direction thereof.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an audio signal processor for performing a signal processing on two audio signals in correspondence with an external operation to produce an output. 
   2. Description of the Related Art 
   In a musical performance in a discotheque or a nightclub, a so-called DJ (disc jockey) plays a role in skillfully operating a plurality of record players and a sound mixer to join or mix sequential pieces of music with each other, thus producing musical sounds suitable for a dance. In the past, the DJ&#39;s operation has been carried out exclusively with the use of analogue records. Decrease in availability of such analogue records leads to the needs for carrying out the above-described DJ&#39;s operation utilizing compact discs, which are widely available. Thus, attention has been directed to a CD player capable of externally controlling functions of reproduction, pause and the like and operational conditions including a reproduction speed in response to the DJ&#39;s operation (hereinafter referred to as the “DJ-compatible CD player”). If such a DJ-compatible CD player is used in combination with a mixer for the DJ&#39;s operation, the availability thereof is enhanced so that it becomes useful to a professional DJ, as well as enables a DJ hobbyist to easily enjoy the DJ&#39;s operation. 
   Typically, in the DJ&#39;s operation utilizing the above-described DJ-compatible CD player in combination with the mixer, when a number being reproduced is to be joined to the next number, a reproduction speed and a reproduction position are previously adjusted, and then at a predetermined timing, the number being reproduced is joined to the next number through cross-fading with the mixer. In order to perform such an operation, the mixer is provided with a cross-fader that outputs two numbers in a mixed state at a predetermined ratio according to a position of the operation device. 
   When the two numbers are joined to each another with the use of such a cross-fader, a user may wish not only to adjust a volume, but also to add certain effects to the number for an enhanced performance effect. For example, when joining the two numbers to each another, the number being reproduced may be joined to the next number by gradually reducing the volume thereof while adding an echo effect to a predetermined part thereof. However, in order to implement such an operation, it is required to simultaneously perform the operations of varying the volume with the use of the cross-fader and of adding an effect, such as echo, to the number. This is highly difficult and burdensome for a DJ. Besides, distracted by such a complicated operation, the basic operation of joining the two numbers may be failed. 
   Therefore, in view of these problems, an object of the present invention is to provide an audio signal processor capable of realizing the operation of joining two numbers by adding an effect corresponding to a DJ&#39;s operation to an audio signal and the DJ&#39;s operation with an enhanced operability and functionality. 
   SUMMARY OF THE INVENTION 
   According to the present invention, when the movable operation device is moved from one end to the other end through the DJ&#39;s operation, two audio signals are output with the effect added to one of the signals at the predetermined timing based on the position and moving direction of the operation device. Therefore, in case where a DJ wants to add an effect such as an echo to the audio signal when joining two numbers together, the DJ&#39;s operation can be performed with a successful effect added to the signal without a complicated operation. 
   According to the present invention, since the effect is added to the audio signal utilizing a parameter associated with the position of the operation device, the numbers can be joined together while the state of the effect is varied in the DJ&#39;s operation, so that the performance effect can be enhanced. 
   According to the present invention, since the effect is added to the audio signal while varying the volume according to the position of the operation device, the numbers can be joined together through a common operation for the volume and the effect in the DJ&#39;s operation, so that the operability can be further improved. 
   According to the present invention, when the operation device is moved, the effect is added if the operation device is located in the range between the two reference positions, so that the effect can be added at an appropriate timing in response to the moving operation when joining the numbers together. 
   According to the present invention, since the effect is added to the signal at the timing when the operation device, which is moved to the center from one end or the other, beyond the first or second reference position, the timing at which the addition of the effect is started is ensured and the operability can be further improved. 
   According to the present invention, the effect to be added to the signal can be selected among from a plurality of kinds of effects and the effect can be previously set by the effect setting device, various effect can be added when joining the numbers together through the DJ&#39;s operation, so that the functionality can be enhanced. 
   According to the present invention, since any one of the effect mode and the normal mode can be selected, the effect mode allowing the above-described function to be realized, on the one hand, and the normal mode allowing the conventional operation with the use of the cross-fader to be realized when joining the numbers together through the DJ&#39;s operation, on the other hand, an appropriate operation method can be applied by a personal preference. 
   According to the present invention, since the effect is added to the audio signal supplied from the reproduction device, and the operation condition of the reproduction device is controlled by the operation device, the operational control of the reproduction device and the addition of the effect can be accomplished with a common operation, so that the operability and functionality can be enhanced. 
