JP3207666B2 - In-car audio equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle acoustic device, and more particularly to a device for improving a sound field in a vehicle compartment.

[0002]

2. Description of the Related Art Some conventional on-vehicle acoustic devices have L-channel and R-channel loudspeakers mounted on a left door and a right door, respectively, or mounted on a rear tray. Also, in order to improve the sound field in the vehicle cabin, Japanese Patent Application No.
In the in-vehicle acoustic device proposed in 294679, a loudspeaker is attached to a headrest.

[0003] However, there has been no on-vehicle acoustic device in which a loudspeaker is mounted on a ceiling above each seat in a vehicle cabin. Also,
There is also a vehicle-mounted acoustic device that has a microphone installed in the vehicle interior and reproduces the sound collected by the microphone. In this case, the distance and positional relationship between the microphone and the loudspeaker differ depending on the type of vehicle and the mounting state, and are not constant.

[0004]

In the conventional on-vehicle acoustic device, a thin and lightweight loudspeaker has not been developed, and the L-channel and R-channel loudspeakers are attached to the housing as described above. Therefore, it is difficult to fix the distance between the L channel and the R channel loudspeakers in various types of vehicles.

In addition, when it is attached to a door, the influence of the reflected wave is particularly large above the middle sound range. For this reason, there has been a problem that correction of frequency characteristics and sound field control cannot be performed as intended.

In the case where a loudspeaker is attached to the headrest, the distance between the loudspeakers of the L channel and the R channel can be made substantially constant. However, as shown in FIG. Since the transmission path reflected by the antenna 16 and reaching the ear is present within 30 ° where the gain due to directivity is large in the radiation direction of the sound wave of the loudspeaker, there is a disadvantage that the reflected wave is so strong that it is difficult to control the sound field. Another problem is that since the loudspeaker is located behind the ear, it is very difficult to control the localization forward.

Further, when a microphone is provided to amplify the sound and conversation in the vehicle compartment or add reverberation and output from the loudspeaker to enhance the conversation in the vehicle compartment, the positional relationship between the microphone and the loudspeaker is improved. Is not pre-defined,
There was a problem that it was very difficult to take measures against howling.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to easily perform correction of frequency characteristics, control of a sound field, and control of localization in a forward direction. An object of the present invention is to provide a vehicle-mounted acoustic device.

Another object of the present invention is to make it easy to take measures against howling by keeping the positional relationship between the microphone and the loudspeaker constant in an on-vehicle acoustic device for improving the conversation in the cabin.

[0010]

In order to achieve the above object, the present invention provides an on-vehicle audio apparatus having a plurality of loudspeakers for reproducing L and R channels, respectively. The L-channel and R-channel loudspeakers for reproducing the low frequency are mounted on the ceiling in front of the upper part of each seat in the vehicle cabin, and the L-channel and the R-channel for low frequency reproduction A loudspeaker was attached to the left or right door or rear parcel. As described above, the housing of the loudspeaker is attached to the ceiling of the passenger compartment. By using a thin and light loudspeaker developed recently, the housing can be made thinner and practical.

Further, the microphone is also attached to the housing of the loudspeaker, so that the positional relationship between the microphone and the loudspeaker is fixed irrespective of the type of vehicle to which the microphone is applied.

[0012]

According to the vehicle audio system of the present invention, the L-channel and R-channel loudspeakers for reproducing the middle band and above are mounted in the same housing, so that the distance between them is constant regardless of the type of vehicle mounted. . The head is positioned so that the center line between the L-channel and the R-channel loudspeakers is bisected vertically and the center of the loudspeakers is located forward of the ear position. If you install
The arrangement is such that the influence of the reflection of the transmission system from the loudspeaker to the ear is extremely small, and the transfer function from the loudspeaker to the ear can be obtained only by defining the distance from the loudspeaker to the ear.

The transfer function can be measured in advance in an anechoic chamber, and the distance between the loudspeaker and the ear can be derived as a parameter. Therefore, sound field control can be performed based on the transfer function. In addition, since the loudspeaker is placed ahead of the ear, the same can be easily performed in front localization.

Further, by fixing the microphone to the same housing as the loudspeaker, the positional relationship between the microphone and the loudspeaker can be accurately determined. Further, as described above, a system that causes howling is uniquely determined because the influence of reflection is small and there is no obstacle between the microphone and the loudspeaker.

