Sound system

Abstract

To provide an acoustic system capable of flexibly setting a position of a microphone and reducing howling with a simple mechanism.SOLUTION: An acoustic system to be used in a cabin R of an automobile comprises: a plurality of speakers including the first speaker; and a microphone 11 arranged inside the cabin R so as to output an output signal based on collected voice. A first input signal including a first sub-signal corresponding to the output signal is input to the first speaker 21. A distance between the first speaker 21 and the microphone 11 is shorter than a distance between the other speaker other than the first speaker 21 included in the plurality of speakers and the microphone 11. A distance between the first speaker 21 and a headrest 51-1 included in a seat arranged inside the cabin R is shorter than a distance between the other speaker and the headrest 51-1.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an acoustic system.

Background Art

[0002] In recent years, karaoke has become enjoyable in automobiles, and various technologies related to in-vehicle karaoke systems have been developed. In an in-vehicle karaoke system, in order to reduce howling, for example, a microphone is installed at the center between the left and right door speakers, and an estimated signal corresponding to the transfer characteristics of the feedback transfer system from the door speakers to the microphone is subtracted from the sound signal to generate a first signal, and a microphone sound processing unit that generates a second signal with the phase of the first signal inverted is provided (see cited reference 1).

[0003] In this technology, from the left door speaker, a sound corresponding to the first output signal generated by synthesizing the first signal and the first music signal is emitted. From the right door speaker, a sound corresponding to the second output signal generated by synthesizing the second signal and the second music signal is emitted. By canceling out both sounds with inverted phases near the microphone, howling is reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technology according to Patent Document 1, the position of the microphone was limited to the center between the left and right door speakers. In addition, since a circuit for phase inversion is required, the mechanism for reducing howling has been complicated.

[0006] In consideration of the above circumstances, one aspect of this disclosure aims to provide an acoustic system that allows for flexible positioning of the microphone and reduces howling with a simple mechanism. [Means for solving the problem]

[0007] To solve the above problems, an acoustic system according to one aspect of the present disclosure is an acoustic system used in the passenger compartment of an automobile, comprising a plurality of speakers including a first speaker, and a microphone installed in the passenger compartment that outputs an output signal based on the sound it has picked up, wherein a first input signal including a first sub-signal corresponding to the output signal is input to the first speaker, the distance between the first speaker and the microphone is shorter than the distance between the microphone and other speakers included in the plurality of speakers other than the first speaker, and the distance between the first speaker and a headrest on a seat installed in the passenger compartment is shorter than the distance between the other speakers and the headrest. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view of a vehicle equipped with the acoustic system 100 according to the first embodiment. [Figure 2] This is a side view of the vehicle. [Figure 3] A block diagram showing the electrical configuration of the sound system 100 of the same embodiment. [Figure 4] This block diagram shows the electrical configuration of the acoustic system 100A according to the second embodiment. [Figure 5] This is a block diagram showing the electrical configuration of the acoustic system 100B of the third embodiment. [Figure 6] This is a plan view of a vehicle equipped with the sound system 100C according to the fourth embodiment. [Figure 7] This is a side view of the vehicle. [Figure 8] A block diagram showing the electrical configuration of the sound system 100C of the same embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. Note that the dimensions and scale of each part in the drawings may differ from those of the actual parts as appropriate. Furthermore, the embodiments described below are preferred specific examples of the present invention. For this reason, these embodiments are subject to various technically preferred limitations. However, the scope of the present invention is not limited to these forms unless otherwise stated in the following description.

[0010] 1. First Embodiment The sound system 100 according to this embodiment is used in a vehicle C1. Figure 1 is a plan view of a vehicle C1 equipped with the sound system 100 according to the first embodiment of the present invention, and Figure 2 is a side view of the vehicle C1.

