Speaker system

Abstract

To provide a speaker system that can switch the sound output range.SOLUTION: A vehicle approach notification device 100 includes a driving sound generating unit 110 that generates the sound to be output, an ultrasonic speaker 120, an SP driving unit 130 that drives the ultrasonic speaker 120 and outputs the sound generated by the output sound generating unit 110 from the ultrasonic speaker 120, and a switching control unit 140 that varies the distance that the sound waves output from the ultrasonic speaker 120 propagate through the air until they become shock waves.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a speaker system that combines a plurality of speakers. [Background technology]

[0002] Conventionally, a vehicle presence warning device has been known that uses a speaker array combining multiple ultrasonic speakers and changes the directivity of the warning sound by adjusting the phase of the sound waves output from each ultrasonic speaker (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-31695 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the vehicle presence notification device disclosed in the above-mentioned Patent Document 1 can change the directivity of the entire speaker array by adjusting the phase of the sound waves output from each speaker constituting the speaker array, but cannot change the output range of the notification sound. For example, it cannot switch between outputting sound to a long distance and outputting sound to a wide area around the vehicle depending on the situation of the vehicle while it is moving.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a speaker system capable of switching the sound output range. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the speaker system of the present invention comprises an output sound generating means for generating sound to be output, an ultrasonic speaker, a speaker driving means for driving the ultrasonic speaker and outputting the sound generated by the output sound generating means from the ultrasonic speaker, and a shock wave distance varying means for varying the distance that the sound waves output from the ultrasonic speaker propagate through the air to become shock waves.

[0007] When the distance to the shock wave is long, the difference sound of two types of carrier waves is repeatedly generated and synthesized before the shock wave is generated, and these difference sounds become a virtual sound source and are synthesized along the direction in which the sound wave travels, narrowing the directional characteristics. On the other hand, when the distance to the shock wave is short, the extension length of the virtual sound source becomes short, and the sound wave is diffused spherically from the position where the virtual sound source disappears, widening the directional characteristics. In this way, by varying the distance to the shock wave, the directional characteristics can be changed, and the output range of the speaker's radiated sound can be switched.

[0008] Also, it is preferable that the shock wave distance varying means varies the distance by sending an instruction to the speaker driving means to change the initial sound pressure of the sound waves when output from the ultrasonic speaker. Alternatively, it is preferable that the shock wave distance varying means varies the distance by sending an instruction to the speaker driving means to change the carrier frequency of the sound waves output from the ultrasonic speaker. It is also preferable that the shock wave distance varying means varies the distance by sending an instruction to the speaker driving means to change the initial sound pressure of the sound waves when output from the ultrasonic speaker and the carrier frequency of the sound waves output from the ultrasonic speaker.

[0009] Shock waves are generated by the cumulative increase in distortion of the sound waveform as one cycle of the waveform propagates repeatedly, and the louder the volume (higher initial sound pressure) the greater the distortion of the waveform, the more likely they are to occur over a short distance. Also, the higher the carrier frequency and the more times one cycle of the waveform propagates, the more likely they are to occur over a short distance. For these reasons, by changing at least one of the initial sound pressure and the carrier frequency, it is possible to switch the directional characteristics, i.e., the output range of the speaker's radiated sound.

[0010] It is also preferable that the device further includes a surrounding situation determination means for determining the surrounding situation, and the shock wave distance varying means varies the distance based on the surrounding situation determined by the surrounding situation determination means. This makes it possible to automatically switch the directional characteristic between wide and narrow in accordance with the surrounding situation.

[0011] Also, in a speaker system mounted on a vehicle and outputting a sound to notify people in the vicinity of an approaching vehicle, the surrounding situation determination means is a speed acquisition means for acquiring the traveling speed of the vehicle, and the shock wave distance variable means preferably issues a switching instruction to set the distance longer so that the directional characteristics of the sound output from the speaker become narrower when the traveling speed acquired by the speed acquisition means is fast, and to set the distance shorter so that the directional characteristics of the sound output from the speaker become wider when the traveling speed acquired by the speed acquisition means is slow. This allows the sound notifying pedestrians around the vehicle of the approach to be heard widely when traveling at low speed, and allows pedestrians at a short distance away to hear the sound that notifies them of the approach of a vehicle when traveling at medium speed or faster.