   According to the present invention, since a CD player, for example, is used as the reproduction device, the above-described DJ&#39;s operation can be realized using a versatile recording medium. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram illustrating an entire configuration of an audio reproduction device according to the embodiment of the present invention; 
       FIG. 2  is a view illustrating essential parts of an operation panel of the audio reproduction device; 
       FIG. 3  is a flow chart illustrating the first processing after a system is put into an effect mode; 
       FIG. 4  is a flow chart illustrating the second or later processing after the system is put into the effect mode; 
       FIG. 5  is a view illustrating a specific operation when a cross-fader knob on the operation panel is operated; and 
       FIG. 6  illustrates an example of a volume control of each channel associated with a cross-fader position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Now, a preferred embodiment of the present invention will be described with reference to the drawings. In this embodiment, there is described an audio reproduction device serving as a DJ-compatible CD player, to which an audio signal processor according to the present invention is applied. 
     FIG. 1  is a block diagram illustrating an entire configuration of the audio reproduction device according to the present invention. The audio reproduction device as shown in  FIG. 1  has a structure that generates an output signal by performing various kinds of processing on an audio signal reproduced by a DJ-compatible CD player externally connected thereto. In FIG,  1 , the audio reproduction device comprises equalizers  11  to  14 , level adjusters  15  to  18 , the first assigning switch section  19 , the second assigning switch section  20 , the first selection switching section  21 , the second selection switching section  22 , a cross-fader  23 , a cross-fader position detection section  24 , the third selection switching section  25 , a master volume control section  26 , and A/D converters  27 ,  28 , a DSP  29 , a D/A converter  30 , and a CPU  31 . 
   It is possible to connect four DJ-compatible CD players in all (not shown) to the audio reproduction device thus configured. More specifically, an audio signal reproduced by the DJ-compatible CD player is input to each of the four channels denoted by CH 1  to CH 4 , and then the signals can be subject to mixing described later according to a DJ&#39;s operation. 
   In  FIG. 1 , the equalizers  11  to  14  receive the audio signals associated with the CH 1  to CH 4 , respectively, from the DJ-compatible CD players. The equalizers  11  to  14  add a prescribed frequency characteristic adjusted according to the operation to the respective input audio signals. 
   The level adjusters  15  to  18  receive the audio signals associated with the channels  1  to  4  output from the equalizers  11  to  14 , respectively. The level adjusters  15  to  18  output the audio signals by level-converting the audio signals to a prescribed level adjusted according to the operation. 
   The first assigning switch section  19  connects to an output side of a particular channel selected according to the operation among from the four channels  1  to  4  (hereinafter referred to as the “channel A”). Similarly, the second assigning switch section  20  connects to an output side of a particular channel selected according to the operation among from the four channels  1  to  4  (hereinafter referred to as the “channel B”). In this way, in the audio reproduction device according to the present invention, two audio signals are arbitrarily selected among from those output from the four DJ-compatible CD players connected thereto, and the two audio signals are subject to the DJ&#39;s operation and the signal processing described later. 
   Now,  FIG. 2  shows essential parts of an operation panel for operating the audio reproduction device. In  FIG. 2 , an assigning switch  41  for channel A associated with the first assigning switch section  19  and an assigning switch  42  for channel B associated with the second assigning switch section  20  are provided. In the example shown in  FIG. 2 , the channel  1  is set as the channel A by the assigning switch  41  for channel A, and the channel  2  is set as the channel B by the assigning switch  42  for channel B. 
   The first switching section  21  is controlled to selectively connect the audio signal of the channel A, which is selected by the first assigning switch section  19 , to the cross-fader  23  or the A/D converter  27 . Besides, the second switching section  22  is controlled to selectively connect the audio signal of the channel B, which is selected by the second assigning switch section  20 , to the cross-fader  23  or the A/D converter  28 . A switching operation between the first assigning switch section  19  and the second assigning switch section  20  is controlled according to a mode associated with the DJ&#39;s operation. 
   In this embodiment, depending on the DJ&#39;s operation, there are two selectable modes, i.e., a normal mode for the operation utilizing a conventional cross-fader and an effect mode for adding an effect to the audio signal. As shown in  FIG. 2 , these two modes can be freely set by a mode setting switch  46 . The first switching section  21  and the second switching section  22  are connected to the side of the cross-fader  23  when the normal mode is set, and to the side of the A/D converters  27 ,  28  when the effect mode is set. 
