JP2008098694A - On-board audio reproduction system and audio reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-board audio reproduction system and an audio reproducing method that provide an easier-to-listen multichannel surround sound field for passengers on rear seats. <P>SOLUTION: Multichannel audio signals L, C, R, LS, RS, and LFE outputted from a signal source 1 are supplied to a plurality of on-board speakers FL, SC, FR, RL, RR, and SW provided at predetermined positions in a cabin to perform audio reproduction. Further, a phon signal processing circuit 5A generates synthesized signals PRL and PRR of the audio signals L, C, R, LS, and RS and supplies them to open air type headphones or earphones connected to a headphone terminal JR. Then the passengers are made to listen to a reproduced sound audio-reproduced by the open air type headphones or earphones and a sound audio-reproduced by the on-board speakers FL, SC, FR, RL, RR, and SW together. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an on-vehicle audio reproduction system, and more particularly to an on-vehicle audio reproduction system and an audio reproduction method for reproducing audio using headphones or earphones in addition to reproducing audio using an on-vehicle speaker.

  2. Description of the Related Art Conventionally, an in-vehicle audio reproduction system that reproduces audio by using headphones or earphones in addition to reproducing audio using an in-vehicle speaker is known with the configuration shown in FIGS.

  As shown in FIG. 1 (a), this in-vehicle audio reproduction system includes a plurality of in-vehicle speakers FL, SC, FR, RL, RR, SW provided in the interior of a car, and a plurality of channels from the car audio unit AU. Audio signals L, C, R, LS, RS, and LFE are supplied to reproduce a sound with a sense of presence.

  For example, when a 5.1 channel audio signal is output from a signal source such as a CD player or a DVD player provided in the car audio unit AU, the center channel audio signal C is supplied to the center provided on the front panel of the automobile. The left and right front channel audio signals L and R are supplied to the speakers SC and the front speakers FL and FR provided on both sides of the front seat, and the left and right rear channel audio signals LS and RS are supplied to the rear seat. The sub-woofer speaker provided to the rear speakers (for example, the trunk room side) behind the rear seat is supplied to the rear speakers RL and RR provided on both sides of the rear seat and the surround channel audio signal LFE for reproducing the low-frequency effect (LFE) sound is reproduced. By supplying to SW, audio can be played back and a sense of reality It is made as to achieve a multi-channel surround sound field to be obtained.

  Further, in this in-vehicle audio reproduction system, when headphones PL, PR are connected to the headphone terminals JL, JR provided on the left and right portions on the rear seat side of the vehicle interior, the passenger in the rear seat uses the headphones PL, PR. It is possible to listen to multi-channel surround sound with a sense of presence.

  That is, as shown in the block diagram of FIG. 1B, the car audio unit AU receives the audio signals L, C, R, LS, RS, and LFE of each channel output from the above-described signal source for each speaker FL. , SC, FR, RL, RR, SW, in addition to the circuit configuration to be supplied, a phone signal output unit is provided. The phone signal output unit generates the right channel audio signal AUR by synthesizing the audio signals C, R, RS, and LFE, and combines the audio signals L, C, LS, and LFE to the left. The audio signal AUL for the channel is generated, and the audio signals AUR and AUL for each channel are supplied to the headphones PL and PR connected to the headphone terminals JL and JR.

  Then, the passenger on the left rear seat wears the headphones PL connected to the headphone terminal JL, the right ear HR plays the right channel audio signal AUR, and the left ear HL plays the left channel audio. By listening to the playback sound of the signal AUL, it is possible to listen to a multi-channel surround sound that provides a sense of presence, and a passenger on the right rear seat is connected to the headphone terminal JR. And listening to the playback sound of the right channel audio signal AUR with the right ear HR and the playback sound of the left channel audio signal AUL with the left ear HL, you can listen to multi-channel surround sound with a sense of presence. It can be done.

  By the way, the conventional in-vehicle audio playback system described above, when a passenger in the rear seat receives a multi-channel surround sound played by the in-vehicle speakers FL, SC, FR, RL, RR, SW, the passenger May cause problems such as difficulty in listening to the reproduction sound (for example, vocal sound) of the center speaker SC provided at a position far from the headphone, but by listening to the reproduction sound with the headphones PL or PR attached, The same effect can be obtained as if the reproduced sound of the center speaker SC is clearly heard.

