JP2008053986A - Television receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a television receiver which allows a volume to be adjusted to a user's desired proper volume in accordance with an ambient noise level and is prevented from immediately reacting to sudden and big noise, thereby not outputting sound of suddenly increased volume. <P>SOLUTION: An adjustment level difference showing a difference between a sound signal level in such a state that a speaker outputs sound with volume set by user's operation, from a sound level detection circuit, and an initial noise signal level at such a preset state that the speaker does not output sound, from a noise level detection circuit, is calculated by an adjustment level difference calculation circuit. When a prescribed time passes after it has been judged that the noise signal level from the noise level detection circuit has become higher than the initial noise signal level due to an increase in ambient noise, a gain of a sound amplification circuit is raised so as to keep the adjustment level difference, and the volume of output sounds from the speaker is increased. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a television receiver, and more particularly to volume control of sound output from a speaker.

  In recent years, since television receivers are equipped with a microcomputer, various functions are added. Among these functions, there is a volume control function for controlling the volume of sound output from a speaker. This volume control function automatically controls the volume according to the ambient noise so that a television program can be enjoyed at a volume suitable for the surrounding environment.

  For example, in the prior art of Patent Document 1, a television receiver or the like is provided with volume control means for setting the output volume of the audio circuit when the power is inserted, so that the output volume of the audio circuit when the power is turned on is reduced to the ambient noise. It is configured so that it can be automatically set to an appropriate value according to the level.

  In the prior art of Patent Document 2, the television receiver has a volume detection sensor and a volume control circuit, detects ambient noise by the volume detection sensor, and sets the initially set volume when there is no ambient noise. When it is output from the speaker and it is detected that the ambient noise has increased, the sound is output from the speaker by increasing the volume based on the volume control circuit.

In the prior art of Patent Document 3, a microphone and a volume measuring unit are provided in the remote controller, and the volume measurement result at the time when the user adjusts the volume of the television receiver is stored in the memory as a reference volume value. The difference between the reference volume value and the subsequent volume measurement value is obtained, and the volume is adjusted by remote control of the remote controller so that this difference becomes a predetermined threshold value.
Japanese Utility Model Publication No. 58-515 JP-A-6-62346 JP 2003-304590 A

  However, in the prior art of Patent Document 1, the output volume of the audio circuit when the power is turned on can be automatically set to an appropriate value in accordance with the ambient noise level. When the noise increases due to surrounding speech during viewing, there arises a problem that the output volume cannot be adjusted to the ambient noise level.

  In the prior art of Patent Document 2, ambient noise is detected by a volume detection sensor, and when there is no ambient noise, an initial volume is output from the speaker to detect that ambient noise has increased. Then, the sound is output from the speaker so as to increase the volume, but for example, even if an external car horn sounds, it reacts immediately and the volume increases suddenly. The problem arises that it can be surprising and uncomfortable.

In the prior art of Patent Document 3, the volume measurement result when the user adjusts the volume of the television receiver is stored in the memory as a reference volume value, and the stored reference volume value and the subsequent volume are stored. The difference from the measured value is obtained, and the volume is adjusted by remote control of the remote control so that this difference becomes a predetermined threshold. However, this conventional technique also sounds, for example, an external car horn. However, it reacts immediately, and the sound volume suddenly increases, which causes a problem that a user in the room may be surprised and uncomfortable.

  The present invention has been made to solve the above-described problems, and can be adjusted to an appropriate volume according to the user's preference according to the ambient noise level, and can be immediately applied to a sudden and loud noise. An object of the present invention is to provide a television receiver capable of preventing the volume from increasing suddenly without reacting.