[0012] Also, in a speaker system mounted on a vehicle and outputting a sound to notify people in the vicinity of an approaching vehicle, the surrounding situation determination means is a driving environment determination means for determining whether the vehicle is traveling in an urban area or a suburban area, and the shock wave distance variable means preferably issues a switching instruction to set the distance longer so that the directional characteristics of the sound output from the speaker array become narrower when the driving environment determination means determines that the vehicle is traveling in a suburban area, and to set the distance shorter so that the directional characteristics of the sound output from the speaker array become wider when the driving environment determination means determines that the vehicle is traveling in an urban area. This makes it possible to widely announce the approach of pedestrians around the vehicle in urban areas where there is a high possibility of many pedestrians around the vehicle, and to announce the approach of a vehicle to pedestrians at a short distance away in suburban areas where there are relatively few people.

[0013] It is also preferable that the shock wave distance varying means performs a switching instruction to alternately set a long distance and a short distance, so that the sound emitted from the speaker can be heard in both the near and far surrounding spaces.

[0014] It is also preferable that the above-mentioned surrounding situation determination means has an imaging means for imaging the surroundings and an image analysis means for analyzing the surrounding situation based on the image obtained by the imaging means, and the shock wave distance variation means issues a switching instruction to switch the distance between long and short based on the surrounding situation analyzed by the image analysis means. This makes it possible to switch the directional characteristics of the speaker's radiated sound between wide and narrow after accurately grasping the surrounding situation.

[0015] The above-mentioned surrounding situation determination means is a congestion state determination means for determining the surrounding congestion state, and the shock wave distance variable means preferably issues a switching instruction for switching the distance between long and short based on the surrounding congestion state determined by the congestion state determination means. This makes it possible to switch the directional characteristics of the radiated sound of the speaker array between wide and narrow depending on the surrounding congestion state. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram showing a configuration of a vehicle approach notification device according to an embodiment; [Diagram 2] FIG. 13 is a diagram illustrating waveform distortion. [Diagram 3] This is an explanatory diagram of the sound field when the distance xS until N waves are generated is changed. [Figure 4] 11A and 11B are diagrams showing a specific example of a case where the directional characteristics of a speaker are switched depending on the traveling speed of a vehicle. [Diagram 5] 11A and 11B are diagrams showing a specific example in which the directional characteristics of a speaker are switched depending on whether the vehicle is traveling in an urban area or in the suburbs. [Figure 6] 11A and 11B are diagrams showing a specific example of a case where the surrounding situation is determined based on an image captured of the surroundings. [Figure 7] 13A and 13B are diagrams showing modified examples in which the directional characteristics of the speakers are changed depending on the crowdedness of the room. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vehicle approach notification device according to an embodiment of the present invention will be described with reference to the drawings.

[0018] Fig. 1 is a diagram showing the configuration of a vehicle approach notification device according to an embodiment. The vehicle approach notification device 100 shown in Fig. 1 is mounted on a vehicle (e.g., an electric vehicle) that produces quiet running sounds, and outputs simulated running sounds around the vehicle to notify surrounding pedestrians and the like of the approach of the vehicle. For this purpose, the vehicle approach notification device 100 includes a running sound generation unit 110, an ultrasonic speaker (parametric speaker) 120, an SP (speaker) driving unit 130, a switching control unit 140, and a surrounding situation determination unit 150.

[0019] The running sound generating unit 110 generates a predetermined sound to notify pedestrians around the vehicle of the approach of the vehicle. This generated sound is assumed to be a simulated running sound of a vehicle, but since the purpose is to notify pedestrians of the approach of a vehicle with sound, it does not necessarily have to be similar to a running sound, and other notification sounds may also be used.

[0020] The ultrasonic speaker 120 reproduces audible sounds with narrow directional characteristics by utilizing waveform distortions caused by emitting two types of ultrasonic waves with high sound pressure. If the frequency of one ultrasonic wave (carrier wave) is f1, distortion components of integer multiples 2f1, 3f1, 4f1, ... are generated. If the frequency of the other ultrasonic wave (carrier wave) is f2, distortion components of integer multiples 2f2, 3f2, 4f2, ... are generated. If the frequencies f1 and f2 are both ultrasonic waves (sounds with frequencies higher than the human audible band), these integer multiple distortions are also higher than the audible band and cannot be heard by the human ear. However, when ultrasonic waves of such two types of carrier waves are emitted simultaneously, components of the difference tone (frequency is f2-f1) and the chord tone (frequency is f1+f2) are generated. Of these, by setting the frequency of the difference tone (f2-f1) to be within the audible band, it becomes possible to emit the generated sound as an audible sound from the ultrasonic speaker 120. For example, if f1 is 41 kHz and f2 is 40 kHz, it is possible to radiate a difference sound of f2-f1=1 kHz. Note that the ultrasonic speaker 120 may be configured as a speaker array combining a plurality of elements.

