JPH07162998A - On-vehicle acoustic device - Google Patents

Abstract

PURPOSE:To provice the on-vehicle acoustic device capable of taking the optimal frequency balance even when a listening position is changed by correcting the sound pressure frequency characteristic at each listening position. CONSTITUTION:The high area of the acoustic signal is corrected by equalizer circuits EQ11-14 so that the high area is increased according to the frequency characteristic of the speaker as the voice pressure frequency characteristic from speakers SP1-SP4 at the selected listening position is to make flat, that is, the angle which crosses at right angles with the straight line connecting the speaker and the listening position becomes large. Further, the level of each acoustic signal is corrected by acoustic adjustment circuits VR11-14 so that the sound pressure level from each speaker becomes the same at the selected listening position. Thus, the deviation of the sound field due to the asymetric stereo listening at each listening position in a car and the deterioration of the sound image localization are prevented and the optimal frequency balance in the required listening position in the car can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted acoustic device mounted on an automobile.

[0002]

2. Description of the Related Art In a typical prior art, speakers are arranged on the left and right sides in a passenger compartment of an automobile,
At each listening position such as the passenger seat and rear seat, a level variable function is provided so that the volume of each speaker can be adjusted, and a sound signal delay function for changing and adjusting the phase of the sound is provided. There is known an acoustic device having a so-called position selector function that appropriately sets the volume and the delay time for each listening position.

[0003]

In such a prior art, the angle formed by the axis of the speaker and the straight line connecting the speaker and the listening position is different for each listening position. Therefore, depending on the directivity of the speaker, There is a problem in that the sound pressure frequency characteristics change at each listening position, and the sound pressure level in the high frequency range decreases when the angle is large.
Nevertheless, in the prior art, such a sound pressure frequency characteristic is not corrected for each listening position, resulting in a biased sound field and a deteriorated sound image localization.

The object of the present invention is to improve the listening position even if the listening position changes.
An object of the present invention is to provide a vehicle-mounted acoustic device that can always obtain an optimum frequency balance.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a speaker disposed on each of the left and right sides of a plurality of listening positions in a passenger compartment of an automobile, an acoustic source for generating a left and right acoustic signal and giving it to each speaker. A delay circuit that delays the acoustic signal given to the closer speaker based on the speaker farther from the listening position so that the sound phases match at the listening position, and the sound from each speaker at each listening position. An equalizer circuit that corrects the high frequency range of the acoustic signal so that the pressure-frequency characteristics become flat, and a volume adjustment circuit that corrects the level of the acoustic signal so that the sound pressure level from each speaker becomes the same at each listening position. It is a vehicle-mounted acoustic device including:

[0006]

According to the present invention, the speakers are arranged on the left and right sides in the passenger compartment of the automobile, and the left and right speakers are respectively provided with acoustic signals from the acoustic source to enable stereo listening. Among a plurality of listening positions, for example, a driver's seat, a passenger seat, left and right rear seats, etc., one selected listening position, for example, a driver's seat, (a) sound from each of the left and right speakers is In order for the left and right ears of the speaker to be in phase with each other, the acoustic signal provided to the speaker closer to the listening position is delayed by the delay circuit with reference to the speaker farther from the listening position, and (b) is also selected. At each listening position, the sound pressure frequency characteristics from each speaker become flat, that is, the larger the angle between the speaker axis and the straight line connecting the speaker and the listening position, the greater the frequency characteristics of that speaker. Then, the high frequency range of the acoustic signal is corrected by the equalizer circuit so as to enhance the high frequency range, and (c) each acoustic signal is adjusted so that the sound pressure level from each speaker becomes the same at the selected listening position. The level of is corrected by the volume control circuit. In this way, the bias of the sound field and the deterioration of the sound image localization due to the asymmetric stereo listening at each listening position in the vehicle interior can be prevented, and the optimum frequency balance can be obtained at each desired listening position in the vehicle interior.

[0007]

FIG. 1 is an electric circuit diagram of an embodiment of the present invention. The sound source 1 may be, for example, a radio receiver, a reproducing device for a recording medium such as a magnetic tape cassette and a compact disc, and the like, and the front left speaker SP1 provided in the passenger compartment 3 of the automobile 2 shown in FIG. , Acoustic signals FL, FR, RL, and RR for the front right speaker SP2, the rear left speaker SP3, and the rear right speaker SP4,
It derives from each of the lines 4 to 7.

