Acoustic system

Abstract

To make, in a vehicular cabin in which a plurality of stereo speakers are provided, a crew member not hearing sound of a stereo speaker hardly hear sound of another stereo speaker.SOLUTION: An acoustic system 1 comprises: four stereo speakers 11 to 14; a sound phase control unit 30 for controlling, for right and left speakers of each of the stereo speakers 11 to 14, which of sound in a normal phase and sound in a reverse phase with respect to a sound source is to be output; and a sound phase information acquisition unit 20 for acquiring phase information on sound output from the right speaker (for example, 11A) being sound in the normal phase or the reverse phase. When the phase information acquired by the sound phase information acquisition unit 20 shows the normal phase, the sound phase control unit 30 performs control so that the left speaker of the stereo speaker and a right speaker of another stereo speaker existing in front of the stereo speaker output sound in the reverse phase and a left speaker of the otter stereo speaker outputs sound in the normal phase.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an acoustic system provided in the passenger compartment of a vehicle such as an automobile.

Background Art

[0002] There is known an acoustic system that constructs a sound field only in the vicinity of the user's head without using earphones or headphones (see, for example, Patent Document 1). In the acoustic system described in Patent Document 1, a plurality of speaker pairs are provided, each speaker pair including a speaker that emits sound based on an acoustic signal of a predetermined sound source and a speaker that emits sound based on an acoustic signal having a phase opposite to that of the acoustic signal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the acoustic system described in Patent Document 1 has a minimum configuration of a four-speaker configuration including a speaker with a positive phase and a speaker with a negative phase for each of the left and right ears, and constructs a sound field only in the vicinity of the user of the acoustic system. However, in Patent Document 1, for example, when this acoustic system is arranged on the headrests of each seat in the passenger compartment of a vehicle such as an automobile, the interference of sound between the acoustic systems is not considered.

[0005] That is, in the four-speaker configuration, in order to be installed in the headrest, the headrest will become large, or the acoustic system will be configured with speakers that are so small that the effect in the low frequency range cannot be exhibited. In addition, it is also necessary to consider the amplification and interference of sound between multiple acoustic systems.

[0006] The object of the present disclosure is to solve such problems, and the object is to provide an acoustic system that can make it difficult for a passenger who is not listening to the sound of a stereo speaker to hear the sound of other stereo speakers in the passenger compartment of a vehicle provided with a plurality of stereo speakers.

Means for Solving the Problems

[0007] An acoustic system according to an aspect of the present disclosure is an acoustic system provided in the passenger compartment of a vehicle, a first stereo speaker provided in a first seat in a first row in the passenger compartment and including a first right speaker and a first left speaker; a second stereo speaker provided in a second seat in a second row in the passenger compartment and including a second right speaker and a second left speaker; a sound phase control unit that controls which of the in-phase sound and the out-of-phase sound with respect to the sound source is output for each of the first left and right speakers of the first stereo speaker and the second left and right speakers of the second stereo speaker; a sound phase information acquisition unit that acquires phase information indicating whether the sound output from the first right speaker of the first stereo speaker is the in-phase sound or the out-of-phase sound; and the sound phase control unit when the phase information acquired by the sound phase information acquisition unit indicates the in-phase, controls the first left speaker of the first stereo speaker and the second right speaker of the second stereo speaker to output the out-of-phase sound, and controls the second left speaker of the second stereo speaker to output the in-phase sound; when the phase information acquired by the sound phase information acquisition unit indicates the out-of-phase, controls the first left speaker of the first stereo speaker and the second right speaker of the second stereo speaker to output the in-phase sound, and controls the second left speaker of the second stereo speaker to output the out-of-phase sound.

[0008] An acoustic system according to another aspect of the present disclosure is an acoustic system provided in the passenger compartment of a vehicle, a first stereo speaker provided on a first seat in a first row in the passenger compartment and including a first right speaker and a first left speaker, a second stereo speaker provided on a second seat in the first row and including a second right speaker and a second left speaker, a sound phase control unit that controls, for each of the first left and right speakers of the first stereo speaker and the second left and right speakers of the second stereo speaker, whether to output sound of a positive phase or a negative phase with respect to a sound source, a sound phase information acquisition unit that acquires phase information indicating whether the sound output from the first right speaker of the first stereo speaker is the sound of the positive phase or the negative phase, and the sound phase control unit when the phase information acquired by the sound phase information acquisition unit indicates the positive phase, controls the first left speaker of the first stereo speaker and the second left speakers of the second stereo speaker to output the sound of the negative phase, and controls the second right speaker of the second stereo speaker to output the sound of the positive phase, when the phase information acquired by the sound phase information acquisition unit indicates the negative phase, controls the first left speaker of the first stereo speaker and the second left speakers of the second stereo speaker to output the sound of the positive phase, and controls the second right speaker of the second stereo speaker to output the sound of the negative phase.

Advantages of the Invention

[0009] According to the acoustic system according to the present disclosure, in the passenger compartment of a vehicle provided with a plurality of stereo speakers, it is possible to make it difficult for a passenger who is not listening to the sound of a stereo speaker to hear the sound of another stereo speaker.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the invention according to the claims is not limited to the following embodiments. Also, not all of the configurations described in this embodiment are essential as means for solving the problems. For the sake of clarity of explanation, the following description and drawings have been appropriately omitted and simplified. In each drawing, the same elements are denoted by the same reference numerals, and duplicate explanations are omitted as necessary.

[0012] (Embodiment 1) <Stereo Speaker> First, the configuration of the stereo speaker that constitutes the acoustic system according to Embodiment 1 of the present disclosure will be described. FIG. 1 is a top view showing one stereo speaker 11 of the acoustic system 1 (see FIG. 3) according to Embodiment 1. FIG. 2 is a conceptual diagram showing an example of the operation of the stereo speaker 11 shown in FIG. 1. In FIGS. 1 and 2, the head H of the user is shown so that the positional relationship between the user of the stereo speaker 11 and the stereo speaker 11 can be understood.

[0013] As shown in FIGS. 1 and 2, the stereo speaker 11 according to Embodiment 1 includes a right speaker 11A and a left speaker 11B. In this example, the stereo speaker 11 is provided in the headrest 2. The headrest 2 is installed integrally or as a separate member behind the head when a user (occupant) sits on the seat of a vehicle such as an automobile.