[0021] The instantaneous sound speed c of a plane sound wave can be expressed by the following formula:

[0022]

number

[0023] From the above formula, we can see that as the pressure p changes, the instantaneous sound speed c also changes, and the waveform becomes distorted as the sound wave progresses. This distortion appears as the integer multiple distortion mentioned above.

[0024] For this reason, waveform distortion is more likely to occur at higher volumes, where the change in pressure p is greater. Furthermore, this waveform distortion increases cumulatively as the number of times the waveform propagates in one cycle increases. For the same propagation distance, the higher the frequency, the more times the waveform propagates in one cycle, making the waveform more likely to distort.

[0025] FIG. 2 is a diagram for explaining waveform distortion. For example, a case where ultrasonic waves having a sine wave waveform are emitted is shown. The distance from the speaker 120 increases in the order of FIG. 2(A), FIG. 2(B), and FIG. 2(C). At a position close to the speaker 120, the waveform distortion is small (FIG. 2(A)), and as the distance increases, the waveform distortion gradually increases (FIG. 2(B)). Then, as the distance increases, the waveform becomes a shock wave close to an N-shape (in this specification, this shock wave is referred to as an "N wave"). The timing when this N wave is reached is the maximum distortion, and no distortion occurs even if the wave propagates thereafter. The fact that no distortion occurs means that when ultrasonic waves of two different frequencies are emitted, no audible sound is generated as a difference tone.

[0026] Distance until N wave x S can be calculated using the following formula:

[0027]

number

[0028] By the way, when considering a vertical speaker array in which speakers are arranged in the direction of sound wave emission, the sound waves are concentrated near the center of the speakers, resulting in a narrow directional characteristic. On the other hand, beyond the end of the area where the speakers are arranged, the synthesized sound waves are diffused spherically, resulting in a wider directional characteristic.

[0029] The difference sound generated by emitting ultrasonic waves of two frequencies is generated sequentially as the distortion of the ultrasonic waves increases, so these sequentially generated difference sounds become multiple virtual sound sources, and the operating principle is the same as that of a vertical speaker array. Since the width and narrowness of the directional characteristics are determined by the length of the vertical array, the distance x until N waves are generated is S The longer the distance, the narrower the directional characteristic. Conversely, the longer the distance x S The shorter the distance, the wider the directional characteristic.

[0030] Figure 3 shows the distance x until the Nth wave S As mentioned above, the distance x until the Nth wave is generated is S By shortening the length, a wide directional characteristic can be obtained, and sound is emitted over a wide range from the speaker 120 installed at the front of the vehicle (FIG. 3(B)). In this case, the sound is diffused widely and is easily attenuated along the direction of emission, allowing pedestrians and others in the vicinity to hear the sound.

[0031] On the other hand, the distance x until N wave S By lengthening the length, a narrow directional characteristic is obtained, so that sound is emitted from the speaker 120 installed at the front of the vehicle toward a narrow range (FIG. 3(A)). In this case, the sound is not diffused much and is not easily attenuated along the direction of emission, so pedestrians at a long distance can hear the sound.

[0032] The SP driving unit 130 drives the ultrasonic speaker 120 with two types of carrier waves so that the sound generated by the running sound generating unit 110 becomes a difference sound, and also drives the ultrasonic speaker 120 with a distance x S is variable.

[0033] The switching control unit 140 controls the SP driving unit 130 to determine the distance x until the sound becomes N waves according to the width or narrowness of the directional characteristics of the sound output from the speaker 120. S The switch instruction is sent to the SP driving unit 130.

[0034] As mentioned above, the distance x S The denominator of the formula for calculating the initial sound pressure p0 and angular frequency ω (=2πf), so by varying these, the distance x S The switching control unit 140 can change the initial sound pressure p 0 And / or, an instruction to change the carrier frequency f (=ω / (2π)) is given to the SP driver 130, and the distance x until N waves are reached is set. S By changing the above, the directional characteristics of the ultrasonic waves and sound waves in the audible band radiated from the ultrasonic speaker 120 can be switched between wide and narrow.

