JP7604072B2 - Audio System - Google Patents

Description

The present invention relates to an audio system with a function to assist passenger conversation, and in particular to an interior-mounted speaker system that uses an exciter built into the interior.

As passengers spend their time in vehicles more diversified, there is an increasing demand for individual sound source playback devices for each seat (zone sound) and in-car communication (ICC) devices. In-car conversation support devices allow passengers to clearly hear each other's conversations even in noisy environments or when music is being played (see, for example, Patent Documents 1, 2, and 3). As shown in FIG. 1, the in-car conversation support device of Patent Document 1 has speakers 101, 102, 103, and 104 installed on each seat, and microphones 105, 106, 107, and 108 installed for each seat. A control unit 200 enables the passengers' conversation voices collected by the microphones to be output from the speakers 101 to 104, and enables audio playback sounds played by an audio device 203 to be output from the speakers 101 to 104.

JP 2002-51392 A JP 2010-163054 A Japanese Patent Application Publication No. 11-342799

Figure 2 is a diagram showing a schematic configuration example of a conventional seat conversation assistance device. Speakers SP1 and SP2 are installed near the front seats in the vehicle, speakers SP3 and SP4 are installed near the rear seats, and speakers SP5 and SP6 are installed at the rear. In addition, microphones MC1, MC2, MC3, and MC4 for inputting the conversation voices of the occupants of each seat are installed according to the position of each seat. The controller 10 inputs the audio signal S1 collected by the microphones MC1 to MC4, and outputs the conversation voice from the speakers SP1 to SP6 based on the input audio signal S1. For example, the controller 10 determines the seat of the occupant who spoke based on the level of the audio signal input to the microphones MC1 to MC4, and outputs the conversation voice from the speakers of the seats of the other occupants. Alternatively, the seat of the occupant who spoke may be determined by using a talk switch or a seat sensor provided on each seat in combination, or the conversation voice may not be output from a seat where no occupant is seated. Furthermore, the controller 10 receives the audio playback signal S2 played by the audio device 20 and outputs the audio playback sound from the speakers SP1 to SP6.

The input and output of conversational voice uses telephone playback technology, which has several performance indicators. For example, the voice from the front seat should be audible in the rear seat, the sound output from the rear seat should have little noise, there should be little delay in signal processing and it should sound natural, there should be sufficient echo cancellation, there should be no howling, the sound quality should be good, and there should be no interruptions in the sound.

In order to satisfy these performance indices, if the microphone capturing the passengers' conversation voices captures the audio playback sound output from the speaker near the driver's seat or road noise, the S/N (signal-to-noise ratio) of the audio signal output from the speaker at the far end seat will be low, making it difficult to hear the conversation voice. In addition, since the conversation voice is output from the speaker with a delay, there is a problem that there is a lot of reverberation and the entire interior of the vehicle feels saturated. This situation will be explained using Figure 3. When the driver U1 speaks, the conversation voice P1 is input from the microphone MC1 attached near the steering wheel, and the input audio signal S1 is signal processed by the controller 10, and the conversation voice of the driver U1 is output from the speaker SP5 on the rear seat side. On the other hand, if the audio playback sound P2 is output from the speaker SP1 installed on the door near the driver U1's seat, when the microphone MC1 collects the audio playback sound P2, the audio playback sound is mixed into the conversation voice output from the speaker SP5 on the rear seat side. This makes it difficult for the passenger U2 in the back seat to hear the driver U1's conversation.

To address these issues, it is possible to use an adaptive filter to remove the audio playback sound from the conversation voice, or to use a directional microphone, but to further improve the performance of the conversation voice, it is desirable to improve the input part of the conversation voice so that the audio playback sound is not mixed into the conversation voice.

The present invention aims to solve these conventional problems and provide an audio system that makes it easier to hear passengers' conversations.

The audio system according to the present invention comprises a plurality of exciters attached to the ceiling corresponding to each seat position in the vehicle and vibrating the ceiling based on an applied drive signal to output sound, a plurality of microphones attached near the headrests of each seat, and a control means for outputting a drive signal for driving the exciters in response to an audio playback signal, and for outputting a drive signal for driving the exciters or another speaker in response to an audio signal input from any of the plurality of microphones.