   The cross-fader  23  is provided with a cross-fader knob  43  on the operation panel ( FIG. 2 ) and controls the volume of the audio signal of the channel A or B input selectively in the normal mode. The volume control by the cross-fader  23  may be conducted by adding a gain corresponding to the position of the cross-fader knob  43  to the audio signal through a VCA (voltage controlled amplifier). 
   The operation panel shown in  FIG. 2  includes the cross-fader knob  43  serving as the operation device of the present invention. By operating the cross-fader knob  43  to move laterally, the volume in the cross-fader  23  can be varied in the normal mode, and a predetermined parameter for the effect processing by the DSP  26  can be controlled in the effect mode. 
   The cross-fader position detection section  24  is a device for detecting the position of the cross-fader knob  43  shown in FIG.  2  and sends a detection signal indicative of the cross-fader position to the CPU  31 . As described later, the cross-fader position detected by the cross-fader position detection section  24  is used by the CPU  31  to control the operation of the DJ-compatible CD player or by the DSP  29  for signal processing. 
   The third selection switching section  25  is controlled to selectively connect one of the audio signal output from the cross-fader  23  and the audio signal effect-processed and output from the D/A converter  30  to the output side. The third selection switching section  25  is connected to the side of the cross-fader  23  in the normal mode, and to the side of the D/A converter  30  in the effect mode. 
   The master volume (VR) control section  26  performs the final volume control on the audio signal output from the third selection switching section  25 . The output signal from the master volume control section  26  is supplied to a loudspeaker and the other audio equipment externally, which are connected thereto. 
   Now, components provided for the effect processing in the audio reproduction device will be described. In this embodiment, the effect processing performed on the audio signal is implemented through a digital signal processing technique. Thus, the A/D converters  27  and  28  sample the audio signals output from the switching sections  21  and  22 , respectively, and convert them into digital signals. 
   The DSP (digital signal processor)  29  serving as the signal processing device of the present invention is a processor that performs a numerical calculation required for the digital signal processing at high speed, and implements various kinds of effect processing and mixing on the digital signals of the channel A or B obtained via the A/D converters  27 ,  28 . The DSP  29  comprises a memory for retaining the digital signal to be processed and performs the effect processing or the like by reading from the memory. A specific effect processing performed by the DSP  29  will be described later. 
   The operation panel shown in  FIG. 2  is provided with effect keys  44 ,  45  for setting plural kinds of effect processing in the DSP  29 . In the example shown in  FIG. 2 , the effect key  44  is associated with an effect of “ZIP” for varying a musical interval of a number while keeping the speed constant, and the effect key  45  is associated with an effect of “echo” for adding an echo effect to a predetermined part of the number. Besides these effects, various kinds of effects may be implemented. However, in the following description, the effect of echo will be described. 
   The CPU  31 , which serves as the control device of the present invention, controls totally the operation of the audio reproduction device according to this embodiment. The CPU  31  recognizes the operation conditions on the operation panel shown in FIG.  5  and controls the signal processing performed by the DSP  29  according to the DJ&#39;s operation. In addition, the CPU  31  sends a control signal to the DJ-compatible CD player externally connected thereto to control functions, such as reproduction or pause, or operational conditions including a reproduction speed, according to the DJ&#39;s operation. 
   Now, an operation of the audio reproduction device according to this embodiment will be described with reference to  FIGS. 3  to  5 . In the audio reproduction device according to this embodiment, when it starts to operate after the system is put into the effect mode, the processing performed immediately after the system is put into the effect mode is slightly different from that performed after that. First, the processing shown in the flow chart of  FIG. 3  is performed immediately after the system is put into the effect mode, and then the processing shown in the flow chart of  FIG. 4  is performed, and after that, the processing shown in the flow chart of  FIG. 4  is repeated at a predetermined timing under the control of the CPU  31 . Here, a predetermined flag may be prepared for determining which processing shown in  FIG. 3  or  4  is to be performed, and the processings may be differentiated from each another by referring to the flag. 
   As shown in  FIG. 3 , when the first processing after the system is put into the effect mode is started, the detection signal for the cross-fader position from the cross-fader position detection section  24  is identified to determine processings to be performed on the channels A and B in accordance with the current cross-fader position resulting from the operation of the cross-fader knob  43  (Step S 11 ). Here, as shown in  FIG. 5 , three cross-fader positions resulting from the operation of the cross-fader knob  43  are defined. 