[0014] The right speaker 11A is configured to emit sound for the right ear based on an acoustic signal (sound source) input from an amplifier (not shown) of the acoustic system 1. The left speaker 11B is configured to emit sound for the left ear based on an acoustic signal input from the amplifier of the acoustic system 1. Further, under the control of a sound phase control unit described later, the right speaker 11A and the left speaker 11B can also emit sound for the right ear and sound for the left ear based on acoustic signals having a phase opposite to that of the acoustic signal input from the amplifier of the acoustic system.

[0015] The right speaker 11A includes a diaphragm 111A, a magnetic circuit unit 112A, and a flat baffle 113A. The left speaker 11B includes a diaphragm 111B, a magnetic circuit unit 112B, and a flat baffle 113B. Each of the speakers 11A and 11B converts an acoustic signal (electrical signal) from an amplifier (not shown) into physical sound (vibration of air) by the diaphragms 111A and 111B and the magnetic circuit units 112A and 112B. Further, the flat baffles 113A and 113B block the diffraction of the bass sound emitted to the rear surface (-X direction) side in the +X direction, which is the sound emission direction of each of the speakers 11A and 11B, to the front surface side.

[0016] As shown in FIG. 1, the diaphragm 111A of the right speaker 11A is arranged such that the central position in its lateral width direction is near the rear of the right ear of the user of the stereo speaker 11, and the diaphragm 111B of the left speaker 11B is arranged such that the central position in its lateral width direction is near the rear of the left ear of the user. Thereby, the sound emitted from the right speaker 11A and the left speaker 11B can reach the user at a short distance.

[0017] Note that since the user's head H may move in the direction perpendicular (lateral direction) to the +X direction which is the sound emission direction of each of the speakers 11A and 11B, within the range allowed as the size of the headrest 2, the distance between the right speaker 11A and the left speaker 11B may be slightly increased.

[0018] A gap is provided in the headrest 2 so that the user's head H of the stereo speaker 11 can rest on the headrest 2 without problem. Also, within the headrest 2, a cushioning material 40 for alleviating the contact pressure with the user's head H is provided in front in the +X direction. Note that it is also possible to omit the cushioning material 40 in consideration of the user's comfort (such as the repulsive force on the head).

[0019] Here, in an example shown in FIG. 2, the right speaker 11A is configured to emit the sound for the right ear based on the acoustic signal in the positive phase, while the left speaker 11B is configured to emit the sound for the left ear based on the acoustic signal in the reverse phase. As a result, a sound field S1 due to the sound in the positive phase emitted from in front of the right speaker 11A and a sound field S3 due to the sound in the reverse phase emitted from in front of the left speaker 11B are constructed. At this time, the sound spreading in front of each of the speakers 11A and 11B and the sound spreading behind each of the speakers 11A and 11B become sounds in the reverse phase with a 180° difference in phase according to the movement of the diaphragms 111A and 111B. That is, a sound field S2 is constructed behind the right speaker 11A by the sound that emits the sound for the right ear based on the acoustic signal in the reverse phase from behind the right speaker 11A, and a sound field S4 is constructed behind the left speaker 11B by the sound that emits the sound for the left ear based on the acoustic signal in the positive phase from behind the left speaker 11B. And at a position away from both speakers 11A and 11B and at the same distance from the left and right speakers of other stereo speakers (not shown), the sound in the positive phase based on the acoustic signal and the sound in the reverse phase based on the acoustic signal interfere with each other and cancel each other out. As a result, sufficient sound pressure is ensured in a range close to both speakers 11A and 11B, and a compact sound field is formed in which the sound pressure rapidly decreases as the distance from both speakers 11A and 11B increases.

[0020] <Acoustic system> Next, the acoustic system 1 according to Embodiment 1 of the present disclosure will be described. FIG. 3 is a block diagram showing an example of the configuration of the acoustic system 1 according to Embodiment 1. FIG. 4 is a conceptual diagram of a vehicle 100 to which the acoustic system 1 according to Embodiment 1 is applied. As shown in FIG. 3, the acoustic system 1 includes four stereo speakers 11 to 14, a sound phase information acquisition unit 20, and a sound phase control unit 30. Further, as shown in FIG. 4, the acoustic system 1 according to the present embodiment is applied to a vehicle 100 in which two seats are arranged in two rows horizontally (a two-row seat). The stereo speakers 11 to 14 are respectively provided in the headrests 2 of the seats A to D.

[0021] Here, the assumed environment for applying the acoustic system 1 according to the present embodiment will be described. First, as described above, personal stereo speakers 11 to 14 are respectively arranged on each of the seats A to D in the passenger compartment of the vehicle 100 shown in FIG. 4(a). Thereby, the passengers in each seat can enjoy the music or the like that they want to listen to by the corresponding stereo speaker in the headrest 2. On the other hand, it is assumed that there are also passengers who do not want to listen to music or the like.

[0022] When each passenger in the vehicle 100 listens to the same music or the like, or when there are no passengers who do not want to listen to music or the like, each of the stereo speakers 11 to 14 outputs sound from the same sound source in the same phase as before. However, when there are passengers who do not want to listen to music or the like, by applying the acoustic system 1 according to the present embodiment and controlling the phase of the sound output from any of the speakers 11 to 14 that outputs sound, the spread of the sound field constructed in the passenger compartment of the vehicle 100 can be suppressed.

[0023] In the case where a plurality of passengers listen to the same music or the like, the sound for the right ear based on the same audio signal is output from the right speakers 11A to 14A of the stereo speakers 11 to 14 of the corresponding seats A to D, and the sound for the left ear based on the same audio signal is output from the left speakers 11B to 14B. Therefore, in this example, the door speakers of the vehicle 100 are unnecessary, and even in the case of a vehicle equipped with door speakers, the door speakers are set to be inactive.

