JP2004364240A - Sound field adjusting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound field adjusting apparatus for generating a 4-channel surround signal on the basis of a difference component of 2-channel stereo signals that suppresses no sounding of a rear speaker and variations in loudness even when separation of the 2-channel stereo signals is deteriorated. <P>SOLUTION: The sound field adjusting apparatus is connected to a surround apparatus that generates a difference signal (L-R) from a received left channel signal L and a received right channel signal R and generates forward incoming sound signals FL, FR coming from the front side of a listener and backward incoming arrival sound signals RL, RR coming from the rear side of the listener, and adds part of the forward incoming sound signals FL, FR or part of the stereo 2-channel signals L, R to the backward incoming arrival sound signals RL, RR. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sound field adjustment device, and more particularly, to an improvement in a sound field adjustment device used by being connected to a surround device that generates a surround signal based on a difference component between two-channel stereo signals.

  2. Description of the Related Art Conventionally, as a system for reproducing realistic sound, a two-channel stereo system in which two speakers are arranged in front of a listener separately on the left and right sides and different sounds are reproduced from each speaker is known. On the other hand, there is also known a surround device in which speakers are arranged on the left and right behind a listener to reproduce stereophonic sound, thereby increasing the sense of reality.

  In the surround device of the past, sounds of four speakers in total, two in front and two in back, are separately created for four channels, and the sound of each channel is reproduced by four speakers corresponding to each channel. I was However, in recent years, due to advances in circuit technology, a four-channel output signal has been generated from a two-channel stereo signal using a surround signal processing circuit, and the four-channel output signals have been arranged on the front and rear sides of the listener, respectively. Surround devices for reproducing with four speakers have appeared (for example, see Patent Documents 1 and 2).

  To the surround signal processing circuit of such a surround device, a two-channel stereo signal (a left channel signal L and a right channel signal R) is input. The surround signal processing circuit internally processes the two-channel stereo signal to generate a channel signal FL reproduced by the left front speaker, a channel signal FR reproduced by the right front speaker, a channel signal RL reproduced by the left rear speaker, And a channel signal RR to be reproduced by the right rear speaker.

JP-A-5-091600 (FIG. 4) JP-A-7-040760 (FIGS. 1 and 2)

  However, such a surround signal processing circuit generally generates a 4-channel surround signal based on a difference component obtained by removing a correlation component of the stereo 2-channel signals L and R, for example, an (LR) component. If the separation of the input two-channel stereo signals L and R fluctuates due to some cause, for example, a change in electric field strength at the time of receiving FM radio waves or multipath noise, the (LR) component is reduced and the surround signal is reduced. However, there is a problem in that the volume of the sound decreases from the rear speaker, and the loudness of the sound output from the rear speaker changes, or in the worst case, no sound is output from the rear speaker.

  This problem will be described with reference to FIG. 1, for example, in which two-channel stereo signals L and R are reproduced from radio waves received by an FM tuner, and four-channel stereophonic sound is reproduced from the two-channel stereo signals L and R. .

  FIG. 1A shows the operation of the surround signal processing circuit 3 when the antenna 1 and the FM tuner 2 are installed in a strong electric field area. In a strong electric field area, the FM tuner 2 outputs the L component and the R component of a two-channel stereo signal having a high separation. At this time, there is a sufficient (LR) component, and the surround signal processing circuit 3 performs a channel signal FL reproduced by the left front speaker SPFL and a channel signal reproduced by the right front speaker SPFR based on the (LR) component. FR, a channel signal RL reproduced by the left rear speaker SPRL, and a channel signal RR reproduced by the right rear speaker SPRR are generated and output. As a result, stereophonic sound is reproduced by the four speakers SPFL, SPFR, SPRL, SPRR.

  FIG. 1B shows the operation of the surround signal processing circuit 3 when the antenna 1 and the FM tuner 2 are installed in a weak electric field area. In the weak electric field area, the L component and the R component of the two-channel stereo signal having a low separation are output from the FM tuner 2, and in the worst case, the output is monaural in which the L component and the R component are equal. At this time, the (LR) component becomes 0, and the surround signal processing circuit 3 can generate the channel signal FL reproduced by the left front speaker SPFL and the channel signal FR reproduced by the right front speaker SPFR, but the left rear speaker SPRL. And the channel signal RR to be reproduced by the right rear speaker SPRR cannot be generated. As a result, sound is reproduced from the left front speaker SPFL and the right front speaker SPFR, but no sound is output from the left rear speaker SPRL and the right rear speaker SPRR.

  Such a situation where the separation of the two-channel stereo signals L and R varies with the electric field strength at the time of FM radio wave reception or fluctuates due to multipath noise is caused by, for example, a case where an FM tuner is mounted on a vehicle. Occurs.

  Therefore, the present invention connects a sound field adjustment device to a surround device that generates a 4-channel surround signal based on the difference component (LR) between the 2-channel stereo signals L and R, and inputs a 2-channel stereo signal input to the surround device. Even if the separation of the signals L and R is deteriorated for some reason, the sound field adjusting device prevents the sound from the rear speakers from fluctuating in magnitude or causing no trouble at all. It is an object.

  According to a first embodiment of the present invention, there is provided a sound field adjusting apparatus comprising: a left channel signal and a right channel signal input from a playback device that outputs a two-channel stereo signal; and a difference generated from these signals. A sound field adjustment device connected to a surround device including a surround signal processing unit that generates a surround signal based on a signal, wherein a signal generated based on one or both of a left channel signal and a right channel signal is provided. And a sound field adjusting means for adjusting the sound field by adding the signal to a predetermined surround signal as an addition signal.

  In addition to the above embodiments, the following second to twenty-first embodiments are possible.

  (A) In the sound field adjustment device according to the first aspect, the surround signal processing unit outputs, as a surround signal, a surround signal for at least two right and left front arriving sounds arriving from the front of the listener, and a rear signal of the listener. And at least one surround sound signal for the rearward arriving sound is output. The sound field adjusting means includes an adder on a line to which the surround sound signal for the rearward arriving sound is input. A second mode in which a part of the signal is guided to the adder as the addition signal, and is added to the surround signal for the rearward arriving sound.

  (B) In the sound field adjustment device according to the first aspect, the surround signal processing means outputs, as a surround signal, a surround signal for at least two right and left front arriving sounds arriving from the front of the listener, and a rear signal of the listener. At least one surround sound signal for the rearward arriving sound is output, and the sound field adjusting means includes an adder on a line to which the surround sound signal for the rearward arriving sound is input, and the left channel signal or the right channel signal is provided. A third form in which a part of the signal for use is guided to this adder as an addition signal, and is added to the surround signal for the rear-arriving sound.

  (C) In the sound field adjusting device according to the second or third aspect, the sound field adjusting means includes two lines to which the left and right front-arriving sound signals output from the surround signal processing means are input, respectively. A fourth mode in which two lines to which two left and right surround sound signals for rear arriving sound output from the surround signal processing means are respectively input are provided.

  (D) In the sound field adjusting device according to the fourth mode, the adder provided on the left surround sound signal line for rear arriving sound includes a part of the left surround sound signal for front arriving sound or the left channel. A part of the surround sound signal for the right front arriving sound or the right channel signal is supplied to an adder provided on the right side of the rear arriving sound surround signal line. Is a fifth form in which a part of is derived as an addition signal.

  (E) In the sound field adjusting device according to the fourth aspect, the adder provided on the left and right rear arriving sound surround signal lines includes the sum of a part of the left and right front arriving sound surround signals, or the left and right left surround sound signals. A sixth mode in which the sum of some of the channel signals is derived as an addition signal.

