In-car audio system

Abstract

To reduce power consumption in an on-vehicle audio system.SOLUTION: An on-vehicle audio system comprises: a plurality of speakers arranged at different places in a vehicle; an amplification device including a plurality of amplification circuits; a determination section for determining whether sound is to be output on each one of the speakers based on crewman information related to a seated state of crewmen in each one of a plurality of seats arranged in the vehicle; and a control section for controlling the amplification device based on a determination result of the determination section. Each one of the amplification circuits is connected to one or more speakers.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle audio system.

Background Art

[0002] Technologies related to audio installed in automobiles (hereinafter referred to as "in-vehicle audio") have been developed. For example, Patent Document 1 discloses an automatic sound field adjustment device that includes a human body sensor and controls the sound field of an in-vehicle audio based on a signal output from the human body sensor. In the automatic sound field adjustment device, for example, when a passenger sits on a seat provided with a human body sensor, the human body sensor detects the presence of the passenger and outputs a signal. The automatic sound field adjustment device controls the in-vehicle audio so as to obtain an appropriate sound field and adjusts the volume according to the signal output from the human body sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the automatic sound field adjustment device described in Patent Document 1 is intended to adjust the sound field according to the seating situation of the passenger, even when the passenger is not sitting on the seat, sound is output from the speaker corresponding to the human body sensor provided on the seat, and power consumption may occur. Therefore, even when using the automatic sound field adjustment device, there is room for improvement in reducing power consumption.

[0005] In consideration of the above circumstances, one aspect of the present disclosure aims to control the on / off of speakers included in an in-vehicle audio system according to the seating situation of the passenger.

Means for Solving the Problems

[0006] One embodiment of the in-vehicle audio system according to this disclosure comprises a plurality of speakers provided at different locations inside the vehicle, an amplification device having a plurality of amplification circuits, a determination unit that determines whether or not to output sound from each of the plurality of speakers based on occupant information relating to the seating status of occupants in each of the plurality of seats provided inside the vehicle, and a control unit that controls the amplification device based on the determination result of the determination unit, wherein each of the plurality of amplification circuits is connected to one or more speakers. [Brief explanation of the drawing]

[0007] [Figure 1] This is a block diagram showing the configuration of the in-vehicle audio system Sys according to the embodiment. [Figure 2] This is a block diagram showing the configuration of the storage device 10 according to the embodiment. [Figure 3] This is a block diagram showing the configuration of the processing apparatus 20 according to the embodiment. [Figure 4] This is an explanatory diagram illustrating the positional relationships of equipment in automobile V. [Figure 5] This is a flowchart illustrating the operation of the in-vehicle audio system Sys according to the embodiment. [Figure 6] This is a block diagram showing the configuration of the in-car audio system SysA according to Modification Example 1. [Figure 7] This is a block diagram showing the configuration of the storage device 10A according to modified example 1. [Figure 8] This is a block diagram showing the configuration of the processing device 20A according to modified example 1. [Figure 9] This is an explanatory diagram illustrating the positional relationships of equipment in an automobile vehicle environment (VA). [Figure 10] This is a flowchart illustrating the operation of the in-vehicle audio system SysA according to Modification 1. [Figure 11] This is a block diagram showing the configuration of the in-vehicle audio system SysB according to Modification 2. [Figure 12]This is a block diagram showing the configuration of the storage device 10B according to modified example 2. [Figure 13] This is a block diagram showing the configuration of the processing unit 20B according to modified example 2. [Figure 14] This is an explanatory diagram illustrating the positional relationships of equipment in a vehicle's VB (Vehicle Building Base). [Figure 15] This is a block diagram showing the configuration of the in-car audio system SysG according to Modification Example 3. [Figure 16] This is a block diagram showing the configuration of the storage device 10G according to modified example 3. [Figure 17] This is a block diagram showing the configuration of the processing unit 20G according to modified example 3. [Modes for carrying out the invention]

[0008] Preferred embodiments of the present disclosure will be described below with reference to the attached drawings. Note that the dimensions and scale of parts in the drawings may differ from actual dimensions, and some parts are shown schematically for ease of understanding. Furthermore, the scope of the present disclosure is not limited to these embodiments unless otherwise stated in the following description.

[0009] 1. Embodiment 1.1. Configuration and Functions of the In-Car Audio System The configuration and functions of the in-vehicle audio system Sys according to the first embodiment will be described below with reference to Figures 1 to 4.

[0010] FIG. 1 is a block diagram showing an in-vehicle audio system Sys according to an embodiment and its surrounding configuration. An in-vehicle audio system Sys is supplied with a signal S0 from a sound source G. The sound source G includes, for example, a CD (Compact Disc) player, a digital audio player, or a smartphone. The signal S0 may be an analog signal or a digital signal. When the signal S0 is an analog signal, the signal S0 is converted into a digital signal by a converter (not shown). Also, the signal S0 may be a monaural signal or a stereo signal. When the signal S0 is a stereo signal, the signal S0 includes two types of signals.

[0011] The in-vehicle audio system Sys includes a storage device 10 that stores various information, a processing device 20 that controls the operation of the in-vehicle audio system Sys, an input device 30 that receives operations from a user of the in-vehicle audio system Sys, speakers 400a to 400f that output sound according to an input signal, an input interface circuit 70 that acquires the signal S0 output from the sound source G, a signal processing device 60 that performs acoustic processing on the input signals S1a to S1d output from the input interface circuit 70, and an amplification device 50 that adjusts the amplitudes of the output signals S2a to S2d output from the signal processing device 60.

[0012] The amplification device 50 includes amplification circuits 500a to 500d. The signal processing device 60 includes signal processing circuits 600a to 600d. The signal processing circuit 600a is connected to the amplification circuit 500a. The signal processing circuit 600b is connected to the amplification circuit 500b. The signal processing circuit 600c is connected to the amplification circuit 500c. The signal processing circuit 600d is connected to the amplification circuit 500d. The amplification circuit 500a is connected to the speakers 400a and 400e. The amplification circuit 500b is connected to the speaker 400b. The amplification circuit 500c is connected to the speaker 400c. The amplification circuit 500d is connected to the speakers 400d and 400f.

[0013] The memory device 10 is configured to include, for example, a volatile memory such as a RAM and a non-volatile memory such as a ROM. Here, RAM is an abbreviation for Random Access Memory, and ROM is an abbreviation for Read Only Memory.

[0014] FIG. 2 is a block diagram showing the configuration of the memory device 10 according to the embodiment. The non-volatile memory included in the memory device 10 includes a program 100 that defines the operation of the in-vehicle audio system Sys, passenger information 101 regarding the seating status of passengers in the automobile V described later, and volume information 102 representing set values for managing the volume of the sound output from the speakers 400a to 400f. Hereinafter, the set value may be referred to as a "volume value".

[0015] In addition, the volatile memory included in the memory device 10 is used by the processing device 20 as a work area when executing the program 100.

[0016] Note that part or all of the memory device 10 may be provided in an external memory device or an external server or the like. Also, part or all of the various information stored in the memory device 10 may be stored in the memory device 10 in advance, or may be acquired from an external memory device or an external server or the like.

[0017] The processing device 20 is configured to include one or more CPUs. However, the processing device 20 may be provided with a programmable logic device such as an FPGA instead of or in addition to the CPU. Here, CPU is an abbreviation for Central Processing Unit, and FPGA is an abbreviation for Field-Programmable Gate Array.

[0018] FIG. 3 is a block diagram showing the configuration of the processing device 20 according to the embodiment. The processing device 20 functions as a control unit 200, a determination unit 201, and a generation unit 202 by executing the program 100.

[0019] The input interface circuit 70 acquires the signal S0 output from the sound source G. The input interface circuit 70 also outputs input signals S1a to S1d based on the signal S0 to the signal processing device 60. The input interface circuit 70 may acquire the signal S0 from the sound source G using wired communication or using wireless communication. When using wireless communication, the input interface circuit 70 is configured to include an antenna for performing wireless communication in accordance with a predetermined communication standard.

[0020] The signal processing circuits 600a to 600d apply acoustic processing to the input signal based on the crew information 101, and output the acoustically processed input signal as an output signal. Examples of acoustic processing performed by the signal processing circuits 600a to 600d include adjusting the delay and frequency characteristics of the output signal.