[0011] In the passenger compartment R of vehicle C1, in addition to the sound system 100, there are four rectangularly arranged seats 51-54, a ceiling 6, a front right door 71, a front left door 72, a rear right door 73, and a rear left door 74. Seat 51 is the driver's seat, seat 52 is the passenger seat, seat 53 is the rear right seat, and seat 54 is the rear left seat. Each of seats 51-54 is made of a material such as cloth or leather and has sound-absorbing properties. Seats 51-54 face a common direction. Each of seats 51-54 is also equipped with a headrest 51-1-54-1.

[0012] The sound system 100 comprises a microphone 11 and a first speaker 21. The first speaker 21 is installed inside the headrest 51-1. The first speaker 21 may be a general-purpose headrest speaker.

[0013] Microphone 11 is equipped with a sound-collecting section that picks up sound and converts the picked-up sound into an audio signal Ma for output. The sound-collecting section can be any configuration that picks up sound, for example, a windbreak structure. Microphone 11 is positioned on the ceiling 6 of the vehicle compartment R and picks up the voice of a user seated in seat 51. Microphone 11 may also be positioned in the center of the dashboard where instruments and other equipment are mounted. The location of microphone 11 is not limited as long as it is within a range that can pick up the voice of a user seated in seat 51, as long as the conditions described later are met.

[0014] In the example shown in Figure 1, the distance between the headrest 51-1 and the first speaker 21 is shorter than the distance between the first speaker 21 and the microphone 11. Furthermore, the vehicle compartment R may be equipped with speakers other than the first speaker 21. In particular, each of the headrests 52-1 to 54-1 may be equipped with a headrest speaker. In this case, an independent amplifier may be installed for each headrest speaker, and each headrest speaker may emit sound based on an independent sound source. With such a configuration, the sound system 100 makes it possible for each user seated in seats 51 to 54 to enjoy different music.

[0015] Figure 3 is a block diagram showing the electrical configuration of the sound system 100. The sound system 100 includes a microphone 11 that outputs a sound signal Ma, a first speaker 21, and an acoustic device 30-1. In this specification, the sound signal Ma is an example of an output signal. Also, the sound represented by the sound signal Ma is an example of a first tone.

[0016] The sound device 30-1 generates a drive signal D1 based on the sound signal Ma output from the microphone 11 and outputs the drive signal D1 to the first speaker 21. In this specification, the drive signal D1 input to the first speaker 21 is an example of a first input signal. The sound device 30-1 is also an example of a generation unit.

[0017] Howling occurs when the sound emitted from the first speaker 21 is picked up by the microphone 11 and positive feedback is applied. Specifically, when the user emits a voice, the voice is picked up by the microphone 11, amplified by the audio device 30-1, and a drive signal D1 for driving the first speaker 21 is generated. The user's voice emitted from the first speaker 21 based on the drive signal D1 is picked up by the microphone 11, amplified again, and positive feedback is applied, which is the cause of howling.

[0018] However, referring to FIGS. 1 and 2, since the head of the user sitting on the seat 51 is substantially in contact with the headrest 51-1, the distance between the position of the user's ear and the first speaker 21 is shorter than the distance between the microphone 11 and the first speaker 21. Compare the technology according to this embodiment with the conventional technology using a door speaker instead of the first speaker 21. In this comparison, it is assumed that the user emits a voice of the same volume in each aspect. In this embodiment, compared with the conventional technology, the volume of the voice output from the first speaker 21 and picked up by the microphone 11 is felt to be larger in terms of the user's sense of hearing. Therefore, the user can reduce the volume of the voice emitted from the first speaker 21 compared with the conventional technology. For this reason, when the volume of the voice emitted from the first speaker 21 is set to an appropriate volume for the user, the volume of the voice from the first speaker 21 picked up by the microphone 11 is suppressed compared with the conventional technology. Therefore, the possibility of howling occurring due to the voice emitted from the first speaker 21 being input to the microphone 11 is suppressed.