  Further, in order to make it easy to hear the reproduced sound that is reproduced from the headphones PL and PR by being cut off from the outside, the headphones PL and PR are sealed headphones that seal the passenger's ears.

  However, there is a problem that when the passenger wears the sealed headphones PL and PR, he / she feels occlusion and feels uncomfortable.

  In addition, if the passenger wears sealed headphones PL and PR, the sound from outside cannot be heard, so it is difficult to hear other passengers' voices, making it inconvenient and inconvenient. There was a problem.

  The present invention has been made in view of such conventional problems, and is provided with an in-vehicle audio reproduction system that provides a sound field that is easier to hear without giving a feeling of obstruction to a passenger on the rear seat. An object is to provide an audio playback method.

  According to the first aspect of the present invention, the audio signals of a plurality of channels output from the signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in the vehicle interior to reproduce the audio and board the rear seat. An in-vehicle audio reproduction system for reproducing audio on a headphone or earphone worn by a passenger based on the audio signals of the plurality of channels, and adjusting frequency characteristics, delay time and amplification for the audio signals of the plurality of channels And adjusting the rate, synthesizing the adjusted audio signals to generate a synthesized signal and supplying the synthesized signal to the headphones or earphones, thereby providing a phone signal processing means for reproducing the synthesized signal as audio. , Open-air headphones or earphones There, a reproduced sound is the audio reproduced by the headphones or earphones, together with sound is the audio reproduced by the plurality of vehicle-mounted speakers, be listening to the occupant, characterized by.

  According to the second aspect of the present invention, the audio signals of a plurality of channels output from the signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in the passenger compartment to reproduce the audio, and board the rear seat. An in-vehicle audio reproduction system for reproducing audio based on the audio signals of a plurality of channels on a speaker having directivity for emitting sound toward a passenger, wherein the frequency characteristics of the audio signals of the plurality of channels are reduced. Phone signal processing means that performs adjustment, adjustment of delay time and amplification factor, synthesizes the adjusted audio signals, generates a synthesized signal, and supplies the synthesized signal to a speaker having directivity, thereby reproducing the synthesized signal as audio A playback sound that is played back by the speaker having directivity and the plurality of in-vehicle speakers. Together with sounds that are audio reproduction in mosquitoes, thereby listening to the occupant, characterized by.

  According to a fourth aspect of the present invention, audio signals of a plurality of channels output from a signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in a vehicle cabin to reproduce the audio, and board the rear seat. An audio reproduction method for reproducing audio on a headphone or an earphone worn by a passenger based on the audio signals of the plurality of channels, wherein the frequency characteristics are adjusted and the delay time and the amplification factor are adjusted for the audio signals of the plurality of channels. A phone signal processing step of performing adjustment, synthesizing the adjusted audio signal to generate a synthesized signal, and supplying the synthesized signal to the headphone or the earphone to reproduce the synthesized signal as an audio is provided, and the headphone or the earphone is opened Air-type headphones or earphones, front Together with reproduced sound is the audio playback with headphones or earphones, the sound is the audio reproduced by the plurality of vehicle-mounted speakers, be listening to the occupant, characterized by.

  According to the fifth aspect of the present invention, the audio signals of a plurality of channels output from the signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in the passenger compartment to reproduce the audio, and board the rear seat. An audio reproduction method for reproducing audio based on the audio signals of the plurality of channels on a speaker having directivity for emitting sound toward a passenger, the frequency characteristics being adjusted for the audio signals of the plurality of channels. A phone signal processing step of adjusting the delay time and amplification factor, synthesizing the adjusted audio signals to generate a synthesized signal, and supplying the synthesized signal to a speaker having directivity to reproduce the synthesized signal as audio. The reproduced sound reproduced by the speaker having the directivity and the audio from the plurality of in-vehicle speakers. Together with sounds that are I Oh reproduction, thereby listening to the occupant, characterized by.

  A preferred embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a block diagram showing the configuration of the in-vehicle audio reproduction system of the present embodiment, and FIG. 3 is a block diagram showing the configurations of the operation unit and the control unit provided in the in-vehicle audio reproduction system of the present embodiment. FIG.

