JPH0479520B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vehicle audio system that allows each occupant to listen to different programs individually in a vehicle interior.

BACKGROUND TECHNOLOGY Conventional vehicle audio systems include individual listening systems in which headphones are installed for each passenger so that each passenger can listen to different programs;
A system in which a speaker for each passenger is attached to the headrest of each seat ("CAR GRAPHIC," March issue, published by Nigensha Co., Ltd., March 1, 1980, p. 316) is in practical use.

Problems to be Solved by the Invention However, in the case of devices using the above-mentioned headphones, an unpleasant pressure sensation occurs when the headphones are worn, and the area around the ears is sealed and external sounds are insulated, so during driving operations. Drivers who are required to hear external sounds have the disadvantage of not being able to use it. On the other hand, in the case of a device in which speakers are arranged in the headrest, the above-mentioned disadvantage can be overcome, but on the other hand, the sound emitted from each speaker may be heard as leakage sound by other passengers other than the passenger concerned. Therefore, the device could not be used as a reproduction means for an individual listening system.

The present invention has been made in view of the conventional situation and focusing on the fact that the degree of influence of leakage noise on other occupants differs depending on the frequency. To provide a vehicle audio system that enables individual listening using speakers without being affected by leakage sound by attenuating and reproducing high-frequency sounds that have a strong influence on other occupants.

Means for Solving the Problems In order to solve the above problems, the present invention provides a plurality of sound sources that output different sound signals, and a plurality of sound sources that output different sound signals, and a plurality of output circuits of the sound sources that are provided corresponding to the occupants. a source selection device that can be selectively linked; a high-frequency attenuation device that attenuates a predetermined high-frequency range of an acoustic signal inputted through the source selection device; a means for amplifying the attenuated acoustic signal; A dedicated speaker for each passenger is provided, which is placed close to the ear position of each passenger and reproduces an acoustic signal.

Effect: Therefore, when the occupant operates the selection device to select a desired sound source, the sound signal output from the sound source is input to the high-frequency attenuation device via the selection device. In the high-frequency range attenuation device, a predetermined high-frequency range of the acoustic signal is attenuated, and the attenuated acoustic signal is amplified and reproduced by a passenger-dedicated speaker. At this time, the reproduced sound is subjected to the above-mentioned attenuation process to attenuate the high frequency range that may interfere with the hearing of other occupants. Therefore, each passenger can listen to a different program under conditions where the influence of sound leakage from other speakers is extremely low.

Embodiments Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, in which a first cassette deck, a first tuner 2, a second cassette deck 3, and a second tuner 4 are provided as a plurality of sound sources. , 3. The output sides of the tuners 2, 4 are provided with changeover switches 5, 6, 7, 8 that operate in conjunction with each other. Each changeover switch 5, 6 provided on the first cassette deck 1 and first tuner 2 side has a fixed contact _9P connected to a pre-main amplifier 9.
9 _P and fixed contacts 10 P and 10 _P connected to the first output circuit 10 and the second output circuit ₁₁ are provided. Further, each of the changeover switches 5 and 6 on the second cassette deck 3 and second tuner 4 side has a third output circuit 12.
and fixed contacts 11 _P and 11 _P of the fourth output circuit 13 are provided. The output side of the integrated amplifier 9 is connected to the door 1 of the automobile 13 as shown in FIG.
Door speakers 16, 17 attached to 4, 15
and rear speakers 19 and 20 mounted on both sides of the rear parcel shelf 18. On the other hand, the first to fourth output circuits 10, 11, 12, 13
includes a selection switch 21a, which is a source selection device;
b, c, d are provided, and the selection switch
21a, b, c, d are the respective output circuits 10, 1
Fixed contacts P ₀ , P ₁ , connected to 1, 12, 13
P ₂ and P ₃ are provided. Each selection switch 21
Low-pass filters 22a, b, c, and d, which are high-frequency attenuation devices, are connected to the movable contacts a, b, c, and d.
c and d attenuate the high frequency range of 1 to 2KHz or more,
It has the characteristic of filtering frequency bands below this range. On the output side of each low-pass filter 22a, b, c, d, a headphone amplifier 23a, b, c, d, which is a means for amplifying the acoustic signal, is provided, and the output of the headphone amplifier 23a, b, c, d is Headrest speakers 24a, b, c, and d, which are speakers exclusively for each passenger, are provided on the sides.
The headrest speakers 24a, b, c, d are
It consists of speakers S _R and S _L for each left and right channel, and is embedded in the headrests 25 a, 26 a of the front seats 25, 25 and the rear seats 26, as shown in FIG. They are placed close to the left and right ear positions.