[0024] Furthermore, each of the stereo speakers 11 to 14 for seats A to D includes a switch (not shown) that can independently switch the output between the in-phase output and the anti-phase output for each of the right speakers 11A to 14A and the left speakers 11B to 14B. And each of the stereo speakers 11 to 14 is set to output a sound in the in-phase from one speaker (for example, the right speakers 11A to 14A) and a sound in the anti-phase from the other speaker (for example, the left speakers 11B to 14B). By controlling the phase of the sound output in this way, as described above, the stereo speakers 11 to 14 each construct a compact sound field. Hereinafter, including these assumptions, it will be specifically described.

[0025] As shown in FIG. 3, the stereo speaker 11 includes a right speaker 11A and a left speaker 11B. The stereo speaker 12 includes a right speaker 12A and a left speaker 12B. The stereo speaker 13 includes a right speaker 13A and a left speaker 13B. The stereo speaker 14 includes a right speaker 14A and a left speaker 14B.

[0026] As described above for the stereo speaker 11, each of the left and right speakers 11A to 14A and 11B to 14B of the stereo speakers 11 to 14 is a speaker capable of outputting a sound based on either an in-phase audio signal or an anti-phase audio signal, and includes a switch (not shown) for switching the phase to be output, as described above.

[0027] The sound phase information acquisition unit 20 is configured to acquire phase information indicating whether the sound output from the first right speaker of the first stereo speaker is in-phase sound or out-of-phase sound. Here, the first stereo speaker is any one of the four stereo speakers 11 to 14, for example, the stereo speaker 11 corresponding to the seat A as the driver's seat. In this case, the sound phase information acquisition unit 20 acquires phase information indicating whether the right speaker 11A of the stereo speaker 11 outputs in-phase sound or out-of-phase sound. Note that the sound phase information acquisition unit 20 may acquire phase information indicating whether the sound output from the first left speaker of the first stereo speaker is in-phase sound or out-of-phase sound. This is because according to the conditions of the sound field analysis model described later, when one of the left and right speakers 11A and 11B outputs in-phase sound, the other outputs out-of-phase sound.

[0028] That is, the sound phase control unit 30 is configured to control which of the in-phase sound and the out-of-phase sound with respect to the acoustic signal (sound source) is output for each of the left and right speakers 11A to 14A and 11B to 14B of the four stereo speakers 11 to 14. The sound phase control unit 30 independently controls whether to output in-phase sound or out-of-phase sound by switching the switches of each of the left and right speakers 11A to 14A and 11B to 14B.

[0029] That is, based on the phase information acquired by the sound phase information acquisition unit 20, the sound phase control unit 30 controls which of the in-phase sound and the out-of-phase sound with respect to the acoustic signal (sound source) is output for each of the left and right speakers 12A to 14A and 11B to 14B of each of the stereo speakers 11 to 14 other than the right speaker 11A of the stereo speaker 11.

[0030] Each of the stereo speakers 11 to 14 is also provided with an ON / OFF switch (not shown). By this ON / OFF switch, the occupant of that seat can activate or stop the corresponding stereo speakers 11 to 14. Note that the ON / OFF of each of the stereo speakers 11 to 14 may be controlled by the ECU (Electronic Control Unit) of the vehicle 100.

[0031] In the present embodiment, the sound phase control unit 30 controls the sound output of positive and reverse phases for the left and right speakers 11A to 14A and 11B to 14B of the ON-state stereo speakers 11 to 14, respectively. In particular, for an occupant who has turned off the stereo speakers 11 to 14, the sound phase control unit 30 controls the sound output of positive and reverse phases of the left and right speakers 11A to 14A and 11B to 14B of the stereo speakers 11 to 14 so that the sound output from the other ON-state stereo speakers 11 to 14 becomes difficult to hear.

[0032] Here, the positional relationship between the head H of each occupant and the left and right speakers of the stereo speaker will be described again. Representing the occupant, the positional relationship between the head H of the driver sitting in seat A and the left and right speakers 11A and 11B of the stereo speaker 11 is shown. FIG. 5 is a diagram for explaining a sound field analysis method by the acoustic system 1 according to Embodiment 1.

[0033] As shown in FIG. 5(a), a sound pressure analysis surface 101 is provided so as to surround the head H of the driver, and as also shown in FIG. 5(b), the left and right speakers 11A and 11B are installed at predetermined positions. Note that in the other seats B to D shown in FIG. 4(a) as well, the left and right speakers 12A to 14A and 12B to 14B are similarly installed.

[0034] <Settings for the sound field analysis model> Next, the setting conditions of the sound field analysis model of the acoustic system 1 according to this embodiment will be described. Here, as shown in Fig. 4(a), in a vehicle 100 having seats arranged in a 2×2 pattern (two rows and two columns), conditions for determining how to set the phases of the sounds output from the left and right speakers 11A - 14A, 11B - 14B of the stereo speakers 11 - 14 provided in each seat A - D will be explained. As shown in Fig. 4(b), in this analysis model, a plane at a height approximately equal to the height of the passengers' ears is defined as the sound pressure analysis plane 101, and the sound reflection on the vehicle body wall surface 102 is also taken into consideration. Also, each stereo speaker 11 - 14 is configured as an open speaker.

[0035] When a passenger who does not want to listen to music or the like is in the vehicle 100, the sound phase control unit 30 controls such that in the left and right speakers of one stereo speaker, one outputs a sound with a positive phase and the other outputs a sound with a reverse phase. For example, when a certain stereo speaker provided in an arbitrary seat is in the OFF state, the acoustic system 1 may determine that a passenger who does not want to listen to music or the like is in the vehicle 100.

[0036] Here, as the reference seat, for example, seat A as the driver's seat in the first row in the vehicle interior is set. When the stereo speaker 11 provided in seat A is in the ON state, the sound phase information acquisition unit 20 acquires the phase information as to whether the right speaker 11A of the stereo speaker 11 is outputting a sound with a positive phase or a sound with a reverse phase. Note that a seat other than the driver's seat may be set as the reference seat. It is preferable that the user of the acoustic system 1 can arbitrarily specify which seat is set as the reference seat.