In one embodiment, the exciter is attached to the back surface of an interior ceiling substrate. In one embodiment, the exciter is attached above the head of the occupant when seated in the seat. In one embodiment, the microphone is attached in a position blocked by the head of the occupant when seated in the seat. In one embodiment, the microphone is attached between the backrest and headrest of the seat. In one embodiment, the other speaker is attached near the headrest of the seat. In one embodiment, the control means has a conversation assistance function that transmits the conversation voice of the occupant to other occupants.

According to the present invention, multiple exciters are attached to the ceiling and multiple microphones are attached near the headrests of the seats, so that the sound output by the exciters is prevented from being directly input to the microphones by the barrier between the passenger's head and the headrest. This allows the conversational sound to be separated from other sound sources such as audio playback sounds and input to the microphones, reducing noise contained in the conversational sound and making it easier to hear.

FIG. 1 is a diagram showing an example of the configuration of a conventional inter-seat conversation assistance device; FIG. 1 is a diagram showing an example of the configuration of a conventional inter-seat conversation assistance device; 1A and 1B are diagrams illustrating problems with a conventional inter-seat conversation assistance device. 1 is a diagram showing a schematic configuration of an audio system having a seat conversation assistance function according to an embodiment of the present invention; FIG. 2 is a cross-sectional view showing an example of installation of an exciter according to an embodiment of the present invention. FIG. 2 is a perspective view showing an example of how a microphone according to an embodiment of the present invention is attached; 1A and 1B are diagrams illustrating the effects of an audio system according to an embodiment of the present invention. FIG. 13 is a diagram showing a schematic configuration of an audio system according to another embodiment of the present invention.

The audio system according to the present invention has the function of outputting audio playback sound inside a moving body such as an automobile, as well as outputting the voices of passengers talking to each other. Furthermore, due to the spread of electric vehicles and the resulting weight reduction in vehicles (changes in vehicle shape, use of resin doors), changes in vehicle structure that prioritize space for the driver and passengers, and changes in signal processing technology, there is a demand for the development of ultra-lightweight speakers that can be installed in locations other than existing positions. Therefore, the audio system according to the present invention uses an interior-mounted speaker with an exciter built into the interior of the vehicle.

Next, an embodiment of the present invention will be described with reference to the drawings. It should be noted that the scale of the drawings is exaggerated to facilitate understanding of the invention and does not necessarily represent the scale of the actual product.

Figure 4(A) is a plan view of the mounting positions of an exciter and microphone in an audio system according to an embodiment of the present invention, and Figure 4(B) is a cross-sectional view of the mounting positions of an exciter and microphone in an audio system in a three-dimensional view. Here, an example is shown in which two front seats Q1, Q2 are arranged at the front of the vehicle interior, and two rear seats Q3, Q4 are arranged at the rear, but this is just one example, and other numbers and arrangements of seats (e.g., three rows of seats) may also be used.

The audio system 1 includes a number of exciters EC1, EC2, EC3, EC4 attached to the ceiling 40 corresponding to the positions of each of the seats Q1, Q2, Q3, Q4, a number of microphones MC1, MC2, MC3, MC4 attached near the headrests of each of the seats Q1, Q2, Q3, Q4, a controller 10 electrically connected to the exciters EC1 to EC4 and the microphones MC1 to MC4 and controls the output of audio, and an audio device 20 that provides an audio playback signal S2 to the controller 10.

Seat Q1 includes a seating portion 30, a backrest portion 32, and a headrest 34, and microphone MC1 is attached near the headrest 34. For example, as shown in FIG. 6, it may be attached in the space between the headrest 34 and the backrest portion 32, or may be embedded in the headrest 34 or the backrest portion 32. Similarly, microphones MC2, MC3, and MC4 are attached near the headrest 34 in the other seats Q2, Q3, and Q4. Microphones MC1 to MC4 input the conversation voices of the occupants, and the audio signal S1 of the conversation voices picked up by microphones MC1 to MC4 is input to the controller 10 via a wired or wireless connection.