  (F) In the sound field adjusting device according to the fourth aspect, the adder provided in the left and right rear arriving sound surround signal lines includes one part of the left and right front arriving sound surround signals, or the right and left rear arriving sound surround signals. A seventh mode in which one part of the channel signal is guided as an addition signal.

  (G) In the sound field adjusting device according to any one of the second to fourth aspects, the sound field adjusting means is supplied with two left and right front arriving sound signals output from the surround signal processing means. In addition to the two lines, there is a line into which a surround signal for the front arriving sound output from the surround signal processing means is input, and an adder provided on the line of the surround signal for the rear arriving sound has a center. An eighth mode in which a part of the surround sound signal for the forward arriving sound is guided as an addition signal.

  (H) In the sound field adjusting device according to the fifth aspect, the sound field adjusting means further includes a line to which a surround sound signal for a front-arriving sound, which is output from the surround signal processing means, is input; A line into which a surround sound signal for incoming sound is input is provided, and a part of the surround sound signal for the front forward sound in the center is provided to the adder provided in the center surround sound signal line for rear incoming sound. Ninth form derived as an addition signal.

  (I) In the sound field adjusting apparatus according to the eighth aspect, the surround signal for the rear arriving sound is input to the two left and right surround signals for the rear arriving sound and the center surround signal for the rear arriving sound. 10th form which is one line.

  (J) In the sound field adjusting device according to the fifth mode, the sound field adjusting means is further provided with a line to which a surround signal for the central rear-arriving sound output from the surround signal processing means is input. An eleventh embodiment in which the sum of a part of the left and right front-arriving sound surround signals is guided as an addition signal to the adder provided in the center rear-arriving sound surround signal line.

  (K) In the sound field adjusting device according to the fifth aspect, the sound field adjusting means is further provided with a line to which a surround signal for the central rear-arriving sound output from the surround signal processing means is input. A part of the output signal of the adder provided on the line of the surround sound signal for the left rear arriving signal and the part of the output signal of the right A twelfth aspect in which a part of an output signal of an adder provided on a line of a sound surround signal is guided as an addition signal.

  (L) A thirteenth embodiment in which the amplifier connected to each line connected to the input side of the adder provided in the sound field adjusting means is provided in the sound field adjusting device according to any one of the first to twelfth embodiments. .

  (M) In the sound field adjusting device according to any one of the first to thirteenth aspects, a delay circuit is provided on a line connected to the output side of the adder provided in the sound field adjusting means, and the rear arrival after the addition is performed. A fourteenth mode in which a surround signal for sound is delayed by a predetermined time by a delay circuit.

  (N) In the sound field adjusting device according to any one of the first to thirteenth aspects, a first delay circuit is provided on a line of an addition signal connected to an input side of an adder provided in the sound field adjusting means. A part of the left and right forward sound surround signals or a part of the left and right channel signals is delayed by a first delay circuit for a predetermined time before being added to the rear arrive sound surround signal. Form.

  (O) In the sound field adjusting device according to the fifteenth aspect, a second delay circuit is provided in a line of the surround sound signal for the rearward incoming sound connected to the input side of the adder provided in the sound field adjusting means. A sixteenth mode in which a surround signal for rear-arriving sound output from the surround signal processing means is delayed for a predetermined time by a second delay circuit before the adder.

  (P) In the sound field adjusting device according to any one of the first to sixteenth aspects, a compression circuit is provided on a line of the surround sound signal for the rearward incoming sound connected to the input side of the adder provided in the sound field adjusting means. A seventeenth mode in which a surround signal for rear arriving sound output from the surround signal processing means is compressed by a compression circuit at a stage preceding the adder.

  (Q) In the sound field adjusting device according to any one of the first to sixteenth aspects, a compression circuit is provided on a line connected to an output side of an adder provided in the sound field adjusting means, and a rearward arrival after the addition is performed. An eighteenth mode in which a surround signal for sound is compressed by a compression circuit.

  (R) In the sound field adjusting device according to any one of the first to eighteenth aspects, the sound field adjusting means is provided with an amplification factor adjusting means for an amplifier and a means for detecting the separation of a two-channel stereo signal. A nineteenth embodiment in which the amplification factor of the amplifier is adjusted by the amplification factor adjusting means according to the magnitude of the separation.

  (S) In the sound field adjusting device according to any one of the first to eighteenth aspects, the sound field adjusting means is provided with an amplification factor adjusting means for the amplifier, and the type of the source of the two-channel stereo signal and the separation of the source are determined. A twentieth aspect in which, in a known case, the amplification factor of the amplifier is adjusted by the amplification factor adjusting means according to the type of the input source.

  (T) In the sound field adjusting device according to any one of the first to twentieth aspects, the sound field adjusting device uses at least one tuner of an AM tuner, an FM tuner, and a TV tuner as a source of a two-channel stereo signal. A twenty-first embodiment connected to a surround circuit of a vehicle-mounted acoustic device.

  As a result, the sound field adjustment device connected to the surround device that generates the four-channel surround signal based on the difference component of the stereo two-channel signal deteriorates the separation of the stereo two-channel signal input to the surround device for some reason. Even in such a case, there is an effect that the magnitude of the sound output from the rear speaker does not fluctuate or the problem that no sound is output does not occur.

  Hereinafter, embodiments of the sound field adjustment device of the present invention will be described in detail based on specific examples with reference to the accompanying drawings.

  FIG. 2 shows an overall configuration of an embodiment of an audio system including a surround circuit 10 according to the present invention. The audio system of this embodiment includes a left front speaker SPFL disposed in the front left of the audio listener 30, a right front speaker SPFR disposed in the front right, a left rear speaker SPRL disposed in the rear left, and a rear right. Is a surround system that uses four speakers of the right rear speaker SPRR arranged in the speaker system.

  In the audio system of this embodiment, a tuner 2 connected to an antenna 1, a CD (compact disc) player 4, an MD (mini disc) player 5, and a cassette are used as audio reproducing devices for outputting two-channel stereo signals L and R. There is a player 6, and the signal output terminals of these playback devices are all connected to a changeover switch 7. The tuner 2 in this case is one of an AM stereo tuner, an FM stereo tuner, and a stereo TV tuner (for receiving terrestrial waves and receiving satellite waves). In addition to players such as MD, CD, and cassette players 4, 5, and 6, there are DVD (digital versatile disc) players, hard disk players, and semiconductor memory playback devices. The changeover switch 7 outputs one of the two-channel stereo signals L and R output from these playback devices to the surround circuit 10. The changeover switch 7 can be included in the surround circuit 10.

  Inside the tuner 2, a front end 2A for converting the frequency of a radio wave received by the antenna 1 and outputting an intermediate frequency, and detecting the intermediate frequency to extract an audio signal and generating two-channel stereo signals L and R therefrom. And a multiplex circuit 2B that outputs the data. An electric field intensity signal of a radio wave received by the antenna 1 is output from the front end 2A, and the electric field intensity signal is input to a microcomputer 9 that controls the entire audio system.

  The microcomputer 9 is connected to a selector 8 of a reproducing device for selecting one of the reproducing devices (the tuner 2, the CD player 4, the MD player 5, and the cassette player 6) for outputting the two-channel stereo signals L and R. A switching signal corresponding to the playback device selected by the selector 8 of the playback device is output from the microcomputer 9 to the changeover switch 7. As a result, only the output from the playback device selected by the selector 8 of the playback device is output to the surround circuit 10 through the changeover switch 7.

  A signal indicating the separation of the received stereo signals L and R is output from the multiplex circuit 2B of the FM tuner 2 to the microcomputer 9, and the microcomputer 9 uses the separation signal in the surround circuit 10 to be described later. The mixing ratio of the other signal to the driving signal of the rear speaker generated in step (1) is instructed to the mixing ratio correction circuit 20. Based on an instruction from the microcomputer 9, the mixing ratio correction circuit 20 outputs instruction signals GL and GR indicating the mixing ratio of other signals to the surround circuit 10. The mixing ratio indicating signals GL and GR will be described in detail in the following embodiments.

