JP2023124179A - audio system - Google Patents

Abstract

To reproduce a sound field to obtain a high sense of presence in individual listening zones in a listening area.SOLUTION: An audio system 10 includes at least one audio output unit 14 that selects sound sources 11 for each listening zone of a plurality of listeners and mixes audio signals from the selected sound sources 11 and outputs as a mixed sound, a cancel sound generation unit 20 that generates a cancel sound for removing from the mixed sound a sound based on sound signals other than a sound signal from the selected sound sources 11 for each listening zone, and cancellation sound output units 15 that are arranged respectively near the plurality of listeners for outputting the cancellation sounds.SELECTED DRAWING: Figure 1

Description

The present invention relates to audio systems.

WO 2005/070301 proposes an audio system for providing separate listening zones for different seat positions within a listening area in a passenger compartment. The audio system includes multiple near field speakers arranged within a listening area. A plurality of near-field speakers are positioned near each listener's head, such as, for example, a headrest. A crosstalk rejection filter is coupled to the near field speaker.

A near field speaker and a crosstalk rejection filter provide first and second listening zones within the listening area such that sound from the first listening zone is rejected in the second listening zone and vice versa. are arranged as follows:

Japanese Patent Publication No. 2018-528681

In Patent Literature 1, speakers are arranged in the vicinity of the positions of the left and right ears of each listener, so the configuration is similar to headphones. The speaker near the listener's left ear reproduces the left channel sound content of the audio signal, and the speaker near the right ear reproduces the right channel sound content. For this reason, the left and right ears can only hear the sound content of one side, and there is a problem that the sense of reality is poor.

The present disclosure has been made in view of the above points, and an object of the present disclosure is to provide an audio system capable of reproducing a sound field for obtaining a high sense of presence in individual listening zones within the listening area. It is to be.

The audio system according to this embodiment includes at least one audio output unit that selects a sound source for each listening zone of a plurality of listeners, mixes audio signals from the selected sound sources, and outputs mixed audio; a canceling sound generating unit for generating a canceling sound based on an audio signal other than the audio signal from the sound source selected for each listening zone from the mixed audio; and a canceling sound output unit that outputs the canceling sound.

According to the present disclosure, it is possible to reproduce a sound field for obtaining a high sense of reality in individual listening zones within the listening area.

1 is a block diagram showing the configuration of an audio system according to Embodiment 1; FIG. 2 is a diagram showing a specific example of the audio system of FIG. 1; FIG. FIG. 3 is a block diagram showing the configuration of a canceling sound generator in FIG. 2; FIG. 3 is a diagram for explaining a canceling sound generated by a canceling sound generation unit in FIG. 2; FIG. 2 is a block diagram showing the configuration of an audio system according to Embodiment 2; FIG. 6 is a diagram showing a specific example of the audio system of FIG. 5; FIG. FIG. 7 is a block diagram showing the configuration of a canceling sound generator in FIG. 6; 7A and 7B are diagrams for explaining a canceling sound generated by the canceling sound generation unit of FIG. 6; FIG.

An audio system according to an embodiment of the present invention will be described below with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

Embodiments relate to an audio system that reproduces an audio signal obtained from a sound source. The audio system includes a speaker system for emitting an audio signal as sound (hereinafter, this sound is referred to as sound based on the audio signal). A speaker system is a device that converts an audio signal, which is an analog signal, into sound.

Audio systems for vehicles, such as automobiles, typically play the same audio signal for all occupants. When each passenger wants to listen to different music, if audio signals from a plurality of sound sources are reproduced at the same time, the sounds are mixed and it is impossible to hear only the desired audio signal.

For this reason, a passenger needs to use headphones or earphones to individually listen to audio signals from each sound source. However, there is a problem that listening for a long time using headphones or earphones is not comfortable, such as hurting the ears.