   In  FIG. 5 , for the cross-fader position resulting from the lateral operation of the cross-fader knob  43 , two operation detecting points A and B are set as reference positions. When the cross-fader knob  43  is located on the left-hand side of the operation detecting point A, the cross-fader position is defined to be on the channel A side. When the cross-fader knob  43  is located on the right-hand side of the operation detecting point B, the cross-fader position is defined to be on the channel B side. When the cross-fader knob  43  is located between the operation detecting point A and the operation detecting point B, the cross-fader position is defined to be in the center. 
   Then, in accordance with the determination in Step S 11 , operation control steps S 12  to S 14  are conducted by sending a control signal from the CPU  31  to each of the DJ-compatible CD players associated with the channels A and B. Here, under the circumstance where the effect mode is set, the first selection switching section  21  and the second selection switching section  22  are switched to the sides of the A/D converters  27  and  28 , respectively, and the digital signal processing is performed by the DSP  29 . 
   In case where the cross-fader position is judged to be on the channel A side in Step S 11 , the DJ-compatible CD player associated with the channel A is caused to start the reproduction operation, and the DJ-compatible CD player associated with the channel B is caused to pause (Step S 12 ). Similarly, in case where the cross-fader position is judged to be on the channel B side, the DJ-compatible CD player associated with the channel A is caused to pause, and the DJ-compatible CD player associated with the channel B is caused to start the reproduction operation (Step S 14 ). Consequently, the audio signal is output only through the channel indicated by the cross-fader position. 
   In case where the cross-fader position is judged to be in the center, the DJ-compatible CD players associated with both the channels A and B are caused to start the reproduction operation (Step S 13 ). Consequently, audio signals of the two channels are output after being mixed in the DSP  29 . In this example, it is only immediately after the system is put into the effect mode as shown in  FIG. 3  that two channels are mixed in the effect mode as in the normal mode. 
   Then, the operation of the cross-fader knob  43  is monitored to judge whether the cross-fader position is changed or not (Step S 15 ). As a result, in case where the cross-fader position is the same as the previous state (if “NO” in Step S 15 ), the processing shown in  FIG. 3  is ended. In this case, an original state is maintained. 
   On the contrary, if the cross-fader position is changed from the previous state (if “YES” in Step S 15 ), the processing to be performed is determined according to the current cross-fader position (Step S 16 ). If the cross-fader position is judged to be on the channel A side resulting from the determination in step S 16 , a predetermined effect based on the effect processing in the DSP  29  is added to the audio signal of the channel B being reproduced and the audio signal is faded out (Step S 17 ). The CD player associated with the channel B is caused to pause under the control of the CPU  29  (Step S 18 ). Similarly, if the cross-fader position is judged to be on the channel B side, a predetermined effect based on the effect processing in the DSP  29  is added to the audio signal of the channel A being reproduced and the audio signal is faded out (Step S 19 ). The DJ-compatible CD player associated with the channel A is caused to pause under the control of the CPU  29  (Step S 20 ). Here, when Step S 18  or S 20  is completed, the processing shown in  FIG. 3  is ended. 
   As a result of performing Steps S 17  to S 20 , of the two channels having been reproduced theretofore, reproduction of the channel on the other side of the cross-fader position is stopped, so that only the channel on the side of the cross-fader position is reproduced. At that time, the audio signal of the channel, in which reproduction is to be stopped, is subject to an effect processing, such as echo, so that a successful performance effect can be provided when the two numbers are joined together. 
   If the cross-fader position is judged to be in the center resulting from the determination in Step S 16 , the processing to be performed is determined according to the previous cross-fader position (Step S 21 ). More specifically, in case where the cross-fader knob  43  is operated so that the position of the cross-fader is shifted from the left-hand side or the right-hand side to the center, the processing depends on from which side, i.e., the channel A side or channel B side, the cross-fader position is shifted to the center. If the previous cross-fader position is judged to be on the channel A side resulting from the determination in Step S 21 , a predetermined effect based on the effect processing in the DSP  29  is added to the audio signal of the channel A (Step S 22 ). Then, the DJ-compatible CD player associated with the channel A is caused to pause (Step S 23 ). 
   Similarly, if the previous cross-fader position is judged to be on the channel B side resulting from the determination in Step S 21 , a predetermined effect based on the effect processing in the DSP  29  is added to the audio signal of the channel B (Step S 24 ). Then, the DJ-compatible CD player associated with the channel B is caused to pause (Step S 25 ). 
   The processing in Steps S 22  to S 25  is based on the assumption that the cross-fader is shifted from the previous position over the central position in which the cross-fader is currently located, to the position on the opposite side. Accordingly, a successful performance effect can be provided by stopping reproduction of the channel associated with the previous cross-fader position and adding an effect to the audio signal. Here, when Step S 23  or S 25  is completed, the processing shown in  FIG. 3  is ended. 