[0021] The input signal S1a is input to the signal processing circuit 600a. The signal processing circuit 600a generates the output signal S2a by applying acoustic processing to the input signal S1a based on the crew information 101. The signal processing circuit 600a then outputs the output signal S2a to the amplification circuit 500a.

[0022] The input signal S1b is input to the signal processing circuit 600b. The signal processing circuit 600b generates the output signal S2b by applying acoustic processing to the input signal S1b based on the crew information 101. The signal processing circuit 600b then outputs the output signal S2b to the amplification circuit 500b.

[0023] The input signal S1c is input to the signal processing circuit 600c. The signal processing circuit 600c generates the output signal S2c by applying acoustic processing to the input signal S1c based on the crew information 101. The signal processing circuit 600c then outputs the output signal S2c to the amplification circuit 500c.

[0024] The input signal S1d is input to the signal processing circuit 600d. The signal processing circuit 600d generates the output signal S2d by applying acoustic processing to the input signal S1d based on the crew information 101. The signal processing circuit 600d then outputs the output signal S2d to the amplification circuit 500d.

[0025] Amplifier circuit 500a adjusts the amplitude of output signal S2a and outputs it as sound signal S3a. Amplifier circuits 500b to 500d adjust the amplitude of output signals S2b to S2d, similar to amplifier circuit 500a, and output them as sound signals S3b to S3d. Amplifier circuit 500a includes an attenuator 501a and an amplifier 502a. Amplifier circuit 500b includes an attenuator 501b and an amplifier 502b. Amplifier circuit 500c includes an attenuator 501c and an amplifier 502c. Amplifier circuit 500d includes an attenuator 501d and an amplifier 502d.

[0026] Attenuator 501a attenuates the amplitude of output signal S2a and outputs it to amplifier 502a. Attenuators 501b to 501d, similar to attenuator 501a, attenuate the amplitude of output signals S2b to S2d and output them to amplifiers 502b to 502d.

[0027] The attenuation rate of each attenuator 501a to 501d is determined, for example, based on the volume information 102 and the determination result of the determination unit 201. The determination result of the determination unit 201 will be explained later. The attenuation rate of each attenuator 501a to 501d is expressed by the formula 100 × (Vin - Vout) / Vin (percentage), where Vin is the amplitude of the input signal and Vout is the amplitude of the output signal.

[0028] Amplifier 502a amplifies the amplitude of the signal input from attenuator 501a at a predetermined amplification factor and outputs it as sound signal S3a. Amplifiers 502b to 502d, similar to amplifier 502a, amplify the amplitude of the signals input from attenuators 501b to 501d at a predetermined amplification factor and output them as sound signals S3b to S3d. Amplifiers 502a to 502d may be so-called analog amplifiers or digital amplifiers.

[0029] The output signal S2a is input to the amplification circuit 500a. The amplification circuit 500a generates the sound signal S3a by attenuating the amplitude of the output signal S2a in the attenuator 501a and amplifying it in the amplifier 502a. The amplification circuit 500a also outputs the sound signal S3a to speakers 400a and 400e. That is, speakers 400a and 400e output sound corresponding to the sound signal S3a.

[0030] The output signal S2b is input to the amplification circuit 500b. The amplification circuit 500b generates the sound signal S3b by attenuating the amplitude of the output signal S2b in the attenuator 501b and amplifying it in the amplifier 502b. The amplification circuit 500b then outputs the sound signal S3b to the speaker 400b. In other words, the speaker 400b outputs sound corresponding to the sound signal S3b.

[0031] The output signal S2c is input to the amplification circuit 500c. The amplification circuit 500c attenuates the amplitude of the output signal S2c in the attenuator 501c and amplifies it in the amplifier 502c to generate the sound signal S3c. The amplification circuit 500c then outputs the sound signal S3c to the speaker 400c. In other words, the speaker 400c outputs sound corresponding to the sound signal S3c.

[0032] The output signal S2d is input to the amplification circuit 500d. The amplification circuit 500d generates the sound signal S3d by attenuating the amplitude of the output signal S2d in the attenuator 501d and amplifying it in the amplifier 502d. The amplification circuit 500d also outputs the sound signal S3d to speakers 400d and 400f. That is, speakers 400d and 400f output sound corresponding to the sound signal S3d.

[0033] In the following, if speakers 400a to 400f are not distinguished, they may be referred to as "speaker 400". Similarly, if amplification circuits 500a to 500d are not distinguished, they may be referred to as "amplification circuit 500". Furthermore, if attenuators 501a to 501d are not distinguished, they may be referred to as "attenuator 501". Similarly, if amplifiers 502a to 502d are not distinguished, they may be referred to as "amplifier 502". Furthermore, if signal processing circuits 600a to 600d are not distinguished, they may be referred to as "signal processing circuit 600". Additionally, if input signals S1a to S1d are not distinguished, they may be referred to as "input signal S1". Furthermore, if output signals S2a to S2d are not distinguished, they may be referred to as "output signal S2". Similarly, if sound signals S3a to S3d are not distinguished, they may be referred to as "sound signal S3".

[0034] When the input device 30 receives an operation from a user of the in-vehicle audio system Sys to set the seating status of occupants in the vehicle V, the generation unit 202 generates occupant information 101 in response to the operation. In the following, the operation to set the seating status of occupants in the vehicle V may be referred to as the "occupant setting operation". The generation unit 202 also stores the generated occupant information 101 in the storage device 10.

[0035] The decision unit 201 determines whether or not to output sound from each of the speakers 400a to 400f based on the crew information 101.

[0036] The control unit 200 controls various operations in the in-vehicle audio system Sys.

[0037] When the input device 30 receives an operation from a user of the in-vehicle audio system Sys to set a volume value, the control unit 200 generates volume information 102 representing the set volume value in response to the operation. The control unit 200 also stores the generated volume information 102 in the storage device 10.

[0038] The volume value may be selected from 51 integers ranging from 0 to 50. However, the volume value is not limited to integers; for example, it may be selected from multiple numerical values ​​including decimals. Furthermore, the volume value may be selected from more than 51 numerical values, or from fewer than 51 numerical values.

[0039] The control unit 200 controls the amplifier 50 based on the volume information 102 and the determination result of the determination unit 201.

[0040] The control unit 200 sets the attenuation rate of each attenuator 501a to 501d based on the volume information 102. The following assumes that the volume value indicated by the volume information 102 is selected from 51 integers ranging from 0 to 50. For example, if the user sets the volume value to 0, the control unit sets the attenuation rate of each attenuator 501a to 501d to 100%. If the user sets the volume value to 50, the control unit sets the attenuation rate of each attenuator 501a to 501d to 0%. Furthermore, the control unit decreases the attenuation rate of each attenuator 501a to 501d as the volume value increases.

[0041] Furthermore, the control unit 200 sets the attenuation rates of each of the attenuators 501a to 501d based on the determination result of the determination unit 201. For example, the control unit 200 sets the attenuation rate of the attenuator in the amplification circuit 500 connected to the speaker 400 that the determination unit 201 has determined not to output sound to 100%, regardless of the volume value indicated by the volume information 102. Also, the control unit 200 sets the attenuation rate of the attenuator 501 in the amplification circuit 500 connected to the speaker 400 that the determination unit 201 has determined to output sound to a value based on the volume information 102.

[0042] The control unit 200 outputs a control signal S5a to the attenuator 501a that specifies an attenuation rate set based on the volume information 102 and the determination result of the determination unit 201. The attenuator 501a attenuates the amplitude of the output signal S2a by the attenuation rate specified by the control signal S5a. Similarly, the control unit 200 outputs control signals S5b, S5c, and S5d to the attenuator 501b, respectively, that specify an attenuation rate set based on the volume information 102 and the determination result of the determination unit 201. The attenuator 501b attenuates the amplitude of the output signal S2b by the attenuation rate specified by the control signal S5b. The attenuator 501c attenuates the amplitude of the output signal S2c by the attenuation rate specified by the control signal S5c. The attenuator 501d attenuates the amplitude of the output signal S2d by the attenuation rate specified by the control signal S5d.