If the configuration of Patent Document 1, which provides individual listening zones within the listening area, is adopted, there is a problem that the presence is poor as described above. Moreover, in Patent Document 1, the number of speakers is limited to two, and surround reproduction cannot be performed.

Also, in a vehicle audio system, generally, all passengers can only listen at the same volume. In addition, when taking turns driving a long-distance vehicle, if a passenger who is not driving wants to sleep due to fatigue or wants to take a quiet break, cover their ears with earplugs, etc. Music can only be interrupted to an extent, and it is not possible to get adequate rest. In view of such problems, the present inventor devised the following invention.

Embodiment 1.
FIG. 1 is a diagram showing the configuration of an audio system 10 according to Embodiment 1. As shown in FIG. As shown in FIG. 1 , the audio system 10 includes a sound source 11 , a passenger-specific sound source selector 12 , a sound source adder 13 , an audio output unit 14 , a cancel sound output unit 15 , and a cancel sound generator 20 .

The passenger-by-passenger sound source selection unit 12 selects a sound source for each listening zone of the listener by the operation of each listener. The sound source adder 13 adds the sound signals from the sound sources 11 selected for each listening zone of a plurality of listeners and outputs the result to the sound output unit 14 . The audio output unit 14 outputs mixed audio. The canceling sound generator 20 generates canceling sounds for removing sounds based on audio signals other than the audio signals selected for each listening zone from the mixed sound. The canceling sound output unit 15 is arranged near each of a plurality of listeners and outputs canceling sounds.

As a result, each listener can listen to the content they want to listen to through speakers without using headphones or earphones. In addition, listeners who want to block content can block content without using special equipment such as earplugs.

A specific example of the audio system 10 according to the first embodiment will be described below. FIG. 2 is a diagram showing a specific example of the audio system of FIG. FIG. 2 shows an example in which the audio system 10 of the embodiment is applied to an automobile. Here, it is assumed that the automobile is a two-seater and has a driver's seat on which the driver sits and a front passenger's seat on which a fellow passenger sits. The car is a right-hand drive vehicle with the steering wheel arranged on the right side. The listeners are the driver sitting in the driver's seat and the passenger sitting in the passenger's seat. Hereinafter, the directions with respect to the driver are defined as the front-rear direction and the left-right direction as shown in FIG.

At least one sound source 11 to be reproduced is provided. The sound source 11 is, for example, a disc player such as a CD (Compact Disc) or a DVD (Digital Versatile Disc), a multimedia memory player, a radio, a digital broadcast, a USB (Universal Serial Bus), a wireless LAN (Local Area Network), Bluetooth ( registered trademark) connected smart phone, tablet, or the like, or may be an external device.

In the example shown in FIG. 2, five sound sources (sound source 1: radio, sound source 2: CD, sound source 3: smartphone, sound source 4: car navigation voice sent from the car navigation system (hereinafter referred to as navigation voice), sound source 5: An emergency vehicle approach warning sound (hereinafter referred to as a warning sound) is provided. Data and signals from the sound source 11 are converted into audio signals by predetermined processing. The sound source 11 outputs Lch and Rch audio signals for the left audio output unit 14L and the right audio output unit 14R to the individual passenger sound source selection unit 12, for example, in order to reproduce music.

The driver and fellow passengers select sound sources (contents) that they want to listen to by using the sound source selection unit 12 for each passenger shown in FIG. For example, the driver selects sound sources 1, 4, and 5 (radio, navigation voice, and warning sound), and the passenger in the front passenger seat selects sound source 2 (CD). The sound source selection unit 12 for each passenger selects Lch and Rch audio signals of each sound source selected by the driver (driver-selected audio signal L/R) and Lch and Rch audio signals of the sound source selected by the passenger (passenger and the user-selected audio signal L/R) are output to the sound source adding section 13 and the canceling sound generating section 20, respectively.

