JPH06292299A - Sound field control system - Google Patents

Abstract

PURPOSE:To make AM broadcast reproduction clear without being hindered by an excessive effect sound devising a system such that the generation of the effect sound is automatically suppressed when reproduction of an AM broadcast is selected. CONSTITUTION:Left/right signals SL, SR of a source are mixed by an adder circuit 11 and the result is inputted to a sound field generating circuit 12 and a mute circuit 14. The circuit 12 generates an effect sound with respect to the input to provide an output to the mute circuit 13. When the circuit 13 sets a control signal Vb to a high level, a switching element TR13b is made conductive and no effect sound from the circuit 12 is outputted and when the signal is set to a low level, the effect sound is outputted. On the other hand, a circuit 14 receiving the signal from the circuit 11 sets a control signal Va to a high level, then a switching element TR13a is made conductive to prevent the output of a signal from the circuit 11 and when the control signal is set to a low level, the output from the circuit 11 is obtained. Thus, in the reproduction source selection, the signal Va is set to a high level and the signal Vb is set to a low level by interlocking with the changeover of an AM tuner, the effect sound reproduction is suppressed and the left right mixing sound of the source is reproduced from a center speaker 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound field control system for adding a sound effect such as a reflected sound when a source is reproduced by a speaker. The invention is particularly applicable, but not exclusively, to sound field control systems mounted on vehicles.

[0002]

2. Description of the Related Art In recent years, a sound field control system has been put into practical use, which is capable of simulating a sound field by adding a reflected sound and a reverberant sound to a reproduced source sound.

FIG. 5 is a block diagram for explaining the configuration of a conventional sound field control system. The source to play, eg C
The D31, AM tuner 32, FM tuner 33 and the like are selected by the source switching circuit 34 and input to the sound field generation circuit 35. In the sound field generation circuit 35, a sound effect such as a reflected sound or a reverberant sound is calculated for the input source sound, and the sound effect is added to the source sound and output.

Then, the source sound to which the above-mentioned sound effect is added is amplified by the power amplifier 36, and the speakers 38, 39.
Will be played. A listener who listens to the sound reproduced in this way can feel as if he / she were in another sound field space, such as a concert hall or a disco, by the sound effect.

The panel 37 is operated to switch the reproduction source and the various parameters in the sound field generation. Further, in reproducing the sound effect, a center speaker may be placed in front of the center of the listener and an initial reflected sound may be reproduced from the center speaker.

[0006]

The sound field control system is also mounted on a vehicle. FIG. 6 is a diagram for explaining a problem in the conventional sound field control system mounted on a vehicle, and is a perspective view seen from the viewpoint of the driver of the vehicle.

Now, the driver adds the above-mentioned sound effect to the C
Suppose you are listening to D and switched to the AM tuner. In this case, since AM broadcasting is not mainly intended for stereo music broadcasting, it is often the case that a broadcast centering on announcement talk such as news and weather forecast is heard.

However, in the conventional sound field control system, the sound effect remains added even if the AM tuner is selected as described above, so that an excessive sound effect is added when listening to the sound. The audio becomes obscured and it becomes difficult for the driver to recognize the broadcast content.

Therefore, the driver feels the need to operate the operation panel 37 to change the setting of the sound field control so that the sound effect is not generated. However, the operation panel 37 is located below the instrument 42. Moving the viewpoint 43 to the operation panel 37 for the operation, which is arranged, causes the driver to lose sight of the front as shown in the figure, which is dangerous for driving.

[0010] It is possible to perform the operation by groping if familiar with it, but even if the sound effect is eliminated by the operation, the localization of the voice is unclear, and the localization 44 is generally lower than that of the instrument panel. And tends to spread to the driver's feet. In other words, the driver often feels as if he / she hears the audio broadcast from his / her feet. Not only music,
Even in the case of listening to an announcement, the low sound field is extremely inconvenient.

The technical problem of the present invention is to pay attention to such a problem and to clarify the reproduction of AM broadcast and clarify the reproduction localization in the sound field control system. Then, the present invention is applied to a vehicle or the like to eliminate a factor of losing sight of the front.

[0012]

FIG. 1 is a block diagram for explaining the basic principle of the present invention. The sound field control system according to claim 1, wherein a plurality of sources 1 including at least an AM tuner, a source switching unit 2 having a unit for selecting a source to be reproduced from the sources 1, and the source switching unit 2 are selected. Sound field generating means 3 having means for adding a sound effect to the source. In such a configuration, the sound field control system according to claim 1 stops adding the sound effect to the sound field generation means 3 when the source switching means 2 selects the AM tuner as the reproduction source. Have means.