In FIG. 2, a driver's seat 8, a passenger seat 9 and a rear seat 10 are provided in a passenger compartment 3, and a position for stereo listening is set in each of these seats 8, 9 and 10.

Each of the acoustic signals from the acoustic source 1 has a line 4 ...
7 through the input changeover switches Si1 to Si4, the driver mode electric circuit 11, the front mode electric circuit 12, the rear mode electric circuit 13, and the family mode electric circuit 14, and then the output changeover switch So.
1 to So4, and are given from the amplifier circuits A1 to A4 to the speakers SP1 to SP4, respectively. Input changeover switches Si1 to Si4 and output changeover switches So1 to S
It is switched in conjunction with o4. The driver mode electric circuit 11 functions to correct and adjust the acoustic signal so that an optimal sound field for the driver in the driver's seat 8 is reproduced.
The front mode electric circuit 12 is for forming an optimum sound field in the passenger seat 9, and the rear mode electric circuit 13 is for forming an optimum sound field in the rear left or right seat 10. The electric circuit 14 for the family mode is provided for each of the plurality of seats 8, 9, 1 in the passenger compartment 3.
When it is 0, it functions to correct and adjust the acoustic signal so as to form the optimum sound field as much as possible.

FIG. 3 is a schematic plan view of the vehicle interior 3 shown in FIG. Driver 1 sitting in driver's seat 8
In order to achieve the driver mode for forming the optimum sound field for the speaker 5, when the same acoustic signal is given to all the speakers SP1 to SP4, the left ear of the driver 15 is reached from the left speakers SP1 and SP3. The phases of the sounds are the same, and the phases of the sounds reaching the right ear of the driver 15 from the right speakers SP2 and SP4 are the same, and the phases of the sounds given to the left and right ears are all the same. Sound signals given to the speakers SP1 to SP4 as shown in FIG.
The delay circuits DL11 to DL14 provided in the driver mode electric circuit 11 of FIG. When setting the delay time, among the speakers SP1 to SP4,
Of the distances L1 to L4 from the ears of the driver 15 at the listening position, the acoustic signal given to the farthest speaker SP3 is used as a reference, the delay time of the acoustic signal given to this speaker SP3 is set to zero, and the distance is As the driver 15 is approached, the delay time is set larger. Each delay circuit DL
The delay times of 11 to DL14 are as shown in Table 1.

[0011]

[Table 1]

Here, L3>L1>L4> L2 (1) Regarding the sound pressure frequency characteristics of the speakers SP1 to SP4,
The axes 17 to 20 of the respective speakers SP1 to SP4 and the driver 1 at the listening position correspond to the respective speakers SP1 to SP4.
The sound pressure at the listening position changes according to the directivity of the speakers SP1 to SP4 according to the angles θ1 to θ4 formed by the straight line connecting the left and right ears of the speaker 5. The speakers SP1 to SP4 are
For example, they have the same configuration and have the sound pressure frequency characteristics shown in FIG.

Regarding the speaker SP1, the line 21 shows the characteristic on the axis line 17 of the speaker SP1. The speaker SP1 is preconfigured to enhance the high frequency range so that the sound pressure frequency characteristic is as flat as possible at a position displaced from the axis line 17. Line 22 is speaker S
The characteristic when the angle θ1 deviated from the axis 17 of P1 is 30 ° is shown, and it is understood that the sound pressure in the high frequency range is reduced. When the angle θ1 reaches 60 °, the line 23
Is obtained and the sound pressure in the high frequency range is greatly reduced. When the speaker SP1 shown in FIG. 4 is used, the equalizer circuit EQ11 is provided to the driver 15 at the listening position in order to correct the high frequency range of the acoustic signal so that the sound pressure frequency characteristic becomes flat. It is provided. This equalizer circuit EQ1
1 serves to enhance the high frequency range so that the acoustic signal applied to the speaker SP1 has a substantially flat sound pressure in the high frequency range of, for example, 1.5 kHz or more. Similarly, the equalizer circuits EQ12 to EQ14 respectively corresponding to the speakers SP2 to SP4 also function to correct the high frequency range corresponding to the angles θ2 to θ4. The high-frequency enhancement levels of these equalizer circuits EQ11 to EQ14 are shown in Table 1 above.
, And each equalizer circuit EQ11
The characteristics of EQ14 are shown by lines 24-27 shown in FIG.
In this case, the angles θ1 to θ4 are as shown in Expression 2.