When one person selects a plurality of sound sources like the driver described above, Lch/Rch audio signals are output for each of the selected sound sources. In the embodiment, among these audio signals, the Lch's and the Rch's are added and output. Also, when the driver and the passenger select the same sound source, the voice data from the same sound source are added as separate selected voice data L/R and output. If no sound source is selected, 0 data is output.

The sound source adder 13 adds the Lch driver selection audio signal L and the fellow passenger selection audio signal L from the inputted driver selection audio signal L/R and fellow passenger selection audio signal L/R to obtain the left audio signal. The driver selection audio signal R and the passenger selection audio signal R of Rch are added and output to the right audio output section 14R.

The audio output unit 14 is a means for reproducing audio signals, and is arranged around the interior of the vehicle in the same manner as a normal vehicle audio system. In the example shown in FIG. 2, one audio output unit 14 is provided on each of the left and right sides of the vehicle interior. Hereinafter, when the left and right constituent elements are specified and described, the respective constituent elements are denoted by L and R symbols. The audio output unit 14 is, for example, a full-range speaker. The left audio output unit 14L is installed, for example, on the left front door, that is, on the front passenger side door. The right audio output unit 14R is installed, for example, on the right front door, that is, the door on the driver's seat side.

The canceling sound output unit 15 is a speaker, and is arranged near the head of each passenger, for example, the headrest of each seat. That is, the canceling sound output unit 15 is arranged near each passenger's ear. The canceling sound generator 20 generates canceling sounds for removing sounds based on audio signals other than the audio signals selected for each listening zone from the mixed sound. The generated canceling sound is transmitted to the canceling sound output unit 15 and output by the canceling sound output unit 15 . It is preferable that the canceling sound output unit 15 is composed of a directional speaker or the like having a directional characteristic such that the output sound is not diffused to the surroundings other than each passenger.

FIG. 3 is a block diagram showing the configuration of the canceling sound generator in FIG. 2. As shown in FIG. As shown in FIG. 2 , the canceling sound generation unit 20 includes a removal sound determination unit 21 , a convolution integration unit 22 , a removal sound addition unit 23 and a phase inverting unit 24 . Each functional block shown in FIG. 2 is realized by processing by a CPU (Central Processing Unit), a DSP (Digital Signal Processor), etc., which constitute the canceling sound generation section 20 . Therefore, the canceling sound generator 20 can be realized by installing a program for operating the canceling sound generator 20 in various information terminals in addition to a dedicated device.

A program includes instructions (or software code) that, when read into a computer, cause the computer to perform one or more of the functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or tangible storage medium. By way of example, and not limitation, computer readable media or tangible storage media may include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD - ROM, DVD, Blu-ray disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disc storage or other magnetic storage device. The program may be transmitted on a transitory computer-readable medium or communication medium. By way of example, and not limitation, transitory computer readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

The canceling sound generating unit 20 generates canceling sounds by arithmetic processing using the response characteristics of the sound from the sound output unit 14 to each listener. Specifically, first, the removed sound determination unit 21 determines a sound (removed sound) based on an audio signal other than the selected audio signal for each listening zone. Here, the removed sound in the driver's listening zone is the sound based on the sound source 2 (CD) selected by the fellow passenger. The removed sounds in the passenger's listening zone are sounds based on sound sources 1, 4, and 5 (radio, navigation sound, and warning sound) selected by the driver.

In the convolution integration unit 22, the removed sound determined by the removal sound determination unit 21 from the sound source selection unit 12 for each passenger (driver selection audio signal L/R, passenger selection audio signal L/R) A removal sound is input. The convolution integration unit 22 performs convolution integration with predetermined response characteristics on each removed sound of the passenger-specific selection audio signal.

4A and 4B are diagrams for explaining the canceling sound generated by the canceling sound generation unit in FIG. 2. FIG. FIG. 4 describes processing executed by each component constituting the audio system 10 . In FIG. 4, C indicates the response characteristic from the right audio output section 14R to the vicinity of the passenger's ear, and D indicates the response characteristic from the right audio output section 14R to the vicinity of the passenger's ear. E indicates the response characteristic from the left audio output section 14L to the vicinity of the passenger's ear, and F indicates the response characteristic from the left audio output section 14L to the vicinity of the driver's ear.