[0019] The audio device 30-1 includes a microphone sound processing unit 30A-1 and a signal processing unit 30B-1. The microphone sound processing unit 30A-1 includes an ADC

[0020] The effect imparting unit 33-1 generates an effect imparting signal Ded by imparting a suitable effect on the voice, such as reverberation or echo, to the digital audio signal Md. In this way, the microphone audio processing unit 30A-1 converts the audio signal Ma as an analog signal into an audio signal Md as a digital signal, and then generates an effect imparting signal Ded by imparting an effect.

[0021] Next, the signal processing unit 30B-1 includes a DAC 37-1 that converts the effect imparting signal Ded from a digital signal into an effect imparting signal Dea as an analog signal, and an amplifier 38-1. The effect imparting signal Ded is converted from a digital signal into an effect imparting signal Dea as an analog signal by the DAC 37-1, then amplified by the amplifier 38-1, and supplied as a drive signal D1 to the first speaker 21.

[0022] In the audio system 100 according to the first embodiment, the distance between the position of the user's ear and the first speaker 21 is shorter than the distance between the microphone 11 and the first speaker 21. By setting the positions of the microphone 11 and the first speaker 21 as described above, when the user enjoys humming or learns English, it is possible to easily feedback their own voice in a state where the howling generated in the passenger compartment R is reduced.

[0023] 2. Second Embodiment Next, the audio system 100A according to the second embodiment will be described. In the following, among the components included in the audio system 100A, the same components as those included in the audio system 100 will be denoted by the same reference numerals, and the description of their functions may be omitted.

[0024] FIG. 4 shows the electrical configuration of the audio system 100A according to the second embodiment. The audio system 100A is configured in the same manner as the audio system 100 of the first embodiment described with reference to FIG. 3, except that it includes a communication device 25 and includes an audio device 30-2 instead of the audio device 30-1.

[0025] The communication device 25 is a device for a user of the sound system 100A to make hands-free calls with a person outside the vehicle C1. The communication device 25 generates a device signal Di indicating the voice of the person being spoken to. In this specification, the device signal Di input to the synthesis unit 36-1 is an example of a second sub-signal. In this embodiment, the device signal Di as the second sub-signal is included in the first input signal.

[0026] The sound device 30-2 includes a microphone sound processing unit 30A-2 in place of the microphone sound processing unit 30A-1 provided in the sound device 30-1 according to the first embodiment. Furthermore, the sound device 30-2 includes a signal processing unit 30B-2 in place of the signal processing unit 30B-1 provided in the sound device 30-1.

[0027] Unlike the microphone sound processing unit 30A-1, the microphone sound processing unit 30A-2 does not include the effect application unit 33-1.

[0028] The signal processing unit 30B-2 includes a DAC37-2 in place of the DAC37-1, and an AMP38-2 in place of the AMP38-1. Furthermore, the signal processing unit 30B-2 includes a combining unit 36-1.

[0029] The combining unit 36-1 generates a combined signal Sd by combining the sound signal Md, which is a digital signal acquired from the microphone sound processing unit 30A-2, and the device signal Di, which is acquired from the communication device 25. The combined signal Sd is converted from a digital signal to a combined signal Sa, which is an analog signal, by the DAC 37-2, then amplified by the amplifier 38-2, and supplied to the first speaker 21 as a drive signal D1. In this specification, the sound indicated by the device signal Di is an example of a second sound.

[0030] In the sound system 100A according to the second embodiment, similar to the sound system 100 according to the first embodiment, the distance between the user's ear and the first speaker 21 is shorter than the distance between the microphone 11 and the first speaker 21. This makes it possible for the user to hear a combined voice from the first speaker 21, consisting of their own voice and the voice of the person they are talking to, while reducing howling that occurs in the vehicle interior R when the user makes a hands-free call with the person they are talking to using the communication device 25.

[0031] 3. Third Embodiment Next, the acoustic system 100B according to the third embodiment will be described. In the following description, components of the acoustic system 100B that are the same as those of the acoustic systems 100 to 100A will be indicated by the same reference numerals, and their functions may be omitted.