Θ4>θ3>θ2> θ1 (2) In order for the driver 15 to correct the level of the acoustic signal so that the sound pressure levels from the speakers SP1 to SP4 are the same, the variable resistors VR11 to VR14 are used. Are provided respectively, and the attenuation amount is, as shown in Table 1,
It is set to increase as L4 decreases.

These variable resistors VR11 to VR14, delay circuits DL11 to DL14 and equalizer circuit EQ1.
1 to EQ 14 are connected in series or connected in series for each of the speakers SP1 to SP4, and are preset so that an optimal sound field for the driver 15 is formed. Residual electric circuit 12
-14 also have the same configuration, and the delay time,
The high frequency correction characteristic and the volume correction amount are preset according to each listening position. Equalizer circuits EQ11 to EQ14
Can also be used together to correct an undesired characteristic portion of the sound propagation characteristic of the passenger compartment 3.

FIG. 6 is an electric circuit diagram of another embodiment of the present invention. In this embodiment, left and right acoustic signals are given from the acoustic source 1 to the digital acoustic processing circuit 29 via the lines 4 and 5, and the processing circuit 29 causes the speakers SP1 to SP1 to operate.
It is given to the amplifier circuits A1 to A4 for SP4, respectively. Using the input means 30, one of the driver mode, the front mode, the rear mode, and the family mode is selected, and the processing circuit 31 realized by the microcomputer or the like by this is stored in the memory 32 in advance. The delay time, the high-frequency correction characteristic, and the volume correction amount for each mode are read out and given to the processing circuit 29, and the acoustic signal is calculated so that the optimum sound field is formed at the listening position in each mode thus selected. Done.

[0017]

As described above, according to the present invention, the speakers are arranged on both the left and right sides in the vehicle compartment, and the left and right acoustic signals are applied to the respective speakers from the acoustic sources. The level is delayed and its level is corrected by the volume adjusting circuit. Especially, in the present invention, the sound pressure frequency characteristics from each speaker become flat at each selected listening position, that is, the axis of the speaker is aligned with the speaker. The larger the angle formed with the straight line connecting the listening position, the lower the high frequency range according to the frequency characteristics of the speaker.Therefore, the high frequency range of the acoustic signal is enhanced and corrected by the equalizer circuit. , It is possible to correct the frequency characteristic, especially the high frequency characteristic difference due to the difference in the directivity of the speaker coming from the speaker to the listener at each listening position. Therefore, it is possible to obtain the optimum frequency balance, and it is also possible to correct the difference in the propagation characteristics of the sound due to the shape of the passenger compartment, which results in the bias of the sound field and the deterioration of the sound image localization due to the asymmetric stereo listening. Will be able to prevent.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an embodiment of the present invention.

FIG. 2 is a plan view showing a passenger compartment 3 of an automobile in a simplified manner.

FIG. 3 is a simplified plan view for explaining a configuration for enabling a driver 15 of a driver's seat 8 in the vehicle interior 3 to obtain an optimum sound field.

FIG. 4 is a graph showing sound pressure frequency characteristics of speakers SP1 to SP4.

FIG. 5 is a diagram illustrating characteristics of equalizer circuits EQ11 to EQ14.

FIG. 6 is an electric circuit diagram of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 audio signal source 2 automobile 3 vehicle interior 8 driver's seat 9 passenger seat 10 rear seat 11 electric circuit for driver mode 12 electric circuit for front mode 13 electric circuit for rear mode 14 electric circuit for family mode 29 digital sound processing circuit 30 input means 31 processing circuit 32 memory Si1 to Si4 input changeover switch So1 to So4 output changeover switch A1 to A4 amplifier circuit SP1 to SP4 speaker VR11 to VR14 variable resistance DL11 to DL14 delay circuit EQ11 to EQ14 equalizer circuit

Claims (1)

[Claims] 1. A speaker disposed on each of left and right sides of a plurality of listening positions in a vehicle compartment of a vehicle, an acoustic source that generates left and right acoustic signals and gives each speaker, and a phase of sound at each listening position. To ensure that they match, a delay circuit that delays the acoustic signal given to the speaker closer to the speaker farther from the listening position, and the sound pressure frequency characteristics from each speaker are flat at each listening position. In addition, an equalizer circuit that corrects the high frequency range of the acoustic signal and a volume control circuit that corrects the level of the acoustic signal so that the sound pressure level from each speaker becomes the same at each listening position. Car audio system.