A response characteristic is a characteristic that expresses, for example, in the form of an impulse response, a change in sound caused by peripheral objects such as an audio output unit, ear shell, and human head. More specifically, the response characteristic is, for example, an impulse response measured in advance by a measuring instrument, or a transfer function measured in advance by a measuring instrument and converted into an impulse response. The response characteristic may be a characteristic obtained by quantifying changes in sound in a sound transmission path using a known acoustic analysis technique. Response characteristics are selected appropriately according to the detected state by detecting various conditions of the passenger from various characteristics data obtained by measuring each condition of each person and posture of the passenger using various sensors (not shown). may be used as

The mixed sound output by the right sound output unit 14R passes through the transmission path defined by the response characteristic C to reach the driver, and passes through the transmission path defined by the response characteristic D to reach the passenger. The mixed sound output by the left sound output unit 14L reaches the fellow passenger through the transmission path defined by the response characteristic E, and reaches the driver through the transmission path defined by the response characteristic F.

Let AL be the audio based on the driver-selected audio signal L, AR be the audio based on the driver-selected audio signal R, BL be the audio based on the passenger-selected audio signal L, and BR be the audio based on the fellow-passenger-selected audio signal R. The voices reaching the driver and passengers are as follows.
Driver arrival voice = C・AR+C・BR+F・AL+F・BL
Passenger arrival voice = D, AR + D, BR + E, AL + E, BL

The convolution unit 22 performs convolution integration on the removed sound using the same response characteristics as the transmission path from each sound output unit 14 to the passenger, and outputs a removed sound source convolution integral output signal. The removed sound adder 23 adds the removed sound convolution source integration output signals. The phase inverting section 24 phase-inverts each removed sound addition output signal from the removed sound adding section 23 to generate a canceling sound. The generated cancellation sounds corresponding to the driver and fellow passengers are as follows.
Driver cancel sound = /C・BR+/F・BL
Passenger cancellation sound = /D・AR+/E・AL

The cancel sound is output to each cancel sound output unit 15 . Therefore, the left cancel sound output unit 15L outputs a cancel sound that removes D, AR, E, and AL into the vehicle, and the right cancel sound output unit 15R outputs a cancel sound that removes C, BR, F, and BL into the vehicle.

As a result, among the mixed sounds output by the sound output unit 14, the sounds based on the sound source selected by the other person (passenger) are canceled in the air, and only the sound based on the sound source selected by the driver is audible. Become.
That is, the listening voice is as follows.
Voice heard by driver = (C・AR+C・BR+F・AL+F・BL)+(/C・BR+/F・BL)=C・AR+F・AL
Voice heard by fellow passenger = (D AR + D BR + E AL + E BL) + (/D AR + /E AL) = D BR + E BL

As described above, according to the first embodiment, each passenger in a vehicle can listen to content such as music and radio that they want to listen to comfortably and realistically from speakers without using headphones or earphones. It becomes possible. In addition, passengers who want to block content can block content without using special equipment such as earplugs, so they can rest and sleep comfortably.

Embodiment 2.
FIG. 5 is a block diagram showing the configuration of an audio system according to the second embodiment. In FIG. 5, the same components as those in FIG. 1 are given the same reference numerals, and the description thereof will be omitted as appropriate. The audio system 10 according to the second embodiment further includes a passenger-specific volume adjustment unit 16 , an ambient sound removal selection unit 17 , and a sound detection unit 18 in addition to the components of the audio system 10 according to the first embodiment.