[0043] When the attenuation rate is 100%, the value Vout, which indicates the amplitude of the output signal, becomes 0. For example, if the attenuation rate of the attenuator 501a is set to 100%, the amplitude of the output signal S2a input to the amplifier circuit 500a becomes 0, and the sound signal S3a is no longer output from the amplifier circuit 500a. Therefore, speakers 400a and 400e connected to the amplifier circuit 500a do not output sound. In other words, the control unit 200 controls the on / off status of each of the speakers 400a to 400f based on the determination result of the determination unit 201.

[0044] Furthermore, even if the decision unit 201 has determined that a speaker 400 will not output sound, this does not necessarily mean that no sound will be produced at all. In other words, even if the volume of sound output from a speaker 400 that the decision unit 201 has determined will not output sound is attenuated by a predetermined value (for example, 10 dB) or more compared to the volume of sound output from a speaker 400 that the decision unit 201 has determined will output sound, it may still be considered that no sound is being output from the speaker 400 that the decision unit 201 has determined will not output sound.

[0045] The control unit 200 sets the acoustic processing method for each of the signal processing circuits 600a to 600d based on the crew information 101. The control unit 200 also outputs a control signal S6a to signal processing circuit 600a that specifies the set acoustic processing method. Signal processing circuit 600a applies the acoustic processing specified by control signal S6a to the input signal S1a. Similarly, the control unit 200 outputs control signals S6b to signal processing circuit 600b, S6c to signal processing circuit 600c, and S6d to signal processing circuit 600d, each specifying the set acoustic processing method. Signal processing circuit 600b applies the acoustic processing specified by control signal S6b to the input signal S1b. Signal processing circuit 600c applies the acoustic processing specified by control signal S6c to the input signal S1c. Signal processing circuit 600d applies the acoustic processing specified by control signal S6d to the input signal S1d.

[0046] In the following, when control signals S5a to S5d are not distinguished, they may be referred to as "control signal S5". Similarly, when control signals S6a to S6d are not distinguished, they may be referred to as "control signal S6".

[0047] The input device 30 receives operations on the in-vehicle audio system Sys from the user of the in-vehicle audio system Sys. The input device 30 is configured to include, for example, a touch panel or operation buttons. If the input device 30 is configured to include a touch panel, the input device 30 outputs data indicating the detected touch position to the processing device 20. If the input device 30 is configured to include operation buttons, the input device 30 outputs data identifying the pressed button to the processing device 20. In this way, the content of the operation on the in-vehicle audio system Sys is transmitted to the processing device 20.

[0048] Figure 4 is an explanatory diagram illustrating the positional relationships of equipment in vehicle V. The in-vehicle audio system Sys is installed in vehicle V.

[0049] Automobile V is equipped with seats P1 to P4. Seats P1 and P2 are located in the front of automobile V. Seats P1 and P2 form seat row L1. Seats P3 and P4 are located in the rear of automobile V. Seats P3 and P4 form seat row L2. Seat row L1 is positioned in front of seat row L2. That is, the direction of travel for automobile V is from seat row L2 towards seat row L1. Occupants of automobile V are seated facing the direction of travel of automobile V. Seat P1 is located to the right of seat P2 in the direction of travel of automobile V. Seat P3 is located to the right of seat P4 in the direction of travel of automobile V.

[0050] In the following, when seats P1 to P4 are not distinguished, they may be referred to as "seat P". Also, when seat row L1 and seat row L2 are not distinguished, seat row L1 and seat row L2 may be referred to as "seat row L". Furthermore, seat row L1 and seat row L2 may be collectively referred to as "multiple seat rows L".

[0051] Furthermore, vehicle V is equipped with doors D1 to D4. Door D1 is for passengers seated in seat P1 to get in and out. Door D2 is for passengers seated in seat P2 to get in and out. Door D3 is for passengers seated in seat P3 to get in and out. Door D4 is for passengers seated in seat P4 to get in and out.

[0052] Speakers 400a and 400e are installed in door D1. Speakers 400d and 400f are installed in door D2. Speaker 400b is installed in door D3. Speaker 400c is installed in door D4. In other words, speakers 400a and 400e are installed in locations corresponding to seat P1. Speakers 400d and 400f are installed in locations corresponding to seat P2. Speaker 400b is installed in locations corresponding to seat P3. Speaker 400c is installed in locations corresponding to seat P4. That is, speakers 400a, 400d, 400e, and 400f are installed in locations corresponding to seat row L1. Additionally, speakers 400b and 400c are installed in locations corresponding to seat row L2.

[0053] The input device 30 is provided, for example, on an instrument panel (not shown). The user (for example, an occupant in seat P1 or seat P2) sets the occupant's seating status in the automobile V by operating the input device 30. The input device 30 transmits information indicating the content of the occupant setting operation received from the user to the processing unit 20. The generation unit 202 generates occupant information 101 according to the occupant setting operation. In this embodiment, the "occupant setting operation" specifically refers to the operation of setting the occupant's seating status in each of the seats P1 to P4 in the automobile V.

[0054] The occupant information 101 does not necessarily have to reflect the actual seating status at seats P1 to P4. For example, the user may perform the occupant setting operation by treating seat P as empty if the occupant is sleeping or otherwise not listening to the sound output from speaker 400. In the following, it is assumed that the occupant seating status shown in the occupant information 101 reflects the actual seating status at seats P1 to P4.

[0055] Specifically, the decision unit 201 decides to output sound from the speaker 400 provided for the seat P where a occupant is seated, based on the occupant seating status indicated by the occupant information 101. The decision unit 201 also decides not to output sound from the speaker 400 provided for the seat P where no occupant is seated, based on the occupant seating status indicated by the occupant information 101.

[0056] For example, if an occupant is seated in any of seats P1 to P4, the decision unit 201 decides, based on the occupant information 101, to output sound from any of the speakers 400a to 400f. The control unit 200 controls the amplification device 50 based on the decision result of the decision unit 201 to output sound signals S3 to each of the speakers 400a to 400f.

[0057] Furthermore, if there are no occupants other than in seat row L1, the decision unit 201 decides, based on the occupant information 101, not to output sound from speakers 400b and 400c located in the area corresponding to seat row L2. Based on the decision result of the decision unit 201, the control unit 200 controls the amplification circuit 500b of the amplification device 50 to prevent the output of sound signal S3b to speaker 400b. Also, based on the decision result of the decision unit 201, the control unit 200 controls the amplification circuit 500c of the amplification device 50 to prevent the output of sound signal S3c to speaker 400c.

[0058] If there are no occupants other than in seat row L1, and occupants are seated in both seats P1 and P2, the decision unit 201 decides, based on the occupant information 101, to output sound from speakers 400a, 400d, 400e, and 400f. The control unit 200 controls the amplification circuit 500a of the amplification device 50 based on the decision result of the decision unit 201 to output sound signals S3a to speakers 400a and 400e. The control unit 200 also controls the amplification circuit 500d of the amplification device 50 based on the decision result of the decision unit 201 to output sound signals S3d to speakers 400d and 400f.

[0059] If there are no occupants other than in seat row L1, and an occupant is seated only in seat P1 (i.e., no occupant is seated in seat P2), the decision unit 201, based on the occupant information 101, decides to output sound from speakers 400a and 400e, and not to output sound from speakers 400d and 400f. The control unit 200 controls the amplification circuit 500a of the amplification device 50 based on the decision result of the decision unit 201 to output sound signals S3a to speakers 400a and 400e. The control unit 200 also controls the amplification circuit 500d of the amplification device 50 based on the decision result of the decision unit 201 to not output sound signals S3d to speakers 400d and 400f.

[0060] 1.2. Operation of the in-car audio system Figure 5 is a flowchart illustrating the operation of the in-vehicle audio system Sys according to the embodiment. The series of operations shown in the flowchart are initiated, for example, when the power to the in-vehicle audio system Sys is turned on and the input device 30 receives an input operation from the user to start the operation. Furthermore, when the power to the in-vehicle audio system Sys is on, the series of operations shown in the flowchart may be started repeatedly at predetermined time intervals.