[0037] Next, when the stereo speakers 13 and 14 provided in the seats C and D in the second row in the vehicle interior are in the ON state, the sound phase control unit 30 sets the phases of the sounds output from the left and right speakers 13A, 13B, 14A, and 14B of the stereo speakers 13 and 14. For example, when the right speaker 11A of the stereo speaker 11 outputs a sound with a positive phase, the sound phase control unit 30 sets the phase of the sound output from the right speakers 13A and 14A of the stereo speakers 13 and 14 provided in the seats C and D in the second row in the vehicle interior to the reverse phase, and also sets the phase of the sound output from the left speakers 13B and 14B of the stereo speakers 13 and 14 to the positive phase.

[0038] Note that the "first row" and "second row" in the vehicle interior described in the claims to be described later may be the first row and the second row in order with respect to the traveling direction of the vehicle 100 as described above, or conversely, the second row and the first row in order with respect to the traveling direction of the vehicle 100. Thus, the horizontal rows of the vehicle 100 are in any order.

[0039] Next, when the stereo speaker 12 provided in the seat B as the passenger seat in the first row in the vehicle interior is in the ON state, the sound phase control unit 30 sets the phases of the sounds output from the left and right speakers 12A and 12B of the stereo speaker 12. For example, when the right speaker 11A of the stereo speaker 11 outputs a sound with a positive phase, the sound phase control unit 30 sets the right speaker 12A of the stereo speaker 12 to output a sound with a positive phase and the left speaker 12B to output a sound with a reverse phase. In this way, for each of the stereo speakers 11 and 12 in the horizontal row (first row) of seats including the reference seat, the sound phase control unit 30 controls the left and right speakers 11A, 11B, 12A, and 12B to output sounds with positive, reverse, positive, and reverse phases in order from the right side of the vehicle 100.

[0040] As described above, when controlling the control target seat (here, seat C) that has a front-back relationship with the reference seat (here, seat A as the driver's seat), the sound phase control unit 30 controls the left speaker 11B of the stereo speaker 11 and the right speaker 13A of the stereo speaker 13 to output sounds with opposite phases and the left speaker 13B of the stereo speaker 13 to output a sound with a positive phase when the phase information of the right speaker 11A of the stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a positive phase.

[0041] Conversely, when the phase information of the right speaker 11A of the stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a reverse phase, the sound phase control unit 30 controls the left speaker 11B of the stereo speaker 11 and the right speaker 13A of the stereo speaker 13 to output sounds with positive phases and the left speaker 13B of the stereo speaker 13 to output a sound with a reverse phase.

[0042] Then, when controlling the control target seat (here, seat B) that has a left-right relationship with the reference seat (here, seat A as the driver's seat), the sound phase control unit 30 controls the left speaker 11B of the stereo speaker 11 and the left speaker 12B of the stereo speaker 12 to output sounds with opposite phases and the right speaker 12A of the stereo speaker 12 to output a sound with a positive phase when the phase information of the right speaker 11A of the stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a positive phase, for example.

[0043] Conversely, when the phase information of the right speaker 11A of the stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a reverse phase, the sound phase control unit 30 controls the left speaker 11B of the stereo speaker 11 and the left speaker 12B of the stereo speaker 12 to output sounds with positive phases and the right speaker 12A of the stereo speaker 12 to output a sound with a reverse phase, for example.

[0044] <Analysis result of sound field> The following shows the analysis results of the sound field obtained by simulation based on the setting conditions of the above sound field analysis model. In principle, due to the cancellation between the in-phase sound and the out-of-phase sound output from the stereo speakers installed in two or more seats, the sound pressure will decrease under certain conditions. Therefore, in the simulation, the case where two or more stereo speakers are in the ON state will be described.

[0045] FIG. 6 and FIG. 7 are diagrams showing the analysis results of the sound field by the acoustic system 1 according to the first embodiment. Note that on the diagrams showing the analysis results of the sound field, whether the left and right speakers of each stereo speaker output in-phase sound or out-of-phase sound is indicated by "+" (in-phase) and "-" (out-of-phase).

[0046] First, the first simulation is shown in FIG. 6(a). At this time, the stereo speaker 11 of seat A and the stereo speaker 13 of seat C are in the ON state, and the right speakers 11A and 13A of each stereo speaker 11 and 13 output in-phase sound, while the left speakers 11B and 13B output out-of-phase sound. On the other hand, the stereo speaker 12 of seat B and the stereo speaker 14 of seat D are in the OFF state, and the passengers sitting in these seats are assumed to be passengers who do not want to listen to music or the like.

[0047] Here, the sound phase information acquisition unit 20 acquires phase information indicating that the right speaker 11A of the stereo speaker 11 of seat A in the first row as the reference seat outputs a sound with a positive phase. Based on the phase information acquired by the sound phase control unit 30, the sound phase control unit 30 controls the phase of the sound output by the right speaker 13A of the stereo speaker 13 of seat C in the second row different from the row of seat A to be an inverted phase, and the phase of the sound output by the left speaker 13B of the stereo speaker 13 to be a positive phase. At this time, sound cancellation occurs between the sounds output by the stereo speaker 11 and the stereo speaker 13. As a result, as can be seen from FIG. 6(b), the sound pressure decreases at seats B and D, and the passengers sitting at seats B and D can hardly hear the sounds of the other stereo speakers 11 and 13. Thereby, the effect of the audio system 1 according to the present embodiment is exhibited.

[0048] Next, the second simulation is shown in FIG. 6(c). The stereo speakers 11, 13, and 14 of seats A, C, and D other than seat B, which is the passenger seat, are in the ON state, the right speakers 11A, 13A, and 14A of the respective stereo speakers 11, 13, and 14 output sounds with a positive phase, and the left speakers 11B, 13B, and 14B output sounds with an inverted phase. On the other hand, the stereo speaker 12 of seat B is in the OFF state, and it is assumed that the passenger sitting on seat B does not want to listen to music or the like.