  The in-vehicle audio playback system of the present embodiment can be widely applied to an audio playback system that performs multi-channel audio playback, but the in-vehicle audio playback system that can perform 5.1 channel surround playback. Will be described.

  In FIG. 2, the in-vehicle audio reproduction system of the present embodiment has a plurality of in-vehicle speakers FL, SC, FR, RL, RR, SW provided in the interior of the automobile, as shown in FIG. In addition to audio reproduction, the headphone terminals JL and JR are provided.

  Here, the in-vehicle speakers FL, SC, FR, RL, RR, SW are respectively a center speaker SC provided on the panel of the automobile, front speakers FL, FR provided on the left and right of the front seat, and a rear seat. Rear speakers RL and RR provided on the left and right sides of the rear and subwoofer speakers SW provided behind the rear seat.

  A car audio unit (not shown) attached to a center panel portion of an automobile, a signal source 1 such as a CD player or a DVD player, a speaker output circuit 2, an operation unit 3, a control unit 4, and phone signal processing circuits 5A and 5B Is provided.

  A passenger operates a car audio unit to reproduce a medium such as a CD or a DVD. From the signal source 1, a plurality of channels of audio signals, that is, a center channel audio signal C and left and right front channel audio signals L and R. When the left and right rear channel audio signals LS, RS and the surround channel audio signal LFE are output, the speaker output circuit 2 amplifies each audio signal L, C, R, LS, RS, LFE, etc. This is supplied to each speaker FL, SC, FR, RL, RR, SW and 5.1 channel multi-channel surround sound is reproduced.

  As shown in the figure, the phon signal processing circuit 5A receives the respective outputs of the filters FTL1 to FTL5, FTR1 to FTR5, and the filters FTL1 to FTL5 and FTR1 to FTR5 for inputting the audio signals L, C, R, LS, RS. Delay circuits DYL1 to DYL5, DYR1 to DYR5 that are delayed by a predetermined time, amplifiers AL1 to AL5, AR1 to AR5 that amplify the outputs of the delay circuits DYL1 to DYL5, DYR1 to DYR5, respectively, with a predetermined amplification factor, and amplifiers AL1 to An adder ADL that adds (synthesizes) the outputs of AL5 to generate a combined signal PRL, and an adder ADR that adds (synthesizes) the outputs of the amplifiers AR1 to AR5 to generate a combined signal PRR. ing.

  Then, the combined signals PRL and PRR are supplied to the headphone terminal JR via the wiring in the vehicle interior, and when the passenger on the right rear seat connects the headphones or the earphone to the headphone terminal JR, the combined signals PRL and PRR are combined. The signals PRL and PRR are supplied to the headphones and earphones via the headphone terminal JR, and the reproduced sound based on the synthesized signal PRL is reproduced on the left ear of the passenger and the reproduced sound based on the synthesized signal PRR is reproduced on the right ear.

  In the present embodiment, open-air headphones or earphones that do not seal the passenger's ears are used.

  Further, the filters FTL1 to FTL5 and FTR1 to FTR5 are formed of variable filters that variably adjust the frequency characteristics of the audio signals L, C, R, LS, and RS in accordance with the control signal CNTA supplied from the control unit 4. The delay circuits DYL1 to DYL5, DYR1 to DYR5 are also formed by variable delay circuits that individually adjust the delay time in accordance with the control signal CNTA supplied from the control unit 4, and the amplifiers AL1 to AL5 and AR1 to AR5 are also controlled by the control unit. 4 is formed by a variable gain amplifier that individually variably adjusts the amplification factor in accordance with the control signal CNTA supplied from 4.