  The surround circuit 10 outputs a signal FL to a left front speaker SPFL disposed on the left front of the listener 30 and a right front signal disposed on the right front based on the two-channel stereo signals L and R input from the changeover switch 7. A signal FR to the speaker SPFR, a signal RL to the left rear speaker SPRL arranged on the left rear, and a signal RR to the right rear speaker SPRR arranged on the right rear are generated and output.

Here, the configuration of the sound field adjusting device of the present invention incorporated in the surround circuit 10 in the four-speaker surround system configured as described above belongs to the first to sixth embodiments and the sixth embodiment. A description will be given based on examples. The surround circuit 10 of the present invention described with reference to FIG. 2 generates a difference signal (LR) from the input left-channel signal L and right-channel signal R to generate two input signals L and R. Drive signals FL and FR of two front speakers SPFL and SPFR arranged in front of the listener 30 and two rear speakers SPRL and SPRR arranged behind the listener based on the difference signal (LR). There is the same surround signal processing circuit 3 as the conventional example having the function of generating the drive signals RL and RR, but the configuration of the surround signal processing circuit 3 is well known and will not be described here. The sound field adjusting device of the present invention is connected to the surround signal processing circuit 3.
(1) First Embodiment A first embodiment of a sound field adjusting device according to the present invention is a two-speaker rear speaker generated by a surround signal processing circuit 3 provided in a surround circuit 10 shown in FIG. In this embodiment, drive signals FL and FR of the two front speakers SPFL and SPFR are mixed with drive signals RL and RR of SPRL and SPRR, respectively.

  FIG. 3A shows the configuration of the first example of the first embodiment. In this embodiment, adders 12 are provided on the lines of the drive signals RL and RR to the two rear speakers SPRL and SPRR, respectively. In addition, amplifiers 11R are provided on the lines before the adder 12, respectively. The lines of the drive signals FL and FR to the two front speakers SPFL and SPFR are branched on the way, and the branched lines are connected to the adder 12 via the amplifier 11F. The amplification factors of the amplifiers 11F and 11R may be fixed, but may be variable according to the separation of the two-channel stereo signals L and R as described later.

  In the first embodiment configured as described above, the lines of the drive signals RL and RR to the two rear speakers SPRL and SPRR are connected to the lines of the drive signals FL and FR of the two front speakers SPFL and SPFR. Are mixed. As a result, even if the drive signals RL and RR to the two rear speakers SPRL and SPRR become 0, one of the drive signals FL and FR of the two front speakers SPFL and SPFR is provided to the two rear speakers SPRL and SPRR. Since the section flows, it is possible to prevent a problem that no sound is output from the two rear speakers SPRL and SPRR.

  FIG. 3B shows the configuration of the second example of the first embodiment. This embodiment is different from the first embodiment described with reference to FIG. 3A in that a delay circuit is provided downstream of the adder 12 provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. 13 are provided respectively. The delay times set in the two delay circuits 13 may be the same. This delay circuit 13 causes a time delay in the sound emitted from the two rear speakers SPRL, SPRR, so that the listener hears the sound as if coming from the front, and gives a sense of direction to the sound. According to the second embodiment, the conventional problem can be solved while maintaining the directionality of the sound from the front.

  FIG. 3C shows the configuration of the third example of the first embodiment. In this embodiment, a delay circuit 13F is provided between the branch point of the line to the two front speakers SPFL and SPFR of the first embodiment described with reference to FIG. 3A and the amplifier 11F. is there. The delay times set in the two delay circuits 13F may be the same. By this delay circuit 13F, a time delay occurs only in the mixed sound for the two front speakers SPFL and SPFR among the sounds emitted from the two rear speakers SPRL and SPRR so that the listener can hear the sound from the front. Hearing, sound is more directional. According to the third embodiment, in addition to the effect of the second embodiment, the directionality of the sound from the front is increased.

  FIG. 3D shows the configuration of the fourth example of the first embodiment. In this embodiment, in addition to the configuration of the third embodiment described with reference to FIG. 3C, a delay circuit 13R is also provided on the front side of the amplifier 11R provided on the line to the two rear speakers SPRL and SPRR. It is provided. The delay times set for the two types of delay circuits 13F and 13R may be the same, but may be different. By making the delay times set for the two types of delay circuits 13F and 13R different, the sound between the two rear speakers SPRL and SPRR and the sound of the two front speakers SPFL and SPFR mixed are different from each other. A time difference can be provided, and as a result, the fourth embodiment makes it easier to adjust the sound field than the third embodiment. For example, the sound emitted from the two rear speakers SPRL, SPRR can have a sense of spreading and a sense of direction.

FIG. 4A shows a configuration of a modification of the third example of the first embodiment. In this modified example, the delay circuit 13F provided before the amplifier 11F in the third embodiment is moved between the amplifier 11F and the adder 12. The effect of this configuration is the same as that of the third embodiment. FIG. 4B shows a configuration of a first modified example of the fourth example of the first embodiment, and FIG. 4C shows a configuration of the fourth example of the fourth example of the first embodiment. 14 shows a configuration of a modification example 2 of the first embodiment. In the first modification, the delay circuit 13F provided before the amplifier 11F in the fourth embodiment is moved between the amplifier 11F and the adder 12. Further, in the second modified example, the delay circuit 13R provided in the preceding stage of the amplifier 11R in the fourth embodiment is moved between the amplifier 11R and the adder 12. The effects of these configurations are the same as in the fourth embodiment.
(2) Second Embodiment A second embodiment of the sound field adjustment device according to the present invention is a sound field adjustment device according to the first embodiment in which the surround signal processing circuit 3 transmits two rear speakers SPRL and SPRR. In this embodiment, a compression circuit 14 is provided in each drive signal line. The first to fourth examples of the second embodiment described here correspond to the configurations of the first to fourth examples of the first embodiment described above.

  The compression circuit 14 in the second embodiment specifically suppresses the dynamic range of a signal from a compressor circuit, a limiter circuit, or the like. Due to the operation of the compression circuit 14, fluctuations in the size of the sound emitted from the two rear speakers SPRL, SPRR are reduced. The effect of suppressing the magnitude fluctuation of the sound emitted from the two rear speakers SPRL, SPRR is further enhanced by mixing the sound emitted from the front speakers SPFL, SPFR with the sound emitted from the rear speakers SPRL, SPRR. Therefore, in the following first to fourth examples of the second embodiment, only the configuration will be described here.

  FIG. 5A shows the configuration of the first example of the second embodiment. The configuration of this embodiment corresponds to the first embodiment of the first embodiment. The difference is that the front stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. Only in that a compression circuit 14 is provided in each of the above.

  FIG. 5B shows a configuration of a modification of the first example of the second embodiment. The only difference between the modification of the first embodiment and the first embodiment is the position of the compression circuit 14. That is, in the first embodiment, the compression circuit 14 is provided in the preceding stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. The circuit 14 is different from the first embodiment in that the circuit 14 is provided on the subsequent stage of the adder 12.

  FIG. 6A shows a configuration of a second example of the second embodiment. The configuration of this embodiment corresponds to the second embodiment of the first embodiment. The difference is that the front stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. Only in that a compression circuit 14 is provided in each of the above.

  FIG. 6B shows the configuration of the third example of the second embodiment. The configuration of this embodiment corresponds to the third embodiment of the first embodiment. The difference is that the front stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. Only in that a compression circuit 14 is provided in each of the above.