As described above, vehicle audio systems usually only play the same volume for all passengers, even if they want to change the volume for each passenger. Even if the volume is adjusted for each passenger, the desired volume cannot be obtained unless the listening zone of each passenger is closed due to crosstalk from the space of other passengers. When speakers are arranged around the interior of a vehicle, such as in a car, there are other passengers on the transmission path of each passenger. If a passenger at a distant position reproduces the sound loudly, passengers nearby will have no choice but to hear the sound loudly.

Therefore, in the second embodiment, the passenger-specific sound volume adjustment unit 16 is provided. The passenger-specific sound source selection unit 12 selects Lch and Rch sound signals of each sound source selected by the driver (driver-selected sound source L/R) and Lch and Rch sound signals of the sound source selected by the passenger (fellow passenger Selected sound sources L/R) are output to the passenger-specific sound volume adjustment unit 16 .

The individual passenger volume adjustment unit 16 adjusts the volume of the sound based on the audio signal from the sound source 11 selected for each listening zone of a plurality of listeners for each listening zone. As described above, in the audio system 10 according to the embodiment, since it is possible to remove the sound based on the sound source of other passengers, by adjusting the volume for each passenger, each passenger can hear the sound at the desired volume. be able to listen. By treating the same content as different sound sources, each passenger can listen to the same content at a desired volume.

Also, the audio system 10 of the second embodiment is provided with a sound detection unit 18 . The sound detection unit 18 is provided for each passenger to remove ambient sounds (noise) such as conversations of other passengers. The sound detection unit 18 is arranged near each of the plurality of listeners, and detects the mixed sound output from the sound output unit 14 and ambient sounds other than the mixed sound.

Each of the canceling sound output units 15 outputs canceling sounds for removing the sounds from the audio signals other than the audio signals selected for each listening zone and the ambient sounds detected by the respective sound detecting units 18 from the mixed sound. Output.

In addition, when noise is removed, sounds other than the sound based on the sound source are shut out, so emergency vehicle sirens, conversations, crying babies, etc. cannot be heard. Therefore, it is desirable to be able to select whether or not to remove ambient sounds other than sound source based speech. The ambient sound removal selection unit 17 selects whether or not to remove the ambient sound detected by the sound detection unit 18 for each listening zone.

However, the emergency vehicle siren can be detected by, for example, a microphone for taking in external sounds separately provided outside the vehicle and can be heard by selecting it as a sound source (the above-mentioned sound source 5 (warning sound)). Further, noise may be always removed without providing the ambient sound removal selection unit 17 if speech recognition such as conversation and crying detection is possible.

A specific example of the audio system 10 according to the second embodiment will be described below. FIG. 6 is a diagram showing a specific example of the audio system of FIG. FIG. 6 also shows an example in which the audio system 10 is applied to an automobile, similar to FIG.

The driver and fellow passengers select sound sources (contents) that they want to listen to by using the passenger-specific sound source selection unit 12 . The passenger-specific sound source selection unit 12 selects Lch and Rch sound signals of each sound source selected by the driver (driver-selected sound source L/R) and Lch and Rch sound signals of the sound source selected by the passenger (fellow passenger Selected sound sources L/R) are output to the passenger-specific sound volume adjustment unit 16 . It should be noted that even if the driver and the passenger select the same sound source, the selected sound signals L/R are output separately. As a result, each passenger can listen to the same content at a desired volume by the passenger-specific volume adjustment unit 16 in the latter stage.

In the second embodiment, when one person selects a plurality of sound sources, Lch/Rch audio signals are output for each of the selected sound sources.

The passenger-by-passenger volume adjustment unit 16 adjusts the audio signals (driver-selected audio signal L/R, fellow-passenger-selected audio signal L/R) based on the sound sources selected by the passenger-by-passenger sound source selection unit 12, for each passenger. By adjusting the amplitude level, the selected audio signal after adjustment for each passenger (selected audio signal L/R after driver output adjustment and selected audio signal L/R after fellow passenger adjustment) is generated by a canceling sound generation unit 20 and a sound source addition unit. 13.