In this embodiment with the above configuration, when each passenger listens to a common program, the changeover switches 5 and 6 on the first cassette deck 1 and first tuner 2 side are turned on as shown by solid lines in FIG. Closed to the pre-main amplifier 9 side. As a result, the first cassette deck 1 and the first tuner 2 are connected to the pre-main amplifier 9. Therefore, the first
By turning on the switch of the cassette deck 1 or the first tuner 2, the door speakers 16, 1
7. Reproduced sound is emitted from the rear speakers 19 and 20, allowing all occupants to listen to the same program.

Next, when each crew member listens to a different program, the changeover switches 6, 7, 8, and 9 are linked to each output circuit 10, 11, 12, and 13 as shown by the dashed line in FIG. Close to. At this time, each cassette deck 1, 3 and tuner 2, 4 is set to play or receive a different program. Therefore, each output circuit 10, 11, 1
2 and 13 are supplied with audio signals of different programs from the corresponding cassette decks 1 and 3 and tuners 2 and 4. Therefore, each passenger selects and connects the selection switches 21a, b, c, and d to the fixed contacts P ₀ , P ₁ , P ₂ , and P ₃ according to his/her own wishes.

With this, each output circuit 10, 11, 12,
13, connected to the cassette deck 1,
3. Audio signals of different programs selected from tuners 2 and 4 are passed through low-pass filters 22a, b,
It is input to c and d. The low pass filter 22
a, b, c, d are headphone amplifiers 23a, b, c, d that attenuate the high frequency components of the acoustic signal.
input. Therefore, the headphone amplifier 2
3a, b, c, and d amplify the acoustic signal in which the high frequency range of 1 to 2 KHz is attenuated, and the headrest speaker 2
From 4a, b, c, and d, the reproduced sound with the high frequency range attenuated is radiated toward the ears of the occupant. Therefore, even if you hear the sound of another program being played from the seat next to you,
In other words, even if leakage sound occurs, the occupant will not be bothered by the leakage sound because, as described above, the high-pitched sound component that has a large impact on hearing and is harsh on the ears is attenuated. This allows you to listen to the music you want with full concentration. Note that the sound emitted from the headrest speaker has only the high frequency range attenuated.
Since the high frequency range is not completely eliminated, the sound does not feel strange to the passengers.

FIG. 3 shows a second embodiment of the present invention in which the volume of each headrest speaker 24a, b, c, d is automatically controlled according to the noise level. That is, between each headphone amplifier 23a, b, c, d and headrest speaker 24a, b, c, d,
Volume limiters 25a, b, c, and d are interposed, and these volume limiters 25a, b, c, and d limit the upper limit level of the acoustic signals amplified by the headphone amplifiers 23a, b, c, and d, so as to prevent sound leakage. It has a function to limit the setting level to a level where it is not a concern. The volume limiters 25a, b, c, and d include a noise detection circuit 27 that detects the noise level based on the input signal from the noise detection microphone 26 and controls the set level according to the noise level. It is connected. In this embodiment, the reproduction volume of the headrest speakers 24a, b, c, d is controlled by the volume limiters 25a, b, c, d to a level that does not cause any noticeable leakage sound. Then, when the ambient noise level increases, the setting level is changed to a large value corresponding to the noise level output from the noise detection circuit 27, taking masking due to noise into consideration. Therefore, while minimizing the influence of leaked sound on other occupants, the occupant can listen to individual programs at the optimum volume without being affected by noise.