  FIG. 6C shows the configuration of the fourth example of the second embodiment. The configuration of this embodiment corresponds to the fourth embodiment of the first embodiment. The difference is that the delay circuit 13R provided on the lines of the drive signals RL and RR to the two rear speakers SPRL and SPRR is different. The only difference is that a compression circuit 14 is provided at the preceding stage. The compression circuit 14 may be provided between the delay circuit 13R and the amplifier 11R.

  FIG. 7A shows a configuration of a modification of the second example of the second embodiment. In this modified example, the compression circuit 14 provided in the preceding stage of the amplifier 11R in the second embodiment is moved between the delay circuit 13 and the adder 12. FIG. 7B shows a configuration of a modification of the third example of the second embodiment. In this modified example, the compression circuit 14 provided in the preceding stage of the amplifier 11R in the third embodiment is moved to the subsequent stage of the adder 12. FIG. 7C shows the configuration of a modification of the fourth example of the second embodiment. In this modification, the compression circuit 14 provided in the preceding stage of the delay circuit 13R in the fourth embodiment is moved to the subsequent stage of the adder 12.

Although various examples and modifications have been described above, the position of the compression circuit 14 provided on the drive signal lines from the surround signal processing circuit 3 to the two rear speakers SPRL and SPRR in the second embodiment is particularly limited. Instead, it may be determined appropriately according to the magnitude of the output signal of the surround signal processing circuit 3.
(3) Third Embodiment A third embodiment of the sound field adjusting device according to the present invention employs surround signal processing for the drive signals RL and RR of the two rear speakers SPRL and SPRR generated by the surround signal processing circuit 3. In this embodiment, a part of the two-channel stereo signals L and R to the circuit 3 is mixed.

  FIG. 8A shows the configuration of the first example of the third embodiment. In this embodiment, adders 12 are provided on the lines of the drive signals RL and RR to the two rear speakers SPRL and SPRR, respectively. In addition, amplifiers 11R are provided on the lines before the adder 12, respectively. The supply lines of the two-channel stereo signals L and R to the surround signal processing circuit 3 are branched on the way, and the branched lines are connected to the adder 12 via the amplifiers 11F. The amplification factors of the amplifiers 11F and 11R may be fixed, but may be variable according to the separation of the two-channel stereo signals L and R as described later.

  In the first example of the third embodiment configured as described above, the lines of the drive signals RL and RR to the two rear speakers SPRL and SPRR flow through the supply lines of the two-channel stereo signals L and R. Since a part of the signals are mixed, even if the drive signals RL and RR to the two rear speakers SPRL and SPRR become 0, the two rear speakers SPRL and SPRR receive the two-channel stereo signals L and R respectively. Since a part of the sound flows, it is possible to prevent a problem that no sound is output from the two rear speakers SPRL and SPRR.

  FIG. 8B shows a configuration of a second example of the third embodiment. This embodiment is different from the first embodiment described with reference to FIG. 8A in that a delay circuit is provided at the subsequent stage of the adder 12 provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. 13 are provided respectively. The delay times set in the two delay circuits 13 may be the same. This delay circuit 13 causes a time delay in the sound emitted from the two rear speakers SPRL, SPRR, so that the listener hears the sound as if coming from the front, and gives a sense of direction to the sound. According to the second embodiment, the conventional problem can be solved while maintaining the directionality of the sound from the front.

  FIG. 8C shows the configuration of the third example of the third embodiment. In this embodiment, delay circuits 13F are provided between the branch point of the supply lines of the two-channel stereo signals L and R of the first embodiment described with reference to FIG. is there. The delay times set in the two delay circuits 13F may be the same. With this delay circuit 13F, the listener hears the sound as if the sound comes from the front due to a time delay only in the mixed two-channel stereo signals L and R among the sounds emitted from the two rear speakers SPRL and SPRR. Gives a sense of direction. That is, according to the third embodiment, in addition to the effects of the second embodiment, the directionality of the sound from the front is increased.

  FIG. 8D shows the configuration of the fourth example of the third embodiment. In this embodiment, in addition to the configuration of the third embodiment described with reference to FIG. 8C, a delay circuit 13R is also provided on the front side of the amplifier 11R provided on the line to the two rear speakers SPRL and SPRR. It is provided. The delay times set for the two types of delay circuits 13F and 13R may be the same, but may be different. By making the delay times set in these two types of delay circuits 13F and 13R different, the sound between the original sound from the two rear speakers SPRL and SPRR and the sound due to the mixed two-channel stereo signals L and R are different. A time difference can be provided, and as a result, the fourth embodiment makes it easier to adjust the sound field than the third embodiment. For example, the sound emitted from the two rear speakers SPRL, SPRR can have a sense of spreading and a sense of direction.

FIG. 9A shows a configuration of a modification of the third example of the third embodiment. In this modified example, the delay circuit 13F provided before the amplifier 11F in the third embodiment is moved between the amplifier 11F and the adder 12. The effect of this configuration is the same as that of the third embodiment. FIG. 9B shows a configuration of a first modification of the fourth example of the third embodiment, and FIG. 9C shows a fourth example of the third embodiment. 13 shows a configuration of a second modified example of FIG. In the first modification, the delay circuit 13F provided before the amplifier 11F in the fourth embodiment is moved between the amplifier 11F and the adder 12. Further, in the second modified example, the delay circuit 13R provided in the preceding stage of the amplifier 11R in the fourth embodiment is moved between the amplifier 11R and the adder 12. The effects of these configurations are the same as in the fourth embodiment.
(4) Fourth Embodiment A fourth embodiment of the sound field adjustment device according to the present invention is a sound field adjustment device according to the third embodiment in which the surround signal processing circuit 3 transmits two rear speakers SPRL and SPRR. In this embodiment, a compression circuit 14 is provided in each drive signal line. The first to fourth examples of the fourth embodiment described here correspond to the configurations of the first to fourth examples of the third embodiment described above.

  The compression circuit 14 according to the fourth embodiment specifically suppresses the dynamic range of signals from a compressor circuit, a limiter circuit, and the like. Due to the operation of the compression circuit 14, fluctuations in the size of the sound emitted from the two rear speakers SPRL, SPRR are reduced. The effect of suppressing fluctuations in the magnitude of the sound emitted from the two rear speakers SPRL, SPRR is further enhanced by mixing the two-channel stereo signals L, R with the drive signals RL, RR of the rear speakers SPRL, SPRR. Therefore, in the following first to fourth examples of the fourth embodiment, only the configuration will be described here.

  FIG. 10A shows the configuration of the first example of the fourth embodiment. The configuration of this embodiment corresponds to the first embodiment of the third embodiment. The difference is that the front stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. Only in that a compression circuit 14 is provided in each of the above.

  FIG. 10B shows a configuration of a modified example of the first example of the fourth embodiment. The only difference between the modification of the first embodiment and the first embodiment is the position of the compression circuit 14. That is, in the first embodiment, the compression circuit 14 is provided in the preceding stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. The circuit 14 is different from the first embodiment in that the circuit 14 is provided on the subsequent stage of the adder 12.

  FIG. 11A shows a configuration of a second example of the fourth embodiment. The configuration of this embodiment corresponds to the second embodiment of the third embodiment. The difference is that the front stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. Only in that a compression circuit 14 is provided in each of the above.

  FIG. 11B shows the configuration of the third example of the fourth embodiment. The configuration of this embodiment corresponds to the third embodiment of the third embodiment. The difference is that the front stage of the amplifier 11R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. Only in that a compression circuit 14 is provided in each of the above.

