JPH11308062A - Automatic volume adjusting device for sound output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic volume adjusting device for a sound output device which performs adjustment that more matches user's needs more in an automatic volume adjusting device which automatically adjusts volume in accordance with ambient sound. SOLUTION: A level deciding part 26 receives ambient sound volume which is picked up by a microphone 22 via an A-D converter 24. The amplification quantity of a variable amplifier 28 is decided in accordance with a preset defined relation. Then, a control signal corresponding to the decided amplification quantity is outputted to a D-A converter 27. Consequently, the volume of a sound signal that is outputted from the amplifier 28 is increased or reduced, in accordance with ambient volume and when the output volume is not appropriate to a user, the user operates an operation button 31 and commands the increase and reduction of output volume manually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio output device for outputting an audio signal to a speaker, a headphone, or the like, and more particularly, to an automatic audio output device for automatically adjusting the output volume of the audio output device.

[0002]

2. Description of the Related Art It is widely practiced to listen to music, conversation, and the like on a train or the like using a small portable headphone stereo or a portable CD player. Since these portable headphone players are provided with a volume adjustment volume, if the volume of the ambient sound becomes too high to make the sound from the portable headphone player difficult to hear, the volume is adjusted by the volume adjustment volume. Can be raised. However, when used in a train or the like, the volume of the ambient sound increases while the train is running, but decreases when the vehicle is stopped. If the volume of the portable headphone player is kept high when the volume of the ambient sound is low, it may cause annoyance to others in the vicinity. Therefore, when using a portable headphone player in a train or the like, in order not to bother others,
The user needs to frequently operate the volume control volume.

In order to eliminate such frequent volume operations, the volume of the ambient sound is detected, and when the volume of the ambient sound is increased, the volume of the portable headphone player is automatically increased, and the volume of the ambient sound is decreased. A method of automatically lowering the volume of a portable headphone player has been proposed. For example, Japanese Utility Model Application Laid-Open No. Sho 62-57426 and Japanese Utility Model Application Laid-Open No. 1-169.
Japanese Patent Publication No. 813 discloses a system which includes a microphone for inputting ambient noise and automatically adjusts the volume of a portable headphone player based on an increase or decrease in the noise level. A similar system is described in Japanese Patent Application Laid-Open No. 4-357707.

[0004]

However, the systems disclosed in the above publications simply increase or decrease the volume of a portable headphone player with an increase or decrease in the ambient noise level. Other adjustments may be made. For example, the automatically adjusted volume may be too high or too low for the user.

In view of the above, the present invention provides an automatic sound volume adjusting device for an audio output device, which can automatically adjust the sound volume according to the ambient sound, and which can make adjustments more suited to the needs of the user. The purpose is to provide.

[0006]

An automatic volume control device for an audio output device according to the present invention includes an automatic volume control device for adjusting the output volume of the audio output device in accordance with an increase or decrease in ambient sound.
Second volume for further adjusting the volume control operation of the automatic volume control means
Are provided. The second adjusting means may include a manual volume adjusting means for adjusting the output volume in accordance with a user operation. Then, the automatic volume adjusting means may be configured to adjust the volume based on the output volume set by the second adjusting means. Further, the second adjusting means may include a warning sound detecting means for detecting a warning sound and lowering the output volume when the warning sound is detected.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a first embodiment of an audio output device including an automatic volume control device according to the present invention. Here, a portable cassette stereo is exemplified as the audio output device. Therefore, as shown in FIG. 1, the portable cassette stereo main body 1, the remote control unit 2, and the headphones 3 are included. In this embodiment, the remote controller 2 has a built-in automatic volume control device. However, the automatic volume control device may be built in the portable cassette stereo main body 1. As shown in FIG. 1, the remote control unit 2 is provided with operation buttons 21 for manually adjusting the volume and a microphone 22 for collecting ambient sounds.