[0032] Figure 5 shows the electrical configuration of the sound system 100B according to the third embodiment. The sound system 100B is configured similarly to the sound system 100 of the first embodiment described with reference to Figure 3, except that it includes a playback device 27-1 and includes a sound device 30-3 instead of a sound device 30-1.

[0033] The playback device 27-1 reads data recorded on a CD (Compact Disk), for example, and generates a device signal Di to the signal processing unit 30B-3 based on the read data.

[0034] The sound device 30-3 includes a microphone sound processing unit 30A-1 and a signal processing unit 30B-3, similar to those in the first embodiment.

[0035] The signal processing unit 30B-3 includes a DAC 37-2 and an amplifier 38-2 similar to those in the second embodiment. Furthermore, the signal processing unit 30B-3 includes a synthesis unit 36-2 that is different from the synthesis unit 36-1 in the second embodiment. Additionally, the signal processing unit 30B-3 includes a singing component attenuation unit 35.

[0036] The vocal component attenuation unit 35 attenuates the vocal component contained in the device signal Di by a predetermined ratio to generate a music signal Dsd. The music signal Dsd is input to the synthesis unit 36-2. In this specification, the music signal Dsd input to the synthesis unit 36-2 is an example of a second sub-signal. In this embodiment, the music signal Dsd as the second sub-signal is included in the first input signal.

[0037] The vocal component attenuation unit 35 is not an essential component for the signal processing unit 30B-3. In other words, the signal processing unit 30B-3 does not need to include the vocal component attenuation unit 35. If the signal processing unit 30B-3 does not include the vocal component attenuation unit 35, the device signal Di from the playback device 27-1 is input directly to the synthesis unit 36-2.

[0038] The synthesis unit 36-2 synthesizes the effect-adding signal Ded, which is a digital signal acquired from the microphone sound processing unit 30A-1, and the music signal Dsd, which is acquired from the singing component attenuation unit 35, to generate a synthesized signal Sd. If the signal processing unit 30B-3 does not have a singing component attenuation unit 35, the synthesis unit 36-2 synthesizes the effect-adding signal Ded and the device signal Di, which is acquired from the playback device 27-1, to generate a synthesized signal Sd. The synthesized signal Sd is converted from a digital signal to an analog synthesized signal Sa by the DAC 37-2, amplified by the amplifier 38-2, and supplied to the first speaker 21.

[0039] In the sound system 100B according to the third embodiment, similar to the sound system 100 according to the first embodiment, the distance between the user's ear and the first speaker 21 is shorter than the distance between the microphone 11 and the first speaker 21. This makes it possible for the user to hear a combined sound of their own singing voice and the karaoke accompaniment from the first speaker 21 while reducing howling that occurs in the car room R when using the playback device 27.

[0040] In the third embodiment described above, a monaural sound system 100B was explained as an example, but the sound system 100B may also be in stereo format. In this case, two first speakers 21 are placed on the headrest 51-1. A drive signal D1 for the right channel is supplied to one of the two first speakers 21, and a drive signal D1 for the left channel is supplied to the other.

[0041] 4. Fourth Embodiment Next, the acoustic system 100C according to the fourth embodiment will be described. In the following, components of the acoustic system 100C that are the same as those of the acoustic systems 100 to 100B will be indicated by the same reference numerals, and their functions may be omitted.

[0042] Figure 6 shows a plan view of a vehicle C2 equipped with the sound system 100C according to the fourth embodiment of the present invention. Figure 7 shows a side view of the vehicle C2. The sound system 100C includes a second speaker 22 in addition to the first speaker 21. The second speaker 22 is a door speaker located in the front light door 71.

[0043] The distance between the first speaker 21 and the microphone 11 is shorter than the distance between the second speaker 22 and the microphone 11. Also, the distance between the headrest 51-1 and the first speaker 21 is shorter than the distance between the headrest 51-1 and the second speaker 22. In addition, the vehicle compartment R may be equipped with speakers other than the first speaker 21 and the second speaker 22.

