JP2007312081A - Audio system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a symmetrical sound field with simple constitution and to form a sound field having surround effect of high sound quality even when left and right speakers are arranged in front of a listening position asymmetrically. <P>SOLUTION: An audio system 1 has a left speaker 15L and a right speaker 15R arranged at asymmetrical positions with respect to the listening position 2, a sub-speaker 15S arranged on the right side where the right speaker 15R closer to the listening position 2 between the right side and left side of the listening position 2, and a correcting unit 14 which processes audio signals input to the respective speakers 15L, 15R, and 15S. The correcting unit 14 performs delay processing and level correction processing for the audio signals input to the right speaker 15R and the sub-speaker 15S closer to the listening position 2 based upon the position relation among the respective speakers 15R, 15L, and 15S. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an audio system such as an in-vehicle audio system.

  In a general two-channel stereo system, for example, when left and right front speakers are arranged at a specified interval from the listening position to the front side, if the left and right speakers are made to correspond to the vertex positions of the bottom edges of an isosceles triangle, the remaining vertices The position and its vicinity are considered to be good listening positions. However, at positions shifted from the right listening position to the right or left side, the distance from each speaker to the listening position is different, which may cause problems such as sound image localization not being determined and sound spread differing in the horizontal direction. is there.

  In particular, in an audio system provided in a vehicle such as an automobile, the left and right speakers are arranged, for example, on the left and right front doors or on the front side depending on factors such as the function of the vehicle, safety, operability, air conditioning, and mounting strength. In addition to being restricted to both sides of the instrument panel, etc., the listening position is restricted to a position shifted to the right or left side with respect to the left and right speaker placement positions, such as the driver's seat and front passenger seat. Problems are likely to occur.

  Therefore, acoustic systems that correct the sound field are known. For example, in the acoustic system disclosed in Patent Document 1, a speaker is provided on a seat on which a viewer is seated and a speaker is disposed in the rear space of the viewer to perform a special correction process using a head acoustic transfer function or the like, A technique for improving a sound field by forming a virtual sound source in a space in front of a viewer is disclosed.

Japanese Patent Laid-Open No. 2003-61997

  However, in the above-described acoustic system, it is necessary to perform a special correction process for forming a virtual sound source in the viewer's front space.

  When left and right speakers are arranged asymmetrically forward and left with respect to the listening position, for example, the reproduced sound from the right speaker near the listening position and the reproduced sound from the other left speaker of the left and right speakers are at the listening position. If the audio signal input to the right speaker is simply corrected so that the phases match, the distance between the listening position and the virtual sound source of the right speaker matches the distance between the listening position and the left speaker. At the listening position, the sound field is twisted to the left side, and in detail, a distorted sound field is formed on the left side and narrow on the right side, and there is a problem that the sound quality such as the surround effect is reduced.

  This invention makes it an example of a subject to cope with such a problem. That is, even when left and right speakers are arranged asymmetrically in front of the listening position, a symmetrical sound field is formed with a simple configuration, and a sound field having a high-quality surround effect is formed. Are the objects of the present invention.

  In order to achieve such an object, the present invention comprises at least the configurations according to the following independent claims.

  The invention according to claim 1 is an audio system in which a left speaker and a right speaker are arranged at positions that are asymmetrical forward with respect to the listening position, and is arranged in the vicinity of the listening position, and the listening position Of the right speaker or the left speaker, the auxiliary speaker disposed on one side of the right speaker or the left speaker close to the listening position, and the audio input to the left speaker, the right speaker, and the auxiliary speaker. A processing unit that processes a signal, and the processing unit is a speaker close to the listening position among the left speaker and the right speaker, based on a positional relationship of the left speaker, the right speaker, and the auxiliary speaker. In addition, the audio signal input to the auxiliary speaker is subjected to delay processing and level correction processing to form a virtual sound source to be listened to. Forming a front symmetrical sound field the location as a reference.

  An audio system according to an embodiment of the present invention is an audio system in which a left speaker and a right speaker are arranged at positions that are asymmetrical forward and left with respect to a listening position. A processing for processing an auxiliary speaker arranged on one side where the right speaker or the left speaker close to the listening position is arranged on the right side or the left side of the position, and an audio signal inputted to the left speaker, the right speaker, and the auxiliary speaker The processing unit delays the audio signal input to the auxiliary speaker and the speaker near the listening position among the left speaker and the right speaker based on the positional relationship of the left speaker, the right speaker, and the auxiliary speaker. Then, a virtual sound source is formed by performing level correction processing, and a sound field that is symmetrical left and right with respect to the listening position is formed. .