FIG. 2 is a block diagram showing a configuration example of the automatic volume control device 20. The microphone 22 inputs an ambient sound and converts it into an electric signal. The amplifier 23 amplifies the output of the microphone 22, and the A / D converter 24 converts the output of the amplifier 23 into a digital value and converts the output into a digital value.
Output to When a pressing operation is performed on the operation button 21 provided on the remote control unit 2, the input determination unit 25
Recognizes the operation content and outputs a signal indicating an increase or decrease in volume to the level determination unit 26. Level determination unit 26
Determines the volume level based on the input from the microphone 22 and the input from the operation button 21;
Via a converter 27, the amplification amount of a variable amplifier 28 provided between the output from the portable cassette stereo main body 1 and the headphones 3 is controlled.

Therefore, in this embodiment, the automatic volume control means is realized by the microphone 22, the amplifier 23, the A / D converter 24, the level determination unit 26, the D / A converter 27, and the variable amplifier 28. The manual volume adjustment means is realized by the input determination unit 25, the level determination unit 26, the DA converter 27, and the variable amplifier 28. Also, here, the level determination unit 26 that determines the gain of the variable amplifier 28 by digital processing is shown, but the gain of the variable amplifier 28 may be controlled by analog processing.

In this embodiment, as shown in FIG.
It is assumed that an instruction to increase the volume is made by pressing the operation button 21 twice shortly by the user, and an instruction to decrease the volume is made when the operation button 21 is pressed once long. When the operation button 21 is pressed three times in a short time, the automatic control is stopped when the automatic volume control based on the volume of the ambient sound is performed, and the automatic control is performed when the automatic volume control is not performed. Is assumed to be started.

Note that the example shown in FIG. 3 is merely an example, and various types of manual volume setting means can be employed. For example, the value itself corresponding to the volume value may be set by a dial type or a rotary switch type.
Also, the automatic volume control based on the volume of the ambient sound is ON / O.
Another switch for performing FF may be provided.

FIG. 4 is an explanatory diagram showing an example of the relationship between the ambient volume and the output volume of the variable amplifier 28 in the automatic volume control. As shown in FIG. 4, the level determining section 26 controls the variable amplifier 2 so that the output volume increases as the ambient volume increases.
8 is controlled. Also, control is performed so that the rate of increase of the output sound volume increases as the level of the surrounding sound volume increases.

Next, the volume adjustment operation will be described with reference to the flowchart of FIG. The audio signal output from the portable cassette stereo main unit 1 is output to an automatic volume control device 20.
Are amplified by the variable amplifier 28 and output to the headphones 3. In this embodiment, the level determination unit 2
In step 6, when the user manually sets the volume, the gain of the variable amplifier 28 is adjusted in accordance with the setting, and thereafter, the gain of the variable amplifier 28 is adjusted based on the ambient sound input by the microphone 22.

When the user presses the operation button 21, the input determination unit 25 determines what type of pressing has been performed. When the operation button 21 is shortly pressed twice (step S1), the level determination unit 26
The amplification amount of the variable amplifier 28 is determined so that the current volume from 8 is increased by a predetermined amount (step S2). Then, a control signal corresponding to the determined amplification amount is output to the DA converter 27. The DA converter 27 DA-converts the control signal and supplies it to the control input of the variable amplifier 28. Therefore, the volume of the audio signal output from the variable amplifier 28 increases in accordance with the operation of the operation button 21.

When the operation button 21 has been pressed once for a long time (step S3), the level determination unit 26 adjusts the current volume from the variable amplifier 28 so that the current volume is reduced by a predetermined amount. The amount of amplification of the amplifier 28 is determined (Step S4). Then, a control signal corresponding to the determined amplification amount is output to the DA converter 27. The DA converter 27 DA-converts the control signal and converts the control signal into a variable amplifier 28.
Supply to the control input. Therefore, the volume of the audio signal output from the variable amplifier 28 decreases according to the operation of the operation button 21.