  FIG. 11C shows the configuration of the fourth example of the fourth embodiment. The configuration of this embodiment corresponds to the fourth embodiment of the third embodiment. The difference is that the delay circuit 13R provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR is different. The only difference is that a compression circuit 14 is provided at the preceding stage. The compression circuit 14 may be provided between the delay circuit 13R and the amplifier 11R.

  FIG. 12A shows a configuration of a modification of the second example of the fourth embodiment. In this modified example, the compression circuit 14 provided in the preceding stage of the amplifier 11R in the second embodiment is moved between the delay circuit 13 and the adder 12. FIG. 12B shows a configuration of a modification of the third example of the fourth embodiment. In this modified example, the compression circuit 14 provided in the preceding stage of the amplifier 11R in the third embodiment is moved to the subsequent stage of the adder 12. FIG. 12C shows the configuration of a modification of the fourth example of the fourth embodiment. In this modification, the compression circuit 14 provided in the preceding stage of the delay circuit 13R in the fourth embodiment is moved to the subsequent stage of the adder 12.

Although various examples and modifications have been described above, the position of the compression circuit 14 provided in the drive signal lines from the surround signal processing circuit 3 to the two rear speakers SPRL and SPRR in the fourth embodiment is particularly limited. Instead, it may be determined appropriately according to the magnitude of the output signal of the surround signal processing circuit 3.
(5) Fifth Embodiment In a fifth embodiment of the sound field adjusting device of the present invention, two front speakers SPRL, SPRR generated by the surround signal processing circuit 3 and drive signals RL, RR for the two rear speakers SPRR, two front speakers In this embodiment, a part of the drive signals FL and FR of the speakers SPFL and SPFR are added by an adder 12F and then branched and mixed. In other words, the drive signals RL and RR of the two rear speakers SPRL and SPRR are added with the drive signals FL and FR of the two front speakers SPFL and SPFR to add a part of the monaural signal.

  In the fifth embodiment, a rear signal is added in order to add a part of the monaural signal obtained by adding the drive signals FL and FR of the two front speakers SPFL and SPFR to the drive signals RL and RR of the two rear speakers SPRL and SPRR. Although the separation of the sound emitted from the speakers SPRL and SPRR is deteriorated, there is an advantage that the sound is reproduced stably from the rear. The fifth embodiment is the same as the first embodiment, except that the drive signals FL and FR of the two front speakers SPFL and SPFR are added to make a monaural signal, and then the signal is branched. Modifications are possible.

  Therefore, in the fifth embodiment, only the basic first to fourth examples corresponding to the first to fourth examples of the first embodiment and the configuration of one modified example will be described. stop.

  FIG. 13A shows the configuration of the first example of the fifth embodiment. In this embodiment, adders 12 are provided on the lines of the drive signals RL and RR to the two rear speakers SPRL and SPRR, respectively. In addition, amplifiers 11R are provided on the lines before the adder 12, respectively. The lines of the drive signals FL and FR to the two front speakers SPFL and SPFR are branched on the way, and the branched lines are connected to the adder 12F via the amplifier 11F. The output of the adder 12F is branched into two and connected to the adder 12, respectively. The amplifier 11F may be provided only one after the adder 12F.

  FIG. 13B shows the configuration of the second example of the fifth embodiment. This embodiment is different from the first embodiment described with reference to FIG. 13A in that a delay circuit is provided after the adder 12 provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. 13 are provided respectively.

  FIG. 13C shows the configuration of the third example of the fifth embodiment. In this embodiment, one delay circuit 13F is provided after the adder 12F of the first embodiment described with reference to FIG.

  FIG. 13D shows the configuration of the fourth example of the fifth embodiment. In this embodiment, in addition to the configuration of the third embodiment described with reference to FIG. 13C, a delay circuit 13R is also provided on the front stage side of the amplifier 11R provided on the line to the two rear speakers SPRL, SPRR. It is provided.

Further, in the fifth embodiment, as in the second embodiment, an example in which a compression circuit 14 is provided in each of drive signal lines from the surround signal processing circuit 3 to the two rear speakers SPRL and SPRR is also possible. It is.
(6) Sixth Embodiment A sixth embodiment of the sound field adjusting device according to the present invention employs surround signal processing on the drive signals RL and RR of the two rear speakers SPRL and SPRR generated by the surround signal processing circuit 3. In this embodiment, a part of the two-channel stereo signals L and R to the circuit 3 is added by an adder 12F and then branched and mixed. That is, a part of the drive signals RL, RR of the two rear speakers SPRL, SPRR, which are monaural by adding the two-channel stereo signals L, R, are added.

  In the sixth embodiment as well, the drive signals RL and RR of the two rear speakers SPRL and SPRR are output from the rear speakers SPRL and SPRR in order to add a part of the monaural signal obtained by adding the two-channel stereo signals L and R. Although the sound separation is deteriorated, there is an advantage that the sound is reproduced stably from the rear. In the sixth embodiment, the same example as the third embodiment and its modified example are possible except that the two-channel stereo signals L and R are added and converted to monaural before branching. .

  Therefore, in the sixth embodiment, only the basic first to fourth examples corresponding to the first to fourth examples of the third embodiment and the configuration of one modified example will be described. stop.

  FIG. 14A shows the configuration of the first example of the sixth embodiment. In this embodiment, adders 12 are provided on the lines of the drive signals RL and RR to the two rear speakers SPRL and SPRR, respectively. In addition, amplifiers 11R are provided on the lines before the adder 12, respectively. The supply lines for the two-channel stereo signals L and R are branched on the way, and the branched lines are connected to the adder 12F via the amplifier 11F. The output of the adder 12F is branched into two and connected to the adder 12, respectively. The amplifier 11F may be provided only one after the adder 12F.

  FIG. 14B shows the configuration of the second example of the sixth embodiment. This embodiment is different from the first embodiment described with reference to FIG. 14A in that a delay circuit is provided after the adder 12 provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRR. 13 are provided respectively.

  FIG. 14C shows the configuration of the third example of the sixth embodiment. In this embodiment, one delay circuit 13F is provided after the adder 12F of the first embodiment described with reference to FIG.

  FIG. 14D shows the configuration of the fourth example of the sixth embodiment. In this embodiment, in addition to the configuration of the third embodiment described with reference to FIG. 14C, a delay circuit 13R is also provided on the front side of the amplifier 11R provided on the line to the two rear speakers SPRL and SPRR. It is provided.

  In the sixth embodiment, as in the fourth embodiment, a form in which a compression circuit 14 is provided in each of drive signal lines from the surround signal processing circuit 3 to the two rear speakers SPRL and SPRR is also possible. is there.

  FIG. 15A is a circuit diagram showing a configuration of a modification of the first example of the fifth embodiment. In the first example of the fifth embodiment, a part of the monaural signal obtained by adding the drive signals FL and FR of the two front speakers SPFL and SPFR to the drive signals RL and RR of the two rear speakers SPRL and SPRR. However, this modification is different in that a part of one of the drive signals FL and FR of the two front speakers SPFL and SPFR is added. In this modification, a part of the drive signal FL of the front speaker SPFL is added, but the drive signal FR of the front speaker SPFR may be added.

FIG. 15B is a circuit diagram showing a configuration of a modification of the first example of the sixth embodiment. In the first example of the sixth embodiment, a part of monaural signals obtained by adding the two-channel stereo signals L and R to the drive signals RL and RR of the two rear speakers SPRL and SPRR is added. This modification is different in that a part of one of the two-channel stereo signals L and R is added. In this modification, a part of the drive signal FR of the front speaker SPFR is added, but the drive signal FL of the front speaker SPFL may be added.
(7) Amplification rate adjustment of amplifier in first to sixth embodiments The amplifiers 11F and 11R are used in the first to sixth embodiments of the sound field adjustment device of the present invention described above. The gain (amplification rate) of these amplifiers can be a fixed value set in advance, but can also be varied. The case where the amplification factors of the amplifiers 11F and 11R are adjusted will be described by taking the circuit of the first example of the first embodiment as an example.