  In the audio system configured as described above, the processing unit delays the audio signal input to the speaker near the listening position and the auxiliary speaker among the left speaker and the right speaker based on the positional relationship of the left speaker, the right speaker, and the auxiliary speaker. Since the virtual sound source is formed by performing the processing and the level correction processing, and the sound field generated from the virtual sound source and the speaker far from the listening position forms a sound field symmetric with respect to the listening position as a reference, a simple configuration Thus, a symmetrical sound field can be formed. In addition, a sound field having a high-quality surround effect can be formed.

  Hereinafter, an audio system according to an embodiment of the present invention will be described.

[First Embodiment]
FIG. 1 is a diagram for explaining an in-vehicle audio system that employs an audio system 1 according to the first embodiment of the present invention. FIG. 1A is a top view of a vehicle 100 that employs an in-vehicle audio system, and FIG. 1B is a functional block diagram of the audio system 1 shown in FIG.

  FIG. 2 is a diagram for explaining the positions of the speakers in the audio system 1 shown in FIG. 2A is a top view for explaining the arrangement positions of the left and right front speakers and the auxiliary speakers, FIG. 2B is a side view, and FIG. 2C is another view of the arrangement positions of the speakers. It is a figure for demonstrating a specific example. FIG. 3 is a top view for explaining the listening position of the audio system 1 shown in FIG. 1 and the positional relationship between each speaker and the virtual sound source.

  1A and 3, the left side corresponds to the front (front side) of the vehicle 100, the right side corresponds to the rear (rear side) of the vehicle 100, and the upper side as viewed in the drawings. It corresponds to the right side of the vehicle 100 and the lower side corresponds to the left side of the vehicle.

  As shown in FIGS. 1A and 1B, the audio system 1 according to the present embodiment includes a communication unit 11, an audio device 12, an audio data processing unit 13, a correction unit 14, a speaker 15, an input circuit 16, and A control circuit 17 is included. The audio data processing unit 13, the correction unit 14, and the control circuit 17 correspond to an embodiment of the processing unit according to the present invention.

  As shown in FIGS. 1A and 1B, the speaker 15 according to the present embodiment includes a left front speaker (left speaker) 15L, a right front speaker (right speaker) 15R, and an auxiliary speaker 15S. The left speaker 15L corresponds to a left channel (channel) sound source, and the right speaker 15R corresponds to a right channel sound source.

  In the audio system 1, the left speaker 15 </ b> L and the right speaker 15 </ b> R are arranged at positions that are asymmetrical forward and left with respect to the listening position 2. For example, when the speaker 15 is arranged in the vehicle 100, the arrangement position is determined by factors such as the function of the vehicle 100, safety aspects, operability, air-conditioning relation, attachment strength, and the like.

  In the audio system 1 according to the present embodiment, for example, as illustrated in FIGS. 1A, 1B, and 2A to 2C, the left speaker 15L and the right speaker 15R are, for example, It is arranged on both sides of the front instrument panel 101. Further, the vehicle 100 is provided with a plurality of seats 102, specifically, a driver seat 102D provided on the front right side, a passenger seat 102P provided on the front left side, and a rear seat 102B. The listening position 2 according to the present embodiment corresponds to the position of the ear of the listener 103 seated in the driver's seat 102D provided in the vehicle 100. That is, the left speaker 15 </ b> L and the right speaker 15 </ b> R are arranged at positions that are asymmetrical forward and left with respect to the listening position 2. In other words, the listening position 2 is set to a position shifted to the right side or the left side with respect to the arrangement position of the right speaker 15R or the left speaker 15L.

  The auxiliary speaker 15S is arranged near the seat position where the listener 103 sits in the vehicle 100, as compared with the left speaker 15L and the right speaker 15R. The auxiliary speaker 15S is arranged on the right side or the left side of the listening position 2 on the one side where the right speaker 15R close to the listening position 2 is arranged, on the right side in the present embodiment. For example, as shown in FIGS. 2A to 2C, the auxiliary speaker 15 </ b> S is disposed at specified positions such as the seat 102, the vehicle ceiling 104, and the vehicle door 105 in the vicinity of the listening position 2 in the vehicle 100. . The arrangement position of the auxiliary speaker 15S is not limited to the above form, and may be arranged at any position as long as the function according to the present invention can be realized.

  For example, under the control of the control circuit 17, the communication unit 11 performs data communication with an external audio device (not shown) by various wireless methods or wired methods, and receives a source signal (digital audio data) S0 received from the external audio device as an audio signal. Output to the data processing unit 13.