The individual passenger sound volume adjustment unit 16 may adjust the Lch/Rch audio signals separately, or may adjust the Lch/Rch audio signals to the same level. Furthermore, the individual passenger volume adjustment unit 16 may perform balance adjustment of the audio signal. Further, when one person selects a plurality of sound sources, the individual passenger volume adjustment unit 16 may adjust the volume for each sound source. In this case, the passenger-specific sound volume adjustment unit 16 adds the Lch and Rch of the selected audio signals after output adjustment, and outputs the output-adjusted selected audio signal L/R. It should be noted that the volume of other sound sources may be lowered when the navigation voice is output.

The sound source adder 13 generates the Lch driver-adjusted selected audio signal L and the passenger-adjusted selected audio signal Lch from the inputted driver-adjusted selected audio signal L/R and fellow-passenger-adjusted selected audio signal L/R. L is added and output to the left audio output unit 14L, and the selected audio signal R after driver adjustment and the selected audio signal R after passenger adjustment of Rch are added and output to the right audio output unit 14R.

The sound detection unit 18 is, for example, a microphone, and is arranged near each passenger's head, for example, a headrest. That is, the sound detection unit 18 is arranged near each passenger's ear. The sound detection unit 18 detects the mixed sound output from the sound output unit 14 and ambient sounds other than the mixed sound. Each passenger can select whether or not to remove the ambient sound using the ambient sound removal selection section 17 . The ambient sound removal selection unit 17 outputs a setting signal (driver ambient sound removal selection signal, passenger ambient sound removal selection signal) based on selection by each passenger.

FIG. 7 is a block diagram showing the configuration of the canceling sound generator 20 of FIG. As shown in FIG. 7, the canceling sound generation unit 20 further includes a post-convolution addition unit 25, a subtraction unit 26, and an ambient sound removal switching unit 27 in addition to the components shown in FIG. The post-convolution integration adding section 25 , the subtracting section 26 , and the ambient sound removal switching section 27 are provided for extracting the ambient sound from the detection result of the sound detecting section 18 .

The convolution integration unit 22 determines the removed sound from the adjusted passenger-specific selected audio signal (driver-adjusted selected audio signal L/R, passenger-adjusted selected audio signal L/R) from the passenger-specific volume adjustment unit 16. The removed sound determined by the unit 21 is input. The convolution integration unit 22 performs convolution integration with predetermined response characteristics for each removed sound in the same manner as described above.

Further, the convolution integration unit 22 convolves all the adjusted passenger-specific selected audio signals with response characteristics corresponding to the transmission paths from the audio output unit 14 to the sound detection unit 18 for removing ambient sounds. An integral is performed. The post-convolution integration adder 25 adds all the input convolution-processed data (all sound source convolution integration output signals).

8A and 8B are diagrams for explaining canceling sounds generated by the canceling sound generating unit of FIG. 6. FIG. FIG. 8 describes processing executed by each component of the audio system 10 .

Here, C indicates the response characteristic from the right sound output section 14R to the right sound detection section 18R, and D indicates the response characteristic from the right sound output section 14R to the left sound detection section 18L. E indicates the response characteristic from the left sound output section 14L to the left sound detection section 18L, and F indicates the response characteristic from the left sound output section 14L to the right sound detection section 18R. The sound detection units 18 are arranged near the ears of each passenger, and the response characteristics C, D, E, and F of the sounds detected by the sound detection units 18 are the responses from the left and right sound output units 14 to the ears. It is considered to be almost equal to the characteristic.

The mixed sound output by the right sound output unit 14R passes through the transmission path defined by the response characteristic C and is detected by the right sound detection unit 18R. Detected at 18L. The mixed sound output by the left sound output unit 14L passes through the transmission path defined by the response characteristic E and is detected by the left sound detection unit 18L. Detected at 18R. Further, each sound detection unit 18 detects ambient sounds other than the mixed voice from the sound output unit 14, including conversations and noise from inside and outside the vehicle.