A sound field control system according to claim 2 includes a plurality of sources 1 including at least an AM tuner, and the sources 1.
Source switching means 2 having means for selecting a source to be reproduced, sound field generating means 3 having means for adding a sound effect to the source selected by the source switching means 2, left to the listener, It has speakers 4, 5 and 6 for reproducing sound from the front right and center. In such a structure, the sound field control system according to claim 2 stops adding the sound effect to the sound field generation means 3 when the source switching means 2 selects the AM tuner as the reproduction source. In addition, the central speaker 6 is provided with means for reproducing a sound obtained by combining the left and right reproduced sounds.

[0014]

In the sound field control system according to claim 1, the sound field generation means 3 has means for stopping the addition of the sound effect to the reproduced sound when the source switching means 2 selects the AM tuner as the reproduction source. ing. As a result, even if a sound effect is added in advance and music or the like is played back, when the AM tuner is selected, the sound effect is automatically excluded unlike the conventional case, so that the AM sound is played back. It does not get obscured by and becomes unclear, and it sounds clear.

If the sound field control system according to claim 1 is applied to a sound field control system mounted on a vehicle, the sound effect is automatically eliminated during the reproduction of the AM broadcast as described above. No need to change settings
By this operation, the driver does not lose sight of the front, and safe driving is secured.

In the sound field control system of claim 2,
In the sound field generating means 3, when the source switching means 2 selects the AM tuner as the reproduction source, the addition of the sound effect to the reproduced sound is stopped, and the sound in which the left and right reproduced sounds are combined is reproduced from the central speaker 6. It has a means to make. As a result, in addition to the operation of claim 1, the reproduction localization of the AM broadcast becomes clear by the sound reproduced from the central speaker 6, unlike the conventional case.

If the sound field control system according to claim 2 is applied to a sound field control system mounted on a vehicle and the center speaker 6 is built in near the center of the instrument panel, the localization of AM broadcasting is the same as the line of sight. It clearly positions at a high level, and even if the position is clear, it concentrates on one point and does not feel uncomfortable, but it has a proper sense of depth.

[0018]

EXAMPLES Next, examples of how the sound field control system according to the present invention is actually embodied will be described.
FIG. 2 is a block diagram showing the first embodiment of the present invention.
The left and right signals S _L and S _R of the selected source are input to amplifiers 16 and 17, respectively. Speakers 19 are provided for the amplifiers 16 and 17,
Since 20 is connected, the selected source is played back in stereo by the speakers 19, 20.

Adder circuit for the left and right signals S _L and S _R of the source
The sound is mixed by 11 and input to the sound field generation circuit 12 and the mute circuit 14. The output of the sound field generation circuit 12 is input to the mute circuit 13, and the output of the mute circuit 13 and the output of the mute circuit 14 are input to the addition circuit 15. Then, the output of the adding circuit 15 is input to the amplifier 18, and the center speaker 21 is connected to the amplifier 18.

In the sound field generating circuit 12, a sound effect is generated and output with respect to the input. In the mute circuit 13, if the control signal V _{b is set} to High, the switching element TR
_The sound effect input from the sound field generation circuit 12 is no longer output because _13b becomes conductive, and the switching element TR _13b is shut off when the control signal _{Vb is set} to Low, and the sound effect input from the sound field generation circuit 12 is output. Like

On the other hand, in the mute circuit 14, when the control signal V _{a is set} to High, the switching element TR _{13 a} becomes conductive and the left and right mixing signals of the source input from the adder circuit 11 are not output and the control signal V _{a is set} to Low. By doing so, the switching element TR _13a is cut off, and the left and right mixing signals of the source input from the adding circuit 11 are output.

With the above-mentioned configuration, the control signal V _a is changed in conjunction with switching to the AM tuner in selecting the reproduction source.
When the control signal _Vb is controlled to be High and the control signal _Vb is controlled to be Low, the reproduction of the sound effect is suppressed, and the left and right mixing sounds of the source are reproduced from the center speaker 21. It should be noted that it is preferable to provide a switch or the like for inverting the control signals V _a and V _b so that the reproduction of the sound effect can be manually selected even during the reproduction of the AM broadcast.

The output of the mute circuit 14 includes resistors R _14a and R _14a .
_It is preferable that the pressure can be divided by _14b . With such a configuration, it is possible to set the reproduction volume of the center speaker 21 to the reproduction volume of the left and right speakers 19 and 20 at the ratio determined by the above-mentioned voltage division ratio in the reproduction of the AM broadcast. By adjusting the ratio by changing the value of the resistor R _14b, the balance of the playback volume of the speaker 19, 20, clearly reproducing position of the audio broadcast is high in the line of sight about the same vehicle driver localization In addition, it is possible to set so that there is an appropriate sense of depth.

Further, with the above configuration, when the main volume is changed to change the reproduction volume of the left and right speakers 19, 20, the reproduction volume of the center speaker 21 is also changed in association with it, and the speakers 19, 20, 21 are also changed. The playback volume balance of is always kept at an adjusted ratio.