  The audio device 12 is a device capable of reproducing audio data stored in a storage medium such as a DVD (Digital Versatile Disc), a CD (Compact Disc), a hard disk, or a semiconductor memory, and the audio data is input to an input source signal S0. To the audio data processing unit 13.

  The source signal S0 is an audio signal of two channels, for example, Lch (left channel) and Rch (right channel).

  The audio data processing unit 13 performs predetermined data processing based on a source signal (digital audio data) S0 input from the communication unit 11 or the audio device 12 under the control of the control circuit 17, and for example, a 2-channel audio signal S1 (S1L, S1R) is generated and output to the correction unit 14.

[Correction unit 14]
The correction unit 14 performs processing according to the present invention on the signal S1 (S1L, S1R) input from the audio data processing unit 13 to generate an audio signal S2 (S2L, S2L, S2S), and the signal S2 is generated from the left speaker. 15L, the right speaker 15R, and the auxiliary speaker 15S.

  More specifically, the correction unit 14 is based on the positional relationship among the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S, and the speaker close to the listening position 2 among the left speaker 15L and the right speaker 15R (the right speaker in this embodiment). 15R), and the audio signal input to the auxiliary speaker 15S is subjected to delay processing and level correction processing to form a virtual sound source 15V, and the virtual sound source 15V and a speaker far from the listening position 2 (the left speaker 15L) are sounded. A sound field symmetric with respect to the front side with respect to the listening position 2 is formed by the sound wave. The virtual sound source 15V corresponds to an embodiment of the virtual sound source according to the present invention.

  For example, as illustrated in FIG. 1B, the correction unit 14 includes a delay unit 141, a delay unit 142, a level correction unit 143, a digital / analog converter (DAC) 40 (40L, 40R, 40S), and an amplifier 41 (41L, 41R, 41S). The delay unit 141 corresponds to an embodiment of the first delay unit of the present invention, and the delay unit 142 corresponds to an embodiment of the second delay unit of the present invention. The level correction unit 143 corresponds to an embodiment of the level correction unit according to the present invention.

  The correction unit 14 according to the present embodiment performs a delay process and a level correction process on an audio signal input to a speaker far from the listening position 2 (the left speaker 15L in the present embodiment) among the left speaker 15L and the right speaker 15R. Not performed. Specifically, the correction unit 14 converts the left channel audio signal S1L input from the audio data processing unit 13 into an analog signal by the DAC 140L, amplifies the analog signal by the amplifier 41, and outputs the audio signal S2L as the left audio signal S2L. Output to the speaker 15.

  The delay unit 141 delays an audio signal input to the right speaker 15R close to the listening position 2 based on the positional relationship between the listening position 2 and the right speaker 15R and the left speaker 15L. Specifically, the delay unit 141 performs a specified delay process on the right-channel audio signal S1R input from the audio data processing unit 13 to generate an audio signal S141. More specifically, the delay unit 141 causes the left speaker 15L and the right speaker 15R to be in phase so that the sound wave generated from the left speaker 15L and the sound wave generated from the right speaker 15R have the same phase at the listening position 2. Among them, the audio signal input to the speaker close to the listening position 2 (the right speaker 15R in this embodiment) is subjected to delay processing to generate the audio signal S141.

  The DAC 40R converts the audio signal (digital signal) S141 generated by the delay unit 141 into an analog signal. The amplifier 41R amplifies the analog signal and inputs it to the right speaker 15R as the audio signal S2R.

  The delay processing is performed so that the phase is matched at the listening position 2 is only the time difference between the propagation time of the sound wave from the left speaker 15L to the listening position 2 and the propagation time of the sound wave from the right speaker 15R to the listening position 2. The audio signal input to the right speaker 15R having the shorter propagation time is delayed.

  By providing the delay unit 141, for example, as shown in FIGS. 1 and 3, a virtual sound source (one-dimensional virtual sound source) 15RV as an Rch sound source is formed. Specifically, the virtual sound source 15RV is formed on the extension of the straight line 50 from the listening position 2 toward the right speaker 15R, and the distance r1 between the listening position 2 and the left speaker 15L, and the listening position 2 and the virtual sound source 15RV. The distance r2 is the same distance.

  However, if the delay unit 141 is simply provided, the distance r1 between the listening position 2 and the left speaker 15L and the distance r2 between the listening position 2 and the virtual sound source 15RV coincide with each other. On the right, a narrow and distorted sound field is formed.

  In the present invention, based on the positional relationship among the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S, the audio signal input to the auxiliary speaker 15S according to the present invention is subjected to delay processing and level correction processing to correct the virtual sound source 15RV. Thus, the virtual sound source 15V is formed.

