JPS6235799A - On-vehicle rear speaker - Google Patents

Abstract

PURPOSE:To easily establish a sound field corresponding to a listener's seat position in a vehicle by varying directional characteristics automatically according to whether a person sits on the rear seat or not. CONSTITUTION:This system is a two-way system equipped with a woofer 24a and a tweeter 24b. The woofer 24a is fitted while embedded in a rear parcel tray 22 and the tweeter 24b is put in a housing projecting from the top surface of a tray 20. This tweeter 24b is fitted to a movable body and the direction of its main shaft is changed. A rotating shaft 26 for changing the direction of the tweeter 26b is arranged in parallel to the width direction of the vehicle body 10 and the tweeter 24b is rotated and displaced from a state in which the main shaft is directed to the head side of a person 14 sitting on the front seat to the position where the main shaft is directed to the rear windshield side by swiveling the main shaft upward. A motor 30 coupled with the rotating shaft 26 is controlled with the output of a piezoelectric sensor 32 which detects whether there is a person 18 sitting on the rear seat 16 or not.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement of a rear speaker system in an automobile audio device.

[Technical background of the invention and its problems] In recent audio systems for passenger cars, speakers are installed not only on the interior panel but also on the cowl side, the door, and even the rear parcel tray. FIG. 3 shows an example of a conventional typical structure and installation of a vehicle-mounted rear speaker system.

In FIG. 3, 10 is the body of a sedan-type passenger car, 12 is a front seat, 14 is a passenger in the front seat 12, 16 is a rear seat, 18 is a passenger in the rear seat 16, and 20 is located behind the rear seat 16. Reference numeral 22 indicates a rear cell tray 20 or a rear cell tray 20, respectively.

The speaker system 22 includes a woofer 22a and a tweeter 22b.
The woofer 22a is mounted so as to be embedded in the rear cell tray 20 with its back facing into the trunk, and the tweeter 22b is mounted with its front facing inside the housing protruding from the upper surface of the rear cell tray 20. installed.

Since the low frequency range generated from the woofer 22a has weak straightness,
The direction of installation doesn't really matter, and it's best to use the trunk as a speaker cabinet. Since the treble range generated by the tweeter 22b has strong straightness, the direction in which it is mounted has a great effect on the frequency characteristics at the listening position, and is an important point in terms of sound field performance.

Generally, the sound field characteristics are designed with the most importance placed on the auditory sensation in the driver's seat. Therefore, the main axis (center axis of directional characteristics) of the tweeter 22b of the A7 speaker system 22
is directed toward the head of the occupant 14 in the front seat 12.

However, in the Yasbika system as mentioned above,
When a passenger 18 sits in the rear seat 16, the high-frequency sound from the tweeter 22b directly enters the passenger's 18's ears, which not only impairs the auditory balance but also causes a harsh and noisy blindness. Cheap. Furthermore, for the occupant 14 in the front seat 12, the direct sound component from the tweeter 22b is obstructed by the occupant 18 in the rear seat 16, which disrupts the frequency balance that has been properly adjusted when the occupant 18 is not present. .

As a countermeasure to the above problem, some conventional glue beaker systems are designed to allow the direction of the main axis of the tweeter 22b to be changed manually. According to this configuration, the direction of the tweeter changes depending on the presence or absence of a passenger in the rear seat.
It is possible to some extent to solve the above-mentioned problems.

By the way, when a person is in the rear seat, the rear passenger changes the direction of the tweeter of the rear speaker system because the rear speaker system is installed near the rear passenger, and the rear passenger is This is a relatively practical operation since it is easy to perceive the sound from the tweeter as too loud. However, it is completely impractical for rear passengers to reorient the tweeter when they exit the vehicle, and the driver remains seated in the seat and cannot move the tweeter. Furthermore, it is not easy to reproduce the appropriate tweeter orientation depending on the presence or absence of a rear passenger.

[Purpose of the Invention] This invention has been made in view of the above-mentioned conventional problems, and has a structure in which the directional characteristics are automatically changed appropriately depending on the presence or absence of a passenger in the rear seat. To provide an on-vehicle rear speaker system that easily forms a suitable sound field.

[Summary of the Invention] The in-vehicle rear speaker system according to the present invention includes a directional characteristic variable means for changing the directional characteristic thereof, a detection means for detecting the presence or absence of a passenger in the rear seat, and a directional characteristic variable means for changing the directional characteristic of the rear speaker system, and a detection means for detecting the presence or absence of a passenger in the rear seat. and control means for controlling the directional characteristic variable means to select and override different directional characteristics depending on the presence or absence of an occupant.

[Embodiments of the Invention] FIG. 1 shows a schematic configuration of an in-vehicle rear speaker system of the present invention. As in Fig. 3, 10 is the vehicle body, 12
is the front seat, 14 is the front passenger, 16 is the rear seat, 18
2 does not indicate the rear passenger, and 20 does not indicate the rear cell tray. Reference numeral 24 is a main part of the Yasbika system to which the present invention is applied, and hereinafter this will be referred to as a rear speaker system.

The glue beaker system 24 of this embodiment has a woofer 24a.
It is a two-way system consisting of a tweeter 24b and a tweeter 24b. Wooha 2
The tweeter 4a is mounted so as to be embedded in the parcel tray 22, and the tweeter 24b is housed in a housing protruding from the upper surface of the tray 20. This tweeter 24b
is attached to a movable body so that the direction of its main axis can be changed. The configuration of the control system for the movable mechanism is shown in FIG.