Let AL be the audio based on the driver-selected audio signal L, AR be the audio based on the driver-selected audio signal R, BL be the audio based on the passenger-selected audio signal L, and BR be the audio based on the fellow-passenger-selected audio signal R. The calculation result by the post-convolution integral addition unit 25 is as follows.
Driver all sound source convolution integral calculation result = C・AR+C・BR+F・AL+F・BL
Passenger all sound source convolution integral calculation result = D AR + D BR + E AL + E BL

The sounds detected by the left sound detection unit 18L and the right sound detection unit 18R have the same response characteristics C, D, E, and F as above, where NA is the ambient sound on the driver's side and NB is the ambient sound on the passenger's side. is used, it becomes as follows.
Sound detected by the right sound detection section 18R=C*AR+C*BR+F*AL+F*BL+NA
Sound detected by the left sound detector 18L=D*AR+D*BR+E*AL+E*BL+NB

The subtraction unit 26 obtains the difference between the detection result of the sound detection unit 18 and the calculation result of the post-convolution addition unit 25 . As a result, ambient sounds (NA, NB) other than the voice output from the voice output unit 14 can be extracted.
Driver ambient sound = (C AR + C BR + F AL + F BL + NA) - (C AR + C BR + F AL + F BL) = NA
Passenger ambient sound = (D AR + D BR + E AL + E BL + NB) - (D AR + D BR + E AL + E BL) = NB

Based on the passenger-specific ambient sound removal selection signal from the ambient sound removal selection unit 17 , the ambient sound removal switching unit 27 switches whether to transmit the ambient sound to the removal sound addition unit 23 . When the passenger selects removal of ambient sound, the ambient sound is transmitted to the removed sound adding section 23 . In addition, when the passenger does not select removal of the ambient sound, the ambient sound is not transmitted (0 data).

The removed sound adder 23 adds the removed sound source convolution integral output signal and the ambient sound. Then, the phase inverting section 24 inverts the phase of the added output signal of the removed sound adding section 23 to generate a canceling sound.
Driver cancel sound =/C・BR+/F・BL+/NA
Passenger cancellation sound = /D・AR+/E・AL+/NB

The cancel sound is output to each cancel sound output unit 15 . Therefore, the left canceling sound output unit 15L outputs a canceling sound that removes D, AR, E, AL, and NB toward the driver inside the vehicle, and the right canceling sound output unit 15R outputs a canceling sound that removes C, BR, F, BL, and NA. Output to the passenger in the car.

As a result, of the mixed sound output by the sound output unit 14 to the driver, the sound based on the sound source selected by the other person (passenger) and the ambient sound are Only audio based on the source will be audible.
That is, the listening voice is as follows.
Voice heard by driver = (C・AR+C・BR+F・AL+F・BL+NA) + (/C・BR+/F・BL+/NA) = C・AR+F・AL
Similarly, the voice heard by the fellow passenger is as follows.
Voice heard by fellow passenger = (D・AR+D・BR+E・AL+E・BL+NB) + (/D・AR+/E・AL+/NB) = D・BR+E・BL

According to the second embodiment, as in the first embodiment, it is possible to obtain a high sense of realism in individual listening zones within the listening area without using headphones or earphones. In addition, each passenger can listen at a desired volume without using headphones or earphones.

In addition, ambient sound cancellation can be performed according to the passenger's selection. In addition, if it is selected not to remove ambient sounds, for example, conversations in the car, cries of babies and children, etc. can be heard.

It should be noted that the response characteristics for performing the convolution operation can be modified in consideration of the response characteristics of the audio output section 14, the canceling sound output section 15, and the sound detection section 18, if necessary.