[0035] The surrounding situation determination unit 150 determines the surrounding situation. The switching control unit 140 issues a switching instruction based on the surrounding situation determined by the surrounding situation determination unit 150.

[0036] The above-mentioned running sound generating unit 110 corresponds to the output sound generating means, the SP driving unit 130 corresponds to the speaker driving means, the switching control unit 140 corresponds to the shock wave distance varying means, and the surrounding situation determining unit 150 corresponds to the surrounding situation determining means.

[0037] The vehicle approach notification device 100 of this embodiment has the above-mentioned configuration, and next, a specific example of the surrounding conditions determination unit 150 that switches between wide and narrow directional characteristics will be described.

[0038] Fig. 4 is a diagram showing a specific example of switching the directional characteristics of speaker 120 according to the traveling speed of the vehicle. Vehicle approach notification device 100A shown in Fig. 4 differs from vehicle approach notification device 100 shown in Fig. 1 in that surrounding condition determination unit 150 is realized by speed acquisition unit 150A, and switching control unit 140 is replaced with switching control unit 140A. Speed ​​acquisition unit 150A corresponds to speed acquisition means.

[0039] The speed acquisition unit 150A acquires the traveling speed of the vehicle. For example, the traveling speed may be detected based on a vehicle speed pulse output every certain distance traveled, or the traveling speed may be acquired from a vehicle control unit or the like that performs display processing such as a speedometer. Note that, since the relative speed of pedestrians and the like around the vehicle changes depending on the traveling speed of the vehicle, the traveling speed of the vehicle is also included in the "surrounding conditions" in this specification and the like.

[0040] When the traveling speed acquired by the vehicle speed acquisition unit 150A is fast, the switching control unit 140A changes the distance x 1 to the N wave so that the directional characteristics of the sound output from the speaker 120 become narrower. S When the traveling speed acquired by the speed acquisition unit 150A is slow, the distance x to the N wave is set to be long so that the directional characteristics of the sound output from the speaker 120 become wider. S For example, a switching command to shorten the long distance x S The initial sound pressure p 0 and / or carrier frequency f and short distance x S The initial sound pressure p 0 And / or the carrier frequency f is prepared in advance, and the distance after switching x S The initial sound pressure p corresponding to the length 0 And / or the carrier frequency f is instructed to the SP driver 130 .

[0041] This allows the sound to be widely heard by pedestrians and others around the vehicle when the vehicle is traveling at low speeds, and the sound to notify pedestrians that a vehicle is approaching can be heard when the vehicle is traveling at medium speeds or higher.

[0042] Fig. 5 is a diagram showing a specific example in which the directional characteristics of speaker 120 are switched depending on whether the vehicle is traveling in an urban area or in the suburbs. Vehicle approach notification device 100B shown in Fig. 5 differs from vehicle approach notification device 100 shown in Fig. 1 in that surrounding condition determination unit 150 is realized by driving environment determination unit 150B, and switching control unit 140 is replaced by switching control unit 140B. Driving environment determination unit 150B corresponds to the driving environment determination means.

[0043] The driving environment determination unit 150B determines whether the driving position of the vehicle is in an urban area or a suburb. For example, a vehicle navigation device that continuously or at regular intervals processes whether the vehicle position is included in an urban area or a suburb based on map data may be used as the driving environment determination unit 150B, or information indicating whether the vehicle is driving in an urban area or a suburb may be obtained from the vehicle navigation device.

[0044] When the driving environment determination unit 150B determines that the vehicle is traveling in the suburbs, the switching control unit 140B changes the distance x 1 to the N wave so that the directional characteristics of the sound output from the speaker 120 become narrower. S , and the distance x to the N wave is set to be longer so that the directional characteristics of the sound output from the speaker 120 become wider when the driving environment determination unit 150B determines that the driving position of the vehicle is in an urban area. S The SP driver 130 is instructed to switch to a shorter period.

[0045] This allows a sound to be played widely to pedestrians around the vehicle in urban areas where there is a high possibility that there will be many pedestrians around the vehicle, and a sound to notify pedestrians around the vehicle of the approach can be played to pedestrians at a short distance away in suburban areas where there are relatively few people.