[0049] Here, the sound phase information acquisition unit 20 acquires phase information indicating that the right speaker 11A of the stereo speaker 11 of seat A in the first row as the reference seat outputs a sound with a positive phase. Based on the phase information acquired by the sound phase control unit 30, the sound phase control unit 30 controls the phase of the sound output by the right speaker 13A of the stereo speaker 13 of seat C in the second row and the right speaker 14A of the stereo speaker 14 of seat D in the second row, which are different from the row of seat A, to be the reverse phase, and controls the phase of the sound output by the left speaker 13B of the stereo speaker 13 and the left speaker 14B of the stereo speaker 14 to be the positive phase. At this time, sound cancellation occurs between the sounds output by the stereo speaker 11 and the stereo speakers 13 and 14. As a result, as can be seen from FIG. 6(d), the sound pressure decreases at seat B, and the passenger sitting at seat B can hardly hear the sounds of the other stereo speakers 11, 13, and 14. Thereby, the effect of the acoustic system 1 according to the present embodiment is exhibited.

[0050] Finally, a third simulation is shown in FIG. 7(a). The stereo speakers 11, 12, and 13 of seats A, B, and C other than seat D are in the ON state, and the left and right speakers 11A, 11B, 12A, 12B, 13A, and 13B of each stereo speaker 11, 12, and 13 output sounds with positive phases, reverse phases, positive phases, reverse phases, positive phases, and reverse phases, respectively. On the other hand, the stereo speaker 14 of seat D is in the OFF state, and the passenger sitting at seat D is assumed to be a passenger who does not want to listen to music or the like.

[0051] Here, the sound phase information acquisition unit 20 acquires phase information indicating that the right speaker 11A of the stereo speaker 11 of seat A in the first row, which is the reference seat, outputs a sound with a positive phase. Based on the phase information acquired by the sound phase information acquisition unit 20, the sound phase control unit 30 controls the phase of the sound output by the right speaker 13A of the stereo speaker 13 of seat C in the second row, which is different from the row of seat A, to be an inverted phase, and controls the phase of the sound output by the left speaker 13B of the stereo speaker 13 to be a positive phase. Also, based on the phase information acquired by the sound phase information acquisition unit 20, the sound phase control unit 30 controls the phase of the sound output by the right speaker 12A of the stereo speaker 12 of seat B in the first row, which is the same as the row of seat A, to be a positive phase, and controls the phase of the sound output by the left speaker 12B of the stereo speaker 12 to be an inverted phase. At this time, sound cancellation occurs between the sounds output by the stereo speakers 11 and 12 and the stereo speaker 13. As a result, as can be seen from FIG. 7(b), the sound pressure decreases at seat D, and the passenger sitting at seat D can hardly hear the sounds of the other stereo speakers 11, 12, and 13. Thus, the effect of the acoustic system 1 according to the present embodiment is exhibited.

[0052] As described above, the acoustic system 1 according to the present embodiment is an acoustic system 1 provided in the passenger compartment of the vehicle 100. The acoustic system 1 is provided in the first seat (for example, seat A) in the first row in the passenger compartment, and includes a first stereo speaker 11 including a first right speaker 11A and a first left speaker 11B, and a second seat (for example, seat C) in the second row in the passenger compartment. A second stereo speaker 13 including a second right speaker 13A and a second left speaker 13B, and for each of the first left and right speakers 11A and 11B of the first stereo speaker 11 and the second left and right speakers 13A and 13B of the second stereo speaker 13, a sound phase control unit 30 that controls whether to output a sound with a positive phase or a sound with a reverse phase with respect to the sound source, and a sound phase information acquisition unit 20 that acquires phase information indicating whether the sound output from the first right speaker 11A of the first stereo speaker 11 is a sound with a positive phase or a sound with a reverse phase. Here, when the phase information of the sound output from the first right speaker 11A of the first stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a positive phase, the sound phase control unit 30 causes the first left speaker 11B of the first stereo speaker 11 and the second right speaker 13A of the second stereo speaker 13 to output a sound with a reverse phase, and the second left speaker 13B of the second stereo speaker 13 outputs a sound with a positive phase. On the other hand, when the phase information of the sound output from the first right speaker 11A of the first stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a reverse phase, the sound phase control unit 30 causes the first left speaker 11B of the first stereo speaker 11 and the second right speaker 13A of the second stereo speaker 13 to output a sound with a positive phase, and the second left speaker 13B of the second stereo speaker 13 outputs a sound with a reverse phase. By configuring the acoustic system 1 according to the present embodiment in this way, in the passenger compartment of the vehicle 100 provided with a plurality of stereo speakers 11 to 14, it is possible to make it difficult for passengers who are not listening to the sound of the stereo speaker to hear the sound of other stereo speakers.

[0053] In addition, the audio system 1 according to the present embodiment is provided in the first seat (for example, seat A) in the first row in the vehicle interior, and includes a first stereo speaker 11 including a first right speaker 11A and a first left speaker 11B, and a second seat (for example, seat B) in the first row. A second stereo speaker 12 including a second right speaker 12A and a second left speaker 12B, and for each of the first left and right speakers 11A and 11B of the first stereo speaker 11 and the second left and right speakers 12A and 12B of the second stereo speaker 12, a sound phase control unit 30 that controls whether to output a sound in the positive phase or a sound in the reverse phase with respect to the sound source, and a sound phase information acquisition unit 20 that acquires phase information indicating whether the sound output from the first right speaker 11A of the first stereo speaker 11 is a sound in the positive phase or a sound in the reverse phase. Here, when the phase information of the sound output from the first right speaker 11A of the first stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates the positive phase, the sound phase control unit 30 causes the first left speaker 11B of the first stereo speaker 11 and the second left speaker 12B of the second stereo speaker 12 to output a sound in the reverse phase, and the second right speaker 12A of the second stereo speaker 12 outputs a sound in the positive phase. On the other hand, when the phase information of the sound output from the first right speaker 11A of the first stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates the reverse phase, the sound phase control unit 30 causes the first left speaker 11B of the first stereo speaker 11 and the second left speaker 12B of the second stereo speaker 12 to output a sound in the positive phase, and the second right speaker 12A of the second stereo speaker 12 outputs a sound in the reverse phase. By configuring the audio system 1 according to the present embodiment in this way, in the vehicle interior of the vehicle 100 provided with a plurality of stereo speakers 11 to 14, similar to the above case, it is possible to make it difficult for the sound of other stereo speakers to be heard by the passengers who are not listening to the sound of the stereo speakers.