[0044] Figure 8 is a block diagram showing the electrical configuration of the sound system 100C. The sound system 100C includes a microphone 11 that outputs a sound signal Ma, a first speaker 21, a second speaker 22, a playback device 27-2, and a sound device 30-4. In this specification, the drive signal D2 input to the second speaker 22 is an example of a second input signal.

[0045] The sound device 30-4 comprises a microphone sound processing unit 30A-3, a signal processing unit 30B-1, and a signal processing unit 30B-4. The microphone sound processing unit 30A-3 includes an ADC 31 that converts the sound signal Ma from an analog signal to a digital sound signal Md, a howling canceller 32 that removes howling components using a reference signal Dref, an effect application unit 33-2, and a singing component attenuation unit 35.

[0046] The vocal component attenuation unit 35 outputs a music signal Dsd obtained by attenuating the vocal component contained in the device signal Di by a predetermined ratio. This music signal Dsd is input to the adaptive filter 321 as a reference signal Dref.

[0047] Furthermore, as with the third embodiment, the singing component attenuation unit 35 is not an essential component for the microphone sound processing unit 30A-3. In other words, the microphone sound processing unit 30A-3 does not need to include the singing component attenuation unit 35.

[0048] The feedback canceller 32 subtracts the sound component emitted from the second speaker 22 from the sound signal Md. The feedback canceller 32 includes an adaptive filter 321, a setting unit 322, and a subtraction unit 323. The adaptive filter 321 simulates the transmission characteristics of the feedback transmission system from the second speaker 22 to the microphone 11 and outputs an estimated signal E corresponding to these transmission characteristics. Specifically, the adaptive filter 321 receives a reference signal Dref from the singing component attenuation unit 35. The adaptive filter 321 obtains an estimated signal E in which the above-mentioned transmission characteristics are applied to the reference signal Dref. In this example, the transmission characteristics are those of the feedback transmission system from the second speaker 22 to the microphone 11. These transmission characteristics include delays and reflections that occur in the feedback transmission system. The adaptive filter 321 is typically a Finite Impulse Response (FIR) filter, and although not specifically shown in the diagram, it includes multiple delay elements connected in cascades, multiple multipliers that multiply each output of the delay elements by a coefficient, and an adder that calculates and outputs the sum of the outputs of each multiplier.

[0049] The subtraction unit 323 subtracts the estimated signal E output from the adaptive filter 321 from the sound signal Md from the microphone 11. The setting unit 322 adaptively sets each coefficient in the adaptive filter 321 so that the subtracted signal Rd, i.e., the result of subtracting the estimated signal E from the sound signal Md, becomes small. Therefore, even if the above transmission characteristics change moment by moment due to the opening and closing of windows or the seats occupied by passengers, the characteristics of the adaptive filter 321 are sequentially updated to match these changes.

[0050] The signal processing unit 30B-1 is the same as the signal processing unit 30B-1 in the first embodiment. The effect-adding signal Ded is converted from a digital signal to an analog effect-adding signal Dea by the DAC37-1, then amplified by the amplifier 38-1 and supplied to the first speaker 21 as a drive signal D1.

[0051] The signal processing unit 30B-4 is the same as the signal processing unit 30B-1.

[0052] Furthermore, the signal processing unit 30B-4 includes a DAC 37-3 that converts the music signal Dsd input from the singing component attenuation unit 35 from a digital signal to an analog music signal Dsa, and an amplifier 38-3.

[0053] The music signal Dsd is converted from a digital signal to an analog music signal Dsa by the DAC37-3, then amplified by the amplifier 38-3 and supplied to the second speaker 22 as a drive signal D2.

[0054] In the sound system 100C according to the fourth embodiment, similar to the sound system 100 according to the first embodiment, the distance between the user's ear and the first speaker 21 is shorter than the distance between the microphone 11 and the first speaker 21. Also, the distance between the first speaker 21 and the microphone 11 is shorter than the distance between the second speaker 22 and the microphone 11. Furthermore, the distance between the user's ear and the first speaker 21 is shorter than the distance between the user's ear and the second speaker 22. In addition, the sound system 100C is equipped with a howling canceller 32.