  Similarly to the above-described phon signal processing circuit 5A, the phon signal processing circuit 5B includes an adder, a variable filter that is variably adjusted according to the control signal CNTB supplied from the control unit 4, a variable delay circuit, and a variable gain amplifier. The audio signals L, C, R, LS, and RS are input, and the frequency characteristic adjustment process, the delay process, and the amplification process are performed, and an addition (synthesis) process is performed to supply to the headphone terminal JL. When the passenger on the left rear seat generates a composite signal PLL, PLR that connects to the headphone terminal JL by connecting an open-air type headphone or earphone, the composite signal PLL, PLR is output from the headphone terminal JL. Is supplied to the headphones and earphones, and the reproduced sound based on the synthesized signal PLL is reproduced on the left ear of the passenger, and the reproduced sound based on the synthesized signal PLR is reproduced on the right ear. The

The operation unit 3 and the control unit 4 are configured as shown in FIG.
The operation unit 3 is provided with changeover switches 3a and 3c for switching between manual operation and automatic operation, and touch panel type operation switches 3b and 3d. When the change-over switch 3a is turned on by the passenger, the switch signal SELA of logic “1, 0” is supplied to the control signal generation unit 4a to manually operate the phone signal processing circuit 5A, and the change-over switch 3a is turned off. Then, the switching signal SELA that becomes logic “0, 1” is supplied to the control signal generation unit 4a to automatically operate the phone signal processing circuit 5A. When the changeover switch 3c is turned on by the passenger, the changeover signal SELB of logic “1, 0” is supplied to the control signal generation unit 4a to manually operate the phone signal processing circuit 5B. When the turning-off operation is performed, the switching signal SELB that becomes the logic “0, 1” is supplied to the control signal generation unit 4a to automatically operate the phone signal processing circuit 5B.

  The operation switch 3b is used to individually adjust the variable filters FTL1 to FTL5, FTR1 to FTR5, the variable delay circuits DYL1 to DYL5, DYR1 to DYR5, and the variable gain amplifiers AL1 to AL5 and AR1 to AR5 of the phone signal processing circuit 5A. When the changeover switch 3a is switched to manual operation, the input information EQA that is operated by the passenger is supplied to the control signal generator 4a.

  The operation switch 3d is also provided to individually adjust the variable filter, variable delay circuit, and variable gain amplifier provided in the phone signal processing circuit 5B. When the changeover switch 3c is switched to manual operation, The switch-operated input information EQB is supplied to the control signal generator 4a.

  The control unit 4 includes the control signal generation unit 4a and the control data storage unit 4b described above.

  When the control data storage unit 4b is switched to automatic operation by the changeover switch 3a, the filter characteristics of the variable filters FTL1 to FTL5 and FTR1 to FTR5 provided in the phone signal processing circuit 5A and the variable delay circuits DYL1 to DYL5, Control data DA for adjusting the delay times of DYR1 to DYR5 and the amplification factors of variable gain amplifiers AL1 to AL5 and AR1 to AR5, and when switched to automatic operation by the changeover switch 3c, are provided in the phone signal processing circuit 5B. Each filter characteristic of the variable filter, each delay time of the variable delay circuit, and control data DB for adjusting each gain of the variable gain amplifier are stored in advance. The details of the control data DA and DB will be described later together with the description of the operation.

  When the control signal generating unit 4a is switched to automatic operation by the changeover switch 3a, the control data DA is read from the control data storage unit 4b, supplied to the phone signal processing circuit 5A as the control signal CNTA, and the variable filters FTL1 to FTL5, The filter characteristics of FTR1 to FTR5, the delay times of variable delay circuits DYL1 to DYL5, DYR1 to DYR5, and the gains of variable gain amplifiers AL1 to AL5 and AR1 to AR5 are automatically adjusted.

  When the control signal generator 4a is switched to the manual operation by the changeover switch 3a, the control signal DA is edited by the input information EQA from the operation switch 3b, and the edited data is converted into the control signal CNTA. And adjust the filter characteristics of the variable filters FTL1 to FTL5, FTR1 to FTR5, the delay times of the variable delay circuits DYL1 to DYL5, DYR1 to DYR5, and the gains of the variable gain amplifiers AL1 to AL5 and AR1 to AR5 To do.

  When the control signal generator 4a is switched to automatic operation by the changeover switch 3c, the control signal DB is read from the control data storage unit 4b and supplied as the control signal CNTB to the phone signal processing circuit 5B. Each filter characteristic of the variable filter provided in 5B, each delay time of the variable delay circuit, and each gain of the variable gain amplifier are automatically adjusted.

  When the control signal generator 4a is switched to the manual operation by the changeover switch 3c, the control data DB is edited by the input information EQB from the operation switch 3d, and the edited data is converted into the control signal CNTB to be the phone signal processing circuit 5B. To adjust the filter characteristics of the variable filter provided in the phone signal processing circuit 5B, the delay times of the variable delay circuit, and the amplification factors of the variable gain amplifier.