[0061] In step S101, the generation unit 202 determines whether the input device 30 has received a crew setting operation from the user. If the input device 30 has received a crew setting operation from the user, i.e., if the result in step S101 is YES, the generation unit 202 proceeds to step S102. If the input device 30 has not received a crew setting operation from the user, i.e., if the result in step S101 is NO, the generation unit 202 proceeds to step S103.

[0062] In step S102, the generation unit 202 generates crew information 101 in response to the crew setting operation from the user. The generation unit 202 also stores the generated crew information 101 in the storage device 10.

[0063] In step S103, the generation unit 202 determines whether or not the crew information 101 is stored in the storage device 10. If the crew information 101 is stored in the storage device 10, i.e., if the result in step S103 is YES, the generation unit 202 proceeds to step S104. If the crew information 101 is not stored in the storage device 10, i.e., if the result in step S103 is NO, the generation unit 202 proceeds to step S101.

[0064] In step S104, the decision unit 201 determines whether or not to output sound from each of the speakers 400a to 400f based on the crew information 101.

[0065] In step S105, the control unit 200 sets the acoustic processing method for each of the signal processing circuits 600a to 600d based on the crew information 101. The control unit 200 also outputs control signals S6a to S6d, which specify the set acoustic processing method, to the corresponding signal processing circuits 600a to 600d.

[0066] In step S111, the control unit 200 determines whether the input device 30 has received an operation from the user to set a volume value. If the input device 30 has received an operation from the user to set a volume value, i.e., if the result in step S111 is YES, the control unit 200 proceeds to step S112. If the input device 30 has not received an operation from the user to set a volume value, i.e., if the result in step S111 is NO, the control unit 200 proceeds to step S113.

[0067] In step S112, the control unit 200 generates volume information 102 in response to the user's operation to set the volume value. The control unit 200 also stores the generated volume information 102 in the storage device 10.

[0068] In step S113, the control unit 200 determines whether or not volume information 102 is stored in the storage device 10. If volume information 102 is stored in the storage device 10, i.e., if the result in step S113 is YES, the control unit 200 proceeds to step S115. If volume information 102 is not stored in the storage device 10, i.e., if the result in step S113 is NO, the control unit 200 proceeds to step S114.

[0069] In step S114, the control unit 200 generates volume information 102 indicating a predetermined volume value. The control unit 200 also stores the generated volume information 102 in the storage device 10.

[0070] In step S115, the control unit 200 sets the attenuation rate of each of the attenuators 501a to 501d based on the volume information 102 and the determination result of the determination unit 201. The control unit 200 also outputs control signals S5a to S5d that specify the set attenuation rate to the corresponding attenuators 501a to 501d.

[0071] If the input device 30 has not received an operation from the user to set a volume value, and the storage device 10 has not stored volume information 102, the processing device 20 generates volume information 102 indicating the initial volume value in step S114. Then, in step S115, the processing device 20 outputs control signals S5a to S5d that specify the attenuation rate set based on the volume information 102 and the determination result of the determination unit 201 to the attenuators 501a to 501d of the amplification device 50.

[0072] After the processing in step S115 is completed, the processing unit 20 completes the series of operations shown in the flowchart of Figure 5.

[0073] As described above, according to this embodiment, the in-vehicle audio system Sys can control the on / off status of each of the speakers 400a to 400f based on occupant information 101 regarding the occupant's seating status. That is, the in-vehicle audio system Sys can reduce power consumption by, for example, turning off the speaker 400 located in the position corresponding to the seat P where the occupant is absent.

[0074] Furthermore, according to this embodiment, the in-vehicle audio system Sys can generate occupant information 101 by receiving occupant setting operations from the user. For example, the user can perform the occupant setting operation by treating a seat P occupied by an occupant who is sleeping or otherwise not listening to the sound output from the speaker 400 as if there were no occupant. In other words, the in-vehicle audio system Sys can further reduce power consumption by turning off the speaker 400 provided in the seat P occupied by an occupant who is not listening to the output sound.

[0075] As described above, the in-vehicle audio system Sys according to the embodiment comprises speakers 400a to 400f provided at different locations within the automobile V, an amplification device 50 having amplification circuits 500a to 500d, a determination unit 201 that determines whether or not to output sound from each of the speakers 400a to 400f based on occupant information 101 regarding the seating status of occupants in each of the seats P1 to P4 provided within the automobile V, and a control unit 200 that controls the amplification device 50 based on the determination result of the determination unit 201, with each of the amplification circuits 500a to 500d being connected to one or more speakers 400.

[0076] In other words, the in-car audio system Sys can control the on / off status of each speaker 400a to 400f depending on the occupant's seating position. This allows the in-car audio system Sys to suppress unnecessary power consumption and improve energy efficiency by, for example, turning off speaker 400 located near seat P when no occupant is present.

[0077] In this embodiment, automobile V is an example of a "vehicle", speakers 400a to 400f are an example of "multiple speakers", speaker 400 is an example of a "speaker", amplification circuits 500a to 500d are an example of "multiple amplification circuits", amplification device 50 is an example of an "amplification device", seats P1 to P4 are an example of "multiple seats", occupant information 101 is an example of "occupant information", determination unit 201 is an example of a "determination unit", and control unit 200 is an example of a "control unit".

[0078] Furthermore, the in-vehicle audio system Sys according to the embodiment further includes an input device 30 that receives operations from the user, and a generation unit 202 that generates occupant information 101 in accordance with the occupant setting operation when the input device 30 receives an occupant setting operation from the user to set the seating status of each of the seats P1 to P4.

[0079] In other words, the user can arbitrarily set the seating status of the occupants. This allows the in-car audio system Sys to control the on / off state of speakers 400a to 400f in response to user input.

[0080] In this embodiment, the input device 30 is an example of an "input device," and the generation unit 202 is an example of a "generation unit."

[0081] Furthermore, in the in-vehicle audio system Sys according to this embodiment, seats P1 to P4 form a plurality of seat rows L arranged front to back, and speakers 400a to 400f are provided at locations corresponding to each of the plurality of seat rows L. When there are no occupants other than in seat row L1 of the plurality of seat rows L, the control unit 200 controls the amplifier 50 to prevent the output of sound signals S3 to the speakers 400 provided at locations corresponding to the seat rows other than L1.

[0082] This allows the in-car audio system Sys to control the on / off switching of speakers 400a to 400f to create an appropriate sound field inside the vehicle V, while reducing power consumption by turning off unnecessary speaker 400.

[0083] In this embodiment, the multiple seat rows L are an example of "multiple rows", seat row L1 is an example of "first row", and sound signal S3 is an example of "sound signal".

[0084] Furthermore, in the in-vehicle audio system Sys according to the embodiment, speakers 400a to 400f include speaker 400a, speaker 400d, speaker 400b, and speaker 400c. Multiple seat rows L include seat row L1 and seat row L2 which is different from seat row L1. Seat row L1 includes seat P1 and seat P2. Seat row L2 includes seat P3 and seat P4. Speaker 400a is provided at the location corresponding to seat P1. Speaker 400d is provided at the location corresponding to seat P2. Speaker 400b is provided at the location corresponding to seat P3. Speaker 400c is provided at the location corresponding to seat P4. If there are no occupants in either seat P3 or seat P4 among seats P1 to P4, the control unit 200 controls the amplifier 50 to prevent the output of sound signal S3 to speakers 400b and 400c.

[0085] As a result, the in-car audio system Sys can reduce power consumption by turning off speaker 400b, which corresponds to seat P3 (which has no occupant), and speaker 400c, which corresponds to seat P4 (which also has no occupant).

[0086] In this embodiment, speaker 400a is an example of a "first speaker," speaker 400d is an example of a "second speaker," speaker 400b is an example of a "third speaker," speaker 400c is an example of a "fourth speaker," seat row L2 is an example of a "second row," seat P1 is an example of a "first seat," seat P2 is an example of a "second seat," seat P3 is an example of a "third seat," and seat P4 is an example of a "fourth seat."

[0087] Furthermore, in the in-vehicle audio system Sys according to this embodiment, if there is no occupant in any of seats P2, P3, or P4 among seats P1 to P4, the control unit 200 controls the amplifier 50 to prevent the output of sound signals S3 to speakers 400d, 400b, and 400c.