When the operation button 21 is shortly pressed three times,
When the automatic volume adjustment based on the ambient sound is being performed, the level determining unit 26 stops the automatic volume adjustment (steps S5 and S6). When the automatic volume adjustment is not performed, the automatic volume adjustment is started (steps S5 and S5).
7).

While the automatic volume adjustment is being performed, the level determining section 26 inputs the volume of the ambient sound picked up by the microphone 22 via the AD converter 24 (step S).
8). Then, the amplification amount of the variable amplifier 28 is determined in accordance with, for example, the relationship shown in FIG.
9). Then, a control signal corresponding to the determined amplification amount is set to D
Output to the -A converter 27 (step S10). Therefore, the volume of the audio signal output from the variable amplifier 28 is
It will increase or decrease according to the surrounding volume. Note that while the automatic volume adjustment is being performed, the processes of steps S8 to S10 are repeatedly performed. However, when the volume of the ambient sound suddenly increases for a short period of time, the level is adjusted so that the automatic volume adjustment does not follow. The determination unit 26 may determine the surrounding sound volume with a certain time constant.

As described above, in this embodiment, since the surrounding sound volume is measured and the output sound volume to the headphones 3 is automatically adjusted according to the measured value, the portable cassette stereo can be used in a train or the like. When the volume of ambient noise increases, the output volume is automatically raised to make it easier to hear the sound of the portable cassette stereo, and when the volume of ambient noise decreases, the output volume is automatically lowered to reduce It can be used to prevent inconvenience to others.

Further, in this embodiment, the present output volume is raised or lowered according to the operation of the user. Therefore, when the result of the automatic volume adjustment is not appropriate for the user, it is possible to perform appropriate volume setting for the user. In that case, the relationship shown in FIG.
It is better to define a relative volume change rather than an absolute volume relationship. For example, as shown in FIG.
It is assumed that the output volume at point b is set by the user's operation when the output volume at point is set. The level determination unit 26 sets the surrounding volume at that time as the volume at point c. Therefore, thereafter, if the ambient volume decreases with reference to the point c, the output volume is decreased, and if the ambient volume increases, the output volume is increased.
By doing so, the automatic volume adjustment is continued from the point of the output volume set by the user, so that a portable cassette stereo that is easier for the user to use is realized.

In FIG. 4, the relationship between the ambient sound volume and the output sound volume is not linear. However, the relationship may be directly proportional or may be stepwise. In addition, various relationships can be adopted.

Embodiment 2 FIG. FIG. 6 is a block diagram showing the second embodiment of the present invention together with the alarm sound generating device 4. The warning sound generating device 4 is a fire alarm or other alarm device installed in a city or indoors. In the first embodiment, the output volume to the headphones 3 increases when the automatic volume control function is activated when the warning sound generating device 4 issues a warning due to a disaster or the like. Then, it becomes difficult to hear the warning. Therefore, in this embodiment, a microphone 29 for inputting an alarm sound is provided in the automatic alarm volume adjusting device 2A.

FIG. 7 is a block diagram showing a configuration example of the automatic volume control device 2A. In the automatic volume control device 2A, the sound input by the microphone 29 is amplified by the amplifier 30 and input to the filter unit 31. Filter unit 31
Is a filter having a characteristic of passing a frequency of a warning sound generated by, for example, a general fire alarm or other warning sound generating device 4. The output of the filter unit 31 is input to the level determination unit 32. In this embodiment, the warning sound detection means is realized by the microphone 29, the amplifier 30, the filter unit 31, and the level determination unit 32. The level determination unit 32 has a warning sound detection function described below, in addition to the function of the level determination unit 26 in the first embodiment.