Next, the operation of the in-vehicle audio playback system of this embodiment will be described. The 5.1-channel multi-channel surround audio signals L, C, R, LS, RS, and LFE are output from the signal source 1, and the multi-channel surround sound is output from each vehicle-mounted speaker FL, SC, FR, RL, RR, and SW. Is played. The operation will be described for each operation mode of the passenger.
(Operation 1)
With the changeover switch 3a switched to automatic operation, a passenger on the right rear seat shown in FIG. 1 (b) attaches an open-air headphone or earphone connected to the headphone terminal JR. In this case, a variable provided in the phone signal processing circuit 5A shown in FIG. 2 by the control signal CNTA generated based on the control data DA read from the control data storage unit 4b by the control signal generator 4a shown in FIG. The filter characteristics of the filters FTL1 to FTL5, FTR1 to FTR5, the delay times of the variable delay circuits DYL1 to DYL5, DYR1 to DYR5, and the gains of the variable gain amplifiers AL1 to AL5, AR1 to AR5 are automatically adjusted and added. The combined signals PRL and PRR are generated by the devices ADL and ADR.

  Here, the above-mentioned control data DA is obtained by the speakers FL, SC, FR, RL, RR, SW on both ears of the passenger on the right rear seat wearing the open-air type headphones and earphones. Data that realizes sound image localization without any sense of incongruity and allows clear sound to be heard when the reproduced multi-channel surround sound and the reproduced sound reproduced by the above headphones or earphones based on the synthesized signals PRL and PRR are input. It has become.

  Specifically, the control data DA is determined in consideration of the time for the multi-channel surround sound reproduced by each speaker FL, SC, FR, RL, RR, SW to reach both ears of the passenger, Adjustment data for adjusting the delay times of the variable delay circuits DYL1 to DYL5 and DYR1 to DYR5 is included.

  Furthermore, the variable filters FTL3, FTL4, FTL5, FTR3, FTR4, and FTR5 are determined to complement the frequency characteristics of the multi-channel surround sound that is attenuated by wearing an open air type headphone or earphone. Adjustment data for adjustment to a high-pass variable filter having a cut frequency (for example, 2 kHz) is included.

  Further, the sound arriving from the distant front speaker FL and the center speaker SC is determined considering that it is difficult to hear as clear sound, and the variable filters FTL1, FTL2, FTR1, and FTR2 are passed through a predetermined pass band. Adjustment data for adjustment to a bandpass variable filter (for example, 300 Hz to 2 kHz) is included.

  Further, the gains of the variable gain amplifiers AL1, AL2, AR1, and AR2 are adjusted to be band pass filters by making the amplification factors larger than those of the other variable gain amplifiers AL3, AL4, AL5, AR3, AR4, and AR5. Adjustment data for making the level of the audio signal that has passed through the filters FTL1, FTL2, FTR1, and FTR2 greater than the level of the audio signal that has passed through the other variable filters FTL3, FTL4, FTL5, FTR3, FTLR, and FTR5 is included. Yes.

Then, control data DA including these adjustment data is supplied as a control signal CNTA to the phone signal processing circuit 5A, and each filter characteristic of each of the variable filters FTL1 to FTL5, FTR1 to FTR5, and variable delay circuits DYL1 to DYL5, DYR1 to Multi-channel surround reproduced by each in-vehicle speaker FL, SC, FR, RL, RR, SW by automatically adjusting each delay time of DYR5 and each gain of variable gain amplifiers AL1-AL5, AR1-AR5 When the passenger listens to the sound and the reproduced sound reproduced by the open-air type headphones or earphones, a sound image localization without discomfort is realized, and a clear and realistic multi-channel surround sound can be heard.
(Operation 2)
With the changeover switch 3a switched to manual operation, a passenger on the right rear seat shown in FIG. 1 (b) attaches an open-air headphone or earphone connected to the headphone terminal JR. When the operation switch 3b is appropriately adjusted, the control signal generator 4a shown in FIG. 3 edits the control data DA based on the input information EQA, and uses the edited data as the control signal CNTA to perform the phone signal processing. Supplied to the circuit 5A, the variable filter characteristics of the variable filters FTL1 to FTL5, FTR1 to FTR5, the delay times of the variable delay circuits DYL1 to DYL5, DYR1 to DYR5, and the gains of the gain variable amplifiers AL1 to AL5 and AR1 to AR5 And adjust.

