JPH07131883A - Intra-cab acoustic field correcting device - Google Patents

Abstract

PURPOSE:To give an acoustic field correction effect most suitable for each person in a vehicle by accurately detecting the position of his head. CONSTITUTION:Speakers 2a to 2h for acoustic field correction are arranged in vicinities of heads of persons setting in respective seats in the cab, and two or more head position detectors 1a to 1h are arranged in head rests, and longitudinal position detectors 11a and 11b and inclination angle detectors 10a and 10b for seats are provided, and reproducing levels and frequency characteristics of speakers 2a to 2h for acoustic field correction are controlled based on head positions calculated by these detectors so that transmission characteristics from main speakers 12a to 12d to ears are corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted sound reproduction system, and more particularly to a vehicle interior sound field correction device capable of always obtaining an optimum sound even when the position of the head of a passenger or a passenger changes.

[0002]

2. Description of the Related Art Conventionally, as a vehicle interior sound field correction device, FIG.
As shown in FIG.
The presence or absence of the head of each occupant is detected by 9d, and the main speakers 12a to 12d are driven to the characteristics matching the position of the person at that time,
There has been proposed a device that can obtain an optimum sound field correction effect.

[0003]

However, in the above-mentioned conventional apparatus, the presence or absence of the head of each occupant can be detected, but the position cannot be detected when the position of the head is delicately moved or deviated from side to side. Therefore, the main speakers 12a to 12d
It was not possible to make detailed corrections to the transmission characteristics from the vehicle to each passenger.

The present invention has been made in view of the above points, and an object of the present invention is to accurately detect the position of the head of each occupant so as to obtain an optimum sound field correction effect for each occupant. An object of the present invention is to provide a vehicle interior sound field correction device that can provide the sound.

[0005]

According to the vehicle interior sound field correction apparatus of the present invention, a sound field correction speaker is arranged near the head of a person sitting in each seat in the vehicle interior, and at least two speakers are provided in the headrest.
Arranging more than one head position detecting device, further providing a seat front-back position detecting device and a tilt angle detecting device, and based on the head position calculated from each of the detecting devices, the transmission characteristics from the main speaker to the ear The reproduction level and frequency characteristics of the sound field correction speaker are controlled so as to correct the sound field.

In the vehicle interior sound field correction device,
The head position detecting device is composed of a distance detecting device having a receiving part or transmitting part attached to the ear of the listener and a transmitting part or receiving part corresponding to the receiving part or transmitting part attached to the headrest. is there.

Further, in the vehicle interior sound field correction apparatus, when the head position deviates from the preset range,
It is configured to maintain the control state immediately before that.

[0008]

According to the vehicle interior sound field correction apparatus of the present invention, the position of the headrest is detected from the front-rear position and the inclination angle of the seat detected by the front-rear position detection apparatus and the inclination angle detection apparatus, and the headrest is further detected. Since the relative position of the head with respect to the headrest is detected from the two or more head position detecting devices provided, the position of each head of the occupant is accurately calculated.

Therefore, the transmission characteristics of the sound from the main speaker to the ears of each occupant are calculated. To correct the transmission characteristics, it is possible to finely control the reproduction level and frequency characteristics of the sound field correction speakers placed near the heads of the respective occupants according to the movement of the head, and to achieve the optimum sound field correction. The effect is obtained.

FIG. 8 and FIG. 9 show frequency characteristics showing how the transmission characteristics of sound from the speaker to the ears of each occupant change depending on the position of the head. This frequency characteristic is obtained by measurement, and the measurement position and speaker arrangement at that time are shown in FIGS. 6 and 7.

As shown in FIG. 6A, the measurement position is 50
It was performed for four height levels (each level of LL, L, C, and H) with mm intervals. The standard position is 170 cm tall
This is equivalent to the position of the ear when a person takes a standard posture. The standard position is 460 mm behind the front end of the ceiling, and the height is C level. The standard position is indicated by a black circle in the figure.

The positions of the measuring points at the same height are shown in FIG. 6 (b).
Is shown in. The positions shown in the figure are standard positions.
As shown in the figure, each measurement point indicated by a circle is 100 mm.
They are arranged in a grid pattern with intervals.