   Now, the processing shown in  FIG. 4  subsequent to the processing shown in  FIG. 3  in the effect mode will be described. The processing in  FIG. 4  is repeated at a predetermined timing during operation of the information reproduction device. For example, when shifted to the processing in  FIG. 4 , it is judged whether the cross-fader position is changed or not by referring to the predetermined flag described above (Step S 31 ). Step S 31  is the same as Step S 15  in FIG.  3 . If the cross-fader position is changed from the previous position, a processing of shifting to Step S 32  is performed successively. 
   Then, the processing to be performed is determined according to the current cross-fader position (Step S 32 ). If the cross-fader position is judged to be on the channel A side resulting from the determination in Step S 32 , the effect currently added to the audio signal of the channel A is cancelled (Step S 33 ). Then, normal reproduction of the channel A is started (Step S 34 ), and the processing in  FIG. 4  is ended. Similarly, if the cross-fader position is judged to be on the channel B side resulting from the determination in Step S 32 , the effect currently added to the audio signal of the channel B is cancelled (Step S 35 ). Then, normal reproduction of the channel B is started (Step S 36 ), and the processing in  FIG. 4  is ended. 
   If the cross-fader position is judged to be in the center resulting from the determination in Step S 32 , the processing to be performed is determined according to the previous cross-fader position (Step S 37 ). Step S 37  corresponds to Step S 21  in FIG.  3 . Therefore, Steps S 38  and S 39 , which are performed in case where the previous cross-fader position is judged to be on the channel A side resulting from the determination in Step S 37 , are the same as Steps S 22  and S 23  in  FIG. 3 , respectively. Furthermore, Steps S 40  and S 41 , which are performed in case where the previous cross-fader position is judged to be on the channel B side, are the same as Steps S 24  and S 25  in  FIG. 3 , respectively. Here, when Step S 39  or S 41  is completed, the processing shown in  FIG. 4  is ended. 
   Now, a specific operation will be described with reference to  FIG. 5  when the cross-fader knob  43  on the operation panel is operated according to the processing shown in  FIGS. 3 and 4 . An operation in the case where a sequential operation over the operation detecting points A and B is implemented with the cross-fader knob  43  will be considered herein. In  FIG. 5 , the cross-fader knob  43  is subject to sequential operations ( 1 ) to ( 4 ) indicated by arrows. In  FIG. 5 , the channel  1  is set as the channel A by the assigning switch  41  for channel A, and the channel  2  is set as the channel B by the assigning switch  42  for channel B, as shown in FIG.  2 . In addition, while other keys and the like are omitted in  FIG. 5 , the effect mode is set by the mode setting switch  46  shown in  FIG. 2 , and the “echo” is set as the effect processing by the effect key  45 . 
   In the operation ( 1 ) shown in  FIG. 5 , the cross-fader knob  43  is moved rightward so that the cross-fader position is shifted from the channel A side toward the center beyond the operation detecting point A. In this case, assuming that the processing shown in  FIG. 3  is performed, the current cross-fader position is judged to be in the center in Step S 16  after completion of Step S 15 . Then, the previous cross-fader position is judged to be on the channel A side in Step S 21 , and Steps S 22  and S 23  are executed. 
   Through the operation ( 1 ) described above, the audio signal of the channel  1  being reproduced is repeatedly reproduced with the echo effect added thereto. More specifically, a predetermined part of the number for the channel  1  is repeatedly reproduced in a short cycle with the echo effect added thereto, and the volume thereof is gradually reduced with the movement of the cross-fader knob  43 . At that time, the DSP  29  utilizes the digital signal retained in the memory to conduct the effect processing for echo, so that the DJ-compatible CD player associated with the channel  1  is controlled to pause. In addition, the state of the DJ-compatible CD player associated with the channel  2  is maintained, and it normally pauses at a predetermined position. 
   In the operation ( 2 ) shown in  FIG. 5 , the cross-fader knob  43  is moved leftward so that the cross-fader position is returned from the center to the channel A side beyond the operation detecting point A. In this case, in the processing shown in  FIG. 4 , the current cross-fader position is judged to be on the channel A side in Step S 32  after completion of Step S 31 , and Steps S 33  and S 34  are executed. 
   Through the operation ( 2 ) described above, the effect processing for the channel  1  performed by the DSP  29  in accordance with the operation ( 1 ) is stopped, and the DJ-compatible CD player associated with the channel  1  starts again reproduction from the position of pause. Here, the state of the DJ-compatible CD player associated with the channel  2  is maintained. 