  In order to achieve the above object, an invention according to claim 1 is directed to a sound level detection circuit for detecting a level of a sound signal from a sound amplifier circuit, a noise microphone for receiving ambient noise, and a noise microphone. A microphone amplification circuit for amplifying a microphone signal; a noise extraction circuit for extracting a noise signal by subtracting the audio signal output from the audio amplification circuit from the microphone signal output from the microphone amplification circuit; The sound level detection circuit for detecting the level of the noise signal, and the sound signal level and sound from the sound level detection circuit in a state where the sound of the volume set by the user operation is output from the speaker, the sound is not output from the speaker. Adjustment level difference that calculates the difference from the initial noise signal level from the noise level detection circuit in the preset state as the adjustment level difference Output circuit, and after the power is turned on and the initial noise signal level is detected by the noise level detection circuit, the volume level is adjusted based on the user operation and the volume level is set. Adjustment level difference storage control means for temporarily storing in a memory, and sound output state noise level detection in which the noise level detection circuit detects a noise signal level when sound is output from a speaker at the set volume. Control means; noise level determination means for determining whether a noise signal level in a state where the sound is output is greater than the initial noise signal level; and a noise signal level in a state where the sound is output Is determined to be greater than the initial noise signal level, the sound level is maintained so that the adjustment level difference is maintained after a lapse of a predetermined time. Instructing to increase the volume by adjusting the gain of the amplifier circuit, and when it is determined that the noise signal level in the state where the sound is output is lower than the noise signal level after the increase, or A system controller having volume control instruction means for instructing to lower the volume by adjusting the gain of the audio amplifier circuit so as to maintain the difference in the adjustment level when it is determined that the level is lower than the initial noise signal level; Provided is a television receiver characterized in that the television receiver is provided.

  In this configuration, first, when the power of the television receiver is turned on, ambient noise is received from the noise microphone, and the initial noise signal level is detected by the noise level detection circuit. Thereafter, the system controller operates the audio amplification circuit to output audio from the speaker. Along with this, a user operation is performed to adjust the volume to a desired level, and the volume is set. Sound is output from the speaker at the set volume, and the sound level detection circuit detects the level of the sound signal from the sound amplification circuit.

  Next, the adjustment level difference calculation circuit is configured to output the audio signal level from the audio level detection circuit in a state where the sound of the volume set by the user operation is output from the speaker, and at the preset time when the audio is not output from the speaker. The difference from the initial noise signal level from the noise level detection circuit in the state is calculated as an adjustment level difference. The adjustment level difference storage control means temporarily stores the adjustment level difference in a memory. The sound is output from the speaker with the volume set by such processing, and the sound output state noise level detection control means determines the noise signal level when the sound is output from the speaker with the set volume as the noise level. It is detected by a detection circuit.

  Thereafter, the noise level determination means determines whether the noise signal level detected by the noise level detection circuit is greater than the initial noise signal level. When it is determined that the noise signal level in the state where the sound is being output is greater than the initial noise signal level, the sound volume control instruction means is configured to maintain the difference between the adjustment levels when a predetermined time has elapsed. An instruction to increase the volume by adjusting the gain of the amplifier circuit is given.

  On the other hand, when it is determined that the noise signal level in a state where sound is output from the speaker is lower than the noise signal level after the increase, or is determined to be lower than the initial noise signal level. The sound volume control instruction means instructs to lower the sound volume by adjusting the gain of the sound amplifier circuit so as to keep the adjustment level difference. As a result, the volume of the sound output from the speaker is reduced, and the sound of the user's preferred volume corresponding to the quietness of the surroundings is output from the speaker.

  According to this configuration, it is possible to adjust the sound volume to the user's preferred volume according to the ambient noise level. Therefore, even when the ambient noise increases while watching a TV program, Therefore, the hearing sensitivity is kept constant for the user, which makes it unnecessary for the user to perform a remote control operation for increasing the volume. In addition, it does not react immediately to sudden and loud noises so that the volume does not increase suddenly. For example, even if an external car horn sounds, the volume does not increase suddenly, Users who are present are not surprised or uncomfortable.