When the warning sound generator 4 generates a warning sound,
The warning sound is input to the microphone 21 but also to the microphone 29. The microphone 29 converts the input warning sound into an electric signal and outputs the electric signal to the filter unit 31. The filter unit 31 outputs a signal of a component including the frequency of the warning sound to the level determination unit 32. It is assumed that the level determination unit 32 has input a significant signal if the input signal is equal to or greater than a certain threshold. When a significant signal is input from the filter unit 31, the level determination unit 32 stops automatic volume adjustment. Also, the output volume to the headphones 3 is reduced. Therefore,
Since the sound level from the headphones 3 heard by the user is reduced, the user can easily hear the warning sound. Other operations are the same as those in the first embodiment.

When no alarm sound is generated, the ambient sound is also input to the microphone 29, and a signal containing the same component as the frequency of the alarm sound is passed through the filter unit 31 to the level determination unit 32.
May be entered. However, the signal level is generally lower than the signal level of the original warning sound. Therefore, by setting the threshold appropriately,
This prevents the level determination unit 26 from erroneously determining the surrounding sound as a warning sound.

In each of the above embodiments, the portable cassette stereo is exemplified as the audio output device. However, the present invention can be applied to other portable headphone players such as a portable CD player. In addition, the present invention can be applied not only to portable devices but also to stationary audio output devices. For example, when the headphones 3 are connected to a stationary stereo device and used, the output volume to the headphones 3 can be increased or decreased according to the increase or decrease of the ambient sound. Further, when the headphone 3 is connected to the stationary stereo apparatus and the headphone 3 is used, if a warning sound is detected and the output volume is automatically lowered, the user can use a fire alarm installed indoors. It is easier to hear the warning.

[0026]

As described above, according to the present invention, the automatic volume control device of the audio output device includes the automatic volume control device for adjusting the output volume of the audio output device according to the increase or decrease of the ambient sound. Since the configuration is provided with the second adjusting means for further adjusting the volume adjusting operation of the adjusting means, there is an effect that an automatic volume adjusting apparatus which is easier for the user to use is provided.

In the case where the second adjusting means includes manual volume adjusting means for adjusting the output volume in accordance with the operation of the user,
There is an effect that adjustment can be performed more in accordance with the needs of the user. When the automatic volume adjustment means adjusts the volume based on the output volume set by the second adjustment means, the automatic volume adjustment is continued from the point of the output volume after the setting by the user. Adjustments that meet the needs of the user can be made. If the second adjusting means is configured to include a warning sound detecting means for detecting a warning sound and lowering the output volume when the warning sound is detected,
There is an effect that it is possible to reliably hear an alarm from an alarm device installed in a city or indoors while using the audio output device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of the automatic volume control device shown in FIG. 1;

FIG. 3 is an explanatory diagram showing a relationship between a pressing state of an operation button and an instruction content.

FIG. 4 is an explanatory diagram illustrating an example of a relationship between an ambient sound volume and an output sound volume.

FIG. 5 is a flowchart showing the operation of the first embodiment.

FIG. 6 is a configuration diagram showing a second embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration example of the automatic volume control device shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Portable cassette stereo main body 2 Remote control part 2 3 Headphones 20, 2A Automatic volume control device 21 Operation button 22 Microphone 23 Amplifier 24 A / D converter 25 Input determination part 26, 32 Level determination part 27 D / A converter 28 Variable Amplifier 29 Microphone 30 Amplifier 31 Filter section

Claims (4)

[Claims] 1. An automatic volume control device for an audio output device comprising an automatic volume control device for adjusting an output volume of an audio output device in accordance with an increase or a decrease in ambient sound, wherein the volume control operation of the automatic volume control device is further adjusted. An automatic volume control device for an audio output device, comprising: 2. The apparatus according to claim 1, wherein said second adjusting means includes a manual volume adjusting means for adjusting an output volume according to a user operation.
An automatic volume control device for the audio output device according to the above. 3. The automatic volume control device for an audio output device according to claim 2, wherein the automatic volume control device adjusts the volume based on the output volume set by the second control device. 4. The volume of the audio output device according to claim 1, wherein the second adjusting unit includes a warning sound detecting unit that detects a warning sound and lowers an output volume when the warning sound is detected. Automatic adjustment device.