As a result, the passenger adjusts the frequency characteristics, delay time, and level of the reproduced sound reproduced by the open-air type headphones and earphones, and adjusts the reproduced sound and each speaker FL, SC, FR, RL, RR, It is possible to easily listen to the multi-channel surround sound reproduced by the SW according to the preference. For example, by appropriately adjusting the frequency characteristics, delay time, and level of the playback sound described above, playback sound played back by headphones or earphones and multi-playback played by each speaker FL, SC, FR, RL, RR, SW It is possible to suppress the sound image localization deviation from the channel surround sound, and to adjust to a desired multi-channel surround sound field without a sense of incongruity.
(Operation 3)
With the changeover switch 3c switched to automatic operation, a passenger on the left rear seat shown in FIG. 1 (b) attaches an open-air headphone or earphone connected to the headphone terminal JL. In this case, a variable provided in the phone signal processing circuit 5B shown in FIG. 2 by the control signal CNTB generated based on the control data DB read from the control data storage unit 4b by the control signal generator 4a shown in FIG. Each filter characteristic of the filter, each delay time of the variable delay circuit, and each gain of the variable gain amplifier are automatically adjusted to generate combined signals PLL and PLR.

  Here, in the same way as the control data DA described above, the control data DB is also mounted on the in-vehicle speakers FL, SC, FR on both ears of the passenger on the left rear seat wearing the open-air headphones and earphones. , RL, RR, SW and multi-channel surround sound, and the above-mentioned reproduced sound reproduced by the headphones or earphones, the data that realizes sound image localization without any sense of incongruity and allows a clear sound to be heard, It has become.

  Specifically, the control data DB is determined in consideration of the time required for the multi-channel surround sound reproduced by the in-vehicle speakers FL, SC, FR, RL, RR, SW to reach both ears of the passenger, The adjustment data for adjusting the delay time of the variable delay circuit provided in the phone signal processing circuit 5B and the frequency characteristics of the multi-channel surround sound attenuated by wearing an open air type headphone or earphone are further complemented. Adjustment data for adjusting a predetermined variable filter provided in the phone signal processing circuit 5B to a high-pass variable filter with a predetermined low-frequency cut frequency (for example, 2 kHz), and a front speaker FR located far away Considering that the sound that arrives from the center speaker SC is difficult to hear as a clear sound Adjustment data for adjusting the other variable filter provided in the phone signal processing circuit 5B to a band pass variable filter of a predetermined pass band (for example, 300 Hz to 2 kHz), and further provided in the phone signal processing circuit 5B. Adjustment data for increasing the level of the audio signal that has passed through the variable filter adjusted to the band pass variable filter by increasing the amplification factor of the predetermined variable gain amplifier.

Then, control data DB including these adjustment data is supplied as a control signal CNTB to the phone signal processing circuit 5B, and each filter characteristic of each variable filter, each delay time of the variable delay circuit, and each gain of the variable gain amplifier. When the passenger listens to the multi-channel surround sound that is played by the in-vehicle speakers FL, SC, FR, RL, RR, and SW and the playback sound that is played by open-air headphones or earphones Therefore, it is possible to listen to a multi-channel surround sound in which sound image localization without a sense of incongruity is realized and a clear and realistic feeling can be obtained.
(Operation 4)
With the changeover switch 3c switched to manual operation, a passenger on the left rear seat shown in FIG. 1 (b) attaches an open-air type headphone or earphone connected to the headphone terminal JL. When the operation switch 3d is appropriately adjusted, the control signal generator 4a shown in FIG. 3 edits the control data DB based on the input information EQB, and uses the edited data as the control signal CNTB to perform the phone signal processing. This is supplied to the circuit 5B, and each filter characteristic of the variable filter, each delay time of the variable delay circuit, and each gain of the variable gain amplifier are adjusted.