  The invention of claim 2 is set by the user operation when the power is turned on and the volume level is set by adjusting the volume based on the user operation after the initial noise signal level is detected by the noise level detection circuit. The sound signal level from the sound level detection circuit in a state where the sound of the volume is output from the speaker and the initial noise signal level from the noise level detection circuit in the preset state where the sound is not output from the speaker. The adjustment level difference storage control means for temporarily storing the adjustment level difference as a difference in the memory, and the noise level detection circuit detecting the noise signal level when the sound is output from the speaker at the set sound volume. A voice output state noise level detection control means for causing the noise signal level when the voice is being output to be the initial noise signal level; Noise level determining means for determining whether the noise level is greater than the initial noise signal level when it is determined that the noise signal level in a state where the sound is being output is greater than the initial noise signal level. An instruction to increase the volume by adjusting the gain of the audio amplifier circuit so as to maintain the level difference is given, and the noise signal level in a state where the audio is output is smaller than the noise signal level after the increase. Volume control for instructing to lower the volume by adjusting the gain of the audio amplifier circuit so as to keep the difference in the adjustment level when it is determined that the level is lower than the initial noise signal level. There is provided a television receiver comprising a system controller having an instruction means.

  In this configuration, first, when the power of the television receiver is turned on, ambient noise is received from the noise microphone, and the initial noise signal level is detected by the noise level detection circuit. Thereafter, the system controller operates the audio amplification circuit to output audio from the speaker. Along with this, a user operation is performed to adjust the volume to a desired level, and the volume is set. Sound is output from the speaker at the set volume, and the sound level detection circuit detects the level of the sound signal from the sound amplification circuit.

  Next, the adjustment level difference storage control means temporarily stores the adjustment level difference in the memory. The sound is output from the speaker with the volume set by such processing, and the sound output state noise level detection control means determines the noise signal level when the sound is output from the speaker with the set volume as the noise level. It is detected by a detection circuit. Thereafter, the noise level determination means determines whether the noise signal level detected by the noise level detection circuit is greater than the initial noise signal level. When it is determined that the noise signal level in the state where the sound is being output is greater than the initial noise signal level, the sound volume control instruction means is configured to maintain the difference between the adjustment levels when a predetermined time has elapsed. An instruction to increase the volume by adjusting the gain of the amplifier circuit is given.

  On the other hand, when it is determined that the noise signal level in a state where sound is output from the speaker is lower than the noise signal level after the increase, or is determined to be lower than the initial noise signal level. The sound volume control instruction means instructs to lower the sound volume by adjusting the gain of the sound amplifier circuit so as to keep the adjustment level difference. As a result, the volume of the sound output from the speaker is reduced, and the sound of the user's preferred volume corresponding to the quietness of the surroundings is output from the speaker.

  According to this configuration, it is possible to adjust the sound volume to the user's preferred volume according to the ambient noise level. Therefore, even when the ambient noise increases while watching a TV program, Therefore, the hearing sensitivity is kept constant for the user, which makes it unnecessary for the user to perform a remote control operation for increasing the volume. In addition, it does not react immediately to sudden and loud noises so that the volume does not increase suddenly. For example, even if an external car horn sounds, the volume does not increase suddenly, Users who are present are not surprised or uncomfortable.

  According to a third aspect of the present invention, in the second aspect of the present invention, the sound level detection circuit for detecting the level of the sound signal from the sound amplifier circuit, the noise microphone for receiving ambient noise, and the microphone from the noise microphone A microphone amplification circuit for amplifying a signal; a noise extraction circuit for extracting a noise signal by subtracting the audio signal output from the audio amplification circuit from the microphone signal output from the microphone amplification circuit; and a noise from the noise extraction circuit Noise level detection circuit for detecting the signal level, and preset audio signal level and sound from the sound level detection circuit in a state where the sound of the volume set by the user operation is output from the speaker Adjustment level difference that calculates the difference from the initial noise signal level from the noise level detection circuit in the state of time as the adjustment level difference It has been configured to include a circuit out.

  With this configuration, it is possible to detect the level of the audio signal from the audio amplifier circuit, receive ambient noise, amplify the microphone signal, extract the noise signal, detect the level of the noise signal, and calculate the adjustment level difference.