  Specifically, the delay unit 142 of the correction unit 14 includes the position of the speaker far from the listening position 2 (the left speaker 15L in the present embodiment) of the left speaker 15L and the right speaker 15R, the listening position 2, and the auxiliary speaker 15S. Based on the relationship, the audio signal input to the auxiliary speaker 15S is delayed.

  More specifically, the delay unit 142 performs a prescribed delay process on the right-channel audio signal S1R input from the audio data processing unit 13 to generate an audio signal S142.

  Specifically, the delay unit 142 includes sound waves generated from a speaker far from the listening position 2 (the left speaker 15L in the present embodiment) of the left speaker 15L and the right speaker 15R, and sound waves generated from the auxiliary speaker 15S. However, the audio signal input to the auxiliary speaker 15S is subjected to delay processing so that the phase is matched at the listening position 2 to generate the audio signal S142.

  The delay processing is performed so that the phase is matched at the listening position 2 is only a time difference between the propagation time of the sound wave from the left speaker 15L to the listening position 2 and the propagation time of the sound wave from the auxiliary speaker 15S to the listening position 2. The audio signal input to the auxiliary speaker 15 having the shorter propagation time is delayed.

  By providing the delay unit 142, a virtual sound source 15SV is formed as shown in FIGS. Specifically, the virtual sound source 15SV is formed on an extension of the straight line 51 from the listening position 2 toward the auxiliary speaker 15S, and the distance r1 between the listening position 2 and the left speaker 15L, and the listening position 2 and the virtual sound source 15RV. The distance r3 is formed to be the same distance.

  The level correction unit 143 corrects the level of the audio signal input to the auxiliary speaker 15S. Specifically, the level correction unit 143 generates sound waves generated from a speaker close to the listening position 2 (the left speaker 15L in the present embodiment) among the left speaker 15L and the right speaker 15R at the listening position 2, and the auxiliary speaker 15S. The level of the audio signal input to the auxiliary speaker 15S is corrected so that the virtual sound source 15V is formed at a symmetrical position with respect to the left speaker 15L far from the listening position 2 by synthesis with sound waves generated from the sound.

  By providing the level correction unit 143, for example, as shown in FIGS. 1 and 3, the virtual sound source 15V is formed by adjusting the amplitude levels of the right speaker 15R and the auxiliary speaker 15S. The virtual sound source 15V is formed on the extension of the straight line 52 from the left speaker 15L to the right speaker 15R, and the distance r1 between the listening position 2 and the left speaker 15L and the distance r4 between the listening position 2 and the virtual sound source 15V. Are the same distance. Further, with the above configuration, the left speaker 15L and the virtual sound source 15V are arranged so as to be equidistant from the straight line 53 as the axis of symmetry.

  The DAC 40S converts the audio signal (digital signal) S1R that has been subjected to the delay process and the level correction process by the delay unit 142 and the level correction unit 143 into an analog signal. The amplifier 41S amplifies the analog signal and inputs it to the auxiliary speaker 15S as the audio signal S2S.

  That is, as shown in FIGS. 1 and 3, when a straight line 53 is provided forward with respect to the listening position 2 (when a straight line 53 passing through the listening position 2 and orthogonal to the straight line 52 is provided), the straight line 53 is provided. The left speaker (Lch sound source) 15L and the Rch virtual sound source 15V are formed at positions symmetrical to the left and right.

  Examples of the input circuit 16 include switches, buttons, a remote controller, operation input devices such as a mouse and a board, a microphone, and the like, and output various signals S16 to the control circuit 17.

  The control circuit 17 comprehensively controls the entire apparatus. The control circuit 17 performs processing according to the present invention on the audio signal S1 based on the signal S16 input from the input circuit 16 configured by, for example, a microphone or an operation input device, according to the acoustic environment in the vehicle 100. The correction unit 14 is controlled so as to be applied. Specifically, the control circuit 17 outputs a control signal CTL 17 for performing the above control to the correction unit 14.

  For example, the control circuit 17 regulates the left and right balance of the reproduction levels by the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S to define the center localization in order to define the center localization. That is, the center localization is defined by adjusting the left / right balance from the left speaker 15L and the virtual sound source 15V. The control circuit 17 according to the present embodiment adjusts the amplification factor of the amplifier 41 of the correction unit 14 and adjusts the left / right balance of the reproduction level by each speaker to realize the function of defining the center localization.

  The control circuit 17 and the correction unit 14 correspond to an embodiment of the left / right balance adjustment unit according to the present invention.