[0046] Fig. 6 is a diagram showing a specific example of a case where the surrounding situation is determined based on an image of the surroundings. The vehicle approach notification device 100C shown in Fig. 6 is different from the vehicle approach notification device 100 shown in Fig. 1 in that the surrounding situation determination unit 150 is realized by a camera 152 and an image analysis unit 150C, and the switching control unit 140 is replaced by a switching control unit 140C. The camera 152 corresponds to the imaging means, and the image analysis unit 150C corresponds to the image analysis means.

[0047] One or more cameras 152 are installed at the front or sides of the vehicle, and capture images of the surroundings including at least the area in front of the vehicle. Based on images captured by the cameras 152, the image analysis unit 150C analyzes the positions and number of pedestrians and the like present around the vehicle, or the conditions around the vehicle, such as the width of the road on which the vehicle is traveling and the driving lanes.

[0048] The switching control unit 140C adjusts the distance x to the N wave so that the directional characteristics of the sound output from the speaker 120 become narrower, based on the situation around the vehicle analyzed by the image analysis unit 150C. S or the distance x to the N wave is increased so that the directional characteristics of the sound output from the speaker 120 become wider. S The SP driver 130 is instructed to switch to a shorter period.

[0049] For example, if the image is analyzed and there are many pedestrians around the vehicle, a switching instruction is given to widen the directional characteristics, and if there are no pedestrians around the vehicle, a switching instruction is given to narrow the directional characteristics. This makes it possible to switch between wide and narrow directional characteristics of the sound emitted from the speaker 120 after accurately grasping the surrounding situation. The captured image may be analyzed and a process equivalent to that of the speed acquisition unit 150A shown in FIG. 4 may be performed, or a process equivalent to that of the driving environment determination unit 150B shown in FIG. 5 may be performed.

[0050] 7 is a diagram showing a modified example in which the directional characteristic of the speaker 120 is changed according to the crowded state of the room. The announcement device 100D shown in FIG. 7 is installed, for example, in a sales floor of a department store, and emits a predetermined announcement sound toward some customers. This announcement device 100D has a configuration similar to that of the vehicle approach notification device 100 shown in FIG. 1, and is different from the vehicle approach notification device 100 in that the surrounding situation determination unit 150 is realized by the crowded state determination unit 150D, the running sound generation unit 110 is replaced by the announcement sound generation unit 110D, and the switching control unit 140 is replaced by the switching control unit 140D. The announcement sound generation unit 110D corresponds to the output sound generation means, and the crowded state determination unit 150D corresponds to the crowded state determination means.

[0051] The crowded state determination unit 150D determines the crowded state of customers in the vicinity (a specific area in the department store). This determination may be performed by analyzing the image captured by the camera 152 as in the image analysis unit 150C shown in Fig. 6, or may be performed based on the detection result of a sensor installed at the entrance to detect the entrance and exit of customers.

[0052] The switching control unit 140D adjusts the distance x to the N wave so that the directional characteristics of the announcement sound output from the speaker 120 become narrower based on the surrounding congestion state determined by the congestion state determination unit 150D. S or the distance x to the N wave is increased so that the directional characteristics of the announcement sound output from the speaker 120 become wider. S The SP driver 130 is instructed to switch the time to a shorter time.

[0053] For example, when it is quiet and there are few customers in a specific area, a switching instruction is given to widen the directional characteristics of the radiated announcement sound in order to attract customers, and when it is busy and there are many customers in a specific area, a switching instruction is given to narrow the directional characteristics of the radiated announcement sound so that only a certain number of customers can hear it. This makes it possible to switch between wide and narrow directional characteristics of the radiated sound from speaker 120 depending on the surrounding congestion state.

[0054] 7 can be used for purposes other than announcement sounds in department stores. For example, in an art museum, when an exhibition room is crowded with many students during a student tour, a switching instruction is given to widen the directional characteristics of the announcement sound to be emitted, and otherwise, a switching instruction is given to narrow the directional characteristics of the announcement sound to be emitted.