[0055] In the conventional technology, both the voice emitted by the user and the voice output from the playback device were output in parallel from the door speaker. Furthermore, the distance between the door speaker and the user's ear is greater in the conventional technology compared to the distance between the first speaker 21 and the user's ear in this embodiment. Therefore, when a user listens to their own voice emitted from the speaker, the conventional door speaker required a higher sound pressure to emit sound compared to the first speaker 21 in this embodiment, in order for the user to hear their own voice at the same volume. If the volume of the voice emitted from the door speaker was increased too much in order to emit sound at a higher sound pressure, howling occurred because the voice emitted from the door speaker was picked up by the microphone. On the other hand, in the sound system 100C of this embodiment, there is no need to increase the volume of the voice emitted from the second speaker 22, which acts as a door speaker, as much as in the conventional technology. Furthermore, the sound device 30-4 is equipped with a howling canceller 32. The howling canceller 32 attenuates the sound component emitted from the second speaker 22 among the sound picked up by the microphone 11. Consequently, the gain of the positive feedback loop, such as second speaker 22 → microphone 11 → first speaker 21 → microphone 11, is reduced. Therefore, when a user enjoys karaoke in the vehicle compartment R using the playback device 27, they can hear their own singing voice from the first speaker 21 and the karaoke accompaniment from the second speaker 22, while reducing howling that occurs in the vehicle compartment R. In the fourth embodiment described above, a monaural sound system 100C was explained as an example, but the sound system 100C may be in stereo format. In this case, two second speakers 22 are used. One second speaker 22 is located in the front right door 71, and the other second speaker 22 is located in the front left door 72. The second speaker 22 located in the front right door 71 is supplied with a drive signal D2 for the right channel. The second speaker 22 located in the front left door 72 is supplied with a drive signal D2 for the left channel.

[0056] 3. Variant The above embodiments can be modified in various ways. Specific examples of modifications are given below. Two or more embodiments arbitrarily selected from the following examples can be combined as appropriate, provided they do not contradict each other.

[0057] 3-1. Variation 1 For example, an obstruction may be present between the microphone 11 and the first speaker 21 and the second speaker 22. By having such a configuration in the sound systems 100 to 100C, the possibility of howling can be further suppressed.

[0058] 3-2. Variation 2 The microphone 11, the first speaker 21, and the second speaker 22 may have directionality. More specifically, it is preferable that the microphone 11 has directionality in the direction that picks up the user's voice. Furthermore, it is preferable that the first speaker 21 and the second speaker 22 emit sound in a direction that is directed towards the user and at the same time deviates from the microphone 11. This reduces the possibility of feedback occurring.

[0059] 3-3. Modified Example 3 The sound system 100C according to the fourth embodiment is equipped with a playback device 27-2 and has a configuration in which karaoke accompaniment sounds are emitted from the second speaker 22, but the configurations of the embodiments of the present invention are not limited to this. For example, the sound system according to this modified example 3 may be equipped with a communication device 25, which is provided in the sound system 100A according to the second embodiment, instead of the playback device 27-2, and has a configuration in which the voice of the person being spoken to is emitted from the second speaker 22.

[0060] 4. Addendum From the embodiments described above, for example, the following embodiments can be understood.

[0061] The acoustic systems 100-100C according to the embodiment of this disclosure (first embodiment) are acoustic systems 100-100C used in the passenger compartment R of an automobile, and include a plurality of speakers including a first speaker 21, and a microphone 11 installed in the passenger compartment R that outputs an audio signal Ma as an output signal based on the sound it has picked up. In the acoustic systems 100-100C, the first speaker 21 is input a drive signal D1 as a first input signal which includes an audio signal Md as a first sub-signal corresponding to the audio signal Ma as an output signal. Furthermore, the distance between the first speaker 21 and the microphone 11 is shorter than the distance between the microphone 11 and other speakers other than the first speaker 21 that are included in the plurality of speakers. Moreover, the distance between the first speaker 21 and the headrest 51-1 provided on the seat installed in the passenger compartment R is shorter than the distance between the other speakers and the headrest 51-1.