Next, the operation of the audio system 1 will be briefly described.
1. The Rch sound source (the right speaker 15R) reproduces the audio signal by correcting the delay so as to be in phase with the Lch sound source (the left speaker 15L), so that the virtual sound source 15RV can receive the Lch on the listening position 2 and the Lch sound source axis. Set to the equidistant position with the sound source.

  2. In the present embodiment, the auxiliary speaker 15S is arranged near the right side of the listening position 2 and reproduces an audio signal with a delay correction so as to be in phase with the Lch sound source.

  3. Since the sound reproduced from the Rch sound source and the sound reproduced from the auxiliary speaker 15S have the same phase, by adjusting the reproduction level, the axis of the Lch sound source and the Rch sound source can be changed without changing the characteristics. In addition, the Rch virtual sound source 15V can be formed at a position symmetrical to the Lch sound source. At this time, if necessary, the left and right level balance adjustment is performed to define the center localization, and a left-right symmetric stereo sound field with reference to the listening position 2 can be formed.

  Next, the operation of the audio system 1 configured as described above will be described in detail with reference to the drawings.

  FIG. 4 is a diagram for explaining the operation of the audio system 1 shown in FIG. Specifically, FIG. 4A shows a specific example of the Lch audio signal S1L (S2L). The vertical axis indicates the signal level, and the horizontal axis indicates time. FIG. 4B is a diagram showing the level of sound waves detected at the listening position 2 by propagation of sound waves generated by the left speaker 15L.

  FIG. 4C shows a specific example of the Rch audio signal S1R. FIG. 4D is a diagram illustrating an audio signal S2R input to the right speaker 15R via the delay unit 141. FIG. 4E is a diagram showing the level of sound waves detected at the listening position 2 by propagation of sound waves generated by the right speaker 15R.

  FIG. 4F shows the audio signal S2S input to the auxiliary speaker 15S via the delay unit 142 and the level correction unit 143. FIG. 4G is a diagram showing the level of sound waves detected at the listening position 2 by propagation of sound waves generated by the auxiliary speaker 15S. FIG. 4 (H) is a diagram showing the level of the composite wave detected at the listening position 2 through the propagation of sound waves generated by the right speaker 15R and the auxiliary speaker 15S.

  First, when the source signal S0 is input from the communication unit 11 or the audio device 12, the audio data processing unit 13 performs predetermined data processing based on the input source signal (digital audio data) S0, for example, two-channel audio. A signal S1 (S1L, S1R) is generated and output to the correction unit 14.

  In the correction unit 14, the Lch audio signal S1 (S1L, S1R) input from the audio data processing unit 13 is processed according to the present invention to generate an audio signal S2 (S2L, S2L, S2S), and the signal S2 is generated. Input to the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S.

  Specifically, the Lch audio signal S1L input from the audio data processing unit 13 is converted from a digital signal to an analog signal by the DAC 40L, and input to the left speaker 15L as the audio signal S2L by the amplifier 41. For example, as shown in FIG. 4A, the rising edge of the level of the audio signal S2L is defined as time t0. Further, it is assumed that the peak of the signal level S1L indicates the peak value ASL.

  The left speaker 15L generates a sound based on the audio signal S2L, and the sound wave WL generated by the left speaker 15L propagates and is detected at the listening position 2 as shown in FIG. The propagation time TL of the sound wave WL is substantially defined by the distance r1 between the left speaker 15L and the listening position 2. At the listening position 2, the sound wave level rises at time t1 after propagation time TL from time t0. The peak of the sound wave level WL is the peak value AWL.

  On the other hand, the Rch audio signal S1R is input from the audio data processing unit 13. At this time, as shown in FIG. 4C, it is assumed that the rise time t0 of the level of the Rch audio signal S1R coincides with the rise time t0 of the level of the Lch audio signal S1L shown in FIG. . That is, the phases match.

  As shown in FIG. 4D, the audio signal S1R is subjected to delay processing by a delay time DR defined in advance by the delay unit 141, and is input to the right speaker 15R as the audio signal S2R. As shown in FIG. 4D, the rise of the level of the audio signal S2R is defined as time tR. Further, the peak of the signal level S1R becomes the peak value ASR.

  The right speaker 15R generates a sound based on the audio signal S2R, and the sound wave WR generated by the right speaker 15R propagates and is detected at the listening position 2 as shown in FIG. The propagation time TR of the sound wave WR is substantially defined by the distance r2 between the right speaker 15R and the listening position 2. At the listening position 2, the level of the sound wave WR rises from time tR to time t1 after the propagation time TR. The peak of the sound wave level WR is the peak value AWR.