[0088] As a result, the in-car audio system Sys can more effectively reduce power consumption by turning off speaker 400d, which corresponds to seat P2 (which has no occupant), speaker 400b, which corresponds to seat P3 (which also has no occupant), and speaker 400c, which corresponds to seat P4 (which also has no occupant).

[0089] Furthermore, the in-vehicle audio system Sys according to the embodiment further includes a signal processing circuit 600 that generates an output signal S2 by applying acoustic processing to the input signal S1 based on occupant information 101. The signal processing circuit 600 is connected to at least one of the amplification circuits 500a to 500d, and the output signal S2 output from the signal processing circuit 600 is supplied to the amplification circuit 500 connected to the signal processing circuit 600.

[0090] In other words, the in-car audio system Sys can adjust the sound output from speakers 400a to 400f according to the occupant's seating position. This allows the in-car audio system Sys to appropriately adjust sound localization and sound quality, for example, by adjusting the timing at which the sound output from each of speakers 400a to 400f reaches the occupant.

[0091] In this embodiment, input signal S1 is an example of an "input signal," output signal S2 is an example of an "output signal," signal processing circuit 600 is an example of a "signal processing circuit," and amplification circuit 500 is an example of an "amplification circuit."

[0092] 2. Variations The above embodiments can be modified in various ways. Specific examples of modifications are given below. Furthermore, two or more embodiments arbitrarily selected from the following examples can be combined as appropriate, within the bounds of mutual consistency. In the modified examples given below, for elements whose operation and function are equivalent to those in the above embodiments, the same reference numerals used in the above description will be reused, and detailed explanations of each will be omitted as appropriate.

[0093] 2.1. Variation 1 In the embodiments described above, an example was given in which occupant information 101 is generated using an input device 30 that accepts occupant setting operations from the user. However, this disclosure is not limited to such embodiments. For example, occupant information 101 may be generated using a sensor that generates different signals depending on whether or not there is an occupant in each of the multiple seats.

[0094] Figure 6 is a block diagram showing the configuration of the in-vehicle audio system SysA according to Modification 1. The in-vehicle audio system SysA is configured similarly to the in-vehicle audio system Sys, except that it includes a storage device 10A instead of a storage device 10, a processing device 20A instead of a processing device 20, and an additional camera 80.

[0095] Camera 80 comprises an imaging lens for focusing light and a sensor 800 that converts the focused light into an electrical signal. Note that the imaging lens is not shown in Figure 6. Sensor 800 is an image sensor, such as a CCD or CMOS. Here, CCD is an abbreviation for Charge Coupled Device, and CMOS is an abbreviation for Complementary Metal Oxide Semiconductor. Camera 80 is installed inside the vehicle VA of the automobile, which will be described later. Camera 80 takes images of the interior of the vehicle VA. Sensor 800 generates a signal S8 that indicates the result of imaging by Camera 80. That is, signal S8 is a signal that represents the captured image. Camera 80 also outputs the signal S8 generated by sensor 800 to the processing unit 20A.

[0096] Figure 7 is a block diagram showing the configuration of the storage device 10A according to Modification 1. The storage device 10A differs from the storage device 10 in that it stores program 100A instead of program 100.

[0097] Figure 8 is a block diagram showing the configuration of the processing unit 20A according to Modification 1. The processing unit 20A is configured similarly to the processing unit 20, except that it has the function of a detection unit 203 instead of a generation unit 202. The processing unit 20A functions as a control unit 200, a determination unit 201, and a detection unit 203 by having a CPU and other components in the processing unit 20A execute program 100A and operating according to program 100A.

[0098] The detection unit 203 analyzes the signal S8 and detects the presence or absence of occupants in the vehicle VA. Based on the detection result, the detection unit 203 generates occupant information 101. The detection unit 203 also stores the generated occupant information 101 in the storage device 10A. Known image processing techniques, such as pattern matching, can be applied to detect the presence or absence of occupants.

[0099] Figure 9 is an explanatory diagram illustrating the positional relationship of equipment in a vehicle VA. The vehicle VA is configured similarly to the vehicle V, except that it is equipped with an in-vehicle audio system SysA instead of the in-vehicle audio system Sys. Note that the input device 30 is not shown in Figure 9.

[0100] Specifically, camera 80 is positioned so that all occupants seated in seats P1 to P4 are within its field of view. More specifically, camera 80 is mounted on the ceiling of the automobile VA or on the rearview mirror, etc. Camera 80 acquires different images depending on whether or not there are occupants in each of seats P1 to P4. That is, the signal S8 generated by sensor 800 changes depending on whether or not there are occupants in each of seats P1 to P4. The detection unit 203 generates occupant information 101 based on the signal generated by sensor 800.

[0101] Figure 10 is a flowchart illustrating the operation of the in-vehicle audio system SysA according to Modification 1. The flowchart shown in Figure 10 is the same as the flowchart shown in Figure 5, except that the processing unit 20A executes the process of step S201 instead of step S101, the process of step S202 instead of step S102, and does not execute the process of step S103.

[0102] In step S201, the detection unit 203 determines whether the processing unit 20A has received a signal S8 indicating the imaging result of the interior of the automobile VA. If the processing unit 20A has received a signal S8 indicating the imaging result of the interior of the automobile VA, i.e., if the result in step S201 is YES, the generation unit 202 proceeds to step S202. If the processing unit 20A has not received a signal S8 indicating the imaging result of the interior of the automobile VA, i.e., if the result in step S201 is NO, the generation unit 202 repeats the processing in step S201.

[0103] In step S202, the detection unit 203 analyzes the signal S8 and detects the presence or absence of an occupant in each of the seats P1 to P4. Based on the results of this detection, the detection unit 203 generates occupant information 101. The detection unit 203 also stores the generated occupant information 101 in the storage device 10A.

[0104] Based on the above, according to this modified configuration, the sensor 800 generates different signals depending on whether or not there is an occupant in each of the seats P1 to P4. Furthermore, the detection unit 203 generates occupant information 101 based on the signals generated by the sensor 800. In other words, the in-vehicle audio system SysA does not require occupant setting operations when generating occupant information 101.

[0105] As described above, the in-vehicle audio system SysA according to Modification 1 further comprises a sensor 800 that generates different signals depending on whether or not there is an occupant in each of the seats P1 to P4, and a detection unit 203 that generates occupant information 101 based on the signal S8 generated by the sensor 800.

[0106] In other words, the SysA in-car audio system can automatically detect the occupant's seating status and control the speaker's on / off function. This eliminates the need for the user to manually set the occupant's seating status.

[0107] In this modified example, the in-vehicle audio system SysA is an example of an "in-vehicle audio system," seats P1 to P4 are an example of "multiple seats," sensor 800 is an example of "one or more sensors," signal S8 is an example of "a signal generated by one or more sensors," occupant information 101 is an example of "occupant information," and detection unit 203 is an example of a "detection unit."

[0108] Furthermore, the sensors used to generate the occupant information 101 are not limited to one; multiple sensors may be used. For example, a separate camera may be provided to detect whether or not there are occupants seated in seat row L1, and another camera may be provided to detect whether or not there are occupants seated in seat row L2. In other words, two sensors may be used to detect the occupancy status of occupants in each of the seats P1 to P4.

[0109] Furthermore, each of seats P1 to P4 may be equipped with a sensor that generates a different signal depending on whether or not there is an occupant. The sensors provided at each of seats P1 to P4 may be, for example, pressure sensors or temperature sensors.

[0110] When detecting the seating status of an occupant using a pressure sensor, the pressure sensor is built into, for example, the seat cushion or backrest of each of the seats P1 to P4. The pressure sensor generates different signals depending on the pressure acting on it when an occupant is seated or when an occupant is not seated. In other words, the pressure sensor generates different signals depending on whether or not an occupant is present in each of the seats P1 to P4. The detection unit 203 analyzes the signals generated by the pressure sensor and detects whether or not an occupant is present in each of the seats P1 to P4. Then, the detection unit 203 generates occupant information 101 based on the results of this detection.