The exciter EC1 is attached to a position on the ceiling 40 corresponding to the seat Q1. As shown in FIG. 4B, the exciter EC1 is attached near the head of the occupant U1 when the occupant U1 sits in the seat Q1. The preferred positional relationship between the exciter EC1 and the microphone MC1 is such that the sound output from the exciter EC1 is blocked by the head or headrest 34 of the occupant U1, and the sound output from the exciter EC1 is not directly input to the microphone MC1. The other exciters EC2, EC3, and EC4 are similarly attached to positions on the ceiling 40 corresponding to the seats Q2, Q3, and Q4, and are attached at positions such that the sound output from the exciters EC2, EC3, and EC4 is blocked by the head or headrest of the occupant, and is not directly input to the microphones MC2, MC3, and MC4.

The exciters EC1 to EC4 are driven by an audio drive signal DV output from the controller 10 via a wired or wireless connection. Like a normal cone-type speaker, the exciters EC1 to EC4 are vibrators that convert the audio drive signal DV into vibrations, but compared to a cone-type speaker, they can be made smaller, more space-saving, and lighter.

Figure 5 is a cross-sectional view showing the installation of exciter EC1. The interior material of the ceiling (ceiling base material) 42 includes a front surface 44 and a back surface 46, and exciter EC1 is installed on the back surface side of interior material 42. For this reason, occupant U1 cannot see exciter EC1 from the front surface 44. Interior material 42 also functions as a diaphragm, and when exciter EC1 is vibrated by audio drive signal DV, the vibration is transmitted to interior material 42, and sound is output from ceiling 40 due to the vibration of interior material 42. The same applies to the other exciters EC2 to EC4.

The audio device 20 is a device with a function for playing back audio signals, and its configuration is not particularly limited. The audio device 20 can be, for example, an AVN (audio-visual navigation) device, a smartphone, a portable audio player, etc. When the audio device 20 receives an instruction from an occupant, it starts playing back an audio signal, and an audio playback signal S2 is output to the controller 10.

The controller 10 has at least the function of causing the audio sound reproduced by the audio device 20 to be output from the exciters EC1 to EC4, and the function of causing the passengers' conversation voices to be output from the exciters EC1 to EC4. The controller 10 can include hardware resources such as a DSP, a microcontroller, an amplifier, and an adaptive filter that are necessary to execute such functions, as well as software resources for controlling the hardware. The controller 10 also works in conjunction with the audio device 20, and can control the audio device 20 or be controlled by the audio device 20.

When the controller 10 receives an audio playback signal S2 from the audio device 20, it outputs an audio drive signal DV corresponding to the audio playback signal S2 to the exciters EC1 to EC4, causing audio sound to be output from the ceiling 40 via the exciters EC1 to EC4.

In addition, when the conversation voice of the occupants is input as an audio signal S1 from the microphones MIC1 to MC4, the controller 10 performs necessary signal processing on the audio signal S1 and drives one or more exciters via an audio drive signal DV to output the conversation voice from the ceiling 40. In one embodiment, the controller 10 identifies the seat from which the speech is made based on the level of the audio signal input to the microphones MIC1 to MC4, and outputs an audio drive signal to the exciter corresponding to the other seats. For example, when the occupant U1 in the driver's seat Q1 shown in FIG. 4(B) speaks, the level of the input audio signal to the microphone MC1 becomes large, so the controller 10 identifies the driver's seat Q1 from which the speech is made and outputs an audio drive signal DV to the exciters EC2 to EC4 corresponding to the other seats Q2 to Q4, causing the conversation voice of the occupant U1 to be output from those ceilings. In yet another embodiment, if a weight sensor is installed to detect the presence or absence of an occupant in a seat, the controller 10 can also prevent the audio drive signal DV from being output to the exciter corresponding to an unoccupied seat based on the detection result of the weight sensor.