[0054] (Embodiment 2) <Audio system> Hereinafter, with reference to FIGS. 8 to 10, the acoustic system according to Embodiment 2 will be described. In this embodiment, a case where the acoustic system 1A of the present disclosure is applied to a vehicle 200 (see FIG. 9) with three longitudinal rows of seats instead of the vehicle 100 with two longitudinal rows of seats shown in Embodiment 1 will be described. Therefore, the acoustic system 1A of this embodiment further includes stereo speakers 15 and 16 (see FIG. 8) provided on seats E and F. However, detailed descriptions of the components overlapping with those of the acoustic system 1 in Embodiment 1 will be omitted.

[0055] FIG. 8 is a block diagram showing an example of the configuration of the acoustic system 1A according to Embodiment 2. FIG. 9 is a conceptual diagram of a vehicle 200 to which the acoustic system 1A according to Embodiment 2 is applied. As shown in FIG. 8, the acoustic system 1A includes six stereo speakers 11 to 16, a sound phase information acquisition unit 20, and a sound phase control unit 30. Further, as shown in FIG. 9, the acoustic system 1A according to the present embodiment is applied to a vehicle 200 in which two seats are arranged in three longitudinal rows (a three-longitudinal-row seat). The stereo speakers 11 to 16 are respectively provided in the headrests 2 of seats A to F.

[0056] Here, the assumed environment for applying the acoustic system 1A according to the present embodiment will be described. Note that the same content as the assumed environment described in Embodiment 1 will be appropriately omitted to avoid redundant description. First, as described above, personal stereo speakers 11 to 16 are respectively arranged on each of the seats A to F in the vehicle interior of the vehicle 200 shown in FIG. 9(a).

[0057] When multiple passengers in the vehicle 200 listen to the same music or the like, sounds for the right ear based on the same audio signal are output from the left and right speakers 11A to 16A of the stereo speakers 11 to 16 corresponding to each seat A to F, and sounds for the left ear based on the same audio signal are output from the left speakers 11B to 16B. Further, the stereo speakers 11 to 16 each include a switch (not shown) capable of independently switching between output in the positive phase and output in the negative phase for each of the right speakers 11A to 16A and the left speakers 11B to 16B. And each stereo speaker 11 to 16 is set to output a sound in the positive phase from one speaker (for example, the right speakers 11A to 16A) and a sound in the negative phase from the other speaker (for example, the left speakers 11B to 16B).

[0058] As shown in FIG. 8, the added stereo speaker 15 includes a right speaker 15A and a left speaker 15B. Further, the stereo speaker 16 includes a right speaker 16A and a left speaker 16B. Each of the left and right speakers 15A, 15B, 16A, and 16B of the added stereo speakers 15 and 16 is a speaker capable of outputting a sound based on either a positive-phase audio signal or a negative-phase audio signal, and includes a switch (not shown) for switching the phase of the sound to be output as described above.

[0059] Also in the present embodiment, the sound phase information acquisition unit 20 is configured to acquire phase information indicating whether the right speaker 11A of the stereo speaker 11 provided in an arbitrary seat, for example, outputs a sound in the positive phase or a sound in the negative phase. Further, the sound phase control unit 30 is configured to control each of the left and right speakers 11A to 16A, 11B to 16B of the six stereo speakers 11 to 16 to output either a sound in the positive phase or a sound in the negative phase with respect to the audio signal (sound source).

[0060] That is, based on the phase information acquired by the sound phase control unit 30, for each of the left and right speakers 12A to 16A, 11B to 16B of each of the stereo speakers 11 to 16 other than the right speaker 11A of the stereo speaker 11, it is controlled whether to output a sound with a positive phase or a sound with a reverse phase with respect to the acoustic signal (sound source).

[0061] <Settings Conditions of Sound Field Analysis Model> Next, the settings conditions of the sound field analysis model of the acoustic system 1A according to the present embodiment will be described. Regarding the conditions similar to those of the sound field analysis model of the acoustic system 1 according to the first embodiment, the description thereof will be omitted as appropriate. As shown in FIG. 9(a), in a vehicle 200 having seats arranged in 3 rows and 2 columns, conditions for determining how to set the phases of the sounds output from the left and right speakers 11A to 16A, 11B to 16B of the stereo speakers 11 to 16 provided in each of the seats A to F will be described. As shown in FIG. 9(b), in this analysis model, a plane having a height approximately equal to the height of the passengers' ears is defined as the sound pressure analysis plane 201, and the reflection of sound on the vehicle body wall surface 202 is also taken into consideration. In addition, each of the stereo speakers 11 to 16 is configured as an open speaker.

[0062] Here, similar to the first embodiment, as a reference seat, for example, seat A as the driver's seat in the first row in the vehicle interior is set. When the stereo speaker 11 provided in seat A is in the ON state, the sound phase information acquisition unit 20 acquires the phase information as to whether the right speaker 11A of the stereo speaker 11 is outputting a sound with a positive phase or a sound with a reverse phase.

[0063] Next, when the stereo speakers 13 and 14 provided in the seats C and D in the second row in the vehicle interior are in the ON state, the sound phase control unit 30 sets the phases of the sounds output from the left and right speakers 13A, 13B, 14A, and 14B of the stereo speakers 13 and 14. For example, when the right speaker 11A of the stereo speaker 11 outputs a sound with a positive phase, the sound phase control unit 30 sets the phase of the sound output from the right speakers 13A and 14A of the stereo speakers 13 and 14 provided in the seats C and D in the second row in the vehicle interior to a reverse phase, and also sets the phase of the sound output from the left speakers 13B and 14B of the stereo speakers 13 and 14 to a positive phase.

[0064] Next, when the stereo speakers 15 and 16 provided in the seats E and F in the third row in the vehicle interior are in the ON state, the sound phase control unit 30 sets the phases of the sounds output from the left and right speakers 15A, 15B, 16A, and 16B of the stereo speakers 15 and 16. For example, when the right speaker 11A of the stereo speaker 11 outputs a sound with a positive phase and any one of the stereo speakers 13 and 14 provided in the seats C and D in the second row in the vehicle interior is in the ON state, the sound phase control unit 30 sets the phase of the sound output from the right speakers 15A and 16A of the stereo speakers 15 and 16 provided in the seats E and F in the third row in the vehicle interior to a positive phase, and also sets the phase of the sound output from the left speakers 15B and 16B of the stereo speakers 15 and 16 to a reverse phase. In this case, the right speakers 13A and 14A of the ON-state stereo speakers 13 and 14 provided in the seats C and D in the second row in the vehicle interior output sounds with a reverse phase. In this way, when there are ON-state stereo speakers in each of the three rows from the first row to the third row, the sound phase control unit 30 sets the left and right speakers of each stereo speaker to output sounds with a positive phase and a reverse phase alternately for the front and rear seats in the first row to the third row.