  Further, as shown in FIG. 4 (F), the Rch audio signal S1R is subjected to delay processing for a delay time DS defined in advance by the delay unit 142, and subjected to level correction processing by the level correction unit 143, The audio signal S2S is input to the auxiliary speaker 15S. As shown in FIG. 4F, the rise of the level of the audio signal S2S is defined as time tS. The peak of the signal level S1S becomes the peak value ASS.

  The auxiliary speaker 15S generates a sound based on the audio signal S2S, and the sound wave WS generated by the auxiliary speaker 15S propagates and is detected at the listening position 2 as shown in FIG. The propagation time TS of the sound wave WS is substantially defined by the distance between the auxiliary speaker 15S and the listening position 2. At the listening position 2, the level of the sound wave WR rises from time tS to time t1 after propagation time TS. The peak of the level of the sound wave WS is the peak value AWS.

  At the listening position 2, the sound wave WR and the sound wave WS are detected as shown in FIG. At this time, as shown in FIG. 4H, the phases of the sound wave WR and the sound wave WS coincide with each other, and the level of the composite wave (WR + WS) rises at time t1, for example. Further, the peak of the level of the composite wave (WR + WS) becomes the peak value (AWR + AWS).

  Next, the control circuit 17 adjusts the amplification factor of the amplifier 41 of the correction unit 14 as necessary, and adjusts the left / right balance of the reproduction levels by the speakers 15R, 15L, 15S to define the center position.

  As described above, the audio system 1 is disposed in the vicinity of the listening position 2 and the left speaker 15L and the right speaker 15R that are disposed at positions that are asymmetrical forward with respect to the listening position 2. Of the right side or the left side, the auxiliary speaker 15S arranged on the right side where the right speaker 15R close to the listening position 2 is arranged, and the correction for processing the audio signal input to the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S The correction unit 14 delays the audio signal input to the right speaker 15R near the listening position 2 and the auxiliary speaker 15S based on the positional relationship among the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S. The virtual sound source 15V is formed by performing processing and level correction processing, and the virtual sound source 15V and the listening position The sound field generated from the left speaker 15L far from the sound field forms a sound field that is symmetrical left and right with respect to the listening position 2, so that the left and right speakers 15L and 15R are arranged asymmetrically in front of the listening position 2. Even if it exists, a symmetrical sound field can be formed with a simple structure. In addition, a sound field having a high-quality surround effect can be formed.

  In addition, the control circuit 17 and the correction unit 14 adjust the left / right balance of the reproduction level by the left speaker, the right speaker, and the auxiliary speaker to define the center localization, thereby forming a symmetrical sound field with higher accuracy. be able to.

  Further, the correction unit 14 includes a delay unit 141 that delays an audio signal input to the right speaker 15R close to the listening position 2 based on the positional relationship between the listening position 2 and the left speaker 15L and the right speaker 15R. Based on the positional relationship between the auxiliary speaker 15S and the left speaker 15L far from the listening position 2, a delay unit 142 that delays the audio signal input to the auxiliary speaker 15S, and a level that corrects the level of the audio signal input to the auxiliary speaker 15S Since the correction unit 143 is provided, a symmetrical sound field can be formed with a simple configuration.

  Specifically, the delay unit 141 causes the right speaker 15R close to the listening position 2 so that the sound wave generated from the left speaker 15L and the sound wave generated from the right speaker 15R have the same phase at the listening position 2. The delay unit 142 performs a delay process on the audio signal input to the sound signal, and the delay unit 142 matches the phase of the sound wave generated from the left speaker 15L far from the listening position 2 and the sound wave generated from the auxiliary speaker 15S at the listening position 2. As described above, the audio signal input to the auxiliary speaker 15S is subjected to delay processing, and the level correction unit 143 generates a sound wave generated from the right speaker 15R near the listening position 2 and a sound generated from the auxiliary speaker 15S at the listening position 2. The auxiliary speaker 1 is formed so that the virtual sound source 15V is formed at a symmetrical position with respect to the left speaker 15L far from the listening position 2 by the generated sound wave. Is corrected to the level of the audio signal to be input to the S, with a simple configuration, it is possible to form a symmetrical sound field.

  Further, the correction unit 14 inputs the audio signal of one channel of at least two channels of audio signals to the left speaker 15L far from the listening position 2, and inputs the audio signal of the other channel of the two channels of audio signals, Since the audio signal of the other channel is input to the right speaker 15R close to the listening position 2 via the delay unit 142, the audio signal of the other channel is input to the auxiliary speaker 15S via the delay unit 142 and the level correction unit 143. Even when the arranged left and right speakers 15L and 15R generate sound in response to two-channel audio signals, a symmetrical sound field can be formed.