FIG. 3A is a block diagram for explaining the second embodiment of the present invention. DSP (Digital Signa) is used for sound field generation.
l Processor). The left and right signals S _L and S _R of the source are input to the A / D converters 21 and 22, and the outputs of the A / D converters 21 and 22 are input to the DSP 23. The output of the DSP 23 is input to the D / A converters 24, 25 and 26, and the D / A converter
The outputs of 24, 25 and 26 are input to amplifiers 27, 28 and 29, respectively. Then, the outputs of the amplifiers 27, 28, 29 are connected to the speakers 30, 31, and the center speaker 32, respectively.

With such a configuration, the speakers 30, 31,
The sound reproduced by the center speaker 32 is controlled by the signal processing in the DSP 23. Figure (b) shows
9 is a flowchart illustrating an example of control in the DSP 23. When the AM tuner is switched to the playback source,
Control is transferred to steps H10, H11, H12, and step H13
The reproduction of the sound effect due to is suppressed, and the left and right mixing sounds are reproduced from the center speaker 32.

In step H12, the coefficient α corresponds to the ratio of the reproduction volume of the left and right speakers and the reproduction volume of the center speaker in the first embodiment. Further, similarly to the first embodiment, it is preferable to incorporate a control such as step H11 so that the addition of the sound effect can be manually selected also in the reproduction of the AM broadcast.

Further, in the case of reproducing and listening to audio-based broadcasting such as AM broadcasting, the clarity may not be sufficient only by suppressing the sound effect as described above. In such a case, it is more preferable to reproduce through a filter having the characteristics shown in FIG. As shown in (a) of the figure, by suppressing the low frequency range (200 Hz or less) of the reproduced sound, the muffled bass is improved and the reproduced sound can be clearly heard.

Further, as shown in (a) of the figure, the S / N ratio is improved by suppressing the extra high frequency band (8 KHz or more) that is not included in AM broadcasting, and the noise mixed in the reproduced sound is reduced. Then, the reproduced sound can be heard clearly.

[0030]

As described above, the sound field control system according to the present invention is configured to automatically suppress the generation of the sound effect when the reproduction of the AM broadcast is selected.
AM broadcasting can now be heard clearly without being obstructed by excessive sound effects. When the sound field control system according to claim 1 is mounted on a vehicle, the operation of sound field control accompanying the reproduction of AM broadcast is unnecessary, and the driver does not lose sight of the front.

As described above, the sound field control system of the present invention automatically suppresses the generation of the sound effect when the reproduction of the AM broadcast is selected, and reproduces the sound of the left and right reproduced sounds from the center speaker. Since it has a configuration, unlike the conventional art, AM broadcasting can be heard clearly without being obstructed by excessive sound effects, and its reproduction localization is also clear. If the sound field control system according to claim 2 is installed in a vehicle,
The playback position of the AM broadcast is as high as the driver's line of sight, and the driver no longer loses his sight.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic principle of the present invention.

FIG. 2 is a block diagram showing a first embodiment of the present invention.

FIG. 3 is a block diagram and a flow chart showing a second embodiment of the present invention.

FIG. 4 is a frequency characteristic diagram illustrating a filter characteristic suitable for reproduction of AM broadcast.

FIG. 5 is a block diagram illustrating a configuration of a conventional sound field control system.

FIG. 6 is a perspective view for explaining a problem in the conventional sound field control system.

[Explanation of symbols]

 1 source 2 source switching means 3 sound field generating means 4 speaker (left) 5 speaker (right) 6 center speaker 11 adder circuit 12 sound field generating circuit 13 mute circuit 14 mute circuit 15 adder circuit 16 amplifier 17 amplifier 18 amplifier 19 speaker ( Left) 20 speaker (right) 21 Center speaker

Claims (2)

[Claims] 1. A plurality of sources (1) including at least an AM tuner, a source switching unit (2) having a unit for selecting a source to be reproduced from the sources (1), and the source switching unit (2). A sound field control system having a sound field generating means (3) having means for adding a sound effect to a source selected by the sound field generating means (3), wherein the source switching means (2) is A
A sound field control system comprising means for stopping addition of a sound effect to a reproduced sound when the M tuner is selected as a reproduction source. 2. A plurality of sources (1) including at least an AM tuner, a source switching unit (2) having a unit for selecting a source to be reproduced from the sources (1), and the source switching unit (2). Sound field generation means (3) having means for adding sound effects to the source selected by, and speakers (4), (5), (6) for reproducing sound from the left, right, center front of the listener In the sound field control system having the above, the sound field generating means (3) has the source switching means (2)
When the M tuner is selected as a reproduction source, a means for stopping the addition of the sound effect to the reproduced sound and reproducing a sound composed of the left and right reproduced sounds from the central speaker (6) is provided. Sound field control system.