  FIG. 16A shows a state in which the gain adjustment circuit 21 is provided in the circuit of the first example of the first embodiment. Upon receiving the mixing ratio indicating signals GL and GR from the mixing ratio correcting circuit 20 described with reference to FIG. 2, the gain adjusting circuit 21 determines the amplification factors of the amplifiers 11F and 11R in accordance with the mixing ratio indicating signals GL and GR. Then, the amplification factors of the amplifiers 11F and 11R are controlled.

  The ratio of the drive signals FL and FR of the two front speakers SPFL and SPFR mixed with the drive signals RL and RR of the two rear speakers SPRL and SPRR, or the ratio of the two-channel stereo signals L and R is two-channel stereo signals L and R. When the separation of R is large, it may be small. For this reason, the microcomputer 9 shown in FIG. 2 stores, for example, data obtained by mapping characteristics as shown in FIG. 16B in the form of a common map or a map for each amplifier. When the separation of L and R is large, the drive signals FL and FR of the two front speakers SPFL and SPFR or the mixing ratio of the two-channel stereo signals L and R, that is, the amplification factors of the amplifiers 11F and 11R are reduced. To control.

  In addition, a predetermined threshold value is set for the separation value of the two-channel stereo signals L and R, and when the separation of the input two-channel stereo signals L and R is larger than this threshold value, two front speakers SPFL and SPFR are set. Or the mixing ratio of the two-channel stereo signals L and R, that is, the amplification factors of the amplifiers 11F and 11R may be controlled to be small.

  By such control, when the separation of the two-channel stereo signal is large, the surround effect is exerted, and when the separation is small, the problem that no sound is output from the rear speaker can be eliminated.

Further, the amount of addition of other signals to be added to the drive signal to the rear speaker is controlled by the type of input source of the two-channel stereo signals L and R, which is switched by the changeover switch 7 described in FIG. You may do it. For example, in a player system that reproduces a stereo signal from a recording medium such as a CD, MD, cassette, DVD, hard disk, or semiconductor memory, the separation of the reproduced stereo signal does not change. In a tuner system that receives a radio wave, depending on the reception environment. Since the separation of the reproduced stereo signal fluctuates, the tuner system controls the addition amount of other signals to be added to the drive signal to the rear speaker, and the player system adds it to the drive signal to the rear speaker. May be controlled so as to reduce the amount of addition of other signals.
(8) Seventh Embodiment In the first to sixth embodiments of the sound field adjusting device of the present invention described above, the left front speaker SPFL arranged on the left front of the listener 30 and the right front speaker SPFL arranged on the right front. The sound field adjustment device of the present invention is applied to a surround system using four speakers: a right front speaker SPFR, a left rear speaker SPRL disposed on the left rear, and a right rear speaker SPRR disposed on the right rear. .

  On the other hand, as shown in FIG. 17A, a seventh embodiment of the sound field adjustment device of the present invention includes a left front speaker SPFL arranged on the left front of the listener 30 and a right front speaker arranged on the right front. The sound field adjustment device of the present invention is applied to a surround system using three speakers, a speaker SPFR and a rear speaker SPRC arranged only one rear. In the seventh embodiment, a part of the drive signals FL and FR of the two front speakers SPFL and SPFR, or the two-channel stereo signals L and R are added to the drive signals RC of the rear speakers SPRC generated by the surround signal processing circuit 3. Are added after mixing.

  FIG. 17B is a circuit diagram illustrating a configuration of one example of the seventh embodiment, and corresponds to the first example of the first embodiment. In this embodiment, an adder 12 is provided on the line of the drive signal RC to the rear speaker SPRC. In addition, an amplifier 11R is provided in a line before the adder 12. The lines of the drive signals FL and FR to the two front speakers SPFL and SPFR are branched on the way, and the branched lines are connected to the adder 12F via the amplifier 11F and then to the adder 12. ing.

  In the seventh embodiment, in addition to this example, the following examples are possible.

  (A) A delay circuit is provided before or after the adder 12.

  (B) A delay circuit is provided before or after the amplifier 11F.

  (C) A delay circuit is provided before or after the amplifiers 11F and 11R.

  (D) A compression circuit is provided on the drive signal line to the rear speaker SPRC.

(E) Part of one of the drive signals FL and FR of the two front speakers SPFL and SPFR, or part of one of the two-channel stereo signals L and R is added to the line of the drive signal to the rear speakers SPRL and SPRR. .
(9) Eighth Embodiment As shown in FIG. 18A, an eighth embodiment of the sound field adjustment device of the present invention includes a left front speaker SPFL, a right front speaker SPFR, a left rear speaker SPRL, and a right rear speaker SPRL. The sound field adjustment device of the present invention is applied to a surround system using five speakers including a front center speaker SPFC arranged in the front center of a listener 30 in addition to the four rear speakers SPRR. In the eighth embodiment, the drive signals RL and RR of the two rear speakers SPRL and SPRR generated by the surround signal processing circuit 3 are partially added to the drive signals FL and FR of the two front speakers SPFL and SPFR, or 2 There are a first mode in which a part of the channel stereo signals L and R are added, and a second mode in which a part of the drive signal FC of the front center speaker SPFC is added.

  FIG. 18B is a first example of the first embodiment, in which only the drive signal FC of the center speaker SPFC at the front center from the surround signal processing circuit 3 is increased, and the remaining configuration is as shown in FIG. Since the configuration is exactly the same as that of the first embodiment of the first embodiment described in (1), description thereof will be omitted. FIG. 18C shows a second embodiment of the second embodiment, in which the adder 12 provided on the lines of the drive signals RL and RR for the two rear speakers SPRL and SPRC has the drive of the front center speaker SPFC. A part of the signal FC is added after being amplified by the amplifier 11F.

  In the eighth embodiment, in addition to this example, the following examples are possible.

  (A) A delay circuit is provided before or after the adder 12.

  (B) A delay circuit is provided before or after the amplifier 11F.

  (C) A delay circuit is provided before or after the amplifiers 11F and 11R.

  (D) Each of the drive signal lines to the rear speakers SPRL and SPRR has a compression circuit.

  (E) Rear speakers SPRL, SPRR after a part after mixing drive signals FL, FR of two front speakers SPFL, SPFR or a part after mixing two-channel stereo signals L, R, respectively. To the drive signal line.

(F) One part of one of the drive signals FL and FR of the two front speakers SPFL and SPFR or one part of the two-channel stereo signals L and R is provided on the line of the drive signal to the rear speakers SPRL and SPRR, respectively. Added.
(10) Ninth Embodiment As shown in FIG. 19A, a ninth embodiment of the sound field adjustment device of the present invention includes a left front speaker SPFL, a right front speaker SPFR, a left rear speaker SPRL, and a right front speaker SPRL. The sound field adjustment device of the present invention is applied to a surround system using six speakers including a front center speaker SPFC and a rear center speaker SPRC in addition to four rear speakers SPRR.

  In the ninth embodiment, the following four examples can be considered depending on what kind of signal is mixed with the rear center speaker SPRC.

  In the first embodiment, a part of the drive signal FC to the front center speaker SPFC is mixed with the rear center speaker SPRC, and this configuration is shown in FIG. Other configurations are the same as those of the first example of the first embodiment, and a description thereof will be omitted.

  In the second embodiment, a part of the drive signal FC to the front center speaker SPFC is mixed with all of the three rear speakers SPRL, SPRC, SPRR, and this configuration is shown in FIG. .