  As a result, the passenger adjusts the frequency characteristics, delay time, and level of the reproduced sound reproduced by the open-air headphones and earphones, thereby adjusting the reproduced sound and the in-vehicle speakers FL, SC, FR, RL, It is possible to easily listen to the multi-channel surround sound reproduced by RR and SW according to preference. For example, by appropriately adjusting the frequency characteristics, delay time, and level of the playback sound described above, playback sound played back by headphones or earphones and multi-playback played by in-vehicle speakers FL, SC, FR, RL, RR, SW It is possible to suppress the sound image localization deviation from the channel surround sound, and to adjust to a desired multi-channel surround sound field without a sense of incongruity.

  As described above, according to the in-vehicle audio playback system of the present embodiment, when a passenger on the back seat wears an open-air type headphone or earphone, the playback sound played back by the headphone or earphone is reduced. Sound image localization without any sense of incongruity is realized by the multi-channel surround sound reproduced by the in-vehicle speakers FL, SC, FR, RL, RR, and SW, and a clear and realistic multi-channel surround sound can be heard. .

  That is, the phone signal processing circuits 5A and 5B perform the above-described predetermined signal processing (frequency characteristic adjustment processing, delay processing, amplification) on the audio signals L, C, R, RL, and RR output from the signal source 1. Process) to adjust the sound image localization and clarity of the reproduced sound reproduced by the open air type headphones and earphones, and the reproduced sound reproduced by the open air type headphones and earphones and the in-vehicle speaker FL, Since the multi-channel surround sound reproduced by SC, FR, RL, RR, and SW is listened to by the passenger on the rear seat, the reproduced sound reproduced by the open-air headphones and earphones and the vehicle-mounted speaker Sound image localization with multi-channel surround sound reproduced by FL, SC, FR, RL, RR, SW is improved, and it is realistic Multi-channel surround sound field can be provided, and even when it is difficult to hear the sound of the center speaker SC and the front speakers FL and FR located far away, playback that is played back with open-air headphones and earphones It can be supplemented with sound to provide a clear multi-channel surround sound field.

  Also, by using open-air headphones and earphones, you can listen to the voices of other passengers without causing the passengers to feel obstruction, while listening to multi-channel surround sound that provides a sense of realism. It is possible to talk.

  In addition, a passenger reproduces a widely used medium such as a CD or DVD recorded in 2-channel stereo, and a 2-channel stereo audio signal (that is, audio signals L and R) is output from the signal source 1. Even in this case, when an open-air type headphone or earphone is connected to the headphone terminal JL or LR, the two-channel stereo sound reproduced by the headphone or earphone is combined with the two-channel stereo sound reproduced by the in-vehicle speaker. I can listen. For this reason, the in-vehicle audio playback system of the present embodiment has versatility capable of performing not only multi-channel surround playback but also widely used stereo playback.

  In the present embodiment described above, open-air headphones and earphones are used in combination, but as a modification, sounds are directed toward the left and right ears of passengers riding on the right rear seat. Two speakers having directivity to be emitted are provided, and the synthesized signals PRL and PRR generated by the phone signal processing circuit 5A are emitted toward the left and right ears of the passengers who ride on the right rear seat. The audio may be supplied to each speaker to be played back. In addition, two speakers having directivity for emitting sound toward the left and right ears of the passenger on the left rear seat are provided, and the synthesized signals PLL and PLR generated by the phone signal processing circuit 5B are described above. The audio may be reproduced by supplying to each speaker that emits sound toward the left and right ears of the occupant on the left rear seat.

  According to such a modification, the passenger who rides in the rear seat can listen to the reproduction sound similar to the case where the open air type headphones or earphones are worn from each speaker having the above directivity. Listening to multi-channel surround sound with a sense of realism in combination with multi-channel surround sound played on in-vehicle speakers FL, SC, FR, RL, RR, SW without wearing headphones or earphones it can. In addition, since the reproduced sound emitted from the directional speaker can be heard only by the passenger to whom the speaker is directed, there is an effect that it does not adversely affect other passengers. It is done.

  The operation unit 3, the control unit 4, and the phone signal processing circuits 5A and 5B described above may be realized by a hardware configuration using a digital circuit or an analog circuit, or the operation unit 3, the control unit 4, and the phone described above. A computer program that exhibits the functions of the signal processing circuits 5A and 5B may be created, and the computer program may be executed by a digital signal processor (DSP) or a microprocessor (MPU).