[0065] In addition, when both the stereo speakers 13 and 14 provided for the seats C and D in the second row in the vehicle interior are in the OFF state, or when both the stereo speakers 15 and 16 provided for the seats E and F in the third row in the vehicle interior are in the OFF state, since the vehicle 200 can be regarded as having a substantially two-row seat, the sound phase control unit 30 according to the present embodiment may perform the same control as the sound phase control unit 30 of the audio system 1 according to the first embodiment.

[0066] <Analysis result of sound field> Hereinafter, based on the setting conditions of the above-described sound field analysis model, the analysis results of the sound field obtained by simulation are shown. In this simulation, a case where five stereo speakers are in the ON state and one stereo speaker is in the OFF state will be described.

[0067] FIG. 10 is a diagram showing the analysis result of the sound field by the audio system 1A according to the second embodiment. Similar to the first embodiment, above the diagram showing the analysis result of the sound field, whether the left and right speakers of each stereo speaker output a sound of positive phase or a sound of negative phase is indicated by "+" (positive phase) and "-" (negative phase).

[0068] First, a first simulation in which only the stereo speaker 12 of the seat B is in the OFF state is shown in FIG. 10(a). At this time, the right speakers 11A, 13A to 16A of the respective stereo speakers 11, 13 to 16 output a sound of positive phase, and the left speakers 11B, 13B to 16B output a sound of negative phase.

[0069] Here, the sound phase information acquisition unit 20 acquires phase information indicating that the right speaker 11A of the stereo speaker 11 of seat A in the first row as the reference seat outputs a sound with a positive phase. Based on the phase information acquired by the sound phase information acquisition unit 20, the sound phase control unit 30 sets the phase of the sound output by the right speaker 13A of the stereo speaker 13 of seat C and the right speaker 14A of the stereo speaker 14 of seat D in the second row different from the row of seat A to a reverse phase, and controls the phase of the sound output by the left speaker 13B of the stereo speaker 13 and the left speaker 14B of the stereo speaker 14 to be a positive phase. In addition, based on the phase information acquired by the sound phase information acquisition unit 20, the sound phase control unit 30 sets the phase of the sound output by the right speaker 15A of the stereo speaker 15 of seat E and the right speaker 16A of the stereo speaker 16 of seat F in the third row different from the rows of seat A and seats C and D to a positive phase, and controls the phase of the sound output by the left speaker 15B of the stereo speaker 15 and the left speaker 16B of the stereo speaker 16 to be a reverse phase. At this time, sound cancellation occurs due to the sounds output by the five stereo speakers 11, 13 to 16. As a result, as can be seen from Fig. 10(b), the sound pressure decreases at seat B, and the passenger sitting at seat B can hardly hear the sounds of the other stereo speakers 11, 13 to 16. Thus, similar to the acoustic system 1 according to the first embodiment, the acoustic system 1A according to the present embodiment exhibits the effects.

[0070] Next, a second simulation in which only the stereo speaker 12 of seat D is in the OFF state is shown in Figs. 10(c) and 10(d). Also in this case, as can be seen from Fig. 10(d), by controlling the phases of the sounds output by the stereo speakers 11 to 13, 15, 16 of each seat, the sound pressure decreases at seat D, and the passenger sitting at seat D can hardly hear the sounds of the other stereo speakers 11 to 13, 15, 16. Thus, similar to the acoustic system 1 according to the first embodiment, the acoustic system 1A according to the present embodiment exhibits the effects.

[0071] As described above, the acoustic system 1A according to the present embodiment is an acoustic system 1A provided in the passenger compartment of the vehicle 200. The acoustic system 1A is provided in the first seat (for example, seat A or seat C) in the first row in the passenger compartment, and includes a first stereo speaker 11 or 13 including first right speakers 11A, 13A and first left speakers 11B, 13B, and a second seat (for example, seat E) in the second row in the passenger compartment. A second stereo speaker 15 including a second right speaker 15A and a second left speaker 15B, and a sound phase control unit 30 that controls whether to output either a positive-phase sound or a negative-phase sound with respect to the sound source for each of the first left and right speakers 11A, 11B or 13A, 13B of the first stereo speaker 11 or 13 and the second left and right speakers 15A, 15B of the second stereo speaker 15, and a sound phase information acquisition unit 20 that acquires phase information indicating whether the sound output from the first right speaker 11A or 13A of the first stereo speaker 11 or 13 is a positive-phase sound or a negative-phase sound. Here, when the phase information of the sound output from the first right speaker 11A or 13A of the first stereo speaker 11 or 13 acquired by the sound phase information acquisition unit 20 indicates a positive phase, the sound phase control unit 30 outputs a negative-phase sound from the first left speaker 11B or 13B of the first stereo speaker 11 or 13 and the second right speaker 15A of the second stereo speaker 15, and outputs a positive-phase sound from the second left speaker 15B of the second stereo speaker 15. to control. On the other hand, when the phase information of the sound output from the first right speaker 11A or 13A of the first stereo speaker 11 or 13 acquired by the sound phase information acquisition unit 20 indicates a negative phase, the sound phase control unit 30 outputs a positive-phase sound from the first left speaker 11B or 13B of the first stereo speaker 11 or 13 and the second right speaker 15A of the second stereo speaker 15, and outputs a negative-phase sound from the second left speaker 15B of the second stereo speaker 15. to control. By configuring the acoustic system 1A according to the present embodiment in this way, in the passenger compartment of the vehicle 200 provided with a plurality of stereo speakers 11 to 16, it is possible to make the sound of other stereo speakers less audible to passengers who are not listening to the sound of the stereo speakers.