  In the third embodiment, the rear center speaker SPRC is added after a part of the drive signals FL and FR to the left front speaker SPFL and the right front speaker SPFR are mixed. This configuration is shown in FIG. Is shown.

  In the fourth embodiment, a drive signal to the left rear speaker SPRL after a part of the drive signal FL to the left front speaker SPFL is mixed with a drive signal RC to the rear center speaker SPRC, and a drive signal to the right front speaker SPFR The drive signal to the right rear speaker SPRR after a part of the drive signal FR to the drive signal FR is mixed is added to the adder 12C via the amplifier circuit 11C, and this configuration is shown in FIG. It is.

  In the ninth embodiment, as in the eighth embodiment, examples having the above-described configurations (A) to (F) are possible.

  Note that the sound field adjustment device of the present invention configured as described above is connected to a surround device equipped with an FM tuner when the surround device is mounted on the vehicle. Especially effective.

  If the sound field adjustment device of the present invention is connected to a surround device that generates a four-channel surround signal based on a stereo two-channel signal or a difference component thereof, the separation of the stereo two-channel signal input to the surround device may cause some cause. Even if the sound quality is deteriorated, there is no problem in which the magnitude of the rear-arriving sound fluctuates or no sound is produced at all, so that the sound field adjusting device can be effectively used. In particular, the present invention is effective when applied to a sound field adjustment device that adjusts sound output from a surround device mounted on an automobile.

(A) is a diagram showing an operation of a surround processing circuit when an FM tuner is installed in a strong electric field area, and (b) is a problem of an operation of the surround processing circuit when an FM tuner is installed in a weak electric field area. It is a figure showing a point. 1 is an overall configuration diagram of an audio system including a surround circuit that incorporates a sound field adjustment device of the present invention. 1 shows a first embodiment in which a sound field adjustment device of the present invention is connected to a surround device of a four-speaker system, and FIG. 2A is a circuit diagram showing a configuration of a first example of the first embodiment. , (B) is a circuit diagram showing a configuration of a second example of the first embodiment, (c) is a circuit diagram showing a configuration of a third example of the first embodiment, and (d) is a circuit diagram of the third example. FIG. 14 is a circuit diagram illustrating a configuration of a fourth example of the first embodiment. (A) is a circuit diagram showing a configuration of a modification of the third example of the first embodiment, and (b) shows a configuration of a first modification of the fourth example of the first embodiment. FIG. 13C is a circuit diagram illustrating a configuration of a second modification of the fourth example of the first embodiment. FIG. 6 shows a second embodiment in which the sound field adjustment device of the present invention is connected to a surround device of a four-speaker system, and FIG. 7A is a circuit diagram showing a configuration of a first example of the second embodiment. And (b) is a circuit diagram showing a configuration of a modification of the first example of the second embodiment. (A) is a circuit diagram showing a configuration of a second example of the second embodiment, (b) is a circuit diagram showing a configuration of a third example of the second embodiment, and (c) is a circuit diagram of the second example. FIG. 13 is a circuit diagram showing a configuration of a fourth example of the embodiment. (A) is a circuit diagram showing a configuration of a modification of the second example of the second embodiment, (b) is a circuit diagram showing a configuration of a modification of the third example of the second embodiment, (C) is a circuit diagram showing a configuration of a fourth example of the second embodiment. FIG. 9 shows a third embodiment in which the sound field adjustment device of the present invention is connected to a surround device of a four-speaker system, and FIG. 10A is a circuit diagram showing a configuration of a first example of the third embodiment. , (B) is a circuit diagram showing a configuration of a second example of the third embodiment, (c) is a circuit diagram showing a configuration of a third example of the third embodiment, and (d) is a circuit diagram of the third example. FIG. 14 is a circuit diagram illustrating a configuration of a fourth example of the third embodiment. (A) is a circuit diagram showing a configuration of a modification of the third example of the third embodiment, and (b) shows a configuration of a first modification of the fourth example of the third embodiment. FIG. 15C is a circuit diagram showing a configuration of a second modification of the fourth example of the third embodiment. FIG. 9 shows a fourth embodiment in which the sound field adjustment device of the present invention is connected to a surround device of a four-speaker system, and FIG. 10A is a circuit diagram showing a configuration of a first example of the fourth embodiment. And (b) is a circuit diagram showing a configuration of a modification of the first example of the fourth embodiment. (A) is a circuit diagram showing a configuration of a second example of the fourth embodiment, (b) is a circuit diagram showing a configuration of a third example of the fourth embodiment, and (c) is a circuit diagram of the fourth example. FIG. 13 is a circuit diagram showing a configuration of a fourth example of the embodiment. (A) is a circuit diagram showing a configuration of a modification of the second example of the fourth embodiment, (b) is a circuit diagram showing a configuration of a modification of the third example of the fourth embodiment, (C) is a circuit diagram showing a configuration of a fourth example of the fourth embodiment. FIG. 11 shows a fifth embodiment in which the sound field adjustment device of the present invention is connected to a surround device of a four-speaker system, and FIG. 10A is a circuit diagram showing a configuration of a first example of the fifth embodiment. (B) is a circuit diagram showing a configuration of a second example of the fifth embodiment, (c) is a circuit diagram showing a configuration of a third example of the fifth embodiment, and (d) is a circuit diagram of the third example. FIG. 21 is a circuit diagram illustrating a configuration of a fourth example of the fifth embodiment; FIG. 14 shows a sixth embodiment in which the sound field adjustment device of the present invention is connected to a surround device of a four-speaker system, and FIG. 14A is a circuit diagram showing a configuration of a first example of the sixth embodiment. (B) is a circuit diagram showing a configuration of a second example of the sixth embodiment, (c) is a circuit diagram showing a configuration of a third example of the sixth embodiment, and (d) is a circuit diagram of the third example. FIG. 21 is a circuit diagram illustrating a configuration of a fourth example of the sixth embodiment. (A) is a circuit diagram showing a configuration of a modification of the first example of the fifth embodiment, and (b) is a circuit diagram showing a configuration of a modification of the first example of the sixth embodiment. is there. (A) is a circuit diagram showing a circuit configuration for adjusting an amplification factor of an amplifier provided in the circuit of the embodiment described above, and (b) explains characteristics of separation of a two-channel stereo signal and gain characteristics of each amplifier. FIG. 9 is a representative characteristic diagram. (A) is a diagram showing an example of the arrangement of each speaker in the seventh embodiment in which the sound field adjustment device of the present invention is incorporated in a surround circuit of a surround device of a three-speaker system, and (b) is a diagram showing the arrangement in the seventh embodiment. FIG. 2 is a circuit diagram showing a configuration of one embodiment. (A) is a diagram showing an arrangement example of each speaker in the eighth embodiment in which the sound field adjustment device of the present invention is incorporated in a surround circuit of a surround device of a five-speaker system, and (b) is a diagram showing an arrangement example in the eighth embodiment. FIG. 14 is a circuit diagram illustrating a configuration of a first example, and FIG. 14C is a circuit diagram illustrating a configuration of a second example in the eighth embodiment. (A) is a figure showing an example of arrangement of each speaker in a ninth embodiment in which a sound field adjustment device of the present invention is incorporated in a surround circuit of a surround device of a six-speaker system, and (b) is a diagram showing an arrangement in the ninth embodiment. FIG. 14 is a circuit diagram showing a configuration of a first example, and FIG. 14C is a circuit diagram showing a configuration of a second example in the ninth embodiment. (A) is a circuit diagram showing a configuration of a third example of the ninth embodiment, and (b) is a circuit diagram showing a configuration of a fourth example of the ninth embodiment.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Antenna 2 ... FM tuner 3 ... Surround signal processing circuit 7 ... Changeover switch 8 ... Operator selector 9 ... Microcomputer 10 ... Surround circuits 11, 11F, 11R of this invention ... Amplifier 12, 12C, 12F ... Adder 13, 13F, 13R delay circuit 14 compression circuit 20 mixing ratio correction circuit 21 amplification factor adjustment circuit 30 listener SPFC front center speaker SPFL left front speaker SPFR right front speaker SPRC rear center speaker SPRL left rear Speaker SPRR: Right rear speaker