[0111] When detecting the seating status of occupants using temperature sensors, the temperature sensors are installed, for example, on the seat surface or backrest of each of seats P1 to P4, or near each of seats P1 to P4. The temperature sensors generate different signals depending on whether the occupant is seated or not. In other words, the temperature sensors generate different signals depending on whether there is an occupant in each of seats P1 to P4. The detection unit 203 analyzes the signals generated by the temperature sensors and detects whether there is an occupant in each of seats P1 to P4. Then, the detection unit 203 generates occupant information 101 based on the results of this detection.

[0112] 2.2. Variation Example 2 In the embodiments and modifications described above, an example was given in which the on / off status of each of the speakers 400a to 400f is controlled based on the decision result of the decision unit 201. In such embodiments, for example, if an occupant is seated only in seat P1, no sound is output from speakers other than speakers 400a and 400e. In such cases, even if the user attempts to increase the volume in the vehicle by setting a volume value, the number of speakers 400 that output sound is limited, and the user may not be able to achieve the desired volume. In light of this situation, this modification discloses an in-vehicle audio system SysB that can achieve the user's desired volume even when there are speakers 400 that the decision unit 201 has decided not to output sound from.

[0113] Figure 11 is a block diagram showing the configuration of the in-vehicle audio system SysB according to Modification 2. The in-vehicle audio system SysB is configured similarly to the in-vehicle audio system Sys, except that it has a storage device 10B instead of a storage device 10, and a processing device 20B instead of a processing device 20.

[0114] Figure 12 is a block diagram showing the configuration of the storage device 10B according to the modified example 2. The storage device 10B differs from the storage device 10 in that it stores program 100B instead of program 100.

[0115] Figure 13 is a block diagram showing the configuration of the processing unit 20B according to Modification 2. The processing unit 20B is configured similarly to the processing unit 20, except that it has the function of a control unit 200B instead of a control unit 200. The processing unit 20B functions as a control unit 200B, a determination unit 201, and a generation unit 202 by having a CPU or other component within the processing unit 20B execute program 100B and operating according to program 100B.

[0116] The control unit 200B controls various operations in the in-vehicle audio system SysB. For example, similar to the control unit 200, when the input device 30 receives an operation from the user to set a volume value, the control unit 200B generates volume information 102 in response to that operation. The control unit 200B also stores the generated volume information 102 in the storage device 10B. The control unit 200B also controls the amplifier 50 based on the volume information 102 and the decision result of the decision unit 201. Specifically, the control unit 200B sets the attenuation rate of each of the attenuators 501a to 501d based on the volume information 102 and the decision result of the decision unit 201. The control unit 200B also outputs control signals S5a to S5d that specify the set attenuation rate to the corresponding attenuators 501a to 501d.

[0117] If the volume value is set to less than a predetermined value, the control unit 200B sets the attenuation rate of the attenuator in the amplification circuit 500 connected to the speaker 400 that the determination unit 201 has determined not to output sound to 100%. The control unit 200B also sets the attenuation rate of the attenuator in the amplification circuit 500 connected to the speaker 400 that the determination unit 201 has determined to output sound to a value based on the volume information 102.

[0118] If the volume value is set to a predetermined value or higher, the control unit 200B sets the attenuation rate of the attenuator in the amplification circuit 500 connected to the speaker 400 that the determination unit 201 has determined not to output sound to be less than 100%. The control unit 200B also sets the attenuation rate of the attenuator in the amplification circuit 500 connected to the speaker 400 that the determination unit 201 has determined not to output sound to a value based on the volume information 102. The attenuation rate of the attenuator in the amplification circuit 500 connected to the speaker 400 that the determination unit 201 has determined not to output sound may decrease monotonically with increasing volume value. Also, when the volume value is at its maximum, the attenuation rate of the attenuator in the amplification circuit 500 may be 0%. Also, the attenuation rate of the attenuator in the amplification circuit 500 may be constant.

[0119] In other words, the control unit 200B controls the amplifier 50 to output the sound signal S3 to both the speaker 400 that the determination unit 201 has decided to output sound to, and the speaker 400 that the determination unit 201 has decided not to output sound to. Therefore, when the volume value is set to a predetermined value or higher, the control unit 200B can adjust the volume using the speaker 400 that would normally be turned off, in addition to the speaker 400 that is normally used, to achieve the volume desired by the user. For example, if the volume value is a value selected from 51 integers from 0 to 50, the predetermined value may be 40. The predetermined value may also be a value smaller than 40 or a value larger than 40. In the following, the operation of setting the volume value to a predetermined value or higher may be referred to as the "volume setting operation".

[0120] Figure 14 is an explanatory diagram illustrating the positional relationship of equipment in vehicle VB. Vehicle VB is configured similarly to vehicle V, except that it has an in-vehicle audio system SysB instead of the in-vehicle audio system Sys.

[0121] If the decision unit 201 decides to output sound from speakers 400a, 400d, 400e, and 400f, and not to output sound from speakers 400b and 400c, and the input device 30 receives a volume setting operation from the user, the control unit 200B controls the amplification device 50 to output sound signals S3 to speakers 400b and 400c in addition to speakers 400a, 400d, 400e, and 400f. Furthermore, if the decision unit 201 decides to output sound from speakers 400a and 400e, and not to output sound from speakers 400b, 400c, 400d, and 400f, and the input device 30 receives a volume setting operation from the user, the control unit 200B controls the amplifier 50 to output sound signals S3 not only to speakers 400a and 400e, but also to speakers 400b, 400c, 400d, and 400f.

[0122] There are cases where the decision result of the decision unit 201 based on the occupant information 101 does not match the speaker 400 that the control unit 200B controls the amplifier 50 to actually output the sound signal S3. As a specific example, consider a case where the decision unit 201 decides to output sound from speakers 400a and 400e, and not from speakers 400b, 400c, 400d, and 400f, and the input device 30 receives a volume setting operation from the user. The occupant information 101 indicates that an occupant is seated only in seat P1. In such a case, the signal processing circuits 600a to 600d of the signal processing device 60 can adjust the timing at which the sound output from each of the speakers 400a to 400f reaches the occupant in seat P1 by appropriately delaying the output signals S2a to S2d based on the occupant information 101. In other words, the signal processing circuits 600a to 600d can appropriately adjust sound localization, sound quality, etc., by outputting an output signal S2 that has undergone acoustic processing based on the crew information 101.

[0123] Based on the above, according to this modified configuration, even if the decision unit 201 has determined that a speaker 400 should not output sound, the control unit 200B will output sound from the speaker 400 by setting the volume value to a predetermined value or higher. In other words, the in-vehicle audio system SysB can achieve the volume desired by the user, regardless of the decision result of the decision unit 201.

[0124] Furthermore, according to this modified version, the in-vehicle audio system SysB can perform acoustic processing based on occupant information 101 on the signals input to each of the speakers 400a to 400f. For example, the in-vehicle audio system SysB can adjust the timing at which the sound output from each of the speakers 400a to 400f reaches the occupant by appropriately delaying the signals input to each of the speakers 400a to 400f based on the occupant information 101.

[0125] As described above, the in-vehicle audio system SysB according to Modification 2 further includes an input device 30 that accepts user operations. When the input device 30 receives a volume setting operation from the user to set a volume value for managing the volume of sound output from speakers 400a to 400f to a predetermined value or higher, the control unit 200B controls the amplification device 50 to output an audio signal S3 to the speaker 400 that the determination unit 201 has determined not to output sound from.

[0126] In other words, if the volume level of the in-vehicle audio system SysB is set to a predetermined value or higher, the decision unit 201 turns on the speaker 400 that it has decided not to output sound from, thereby adjusting the volume within the vehicle VB. As a result, the in-vehicle audio system SysB can achieve the volume level desired by the user, regardless of the decision result of the decision unit 201.

[0127] In this modified example, the in-vehicle audio system SysB is an example of an "in-vehicle audio system," the input device 30 is an example of an "input device," the speakers 400a to 400f are an example of "multiple speakers," the volume value is an example of a "set value," the control unit 200B is an example of a "control unit," the amplification device 50 is an example of an "amplifier," the determination unit 201 is an example of a "determination unit," the speaker 400 is an example of a "speaker," and the sound signal S3 is an example of a "sound signal."