[0072] Further, in the acoustic system 1A according to the present embodiment, when the sound phase control unit 30 controls only the first stereo speaker 11 or 13 or 11 and the second stereo speaker 15 or 13 or 15, the arrangement order of the first row, the second row, and the third row in the vehicle interior may be arbitrary with respect to the traveling direction of the vehicle 200. Even with such an arrangement, in the vehicle interior of the vehicle 200 provided with the plurality of stereo speakers 11 to 16, it is possible to make the sound of other stereo speakers less audible to passengers who are not listening to the sound of the stereo speakers.

[0073] Also, in the vehicle 200, in the acoustic system 1A according to the present embodiment, the first row, the second row, and the third row are provided in this arrangement order with respect to the traveling direction of the vehicle 200. When the first seat (for example, seat A), the second seat (for example, seat C), and the third seat (for example, seat E) are arranged in a row with respect to the traveling direction of the vehicle 200, in addition to controlling the first stereo speaker 11 and the second stereo speaker 13 described above, when the phase information of the sound output from the first right speaker 11A of the first stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a positive phase, the sound phase control unit 30 may control the third right speaker 15A of the third stereo speaker 15 to output a positive-phase sound and the third left speaker 15B to output a reverse-phase sound. On the other hand, in addition to controlling the first stereo speaker 11 and the second stereo speaker 13 described above, when the phase information of the sound output from the first right speaker 11A of the first stereo speaker 11 acquired by the sound phase information acquisition unit 20 indicates a reverse phase, the sound phase control unit 30 may control the third right speaker 15A of the third stereo speaker 15 to output a reverse-phase sound and the third left speaker 15B to output a positive-phase sound.

[0074] As described above, the present disclosure has been described with reference to the embodiments. However, the present disclosure is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. And each embodiment can be combined with other embodiments as appropriate.

[0075] The respective drawings are merely examples for explaining one or more embodiments. Each drawing is not associated with only one specific embodiment, but may be associated with one or more other embodiments. As can be understood by those skilled in the art, the various features described with reference to any one drawing can be combined with the features shown in one or more other drawings, for example, to create embodiments that are not explicitly illustrated or described.

Explanation of Reference Numerals

[0076] 1 Acoustic system 11 - 16 Stereo speakers 11A - 16A Right speakers 11B - 16B Left speakers 111A, 111B Diaphragms 112A, 112B Magnetic circuit parts 113A, 113B Flat baffles 20 Sound phase information acquisition unit 30 Sound phase control unit 40 Cushion material 2 Headrests 100, 200 Vehicles 101, 201 Analysis surfaces of sound pressure 102, 202 Vehicle body wall surfaces

Claims

1. An audio system provided in the passenger compartment of a vehicle, a first stereo speaker provided in a first seat in the first row in the passenger compartment, and including a first right speaker and a first left speaker; a second stereo speaker provided in a second seat in the second row in the passenger compartment, and including a second right speaker and a second left speaker; a sound phase control unit that controls, for each of the first left and right speakers of the first stereo speaker and the second left and right speakers of the second stereo speaker, whether to output a sound in the positive phase or a sound in the reverse phase with respect to the sound source; a sound phase information acquisition unit that acquires phase information indicating whether the sound output from the first right speaker of the first stereo speaker is a sound in the positive phase or a sound in the reverse phase; comprising: the sound phase control unit: when the phase information acquired by the sound phase information acquisition unit indicates the positive phase, controls the first left speaker of the first stereo speaker and the second right speaker of the second stereo speaker to output a sound in the reverse phase, and controls the second left speaker of the second stereo speaker to output a sound in the positive phase; when the phase information acquired by the sound phase information acquisition unit indicates the reverse phase, controls the first left speaker of the first stereo speaker and the second right speaker of the second stereo speaker to output a sound in the positive phase, and controls the second left speaker of the second stereo speaker to output a sound in the reverse phase. An audio system.

2. The first row and the second row in the passenger compartment are each provided with two seats, the first seat and the second seat are arranged one behind the other with respect to the traveling direction of the vehicle. The audio system according to Claim 1.

3. The first row and the second row in the passenger compartment are each provided with two seats, the passenger compartment further includes a third row provided with two seats, the audio system: further includes a third stereo speaker provided in a third seat in the third row, and including a third right speaker and a third left speaker; the first row, the second row, and the third row are provided in this order of arrangement with respect to the traveling direction of the vehicle, and the first seat, the second seat, and the third seat are arranged in a row with respect to the traveling direction of the vehicle, the sound phase control unit: When the phase information acquired by the sound phase information acquisition unit indicates the positive phase, the third right speaker of the third stereo speaker outputs the sound of the positive phase, and the third left speaker outputs the sound of the reverse phase, and When the phase information acquired by the sound phase information acquisition unit indicates the reverse phase, the third right speaker of the third stereo speaker outputs the sound of the reverse phase, and the third left speaker outputs the sound of the positive phase, and control is performed so that The acoustic system according to claim 1.

4. An acoustic system provided in a vehicle interior, A first stereo speaker provided in a first seat in the first row in the vehicle interior, and including a first right speaker and a first left speaker; A second stereo speaker provided in a second seat in the first row, and including a second right speaker and a second left speaker; A sound phase control unit that controls which of the positive-phase sound and the reverse-phase sound with respect to a sound source is output for each of the first left and right speakers of the first stereo speaker and the second left and right speakers of the second stereo speaker; A sound phase information acquisition unit that acquires phase information indicating whether the sound output from the first right speaker of the first stereo speaker is the positive-phase sound or the reverse-phase sound; Comprising The sound phase control unit When the phase information acquired by the sound phase information acquisition unit indicates the positive phase, the first left speaker of the first stereo speaker and the second left speaker of the second stereo speaker output the sound of the reverse phase, and the second right speaker of the second stereo speaker outputs the sound of the positive phase, and control is performed so that When the phase information acquired by the sound phase information acquisition unit indicates the reverse phase, the first left speaker of the first stereo speaker and the second left speaker of the second stereo speaker output the sound of the positive phase, and the second right speaker of the second stereo speaker outputs the sound of the reverse phase, and control is performed so that Acoustic system.

Images