The front speakers used for the measurement were attached to the left and right doors at the positions shown in FIG. 6 (a). Also, R
The rear speaker is attached to the rear shelf of the seat, as shown in FIG.
The position is shown in (b). The L rear speaker is mounted symmetrically with the R rear speaker.

FIG. 8 shows frequency characteristic data at each measurement position on the right seat in the front part of the passenger compartment. The height of the measuring position is C
This is a level, and the position on the plane is the position indicated by the circled numbers in FIG. 6B, and the measured position is shown as the corresponding circled number above the data of each frequency characteristic.

FIG. 9 shows data of frequency characteristics at each measurement position on the left seat in the front part of the passenger compartment. The measurement position is the same as that shown in FIG. From these measurement data, it can be seen that a large dip occurs near 500 Hz when the head position moves forward.

This can be corrected by enhancing the band of the speaker provided in the headrest. If this correction is attempted by the main speaker, this dip is caused by the cancellation of the reflected wave, so even if this band is increased, the reflected wave is also strengthened in the same way, and the effect is hardly improved. Therefore, it is preferable to arrange the correction speaker as close to the ear as possible according to the present invention.

When the position of the head is determined, the frequency characteristic can be predicted as shown in the above data. That is, the transfer functions at several transfer paths are measured and stored in advance, and the transfer functions at the positions of the respective heads are obtained by reading them. Then, the reproduction level and the frequency characteristic of the sound field correction speaker may be controlled so as to correct it.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle interior sound field correcting apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an arrangement of respective components in a vehicle interior sound field correction device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration of the vehicle interior sound field correction device.

As shown in the figure, the headrest 8 of each seat
Sensors 1a to 1h of the head position detecting device and sound field correction speakers 2a to 2h are attached to a to 8d.
FIG. 3A shows a connection diagram between the sensors of the two head position detecting devices and the head position detecting device which form a pair with the receiving part and the oscillating part. As shown in the figure, the oscillator outputs an ultrasonic signal to the oscillator and the time difference detection distance calculation device, and the ultrasonic signal detected by the reception unit is output to the time difference detection distance calculation device.

The pair of receiver and oscillator are arranged side by side as shown in FIG. 3B, and the ultrasonic wave emitted from the oscillator and reflected by the head is received by the receiver. Since signals are input to the time difference detection distance calculation device at the time of emitting and receiving ultrasonic waves, it is possible to detect the time until it is emitted from the oscillating unit, reflected by the head and received by the receiving unit. The distance can be calculated. Two pairs of these sensors are installed in each headrest at intervals of about 10 cm in the lateral direction.

FIG. 4A shows a state in which the head is in the center of the headrest, and FIG. 4B shows a state in which the head is displaced to the left from the center of the headrest. When the head is in the center of the headrest, the distance between the head and each sensor is equal, but when the position of the head deviates from the center of the headrest, the distance between the head and each sensor is different, so the deviation of the head is detected. .

Further, seat angle detecting devices 10a and 10b for detecting the seat angle and front and rear position detecting devices 11a and 11b for detecting the front and rear positions of the seat are provided in the front seat.

The seat is tilted in several steps at regular angular intervals, and a plurality of microswitches that operate at each position of the member that contacts the stopper at each step are provided. The microswitches detect the seat angle. Is configured. As the sheet angle detecting device, a device in which a liquid is enclosed in a container and a change in capacitance due to the inclination thereof is converted into an angle may be used.

The seat moves in several steps in the front-rear direction at intervals of about 5 cm, and microswitches are arranged at the moving intervals, and these microswitches sequentially operate as the seat moves. These micro switches constitute a seat front-back position detecting device.

A microphone 4 is arranged in front of the ceiling. Signals from these microphones and detection devices and signals from the audio source 3 are input to the controller 5 as shown in FIG.

Microphone 4, seat angle detection device 1
0a, 10b and the seat front-back position detection device 11a,
The signal from 11b is directly input to the controller 5, and the output signals of the sensors 1a to 1h of the head position detecting device are input to the time difference detection distance calculating devices 6a to 6h so that the distance from the sensors 1a to 1h to the head position is calculated. The calculated distance data is input to the controller 5.

The positions of the headrests 8a to 8d are calculated from the signals from the seat angle detecting devices 10a and 10b and the seat front-rear position detecting devices 11a and 11b, and from the relationship with the distance from the sensors 1a to 1h to the head position. The head position of each occupant can be calculated.