In FIG. 2, 26 is a rotating shaft for changing the direction of the tweeter 24b, and this rotating shaft 26 is disposed parallel to the width direction of the vehicle body 10, and the tweeter 22b is placed on the head side of the front passenger 14. From the state where the main shaft is directed, the main shaft is rotated upward and rotationally displaced to a position where the main shaft is directed toward the rear window. Of course, this rotational displacement can be reciprocated.

A motor 30 is connected to the rotation @26, and this motor 3
Tweeter 24 by 0. b is rotationally displaced as described above. This drive system also includes a switch 28a that operates with the main axis of the tweeter 24b facing toward the head of the front passenger 14 (this is usually referred to as a normal state);
With the main axis of the tweeter 24b facing the rear window (
A limit switch 28b is provided which operates in this state (referred to as the rear riding state). The motor 30 is controlled as follows by the limit switches 28a and 28b and the output of a piezoelectric sensor 32 that detects the presence or absence of the occupant 18 in the rear seat 16.

The piezoelectric sensor 32 is installed in the seat surface of the rear seat 16, and its output signal changes depending on the pressure when a person sits there. The output of the piezoelectric sensor 32 is shaped by a waveform shaping circuit 34 into two genital numbers, and is at L level when the rear passenger 18 is not present, and becomes H level when the rear passenger 18 is sitting. This change in output signal is delayed by a delay circuit 36, ignoring conditions such as when the rear passenger 18 stands or sits for a short time.
To create a stable signal when there is no occupant 18 for more than a certain period of time and when there is an occupant 18 for more than a certain period of time.

When the output signal of the delay circuit 36 rises to the H level, this is detected by the differentiating circuit 38, and the 7-lip flop 42b is set by its output. When the signal from the delay circuit 36 falls to the L level, this is detected by the differentiating circuit 40, and the output of the differentiating circuit 40 sets the flip-flop 42a. Flip 70 tabs 42a, 42b are reset by the output signals of limit switches 28a, 28b, respectively. The set output of the flip-flop 42b becomes a normal rotation command signal to the drive circuit 44 of the motor 30, and
The set output of 2a becomes a reverse rotation command signal.

Note that in FIG. 1, 46 is a control circuit that includes the circuit configuration shown in FIG.

In the above configuration, if the rear passenger 18 is not present, the tweeter 24b is in the above-mentioned normal state, and the high-frequency sound emitted from it directly reaches the front passenger 14, as shown by A in FIG. When the passenger 18 sits on the rear seat 16, the piezoelectric sensor 32 detects this, and the output of the waveform shaping circuit 34 changes from the L level to the 1'' level, and the output of the delay circuit 36 changes to the L level after an appropriate time delay. Changes from level to H level. Then, the output of the rising differentiation circuit 38 sets the Noritsubu flop 42b, and the drive circuit 44 controls the motor 3.
0 is driven in forward rotation. As a result, the tweeter 24b turns from the upper position to the rearward position, and when the vehicle enters the rear riding state described above, the limit switch 28b is activated. As a result, the flip-flop 42b is reset and the motor 3
0 stops. In this rear riding condition, the tweeter 24b
Most of the high-frequency sounds emitted from the vehicle are reflected by the rear window, as shown by 8 in FIG. 1, and radiated forward through the space above the vehicle interior. As a result, the sound pressure of the tweeter 24b does not act too much on the rear passenger 18, and the sound pressure from the tweeter 24b does not decrease too much on the front passenger 14.

When the rear passenger 18 disappears, the piezoelectric sensor 32 detects this and the output of the delay circuit 36 falls to the L level, so that the output of the falling differentiation circuit 40 sets the flip-flop 42a. This allows the motor 30
is reversed and the tweeter 24b returns to its normal state, the limit switch 28a is activated and the motor 30 is stopped.

By the way, in the above embodiment, the directivity characteristics are changed by rotating the motor itself, but the present invention is not limited to this. For example, the directivity characteristics may be changed by using a speaker for a normal state and a speaker for a rear riding state. It is also possible to change the directional characteristics by moving other mechanical parts such as the acoustic lens. There is also a method of changing the directional characteristics by using a plurality of speakers and supplying signals with shifted phases to them, and this may be used in the present invention.

Note that, as described in the embodiments, the present invention is not limited to the 2-way system, but can also be applied to other speaker systems such as a 3-way system.

[Effects of the Invention] As explained in detail above, according to the in-vehicle rear speaker system according to the present invention, the directional characteristics set centering around the driver and the directional characteristics also taking into account passengers in the rear seats,
Since the seat is automatically selected depending on whether there is a person in the rear seat or not, the driver and rear passengers do not have to perform any troublesome operations and can always enjoy music in good condition.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall outline of an in-vehicle rear speaker system according to an embodiment of the present invention, FIG. 2 is a block diagram showing the detailed structure of the control system of the same system, and FIG.
The figure is a configuration diagram showing an overall outline of a conventional vehicle-mounted glue beaker system. 16... Rear seat 20... Rear bar cell tray 22... Rear speaker system (conventional) 24...
Rear speaker system (present invention) 24a...woofer
24b... Tweeter 30... Motor

Claims (1)

[Claims] (1) A speaker system installed behind the rear seat, including a directional characteristic variable means for changing the directional characteristic of the speaker system, a detection means for detecting the presence or absence of an occupant in the rear seat, and an output of this detection means. 1. A rear speaker system for a vehicle, comprising: control means for controlling the directional characteristic variable means in accordance with the above, and selecting a different directional characteristic depending on the presence or absence of an occupant.