Claims (21)

A surround device including surround signal processing means for generating a surround signal based on a left channel signal and a right channel signal input from a playback device that outputs a two-channel stereo signal, and a difference signal generated from these input signals. A sound field adjustment device to be connected,
A signal generated based on one or both of the left-channel signal and the right-channel signal is added to a predetermined surround signal as an addition signal, and a sound field adjustment unit that adjusts a sound field is provided. Sound field adjustment device. The sound field adjustment device according to claim 1,
From the surround signal processing means, as the surround signals, surround signals for at least two right and left front arriving sounds arriving from the front of the listener, and at least one surround arriving sound for the rear arriving sounds arriving from the rear of the listener. Signal is output,
The sound field adjusting means includes an adder on a line to which the surround sound signal for the rear arriving sound is input, and a part of the surround sound signal for the front arriving sound is guided to the adder as the addition signal. And a sound field adjusting device for adding the sound signal to the surround sound signal for the rear incoming sound. The sound field adjustment device according to claim 1,
From the surround signal processing means, as the surround signals, surround signals for at least two right and left front arriving sounds arriving from the front of the listener, and at least one surround arriving sound for the rear arriving sounds arriving from the rear of the listener. Signal is output,
The sound field adjusting means includes an adder on a line to which the surround signal for the rearward arriving sound is input, and a part of the left channel signal or the right channel signal is supplied to the adder as the addition signal. A sound field adjustment device, wherein the sound field adjustment device is guided and added to the surround sound signal for the rearward arriving sound. The sound field adjustment device according to claim 2 or 3,
The sound field adjusting means includes two lines to which two front left and right surround sound signals output from the surround signal processing means are respectively input, and two left and right rear signals output from the surround signal processing means. A sound field adjustment device comprising two lines to which a surround signal for an incoming sound is input. The sound field adjustment device according to claim 4,
In the adder provided on the line of the surround sound signal for the left rear arrival sound, a part of the surround signal for the left front arrival sound or a part of the left channel signal is used as the addition signal. The adder provided on the line of the surround signal for the rearward arriving sound on the right side includes a part of the surround signal for the rightward arriving sound or a part of the signal for the right channel. A sound field adjustment device, which is guided as an addition signal. The sound field adjustment device according to claim 4,
The adder provided in the left and right rear arriving sound surround signal lines has a sum of a part of the left and right front arriving sound surround signals or a part of the left and right channel signals. A sound field adjustment device, wherein each of the sound field adjustment devices is guided as the addition signal. The sound field adjustment device according to claim 4,
The adder provided on the left and right rear arriving sound surround signal lines has one part of the left and right front arriving sound surround signals, or one part of the left and right channel signals, A sound field adjustment device, wherein each of the sound field adjustment devices is guided as the addition signal. The sound field adjustment device according to any one of claims 2 to 4,
The sound field adjusting means includes a center line output from the surround signal processing means, in addition to two lines to which surround signals for two right and left front sounds output from the surround signal processing means are respectively input. There is a line to which the surround signal for the incoming sound is input,
The sound field adjusting device according to claim 1, wherein a part of the center surround sound signal for the front incoming sound is guided as the addition signal to the adder provided on the line of the surround sound signal for the rear incoming sound. The sound field adjusting device according to claim 5,
The sound field adjusting unit further includes a line to which a surround signal for a central forward arriving sound, which is output from the surround signal processing unit, and a line to which a surround signal for a central rear arriving sound are inputted. Is provided,
A sound field adjustment, wherein a part of the center front-arriving sound surround signal is guided as the addition signal to the adder provided on the center rear-arriving sound line. apparatus. The sound field adjusting device according to claim 8,
The sound field adjustment device according to claim 1, wherein the lines of the rear-arriving sound surround signal are three lines to which two left and right rear-arriving sound surround signals and a center rear-arriving sound surround signal are input. . The sound field adjusting device according to claim 5,
The sound field adjusting means is further provided with a line to which a surround signal for the central rear arriving sound output from the surround signal processing means is input,
The sound is characterized in that a sum of a part of the left and right front-arriving sound surround signals is guided as the addition signal to the adder provided on the center rear-arriving sound line. Field adjustment device. The sound field adjusting device according to claim 5,
The sound field adjusting means is further provided with a line to which a surround signal for the central rear arriving sound output from the surround signal processing means is input,
The adder provided in the center rear-arriving sound surround signal line includes a part of the adder output signal provided in the left rear-arriving sound surround signal line, A sound field adjustment device, wherein a part of an output signal of the adder provided on a right-side surround sound signal line for a rearward-arriving sound is guided as the addition signal. The sound field adjusting device according to any one of claims 1 to 12,
A sound field adjusting device, wherein an amplifier is provided in each line connected to the input side of the adder provided in the sound field adjusting means. The sound field adjustment device according to any one of claims 1 to 13,
A delay circuit is provided on a line connected to the output side of the adder provided in the sound field adjusting means, and the surround signal for the rearward arriving sound after the addition is delayed by a predetermined time by the delay circuit. A sound field adjusting device, characterized in that: The sound field adjustment device according to any one of claims 1 to 13,
A first delay circuit is provided on a line of the addition signal connected to an input side of the adder provided in the sound field adjustment unit,
A part of the left and right front arriving sound surround signals or a part of the left and right channel signals is delayed for a predetermined time by the first delay circuit before being added to the rear arriving sound surround signal. A sound field adjusting device, characterized in that: The sound field adjustment device according to claim 15,
A second delay circuit is provided on a line of the surround sound signal for the rear arriving sound connected to the input side of the adder provided in the sound field adjusting unit,
A sound field adjusting device, wherein the surround signal for the rearward arriving sound output from the surround signal processing means is delayed by a predetermined time by the second delay circuit at a stage preceding the adder. The sound field adjustment device according to any one of claims 1 to 16,
A compression circuit is provided on a line of the surround sound signal for the rear arriving sound connected to the input side of the adder provided in the sound field adjustment unit,
A sound field adjustment device, wherein the surround sound signal for the rearward incoming sound output from the surround signal processing means is compressed by the compression circuit at a stage preceding the adder. The sound field adjustment device according to any one of claims 1 to 16,
A compression circuit is provided on a line connected to the output side of the adder provided in the sound field adjusting means,
The sound field adjustment device, wherein the surround signal for the rearward arriving sound after the addition is compressed by the compression circuit. The sound field adjustment device according to any one of claims 1 to 18, wherein
The sound field adjusting means includes an amplification factor adjusting means for the amplifier and a detecting means for detecting the separation of the two-channel stereo signal,
A sound field adjusting device, wherein the amplification factor of the amplifier is adjusted by the amplification factor adjusting means in accordance with the detected magnitude of the separation. The sound field adjustment device according to any one of claims 1 to 18, wherein
The sound field adjusting means is provided with an amplification factor adjusting means of the amplifier,
Wherein the amplification factor of the amplifier is adjusted by the amplification factor adjusting means according to the type of the input source when the type of the source of the two-channel stereo signal and the separation of the source are known. Field adjustment device. The sound field adjustment device according to any one of claims 1 to 20,
This sound field adjustment device is connected to a surround circuit of a vehicle-mounted audio device having at least one of an AM tuner, an FM tuner, and a TV tuner as a source of the two-channel stereo signal. Field adjustment device.

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