Therefore, the controller 5 processes the signal from the audio source 3 with an optimum transfer function (gain and phase characteristics at each frequency) so that the transmission characteristics from the main speakers 12a to 12d can be obtained and corrected. , The sound field correction speaker 2 which is amplified by the power amplifiers 7a to 7h.
By driving a to 2h, the optimum sound field correction effect (good frequency characteristic and localization correction) can be given to each occupant.

Further, the microphone 4 detects each frequency and phase of noise, a signal for canceling the noise is output from the controller 5, amplified by the power amplifiers 7a to 7h, and the sound field correction speakers 2a to 2h are output. Noise can be controlled by driving.

In the above control, the positional deviation of the head is performed within a predetermined range. When the displacement of the head becomes large beyond that range, it becomes difficult to control the correction, so fix with the correction characteristics before exceeding that range,
Correction control limits are provided.

The embodiment is constructed as described above,
The invention is not limited to this. For example, in the head position detecting device, an ultrasonic wave receiving unit or transmitting unit attached to the listener's ear and the transmitting unit or receiving unit corresponding to the receiving unit or transmitting unit attached to the headrest. A distance detecting device having a section may be used, or a distance detecting device using light or laser light may be used.

[0032]

According to the vehicle interior sound field correction apparatus of the present invention, since the position of the head of the occupant in each seat can be accurately grasped, the correction characteristic can be controlled according to the position of the head.
Optimal correction is always possible regardless of the position of the head.

Further, when the head is moved largely, the correction characteristic is fixed to the value before the movement exceeds the predetermined range, so that there is no fear that the correction circuit operates abnormally, and the operation of the speaker becomes stable.

[Brief description of drawings]

FIG. 1 (a) is a plan view showing an arrangement of respective components in a vehicle interior sound field correction apparatus according to an embodiment of the present invention, and FIG. 1 (b) is a side view of the same.

FIG. 2 is a block diagram showing a configuration of a vehicle interior sound field correction device.

FIG. 3 (a) is a block diagram showing a head position detecting device of the vehicle interior sound field correction device, and FIG. 3 (b) is a sensor layout diagram of the head position detecting device.

FIG. 4 is a diagram showing a positional relationship between the head position detecting device and the head.

FIG. 5 is a plan view showing an arrangement of each component in a conventional vehicle interior sound field correction device.

6 (a) is a side view showing measurement points for measuring changes in frequency characteristics caused by displacement of the head, FIG.
(B) is a plan view showing the same measurement point.

FIG. 7 (a) is a side view showing the arrangement of front speakers used in the measurement, and FIG. 7 (b) is a plan view showing the arrangement of rear speakers used in the measurement.

FIG. 8 is a graph showing frequency characteristics at each measurement point on the right seat in the front part of the passenger compartment.

FIG. 9 is a graph showing frequency characteristics at each measurement point on the left seat in the front part of the passenger compartment.

[Explanation of symbols]

1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h sensor 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h sound field correction speaker 3 audio source 4 microphone 5 controller 6a, 6b, 6c, 6d , 6e, 6f, 6g, 6h Time difference detection distance calculation device 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h Power amplifier 8a, 8b, 8c, 8d Headrest 9a, 9b, 9c, 9d Sensor 10a, 10b Seat Angle detection device 11a, 11b Seat front-back position detection device 12a, 12b, 12c, 12d Main speaker

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04R 3/12 Z

Claims (3)

[Claims] 1. A speaker for correcting a sound field is arranged near a head of a person sitting in each seat in a vehicle compartment, at least two head position detecting devices are arranged on a headrest, and front and rear position detection of the seat is performed. A device and a tilt angle detection device are provided, and the reproduction level and frequency characteristic of the sound field correction speaker are adjusted so as to correct the transmission characteristic from the main speaker to the ear based on the head position calculated from each of the detection devices. A vehicle interior sound field correction device configured to be controlled. 2. The head position detecting device is a distance detecting device having a receiving portion or transmitting portion attached to a listener's ear and a transmitting portion or receiving portion corresponding to the receiving portion or transmitting portion attached to a headrest. The vehicle interior sound field correction device according to claim 1, which is configured. 3. The vehicle interior sound field correction apparatus according to claim 1, wherein when the head position is out of the preset range, the control state immediately before that is maintained.