[0128] 2.3. Variation 3 In the embodiments and modifications described above, an example was given in which the on / off status of each of the speakers 400a to 400f is controlled by setting the attenuation rate of the attenuator 501 based on the determination result of the determination unit 201. However, this disclosure is not limited to such embodiments. For example, the on / off status of each of the speakers 400a to 400f may be controlled by controlling the power supply to the amplifier based on the determination result of the determination unit 201.

[0129] Figure 15 is a block diagram showing the configuration of the in-vehicle audio system SysG according to Modification 3. The in-vehicle audio system SysG is configured similarly to the in-vehicle audio system Sys, except that it has a storage device 10G instead of a storage device 10, a processing device 20G instead of a processing device 20, and an amplifier 50G instead of an amplifier 50. The amplifier 50G is configured similarly to the amplifier 50, except that it has multiple amplifier circuits 500G instead of multiple amplifier circuits 500 (amplifier circuits 500a to 500d). The amplifier circuit 500G differs from the amplifier circuit 500 in that it has an amplifier 502G instead of an amplifier 502. It is assumed that the number of amplifier circuits 500G in the amplifier 50G is the same as the number of amplifier circuits 500 in the amplifier 50, which is 4. In addition, each of the multiple amplifier circuits 500G is connected to speakers 400a to 400f, similar to amplifier circuits 500a to 500d.

[0130] In Figure 15, for convenience, all but one of the multiple amplification circuits 500G provided by the amplification device 50G are omitted from the illustration. Also, the input device 30, speakers 400a to 400f, signal processing device 60, input interface circuit 70, and sound source G are omitted from the illustration.

[0131] Amplifier 502G is electrically connected to the feed line Wr, which is set to a high potential VDD, via switch Cs. Amplifier 502G is also electrically connected to the low potential ground Gnd. Switch Cs is opened and closed based on a control signal S9 output from the processing unit 20G. When switch Cs is closed, amplifier 502G is supplied with potential VDD from the feed line Wr. When switch Cs is open, amplifier 502G is isolated from the feed line Wr.

[0132] When a potential VDD is supplied, the amplifier 502G amplifies the amplitude of the signal input from the attenuator 501 at a predetermined amplification factor and outputs it as an audio signal S3. That is, when the switch Cs is closed, the speaker 400 connected to the amplification circuit 500G, which includes the amplifier 502G connected to the switch Cs, outputs sound corresponding to the audio signal S3.

[0133] On the other hand, if no potential VDD is supplied, the amplifier 502G will not output the sound signal S3, even if a signal is input from the attenuator 501. In other words, when switch Cs is open, the speaker 400 connected to the amplification circuit 500G, which includes the amplifier 502G connected to switch Cs, will not output sound.

[0134] Figure 16 is a block diagram showing the configuration of the storage device 10G according to Modification 3. The storage device 10G differs from the storage device 10 in that it stores program 100G instead of program 100.

[0135] Figure 17 is a block diagram showing the configuration of the processing unit 20G according to Modification 3. The processing unit 20G is configured similarly to the processing unit 20, except that it has the function of a control unit 200G instead of a control unit 200. The processing unit 20G functions as a control unit 200G, a determination unit 201, and a generation unit 202 by having a CPU and other components within the processing unit 20G execute program 100G and operating according to program 100G.

[0136] The control unit 200G controls various operations in the in-vehicle audio system SysG. For example, similar to the control unit 200, when the input device 30 receives an operation from the user to set a volume value, the control unit 200G generates volume information 102 in response to that operation. The control unit 200G also stores the generated volume information 102 in the storage device 10G. The control unit 200G also sets the attenuation rate of the attenuator 501 based on the volume information 102. The control unit 200G also outputs a control signal S5 to the attenuator 501 specifying the set attenuation rate.

[0137] Furthermore, the control unit 200G generates a control signal S9 based on the decision result of the decision unit 201. For example, the control unit 200G generates a control signal S9 to open switch Cs, which is connected to the amplifier 502G of the amplification circuit 500G connected to speaker 400 that the decision unit 201 has determined not to output sound. The control unit 200G then outputs this control signal S9 to switch Cs, thereby opening switch Cs. Also, the control unit 200G generates a control signal S9 to close switch Cs, which is connected to the amplifier 502G of the amplification circuit 500G connected to speaker 400 that the decision unit 201 has determined to output sound. The control unit 200G then outputs this control signal S9 to switch Cs, thereby closing switch Cs. In other words, the control unit 200G can control the on / off state of each of the speakers 400a to 400f by controlling the power supply to the amplifier 502G based on the decision result of the determination unit 201.

[0138] 2.4. Variation 4 In the embodiments and modifications described above, examples were given in which a speaker 400 is provided in each of the doors D1 to D4, but this disclosure is not limited to such embodiments. For example, it may be provided in the ceiling portion of the automobile, directly above each of the seats P1 to P4. Alternatively, it may be built into the headrest of each of the seats P1 to P4.

[0139] 2.5. Variation 5 In the embodiments and modifications described above, examples were given in which the same signal is input to multiple speakers 400 connected to a single amplification circuit 500, for example, speaker 400a and speaker 400e. However, this disclosure is not limited to such embodiments. For example, the sound signal S3 output from the amplification circuit 500 may be divided by a so-called passive network into a signal for outputting high-frequency sounds and a signal for outputting mid-low frequency sounds, and the two divided signals may be input to separate speakers 400. The passive network includes a high-pass filter and a low-pass filter. The high-pass filter attenuates and outputs components of the input signal below a predetermined frequency. The low-pass filter attenuates and outputs components of the input signal above a predetermined frequency. The signal output from the high-pass filter is input to a speaker 400 that outputs high-frequency sounds, such as a tweeter. The signal output from the low-pass filter is input to a speaker 400 that outputs mid-low frequency sounds, such as a midrange speaker. In other words, when using speakers specialized for a specific frequency range, adjusting the signal frequency to match the input speaker makes it possible to output sound that takes advantage of the speaker's performance, thereby improving sound quality.

[0140] 2.6. Variation 6 In the embodiments and modifications described above, an example was given in which speakers 400 are provided corresponding to four seats P1 to P4. However, for example, the number of seats may be more than four or less than four. Specifically, the in-vehicle audio system according to this disclosure may be installed in an eight-seater, so-called minivan-type vehicle. Alternatively, the in-vehicle audio system according to this disclosure may be installed in a two-seater, so-called two-seater-type vehicle. The in-vehicle audio system according to this disclosure can be used by appropriately changing the number of amplification circuits and speakers, etc., in accordance with the increase or decrease in the number of seats.

[0141] 2.7. Example 7 In the embodiments and modifications described above, examples were given in which the signal processing circuits 600a to 600d correspond one-to-one with the amplification circuits 500a to 500d. However, this disclosure is not limited to such embodiments. For example, the signal processing circuit 600 may be connected to a plurality of amplification circuits 500. That is, the output signal S2 output from the signal processing circuit 600 may be input to a plurality of amplification circuits 500 connected to the signal processing circuit 600. As a result, the number of signal processing circuits 600 is less than the number of amplification circuits 500, making it possible to miniaturize the signal processing device 60 and contributing to cost reduction and space saving.

[0142] 3. Addendum From at least one of the embodiments and modifications described above, the following aspects can be understood.

[0143] 3.1. Appearance 1 An in-vehicle audio system according to Embodiment 1 of the present disclosure comprises: a plurality of speakers provided at different locations inside the vehicle; an amplification device having a plurality of amplification circuits; a determination unit that determines whether or not to output sound from each of the plurality of speakers based on occupant information relating to the seating status of occupants in each of the plurality of seats provided inside the vehicle; and a control unit that controls the amplification device based on the determination result of the determination unit, wherein each of the plurality of amplification circuits is connected to one or more speakers.

[0144] According to this embodiment, the on / off status of each of the multiple speakers can be controlled according to the seating status of the occupants. This makes it possible to suppress unnecessary power consumption by, for example, turning off speakers located near seats where occupants are not present, thereby improving energy efficiency.

[0145] 3.2. Appearance 2 An in-vehicle audio system according to Embodiment 2 of this disclosure further comprises, in an in-vehicle audio system according to Embodiment 1, an input device that receives operations from a user, and a generation unit that generates occupant information in response to an occupant setting operation when the input device receives an occupant setting operation from a user to set the seating status of occupants in each of the plurality of seats.