[0055] The present invention is not limited to the above embodiment, and various modifications are possible within the scope of the present invention. In the above embodiment, the distance x S The distance to N waves is xS The long and short lengths may be alternately switched over a predetermined period of time to alternate between wide and narrow directional characteristics of the sound emitted from the speaker 120. This makes it possible to make the sound emitted from the speaker 120 audible in both near and far surrounding spaces. [Industrial Applicability]

[0056] As described above, according to the present invention, when the distance to the shock wave is long, the difference sound of two types of carrier waves is repeatedly generated and synthesized before the shock wave is generated, and these difference sounds become a virtual sound source and are synthesized along the direction in which the sound wave travels, narrowing the directional characteristics. On the other hand, when the distance to the shock wave is short, the extension length of the virtual sound source becomes short, and the sound wave is diffused spherically from the position where the virtual sound source disappears, widening the directional characteristics. In this way, by varying the distance to the shock wave, the directional characteristics can be changed, and the output range of the radiated sound of the speaker can be switched. [Explanation of symbols]

[0057] 100, 100A, 100B, 100C Vehicle approach notification device 100D Announcement Device 110 Running sound generation unit 110D Announcement sound generator 120 Speaker 130 SP (Speaker) drive unit 140, 140A, 140B, 140C, 140D Switching control unit 150 Surrounding situation judgment unit 150A speed acquisition part 150B Driving environment judgment unit 150C Image analysis section 150D Congestion state determination unit 152 Cameras

Claims

1. an output sound generating means for generating a sound to be output; An ultrasonic speaker; a speaker driving means for driving the ultrasonic speaker and outputting the generated sound of the output sound generating means from the ultrasonic speaker; a shock wave distance varying means for varying a distance over which a sound wave output from the ultrasonic speaker propagates through the air and becomes a shock wave; A speaker system comprising:

2. 2. The speaker system according to claim 1, wherein the shock wave distance varying means varies the distance by sending an instruction to the speaker driving means to change the initial sound pressure of the sound wave when it is output from the ultrasonic speaker.

3. 2. The speaker system according to claim 1, wherein the shock wave distance varying means varies the distance by sending an instruction to the speaker driving means to change the carrier frequency of the sound waves output from the ultrasonic speaker.

4. The speaker system according to claim 1, characterized in that the shock wave distance varying means varies the distance by sending an instruction to the speaker driving means to change the initial sound pressure of the sound waves when output from the ultrasonic speaker and the carrier frequency of the sound waves output from the ultrasonic speaker.

5. A surrounding situation determination means for determining a surrounding situation is further provided, 2. The speaker system according to claim 1, wherein the shock wave distance varying means varies the distance based on the surrounding conditions determined by the surrounding conditions determining means.

6. A speaker system that is mounted on a vehicle and outputs a sound to notify people in the vicinity of the approach of the vehicle, the surrounding situation determination means is a speed acquisition means for acquiring a traveling speed of the vehicle, The speaker system according to claim 5, characterized in that the shock wave distance variable means issues a switching instruction to set the distance longer so that the directional characteristic of the sound output from the speaker becomes narrower when the driving speed acquired by the speed acquisition means is fast, and to set the distance shorter so that the directional characteristic of the sound output from the speaker becomes wider when the driving speed acquired by the speed acquisition means is slow.

7. A speaker system that is mounted on a vehicle and outputs a sound to notify people in the vicinity of the approach of the vehicle, the surrounding condition determination means is a driving environment determination means for determining whether the vehicle is traveling in an urban area or a suburban area; The speaker system according to claim 5, characterized in that the shock wave distance varying means performs a switching instruction to set the distance longer so that the directional characteristic of the sound output from the speaker array becomes narrower when the driving environment determination means determines that the vehicle is traveling in a suburban area, and to set the distance shorter so that the directional characteristic of the sound output from the speaker array becomes wider when the driving environment determination means determines that the vehicle is traveling in an urban area.

8. 2. The speaker system according to claim 1, wherein the shock wave distance varying means issues a switching instruction to alternately set the distance between long and short.

9. The surrounding situation determination means includes an imaging means for imaging the surroundings, and an image analysis means for analyzing the surrounding situation based on an image obtained by imaging the surroundings, 6. The speaker system according to claim 5, wherein the shock wave distance varying means issues a switching instruction for switching between long and short distances based on the surrounding conditions analyzed by the image analyzing means.

10. The surrounding situation determination means is a congestion state determination means for determining a surrounding congestion state, 6. The speaker system according to claim 5, wherein the shock wave distance varying means issues a switching instruction to switch the distance between long and short based on the surrounding crowded state determined by the crowded state determining means.

Images