Next, the effects of the audio system of this embodiment will be described. In conventional audio systems, as shown in FIG. 3, a microphone MC1 attached near the steering wheel inputs the conversation voice P1 of the occupant U1 and the audio voice P2 output from the door speaker SP1, and therefore it is not possible to input the conversation voice P1 separately from the audio voice P2. Furthermore, the microphone MC1 is prone to picking up road noise, etc. This causes the noise in the conversation voice output from the speaker to increase, making it difficult to hear the conversation voice.

In contrast, in the audio system of this embodiment, as shown in FIG. 7, when occupant U1 speaks while audio sound reproduced by audio device 20 is being output by exciter EC1, audio sound P2 output by exciter EC1 is blocked by the head of occupant U1, and is prevented from being directly input to microphone MC1. Furthermore, road noise is also less likely to be picked up. In addition, since microphone MC1 is attached near headrest 34, microphone MC1 can input the speech sound propagating through the bones and skin of occupant U1's head, and even if the input level of occupant U1's speech sound propagating through the air decreases, this decrease is offset. This makes it possible to reduce the noise of the conversation sound output from the exciter, making the conversation sound easier to hear.

Next, another embodiment of the present invention will be described. In the above embodiment, an example was shown in which the conversational voices of the occupants were output from an exciter, but the conversational voices of the occupants can also be output from a speaker other than the ceiling exciter. Figure 8 shows an audio system 1A according to another embodiment. Here, an example is shown in which speakers SP7 and SP8 are installed for rear seats Q3 and Q4. Speakers SP7 and SP8 are installed near or inside the headrests of seats Q3 and Q4 to make it easier for the occupants in seats Q3 and Q4 to hear the conversational voices.

When the controller 10 outputs audio sound from the audio device 20, it drives the exciters EC1 to EC4 via the audio drive signal DV1, and when the controller 10 outputs conversation sound from the rear seats Q3 and Q4, it drives the speakers SP7 and SP8 via the audio drive signal DV2. When the controller 10 outputs conversation sound from the front seats Q1 and Q2, it drives the exciters EC1 and EC2 via the audio drive signal DV1. By outputting conversation sound from speakers other than the ceiling exciters in this way, the conversation sound can be heard even more clearly. In the example of FIG. 8, the speakers SP7 and SP8 are attached near the headrests of the rear seats Q3 and Q4, but speakers may also be attached near the headrests of the front seats Q1 and Q2. In this case, all conversation sound is output from the speakers, not the exciters.

The above describes in detail the preferred embodiment of the present invention, but the present invention is not limited to a specific embodiment, and various modifications and variations are possible within the scope of the gist of the invention described in the claims.

SP1 to SP6: Speakers MC1 to MC4: Microphones EC1 to EC4: Exciters 10: Controller 20: Audio device 30: Seat section 32: Backrest 34: Headrest 40: Ceiling 42: Interior panel

Claims (5)

a plurality of exciters attached to a ceiling corresponding to each seat position in the vehicle and vibrating the ceiling based on a drive signal applied thereto to output a sound;
Multiple microphones attached near the headrests of each seat;
a control means for outputting a drive signal for driving the exciter in response to an audio playback signal, and for outputting a drive signal for driving the exciter or another speaker in response to an audio signal input from any one of the plurality of microphones;
The exciter is mounted above the head of an occupant when seated in the seat,
The microphone is mounted in a position that is blocked by the head of an occupant when seated in the seat . The audio system of claim 1, wherein the exciter is attached to the back surface of an interior ceiling substrate. 10. The audio system of claim 1 , wherein the microphone is mounted between a seat back and a headrest. The audio system of claim 1, wherein the other speaker is mounted near a headrest of the seat. The audio system further includes a detection means for detecting the presence or absence of an occupant in each seat;
The control means has a conversation assistance function for transmitting the conversation voice of the occupant to other occupants,
2. The audio system according to claim 1, wherein the control means identifies the seat from which speech is being spoken based on the level of the audio signal input from the microphone, outputs drive signals to exciters corresponding to other seats based on the identification result, and does not output drive signals to exciters corresponding to seats with no occupant based on the detection means .

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