[0146] In this configuration, the user can arbitrarily set the seating status of the occupants and control the on / off status of each of the multiple speakers according to the setting.

[0147] 3.3. Aspect 3 An in-vehicle audio system according to Embodiment 3 of this disclosure further comprises, in an in-vehicle audio system according to Embodiment 1, one or more sensors that generate different signals depending on whether or not there is an occupant in each of the plurality of seats, and a detection unit that generates occupant information based on the signals generated by the one or more sensors.

[0148] According to this embodiment, the seating status of the occupants can be detected, and the on / off status of the speakers can be automatically controlled.

[0149] 3.4. Aspect 4 The in-vehicle audio system according to Embodiment 4 of the present disclosure is an in-vehicle audio system according to Embodiment 1, wherein the plurality of seats form a plurality of rows arranged front to back, the plurality of speakers are provided at locations corresponding to each of the plurality of rows, and when there are no occupants in any row other than the first row of the plurality of rows, the control unit controls the amplification device to prevent sound signals from being output to the speakers provided at locations corresponding to the rows other than the first row.

[0150] According to this embodiment, power consumption can be reduced by controlling the on / off status of each of the multiple speakers to create an appropriate sound field inside the vehicle, while turning off unnecessary speakers.

[0151] 3.5. Aspect 5 An in-vehicle audio system according to Embodiment 5 of the present disclosure is an in-vehicle audio system according to Embodiment 4, wherein the plurality of speakers include a first speaker, a second speaker, a third speaker, and a fourth speaker; the plurality of rows include a first row and a second row different from the first row; the first row includes a first seat and a second seat; the second row includes a third seat and a fourth seat; the first speaker is provided at a location corresponding to the first seat; the second speaker is provided at a location corresponding to the second seat; the third speaker is provided at a location corresponding to the third seat; and the fourth speaker is provided at a location corresponding to the fourth seat; and when there is no occupant in either the third seat or the fourth seat among the plurality of seats, the control unit controls the amplifier to prevent the output of sound signals to the third speaker and the fourth speaker.

[0152] According to this embodiment, power consumption can be reduced by turning off the third speaker corresponding to the third seat which is unoccupied, and the fourth speaker corresponding to the fourth seat which is also unoccupied.

[0153] 3.6. Appearance 6 An in-vehicle audio system according to aspect 6 of this disclosure is an in-vehicle audio system according to aspect 4, wherein the plurality of speakers include a first speaker, a second speaker, a third speaker, and a fourth speaker, the plurality of rows include a first row and a second row different from the first row, the first row includes a first seat and a second seat, the second row includes a third seat and a fourth seat, and the first speaker is provided at a location corresponding to the first seat, The second speaker is provided in a location corresponding to the second seat, the third speaker is provided in a location corresponding to the third seat, and the fourth speaker is provided in a location corresponding to the fourth seat. If there is no occupant in any of the second, third, or fourth seats among the plurality of seats, the control unit controls the amplification device to prevent the output of sound signals to the second, third, and fourth speakers.

[0154] According to this embodiment, power consumption can be reduced more effectively by turning off the second speaker corresponding to the second seat which is unoccupied, the third speaker corresponding to the third seat which is also unoccupied, and the fourth speaker corresponding to the fourth seat which is also unoccupied.

[0155] 3.7. Aspect 7 An in-vehicle audio system according to Embodiment 7 of the present disclosure further comprises an input device for receiving user operations in an in-vehicle audio system according to Embodiment 1, wherein when the input device receives a volume setting operation from the user to set a setting value for managing the volume of sound output from the plurality of speakers to a predetermined value or higher, the control unit controls the amplification device to output an audio signal to the speaker that the determination unit has determined not to output sound.

[0156] According to this embodiment, when the set value is set to a predetermined value or higher, it becomes possible to adjust the volume using a speaker that the decision unit has decided not to output sound from, in addition to the speaker that is normally turned on, thereby achieving the volume desired by the user.

[0157] 3.8. Aspect 8 An in-vehicle audio system according to aspect 8 of the present disclosure further comprises a signal processing circuit that generates an output signal by applying acoustic processing based on the occupant information to an input signal, the in-vehicle audio system according to aspect 1, the signal processing circuit is connected to at least one of the plurality of amplification circuits, and the output signal output from the signal processing circuit is supplied to the amplification circuit connected to the signal processing circuit.

[0158] According to this embodiment, by adjusting, for example, the timing at which the sound output from each of the multiple speakers reaches the occupants according to the occupants' seating arrangement, the sound image localization and sound quality can be appropriately adjusted. [Explanation of Symbols]

[0159] 10...Storage device, 100...Program, 101...Occupant information, 102...Volume information, 20...Processing device, 200...Control unit, 201...Decision unit, 202...Generation unit, 203...Detection unit, 30...Input device, 400...Speaker, 50...Amplifier, 500...Amplification circuit, 501...Attenuator, 502...Amplifier, 60...Signal processing device, 600...Signal processing circuit, 70...Input interface circuit, 80...Camera, 800...Sensor, G...Sound source, D1...Door, P1...Seat, L1...Front row, L2...Rear row, V...Automobile, Sys...In-car audio system.

Claims

1. Multiple speakers are installed in different locations inside the vehicle, An amplifier having multiple amplification circuits, An input device that accepts operations from the user, A determination unit that determines whether or not to output sound from each of the multiple speakers based on occupant information regarding the seating status of occupants in each of the multiple seats provided in the vehicle, Based on the determination result of the determination unit, a control unit controls the amplification device, Equipped with, Each of the aforementioned amplification circuits is connected to one or more speakers. When the input device receives a volume setting operation from the user to set a setting value for managing the volume of sound output from the plurality of speakers to a predetermined value or higher, the control unit controls the amplification device to output an audio signal to the speaker that the determination unit has determined not to output sound. In-car audio system.

2. When the input device receives an occupant setting operation from the user to set the seating status of occupants in each of the plurality of seats, a generation unit generates occupant information in accordance with the occupant setting operation, It also has, The in-car audio system according to claim 1.

3. One or more sensors that generate different signals depending on whether or not there is an occupant in each of the aforementioned multiple seats, A detection unit that generates the occupant information based on the signals generated by the one or more sensors, It also has, The in-car audio system according to claim 1.

4. The aforementioned multiple seats form multiple rows arranged front to back. The plurality of speakers are provided at locations corresponding to each of the plurality of rows, If there are no occupants in any row other than the first row among the aforementioned multiple rows, the determination unit decides not to output an audio signal to the speaker located in the position corresponding to the row other than the first row. The in-car audio system according to claim 1.

5. The plurality of speakers include a first speaker, a second speaker, a third speaker, and a fourth speaker. The plurality of columns include the first column and a second column different from the first column. The aforementioned first row includes a first seat and a second seat, The aforementioned second row includes a third seat and a fourth seat, The first speaker is provided at a location corresponding to the first seat. The second speaker is provided at a location corresponding to the second seat. The third speaker is provided at a location corresponding to the third seat. The fourth speaker is provided at a location corresponding to the fourth seat. If there are no occupants in either the third seat or the fourth seat among the plurality of seats, the determination unit decides not to output sound signals to the third speaker and the fourth speaker. The in-car audio system according to claim 4.

6. The plurality of speakers include a first speaker, a second speaker, a third speaker, and a fourth speaker. The plurality of columns include the first column and a second column different from the first column. The aforementioned first row includes a first seat and a second seat, The aforementioned second row includes a third seat and a fourth seat, The first speaker is provided at a location corresponding to the first seat. The second speaker is provided at a location corresponding to the second seat. The third speaker is provided at a location corresponding to the third seat. The fourth speaker is provided at a location corresponding to the fourth seat. If there are no occupants in any of the second, third, and fourth seats among the plurality of seats, the determination unit decides not to output sound signals to the second speaker, the third speaker, and the fourth speaker. The in-car audio system according to claim 4.

7. The system further comprises a signal processing circuit that generates an output signal by applying acoustic processing based on the crew information to the input signal, The signal processing circuit is connected to at least one of the plurality of amplification circuits, The output signal from the signal processing circuit is supplied to an amplification circuit connected to the signal processing circuit. The in-car audio system according to claim 1.

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