It is a block diagram showing the structure of the conventional vehicle-mounted audio reproduction system. It is a block diagram showing the structure of the vehicle-mounted audio reproduction system of this embodiment. FIG. 4 is a block diagram illustrating configurations of an operation unit and a control unit illustrated in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sound source FL, SC, FR, RL, RR, SW ... Car-mounted speaker 5A, 5B ... Phone signal processing circuit FTL1-FTL5, FTR1-FTR5 ... Variable filter DYL1-DYL5, DYR1-DYR5 ... Variable delay circuit AL1-AL5, AR1 to AR5 ... Variable gain amplifier

Claims (5)

A plurality of channels of audio signals output from the signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in the passenger compartment to reproduce the audio, and to headphones or earphones worn by passengers riding in the rear seat An in-vehicle audio reproduction system for reproducing audio based on the audio signals of the plurality of channels,
By adjusting the frequency characteristics and adjusting the delay time and amplification factor for the audio signals of the plurality of channels, synthesizing the adjusted audio signals to generate a synthesized signal, and supplying it to the headphones or earphones, Phone signal processing means for audio reproduction of the synthesized signal,
The headphone or earphone is an open air type headphone or earphone,
Combining the reproduced sound reproduced by audio with the headphones or earphones and the sound reproduced by audio with the plurality of in-vehicle speakers, to be heard by the passenger.
An in-vehicle audio playback system characterized by The audio signals of a plurality of channels output from the signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in the passenger compartment to reproduce the audio, and sound is emitted toward the passengers who ride on the rear seat. An in-vehicle audio playback system for reproducing audio based on the audio signals of the plurality of channels on a speaker having directivity,
The frequency characteristics are adjusted, the delay time and the amplification factor are adjusted for the audio signals of the plurality of channels, the synthesized audio signals are synthesized to generate a synthesized signal, and the synthesized signal is supplied to the directional speaker. And a phone signal processing means for reproducing the synthesized signal as audio,
Combining the reproduced sound reproduced by the speaker having the directivity and the sound reproduced by the plurality of in-vehicle speakers together with the passenger,
An in-vehicle audio playback system characterized by The phone signal processing means includes:
Variable filter means for adjusting frequency characteristics of the audio signals of the plurality of channels;
Variable delay means for performing the delay processing on the output of the filter means;
Variable gain amplification means for adjusting the amplification factor with respect to the output of the delay means;
Adding means for generating the combined signal by adding the outputs of the variable gain amplifying means;
The in-vehicle audio reproduction system according to claim 1 or 2, characterized by the above-mentioned. A plurality of channels of audio signals output from the signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in the passenger compartment to reproduce the audio, and to headphones or earphones worn by passengers riding in the rear seat An audio playback method for playing back audio based on the audio signals of the plurality of channels,
By adjusting the frequency characteristics and adjusting the delay time and amplification factor for the audio signals of the plurality of channels, synthesizing the adjusted audio signals to generate a synthesized signal, and supplying it to the headphones or earphones, A phone signal processing step for reproducing the synthesized signal as audio;
The headphone or earphone is an open air type headphone or earphone,
Combining the reproduced sound reproduced by audio with the headphones or earphones and the sound reproduced by audio with the plurality of in-vehicle speakers, to be heard by the passenger.
An audio playback method characterized by the above. The audio signals of a plurality of channels output from the signal source are supplied to a plurality of in-vehicle speakers provided at predetermined positions in the passenger compartment to reproduce the audio, and sound is emitted toward the passengers who ride on the rear seat. An audio reproduction method for causing a speaker having directivity to reproduce audio based on the audio signals of the plurality of channels,
The frequency characteristics are adjusted, the delay time and the amplification factor are adjusted for the audio signals of the plurality of channels, the synthesized audio signals are synthesized to generate a synthesized signal, and the synthesized signal is supplied to the directional speaker. And comprising a phone signal processing step for audio reproduction of the synthesized signal,
Combining the reproduced sound reproduced by the speaker having the directivity and the sound reproduced by the plurality of in-vehicle speakers together with the passenger,
An audio playback method characterized by the above.

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