FIG. 4 shows a third embodiment of the present invention, in which when each passenger selects the same sound source, the attenuation process in the high frequency range is avoided because there is no effect of leaked sound. It is. In other words, the circuits provided around each of the low-pass filters 22a, b, c, and d are normally open and
Relays 29a, b, c, and d are interposed, which are excited by the output of the AND gate 28 and closed.
Between the AND gate 28 and the power supply 29, there are connected a plurality of parallel circuits 30, 31, 32, 33 corresponding to the output circuits 10, 11, 12, 13, and each parallel circuit 30, 31, 32, 33. the selection switches 21a,
First to fourth driven switches 34a, b, c, and d are provided which are linked to the switches b, c, and d. Said first
The movable contact of the driven switch 34a is connected to the power source 29, and the movable contact of the driven switch 34a is connected to the power source 29.
b, c, and d are connected to the AND gate 28.

In this embodiment having the above configuration, if the selection switches 21a, b, c, and d select the same sound source as shown in the figure, the second to fourth driven switches 34b, c, and d select the same sound source, for example. parallel circuit 30
and the first driven switch is connected to the same parallel circuit 3.
0 to the power supply 29. Yotsute AND Gate 2
8 is turned on, and each relay 29a, b, c, d is excited and closed.

Therefore, the acoustic signal is passed through the low pass filter 22.
Bypassing a, b, c, d, headphone amplifier 2
3a, b, c, d (Fig. 1) and amplified. Therefore, the headrest speaker 24a,
From b, c, and d, natural reproduced sound without attenuation in the high range can be obtained. Note that if any of the occupants changes the selection of the sound source, the AND gate 28 will be turned OFF, and the high-frequency sound components will of course be attenuated by each of the low-pass filters 22a, b, c, and d. .

Further, the volume limiter 25 shown in the second embodiment
By using the microphones a, b, c, and d, the microphone 26, and the noise detection circuit 27 in the third embodiment, it is possible to further control the amount of attenuation according to the noise level.

Effects of the Invention As explained above, the present invention provides a plurality of sound sources, reproduces different sound signals from each sound source through a speaker dedicated to each sound source according to the passenger's selection, and reproduces a predetermined high frequency range of each sound signal. Processed attenuation. Therefore, it is possible to eliminate the disadvantages of an individual listening system using headphones, such as the feeling of oppression and the inability of the driver to use the system. In addition, regarding leakage sound that can interfere with the hearing of the occupants in the adjacent seat, the high-frequency range, which has the greatest impact, is attenuated, so the interference caused by leakage sound can be minimized, and it can be used as a reproduction means in an individual listening system. This makes it possible to use speakers.

In addition, in the second embodiment, since the volume is controlled to be below a predetermined level, the influence of leaked sound can be further reduced.
Moreover, since the volume level is controlled according to the noise level, the optimal volume that can withstand the noise can always be obtained. Furthermore, in the third embodiment, if all the occupants select the same sound source, the high frequency attenuation process is automatically avoided, so that the sound quality characteristics when listening to the same program can be improved. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing a first embodiment of the present invention, FIG. 2 is an explanatory diagram showing a speaker arrangement structure of the same embodiment, and FIG. 3 is a block circuit diagram showing a second embodiment of the present invention. Circuit Diagram FIG. 4 is a block circuit diagram showing a third embodiment of the present invention. 1, 3... Cassette deck (acoustic source), 2,
4... Chuyuna (acoustic source), 10, 11, 1
2, 13... Output circuit, 21a, b, c, d...
Selection switch (source selection device), 22a, b,
c, d...Low pass filter (high frequency attenuation device),
23a, b, c, d...Headphone amplifier (amplifying means), 24a, b, c, d...Headrest speaker (speaker dedicated to each passenger).

Claims (1)

[Claims] 1. A plurality of sound sources that output different sound signals, a source selection device that is provided corresponding to the passenger and can be selectively linked to each output circuit of the sound sources, and a sound signal that is input via the source selection device. a treble attenuation device that attenuates only a predetermined treble range of an acoustic signal; a means for amplifying the sound signal in which the treble range has been attenuated; A vehicle audio device characterized by comprising a speaker.