  In particular, by adopting the audio system according to the present invention in the in-vehicle audio system 1, it is possible to form a symmetrical sound field at, for example, a seat position in the vehicle 100. Specifically, the left speaker 15L and the right speaker 15R are disposed at positions that are asymmetrical forward and left with respect to the seat position where the listener in the vehicle 100 is seated, and the auxiliary speaker 15S is compared with the left speaker 15L and the right speaker 15R. Since the correction unit 14 processes the audio signal in accordance with the acoustic environment in the vehicle 100, the listening seated in the seat position in the vehicle 100 is arranged near the seat position in which the listener in the vehicle 100 is seated. A symmetrical sound field can be formed at the listener's listening position.

  Further, by arranging the auxiliary speaker 15S at a predetermined position such as a seat near the listening position 2 in the vehicle 100, a vehicle door, or a vehicle ceiling, the audio system 1 according to the present invention can be easily realized.

The present invention is not limited to the embodiment described above.
For example, in the above-described embodiment, the audio system 1 that processes digital audio data using the digital audio data as an input source signal (audio signal) has been described. However, the present invention is not limited to this form. For example, the audio system 1 may use an analog signal as an input source signal (audio signal) and perform processing according to the present invention on the audio signal.

  In the above-described embodiment, the level correction unit 143 is provided after the delay unit 142. However, the present invention is not limited to this configuration. For example, conversely, the delay unit 142 may be provided after the level correction unit 143.

  In the above-described embodiment, the auxiliary speaker 15S is provided in the vicinity of the listener seated in the right seat (driver's seat), but the present invention is not limited to this form.

  For example, the auxiliary speaker 15S may be provided in the vicinity of the listener sitting on the left seat. In this case, the auxiliary speaker 15S is provided on the left side of the listening position. In addition, as for processing of the processing unit, processing that is opposite to that of the above embodiment is performed.

  Further, in the above-described embodiment, the control circuit 17 adjusts the amplification degree of the amplifier 41 (41L, 41R, 41S), adjusts the left / right balance of the reproduction level by the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S. Although the localization is defined, it is not limited to this form.

  For example, as shown in FIG. 5, a level correction unit 144 that performs level correction processing on an audio signal input to the right speaker 15R is provided as the correction unit 14a, and the control circuit 17a controls the level correction values by the level correction units 143 and 144. By doing so, the center localization may be defined by adjusting the left / right balance of the reproduction level by the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S.

  In the above-described embodiment, the left speaker 15L, the right speaker 15R, and the auxiliary speaker 15S are provided. However, the present invention is not limited to this form. For example, as shown in FIG. 6, four or more speakers, for example, a front left speaker 15FL, a rear left speaker 15RL, a front right speaker FR, and a rear right speaker RR are provided, and an audio signal S1 input to each speaker as a correction unit 14b. (S1FL, S1RL, S1FR, S1RR) delay units 1401 to 1404, level correction units 1405 to 1408, DAC 40 (40FL, 40RL, 40FR, 40RR), amplifier 41 (41FL, 41RL, S1RR), each of which performs processing according to the present invention. 41FR, 41RR) may be provided. In this embodiment, when the vehicle 100 is provided with four speakers in advance, the function according to the present invention can be easily realized by providing the correction unit 14b and the control circuit 17b.

It is a figure for demonstrating the vehicle-mounted audio system which employ | adopted the audio system 1 which concerns on 1st Embodiment of this invention. (A) is a top view of the vehicle 100 which employ | adopted the vehicle-mounted audio system, (B) is a functional block diagram of the audio system 1 shown to (A). It is a figure for demonstrating the arrangement position of the speaker of the audio system 1 shown in FIG. (A) is a top view for explaining the arrangement positions of the left and right front speakers and auxiliary speakers, (B) is a side view, and (C) is for explaining other specific examples of the arrangement positions of the speakers. FIG. It is a top view for demonstrating the positional relationship of the listening position of each audio system 1 shown in FIG. 1, each speaker, and a virtual sound source. It is a figure for demonstrating operation | movement of the audio system 1 shown in FIG. (A) is a figure which shows a specific example of Lch audio signal S1L (S2L), (B) is a figure which shows the level of the sound wave which the sound wave sounded by the speaker 15L propagated and detected in the listening position 2 (C) is a diagram illustrating a specific example of the Rch audio signal S1R, (D) is a diagram illustrating the audio signal S2R input to the right speaker 15R via the delay unit 141, and (E) FIG. 6 is a diagram showing the level of sound waves detected at the listening position 2 by propagation of sound waves generated by the right speaker 15R, and (F) is input to the auxiliary speaker 15S via the delay unit 142 and the level correction unit 143. (G) is a diagram showing the level of the sound wave detected at the listening position 2 by propagation of the sound wave generated by the auxiliary speaker 15S, and (H) is the right side. Speaker 15R and sound waves pronunciation by the auxiliary speaker 15S is a diagram showing the level of the detected composite wave at a listening position 2 propagates. It is a functional block diagram for demonstrating the audio system 1a which concerns on other embodiment of this invention. It is a functional block diagram for demonstrating the audio system 1b which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Audio system 2 Listening position 11 Communication part 12 Audio apparatus 13 Audio data processing part 14 Correction | amendment part 15 Speaker 15L Left front speaker (left speaker)
15R Right front speaker (right speaker)
15S auxiliary speaker 15V virtual sound source (two-dimensional virtual sound source)
15RV virtual sound source (one-dimensional virtual sound source)
15SV virtual sound source (auxiliary virtual sound source)
16 input circuit 17 control circuit 40, 40L, 40R, 40S digital / analog converter (DAC)
41, 41L, 41R, 41S Amplifier 100 Vehicle 101 Instrument panel 102 Seat 102B Rear seat 102D Driver's seat (front right seat)
102P Passenger seat (front left seat)
DESCRIPTION OF SYMBOLS 103 Listener 104 Vehicle ceiling 105 Vehicle door 141 Delay part (1st delay part)
142 delay unit (second delay unit)
143 Level correction unit