[0062] The sound system 100-100C has this configuration, which allows for flexible positioning of the microphone 11 and reduces howling with a simple mechanism using elements commonly found in automobiles. The distance between the first speaker 21 and the microphone 11 is shorter than the distance between the microphone 11 and other speakers included in the group of speakers other than the first speaker 21. As a result, sounds emitted from other speakers are less likely to be picked up by the microphone 11 compared to sounds emitted from the first speaker 21. Also, the distance between the first speaker 21 and the headrest 51-1 on the seat installed in the vehicle compartment R is shorter than the distance between other speakers and the headrest 51-1. As a result, sounds emitted from other speakers are less likely to be heard by a person seated in the seat 51 compared to sounds emitted from the first speaker.

[0063] Furthermore, in the example of the first embodiment (second embodiment), the sound signal Md as the first sub-signal indicates the first tone. The drive signal D1 as the first input signal includes the device signal Di as the second sub-signal indicating the second tone. The first speaker 21 emits the first tone and the second tone.

[0064] With this configuration, the sound systems 100-100B can mix human voices with other sounds and then emit the resulting sound from the first speaker 21. In particular, it becomes possible to use, for example, a hands-free karaoke system or a call system in the passenger compartment R of vehicle C1.

[0065] Furthermore, in the example of the first embodiment (third embodiment), the multiple speakers include a second speaker 22, and a drive signal D2, which is a second input signal different from the drive signal D1, which is a first input signal, is input to the second speaker 22.

[0066] With this configuration, the sound system 100C can emit human voices from the first speaker 21 and other sounds from the second speaker 22. In particular, it becomes possible to use, for example, a hands-free karaoke system or a call system in the passenger compartment R of vehicle C.

[0067] Furthermore, an example of the first embodiment (fourth embodiment) may further include an acoustic device 30-4 that generates a drive signal D1 as a first input signal by reducing the signal component corresponding to the sound emitted from the second speaker 22 from the sound signal Md as a first sub-signal.

[0068] The sound system 100C has this configuration, which makes it possible to suppress howling caused by the microphone 11 picking up sound emitted from the second speaker 22, the microphone 11 picking up the sound picked up by the microphone 11 being emitted from the first speaker 21, and the microphone 11 picking up the sound emitted from the first speaker 21.

[0069] Furthermore, in the example of the first embodiment (fifth embodiment), the first tone is a human singing tone, and the second tone is an accompanying tone for the singing tone.

[0070] With this configuration, the sound system 100B makes it possible to use a hands-free karaoke system in the passenger compartment R of vehicle C1.

[0071] Furthermore, in the example of the first embodiment (sixth embodiment), the sound signal Md as the first sub-signal represents human singing, and the drive signal D2 as the second input signal includes a music signal Dsd as the second sub-signal, which represents an accompanying sound for the singing.

[0072] With this configuration, the sound system 100C makes it possible to use a hands-free karaoke system in the passenger compartment R of vehicle C2.

[0073] Furthermore, in the example of the first embodiment (seventh embodiment), the first sound is the voice of a first human, and the second sound is the voice of a second human.

[0074] With this configuration, the sound system 100A makes it possible to use a hands-free calling system in the passenger compartment R of vehicle C1.

[0075] Furthermore, in the example of the first embodiment (eighth embodiment), the sound signal Md as the first sub-signal represents the voice of a first human, and the drive signal D2 as the second input signal includes the device signal Di as the second sub-signal representing the voice of a second human.

[0076] With this configuration, the sound system 100B makes it possible to use a hands-free calling system in the passenger compartment R of vehicle C1.