   In the operation ( 3 ) shown in  FIG. 5 , the cross-fader knob  43  is moved rightward again so that the cross-fader position is shifted to the channel B side beyond the operation detecting point A, passing through the central position, and beyond also the operation detecting point B. In this case, in the processing shown in  FIG. 4 , when the current cross-fader position is in the center, Steps S 38  and S 39  are executed via Steps S 31 , S 32 , and S 37 . Then, when the current cross-fader position is shifted to the channel B side, Steps S 35  and S 36  are executed via Steps S 31  and S 32 . 
   Through the operation caused by the operation ( 3 ) described above, in addition to the operation caused by the operation ( 1 ), the cross-fader position reaches the channel B side, so that transition from the channel  1  to the channel  2  while adding the echo effect to the channel  1  is possible. At the time when the cross-fader position reaches the channel B side, the DJ-compatible CD player associated with the channel  2  starts again reproduction from the position of pause. 
   Now, volume variation caused when the cross-fader knob  43  is operated according to the operation ( 3 ) will be described.  FIG. 6  illustrates a volume control of each channel associated with cross-fader position, and corresponds to the case of the operation ( 3 ). As shown in  FIG. 6 , in a region on the left-hand side of the operation detecting point A, the volume does not vary according to the cross-fader position, and the channel A is normally reproduced. In a region from the operation detecting point A to the operation detecting point B, the effect processing is added to the channel A, and the volume is reduced as the cross-fader position is shifted rightward, and the volume becomes zero at a predetermined position. In a region on the right-hand side of the operation detecting point B, the volume does not vary according to the cross-fader position, and the channel B is normally reproduced. In this way, since the cross-fader knob  43  enables addition of the effect to the audio signal and control of the volume simultaneously, an improved operability is provided. 
   While in the example shown in  FIG. 6 , the volume of the audio signal to be processed is associated with the cross-fader position, any parameter other than the volume may be controlled by associating it with the cross-fader position. For example, various parameters including a period or frequency characteristic of the audio signal to be effect-processed, an attenuation characteristic of echo, and a frequency variation of ZIP may be associated with the cross-fader position. Alternatively, a fixed effect processing may be performed within a region between the operation detecting points A and B without varying the parameter according to the cross-fader position. 
   Finally, in the operation ( 4 ) shown in  FIG. 5 , the cross-fader knob  43  is moved leftward again so that the cross-fader position is returned to the central position from the channel B side beyond the operation detecting point B. In this case, in the processing shown in  FIG. 4 , Steps S 40  and S 41  are executed via Steps S 31 , S 32  and S 37 . 
   Through the operation ( 4 ) described above, the audio signal of the channel  2  being reproduced is repeatedly reproduced with the echo effect added thereto. More specifically, the same operation performed on the channel  1  during the operation ( 1 ) is performed on the channel  2  during the operation ( 4 ). Here, the relationship between the cross-fader position and the volume of the channel  2  when the cross fader moves over the operation detecting point B is represented by the same graph shown in  FIG. 6  but reversed laterally. 
   As described above, with the audio reproduction device according to this embodiment, by operating the cross-fader knob  43  to move, an effect can be added to the audio signal when joining two numbers together through the DJ&#39;s operation. Thus, while in the past, when two numbers are to be joined together, it has been required to perform operations of controlling the volume thereof with the cross-fader and adding the effect thereto separately, these operations can be simultaneously performed. Therefore, a complicated operation in the DJ&#39;s operation become unnecessary so that it is possible to prevent the operation from being failed and to provide an improved functionality by selectively adding an effect to the audio signal. 
   In this embodiment, a configuration in which a plurality of DJ-compatible CD players is externally connected to the audio reproduction device is described. However, the present invention is not limited only thereto and can be applied to the audio reproduction device integral with a plurality of DJ-compatible CD players. In addition, the recording medium used by the reproduction device is not limited to CD, and the present invention can be applied to cases where various information recording medium are used. 
   As described above, according to the present invention, since the audio signal is processed according to the operation with the use of the operation device to add an effect to the signal, an audio signal processor that exhibits high operability and functionality when two numbers are to be joined together through the DJ&#39;s operation can be provided. 
   The entire disclosure of Japanese Patent Application No. 2001-133292 filed on Apr. 27, 2001 including the specification, claims, drawings and summary is incorporated herein by reference in its entirety.