Claims (7)

An audio system in which a left speaker and a right speaker are arranged at a front left-right asymmetric position with respect to a listening position,
An auxiliary speaker that is arranged in the vicinity of the listening position and that is arranged on one side of the right or left side of the listening position where the right speaker or the left speaker near the listening position is arranged;
A processing unit for processing an audio signal input to the left speaker, the right speaker, and the auxiliary speaker;
Based on the positional relationship among the left speaker, the right speaker, and the auxiliary speaker, the processing unit outputs an audio signal to be input to the speaker near the listening position and the auxiliary speaker among the left speaker and the right speaker. An audio system characterized by forming a virtual sound source by performing a delay process and a level correction process, and forming a sound field that is symmetrical forward and left with respect to the listening position. The processing unit, based on the positional relationship between the listening position and the left speaker and the right speaker, a first delay unit that delays an audio signal input to the right speaker or the left speaker close to the listening position;
A second delay unit that delays an audio signal input to the auxiliary speaker based on a positional relationship with the listening position, the auxiliary speaker, the left speaker or the right speaker far from the listening position;
The audio system according to claim 1, further comprising: a level correction unit that corrects a level of an audio signal input to the auxiliary speaker. The first delay unit includes the left speaker and the right speaker so that the sound wave generated from the left speaker and the sound wave generated from the right speaker are in phase with each other at the listening position. The audio signal input to the speaker close to the listening position is subjected to delay processing,
The second delay unit is configured such that a sound wave generated from a speaker far from the listening position of the left speaker and the right speaker and a sound wave generated from the auxiliary speaker have a phase matching at the listening position. As described above, the audio signal input to the auxiliary speaker is subjected to delay processing,
The level correction unit is far from the listening position at the listening position due to a sound wave generated from a speaker near the listening position among the left speaker and the right speaker and a sound wave generated from the auxiliary speaker. The audio system according to claim 2, wherein a level of an audio signal input to the auxiliary speaker is corrected so that a virtual sound source is formed at a position symmetrical to the speaker.   The said processing part is provided with the left-right balance adjustment part which adjusts the left-right balance of the reproduction level by a left speaker, a right speaker, and an auxiliary speaker, and prescribes | regulates a center localization. Audio system described in. The processing unit inputs an audio signal of one of the audio signals of at least two channels to a speaker far from the listening position among the left speaker and the right speaker,
The audio signal of the other channel among the audio signals of the two channels is input to the auxiliary speaker via the second delay unit and the level correction unit, and the audio signal of the other channel is input to the first channel. 5. The audio system according to claim 3, wherein the audio signal is input to a speaker close to the listening position among the left speaker and the right speaker via the delay unit. The left speaker and the right speaker are arranged at positions that are asymmetrical forward and left with respect to a seat position where a listener in the vehicle is seated,
The auxiliary speaker is disposed in the vicinity of a seat position where a listener in the vehicle is seated, compared with the left speaker and the right speaker.
The audio system according to claim 1, wherein the processing unit performs the processing on the audio signal in accordance with an acoustic environment in the vehicle.   The audio system according to any one of claims 1 to 6, wherein the auxiliary speaker is disposed in any one of a seat, a vehicle door, and a vehicle ceiling near a listening position in the vehicle.

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