[0077] Furthermore, in the example of the first embodiment (ninth embodiment), the first speaker 21 is installed on the headrest 51-1.

[0078] Because the sound system 100-100C has this configuration, it becomes possible to place the first speaker 21 closer to the human ear compared to when the first speaker 21 is placed in a location other than the headrest.

[0079] Furthermore, in the example of the first embodiment (the tenth embodiment), the microphone 11 is installed on the dashboard or ceiling 6 inside the vehicle compartment R.

[0080] With the sound systems 100-100C having this configuration, if the microphone 11 is installed on the dashboard, a person in the driver's seat or passenger seat of vehicle C1 or C2 can use the sound systems 100-100C of the present invention. If the microphone 11 is installed on the ceiling 6, a person in the driver's seat or passenger seat of vehicle C1 or C2 and a person in the rear seat can use the sound systems 100-100C of the present invention. [Explanation of symbols]

[0081] 6...Ceiling, 11...Microphone, 21...First speaker, 22...Second speaker (door speaker), 25...Communication device, 27...Playback device, 30...Sound device, 30A...Microphone sound processing unit, 30B...Signal processing unit, 31...ADC, 32...Howling canceller, 33-1, 33-2...Effect application unit, 35...Singing component attenuation unit, 36-1, 36-2...Synthesis unit, 37-1, 37-2, 37-3...DAC, 38-1, 38-2, 38-3...Amplifier, 51~54...Seats, 51-1~54-1...Headrest, 71...Front right door, 72...Front left door, 73...Rear right door, 74...Rear left door, 100~100C...Sound system, 321...Adaptive filter, 322...Setting unit, 323...Subtraction unit, 351...Singing component attenuation unit,

Claims

1. An acoustic system used in the cabin of an automobile, Multiple speakers, including a first speaker and a second speaker, The vehicle interior is equipped with a microphone that outputs an output signal based on the sound it has picked up, A first input signal, including a first sub-signal corresponding to the output signal, is input to the first speaker. The distance between the first speaker and the headrest of the seat installed in the vehicle interior is shorter than the distance between the first speaker and the microphone. The distance between the first speaker and the microphone is shorter than the distance between the second speaker and the microphone. The distance between the first speaker and the headrest is shorter than the distance between the second speaker and the headrest. The first sub-signal indicates the first tone, The first input signal includes a second sub-signal indicating a second tone, The first speaker is an acoustic system that emits the first sound and the second sound.

2. An acoustic system used in the cabin of an automobile, Multiple speakers, including a first speaker and a second speaker, The vehicle interior is equipped with a microphone that outputs an output signal based on the sound it has picked up, A first input signal, including a first sub-signal corresponding to the output signal, is input to the first speaker. The distance between the first speaker and the headrest of the seat installed in the vehicle interior is shorter than the distance between the first speaker and the microphone. The distance between the first speaker and the microphone is shorter than the distance between the second speaker and the microphone. The distance between the first speaker and the headrest is shorter than the distance between the second speaker and the headrest. A second input signal different from the first input signal is input to the second speaker. An acoustic system further comprising a generation unit that generates the first input signal by reducing the signal component corresponding to the sound emitted from the second speaker from the first sub-signal.

3. The acoustic system according to claim 1, wherein the first sound is a human singing sound, and the second sound is an accompanying sound for the singing sound.

4. The acoustic system according to claim 2, wherein the first sub-signal represents a human singing sound, and the second input signal includes a second sub-signal representing an accompaniment sound for the singing sound.

5. The acoustic system according to claim 1, wherein the first sound is the voice of a first human, and the second sound is the voice of a second human.

6. The acoustic system according to claim 2, wherein the first sub-signal indicates a first human voice, and the second input signal includes a second sub-signal indicating a second human voice.

7. The first speaker is installed in the headrest, as described in any one of claims 1 to 6.

8. The sound system according to any one of claims 1 to 7, wherein the microphone is installed on the dashboard or ceiling inside the vehicle.

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