The radiation angle of the loudspeaker with respect to the microphone is 90 °, and the setting in the cabin is such that the sound from the loudspeaker is minimized to enter the microphone. It will be easier.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An on-vehicle acoustic device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view and a side view showing a configuration of an embodiment of the present invention. In the figure, reference numeral 1 denotes a housing mounted on the upper right side of the front seat, to which a microphone 1c and loudspeakers 1a and 1b are mounted.

Housings 2, 3 and 4 having the same configuration are mounted on the upper left portion of the front seat, the upper right portion of the rear seat and the upper left portion of the rear seat, respectively. The center position between the loudspeakers in each housing is set to be about 20 cm ahead of the position where the ears come in a normal sitting posture.

The loudspeakers 1a, 1b, 2a, 2b, 3a, 3b, 4a, and 4b attached to these housings have a subscript “b” side for each case and an Lch (channel) for each housing. Channel), and is set so as to reproduce a signal in the middle frequency range or higher (mainly 200 Hz or higher in this case). And the distance between the center of the loudspeaker with the subscript a and the loudspeaker with the subscript b is about 20 cm,
The microphones are set to be located 15 cm from the centers of the loudspeakers with the subscripts a and b, respectively.

Further, the loudspeakers 5a, 5b, 6a, 6b
Are mounted on the right front door, the left front door, the right side of the rear parcel, and the left side of the rear parcel, respectively, which are set to reproduce a low frequency range (mainly 200 Hz or less here).

FIG. 2 shows the configuration of a circuit for driving each of the above speakers. The sounds and conversations in the vehicle interior collected by the microphones 1c to 4c are transmitted to the microphone amplifiers 1d to 1d.
After being amplified by 4d, it is converted into a digital signal by an A / D (analog to digital) converter 14 and input to a DSP (digital signal processor) 13. The DSP 13 subjects the input signal to processing such as adding reverberation, and performs D / A (digital to analog) conversion.
2 and the D / A converter 12 converts the signal into an analog signal and outputs it to the mixer 11.

On the other hand, a head unit 7 such as a CD player
Is also converted to a digital signal by the A / D converter 8 and input to the DSP 9. The DSP 9 performs processing such as transfer function correction and reverberation, and then converts the signal to an analog signal by the D / A converter 10. Mixer 11
Is input to

The signals input to the mixer 11 in this manner are appropriately mixed and output, amplified by the power amplifiers 1e, 1f to 6e and 6f, and output as sound outputs by the loudspeakers 1a, 1b to 6a and 6b. Radiated.

In the above configuration, L for one seat
Since the loudspeakers for reproducing the middle and higher frequencies of ch and Rch are fixed to one housing, their distances are kept constant even when they are attached to an arbitrary car. Therefore, when the distance from the center to the ear between the loudspeakers attached to the housing is known, the correction value of the transfer function measured and determined in advance in an anechoic room or the like is manually or automatically controlled using the distance as a parameter. If the data can be input to the device (the DSP 9 in this embodiment), an optimum correction value can be given. Of course, it is also possible to fix the above parameters assuming the distance.

Manual input of a parameter is performed by directly inputting a numerical value corresponding to a distance to a control device and switching a correction value. Automatic input is performed by using a distance sensor (such as an ultrasonic wave or a laser) on a housing of a loudspeaker. ) To measure the distance to the head and send the value to the control device, and the control device detects the voltage to judge the distance to the ear and switches the correction value.

Here, the correction value is a value for correcting the disturbance of the frequency characteristic of the transfer function before correction, or a loudspeaker at a completely different position (for example, the position of a loudspeaker when listening in a normal room). Is corrected so as to match the transfer function assuming that the.

The correction of the transfer function as described above is particularly important in the mid-high range, but it requires that the influence of reflection be small in the transfer path between the loudspeaker and the ear. However, in the present invention, the housing to which the loudspeaker is attached is attached to the ceiling above the seat. As shown in FIG. 3, the side window 16 is inclined inward,
The sound radiated from the loudspeaker 1a has a main radiation direction (radiation angle 3
(Less than 0 °) as well as in the radiation direction of about 60 °, the light is reflected by the side window and does not reach the ear, so that the influence of the reflection is small. On the other hand, when a loudspeaker is attached to the headrest as in the conventional example, the influence of the side window is greatly affected as shown in FIG.