The invention made by the present inventor has been specifically described above based on the embodiment, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

In the above example, the audio system 10 according to the embodiment of the configuration of the audio output unit of a pair of left and right full-range speakers in a two-seater car has been described, but the present invention is not limited to this. For example, in a four-seater car, the driver's seat is arranged on the right side of the front row, the passenger's seat is arranged on the left side of the front row, and the right rear seat and the left rear seat are arranged behind the driver's seat and the front passenger's seat, respectively. It is also possible to apply In this case, a passenger sitting in each seat becomes a listener, and each seat is provided with a cancel sound output unit 15 and a sound detection unit 18, respectively.

As described above, by generating a canceling sound through arithmetic processing using the response characteristics from the audio output unit 14 to each listener, different music can be played for each listening zone of each listener with a high degree of realism. Playback becomes possible. Also, the number and arrangement positions of the audio output units 14 are not limited to the above examples. For example, the audio output units 14 may be arranged next to the left and right rear seats, respectively, or the center channel, the rear channel, and the like may be arranged as the audio output units 14 . And by handling surround sound sources that support multi-channels, it becomes possible to reproduce more realistic sound. Further, in the present invention, it is not necessary to arrange the audio output section 14 of three or more channels for each passenger seat, and the configuration can be implemented by one set of multi-speakers.

Further, the numbers and positions of the cancel sound output units 15 and the sound detection units 18, and the related arithmetic processing are examples, and other configurations are also possible. For example, as the canceling sound output unit 15, two speakers may be provided near the left and right ears, respectively, or may be configured in combination with a wearable speaker worn by the listener. The sound detection unit 18 has been described as detecting the mixed sound output from the sound output unit 14 and ambient sounds other than the mixed sound. , and the subtraction unit 26 may perform arithmetic processing in consideration of the voice component.

Further, the response characteristic in the canceling sound generation unit 20 may be, for example, a previously measured transfer function or a characteristic obtained by converting a previously measured impulse response into a transfer function. Multiplication of the frequency-varying numerical value and the transfer function may be performed.

10 audio system 11 sound source 12 sound source selection unit for each passenger 13 sound source addition unit 14 sound output unit 14L left sound output unit 14R right sound output unit 15 cancel sound output unit 15L left cancel sound output unit 15R right cancel sound output unit 16 passenger Separate sound volume adjustment unit 17 Ambient sound removal selection unit 18 Sound detection unit 18L Left sound detection unit 18R Right sound detection unit 20 Canceled sound generation unit 21 Removal sound determination unit 22 Convolution integration unit 23 Removal sound addition unit 24 Phase inversion unit 25 Convolution integration Post-adding unit 26 Subtracting unit 27 Ambient sound removal switching unit

Claims (5)

at least one audio output unit that selects a sound source for each listening zone of a plurality of listeners, mixes audio signals from the selected sound sources, and outputs mixed audio;
a canceling sound generator for generating a canceling sound for removing, from the mixed sound, a sound based on an audio signal other than the audio signal from the sound source selected for each of the listening zones;
A canceling sound output unit that is arranged near each of a plurality of listeners and outputs the canceling sound;
comprising a
audio system. The canceling sound is generated by arithmetic processing using response characteristics from the audio output unit to each listener,
An audio system according to claim 1. Further comprising a sound detection unit arranged near each of a plurality of listeners and detecting the mixed sound output from the sound output unit and ambient sounds other than the mixed sound,
Each of the canceling sound generation units generates, from the mixed sound, sound from an audio signal other than the sound signal from the sound source selected for each of the listening zones, and ambient sound detected by each of the sound detection units. generate a canceling sound that removes the
An audio system according to claim 1. Further comprising an ambient sound removal selection unit that sets whether or not to remove the ambient sound detected by the sound detection unit for each listening zone,
4. Audio system according to claim 3. Further comprising a volume adjustment unit that adjusts, for each listening zone, the volume of the audio based on the audio signal from the sound source selected for each listening zone of a plurality of listeners,
The audio system according to any one of claims 1-4.

Images