Further, in the present invention, the microphone is also Lc
h and Rch loudspeakers are fixed in a fixed positional relationship irrespective of the type of vehicle, and since the microphone is located in a direction of 90 ° with respect to the main radiation direction of the loudspeaker, sound from the loudspeaker to the microphone is sounded. Is reduced, and as described above, there is almost no influence of the reflection, so that the howling path is determined substantially uniquely, and it is very easy to take measures against howling.

[0028]

According to the on-vehicle acoustic device of the present invention, a microphone and a loudspeaker for reproducing a sound range higher than the middle range are mounted on a single housing, and the loudspeakers are mounted on the upper front of each seat, whereby the transfer function of the transfer function can be reduced. Correction can be easily performed, and sound field control and localization control can be easily performed.

Further, it is possible to obtain the front localization without difficulty, and furthermore, it is possible to obtain the effects such as easy howling countermeasures with a simple configuration.

[Brief description of the drawings]

FIG. 1A is a plan view showing an arrangement in an embodiment in which the present invention is applied to a sedan type vehicle, and FIG. 1B is a side view thereof.

FIG. 2 is a block diagram showing a configuration of the embodiment.

FIG. 3 is a diagram showing a path of reflection from a side window in the embodiment.

FIG. 4 is a diagram showing a path of reflection from a side window in a conventional example.

[Explanation of symbols]

1 Front seat right housing, 1a Front seat right Rch loudspeaker, 1b
Front right Lch loudspeaker, 1c Front right microphone, 1d Front right microphone amplifier, 1e Front right Rch loudspeaker, 1f Front right Lch
Power amplifier for loudspeaker 2 Front left chassis, 2a Front left Rch loudspeaker, 2b
Front left Lch loudspeaker, 2c Front left microphone, 2d Front left microphone amplifier, 2e Front left Rch loudspeaker, 2f Front left Lch
Power amplifier for loudspeaker 3 Rear right chassis, 3a Rear right Rch loudspeaker, 3b
Rear right Lch loudspeaker, 3c Rear right microphone, 3d Rear right microphone amplifier, 3e Rear right Rch loudspeaker, 3f Rear right Lch
Power amplifier for loudspeaker 4 Rear left chassis, 4a Rear left Rch loudspeaker, 4b
Rear left Lch loudspeaker, 4c Rear left microphone, 4d Rear left microphone amplifier, 4e Rear left Rch loudspeaker power amplifier, 4f Rear left Lch
Power amplifier for loudspeaker 5a Right front door loudspeaker 5b Left front door loudspeaker 5
e Power amplifier for right front door loudspeaker, 5f Power amplifier for left front door loudspeaker 6a Rear parcel right loudspeaker, 6b Rear parcel left loudspeaker, 6e Rear parcel right loudspeaker power amplifier, 6f Rear parcel left loudspeaker power amplifier 7 bed Unit 8 A / D converter 9 DSP 10 D / A converter 11 Mixer 12 D / A converter 13 DSP 14 A / D converter 15 Headrest loudspeaker 16 Side window

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04R 1 / 02,3 / 04,5 / 02 H04S 1/00 B60R 11/02

Claims (3)

(57) [Claims] 1. An on-vehicle audio device having a plurality of loudspeakers for reproducing an L channel and an R channel, respectively.
An L-channel and an R-channel loudspeaker for reproducing the middle frequency band and above are mounted on the ceiling in front of the upper part of each seat in the vehicle cabin with a housing attached with a predetermined distance between the loudspeakers, and an L-channel and a low frequency band for reproducing the low frequency band are provided. An in-vehicle acoustic device comprising an R-channel loudspeaker mounted on left and right doors or a rear parcel. 2. At least one or more microphones are mounted on the housing at a distance of 7.5 to 20 cm from the center of each loudspeaker in the housing, and the microphones collect the occupant's voice. 2. The on-vehicle acoustic device according to claim 1, wherein the audio signal obtained through the control is output from a loudspeaker attached to each housing via the control device. 3. An output signal from each of the loudspeakers mounted on the housing is output through a control device, and the control state of the control device is a parameter of a distance from each loudspeaker to an occupant's ear. 3. The on-vehicle acoustic device according to claim 1, wherein the on-vehicle acoustic device can be set manually or automatically.