  As described above, according to the present invention, it is possible to adjust the sound volume to a user's preferred volume according to the ambient noise level, so that the ambient noise increases while watching a TV program. However, since the volume automatically increases, the sensitivity of hearing is kept constant for the user, which makes it unnecessary for the user to perform a remote control operation for increasing the volume. In addition, it does not react immediately to sudden and loud noises so that the volume does not increase suddenly. For example, even if an external car horn sounds, the volume does not increase suddenly, Users who are present are not surprised or uncomfortable.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing components related to volume control in a television receiver according to an embodiment of the present invention.

  The television receiver includes a volume circuit 1 for adjusting the volume, an audio amplifier circuit 2 for amplifying an audio signal from an audio detector circuit (not shown), and power-amplifying the audio signal from the audio amplifier circuit 2. The audio output circuit 3 supplied to the speaker 4, the audio level detection circuit 5 that receives the audio signal from the audio amplification circuit 2 and detects the level of the audio signal, and the audio level signal from the audio level detection circuit 5 is digitally converted. And an A / D conversion circuit 6 for converting into a voice level signal.

  The television receiver includes a noise microphone 7 for receiving noise around the receiver, a microphone amplifier circuit 8 for amplifying a microphone signal from the noise microphone 7, and a sound amplifier circuit 2. The delay circuit 9 delays the audio signal from the audio amplifier circuit 2 for a predetermined time to output the audio signal from the microphone amplifier circuit 8 in phase with the audio signal from the microphone amplifier circuit 8 and the delay circuit 9 from the microphone signal from the microphone amplifier circuit 8. A noise extraction circuit 10 for extracting a noise signal by subtracting a voice signal from the noise, a noise level detection circuit 11 for detecting the level of the noise signal by inputting the noise signal from the noise extraction circuit 10, and the noise level detection circuit The A / D conversion circuit 12 that converts the noise signal from the digital signal 11 into a digital noise signal, and the sound of the volume set by the user operation are output from the speaker 4 The audio signal level from the audio level detection circuit 5 (digital audio signal level from the A / D conversion circuit 6) and the noise level detection circuit 11 in a preset state where no audio is output from the speaker 4 And an adjustment level difference calculation circuit 13 for calculating a difference from the initial noise signal level (digital initial noise signal level from the A / D conversion circuit 12) as an adjustment level difference.

  The television receiver also includes a memory 14 for storing data necessary for processing, a timer 15 for measuring time, a remote control 16 having a plurality of operation keys such as a power key, a volume adjustment key, and a channel key, and a television. And a system controller 17 realized by a microcomputer for controlling the entire John receiver. The volume for adjusting the volume corresponds to a volume adjustment key in the remote controller 16 and also corresponds to a volume adjustment key in a main body operation unit (not shown). In this embodiment, the volume adjustment key of the remote controller 16 is operated. A description will be given assuming that the volume is adjusted. The volume adjustment key of the remote controller 16 will be referred to as volume 16a.

  The system controller 17 is a component that characterizes the present embodiment. After the power is turned on and the initial noise signal level is detected by the noise level detection circuit 11, the volume is adjusted and the volume is set based on a user operation. Adjustment level difference storage control means for temporarily storing the adjustment level difference in the memory 14 and a noise signal level in a state where sound is output from the speaker 4 at the set volume. A sound output state noise level detection control means to be detected by the detection circuit 11; a noise level determination means for determining whether a noise signal level in a state where the sound is output is greater than the initial noise signal level; When it is determined that the noise signal level in a state where sound is output is greater than the initial noise signal level, An instruction to increase the volume by adjusting the gain of the audio amplifier circuit 2 so as to keep the adjustment level difference after a predetermined time has elapsed and the noise signal level in a state where the audio is being output is increased after the increase. When it is determined that the level is lower than the noise signal level, or when it is determined that the level is lower than the initial noise signal level, the gain is adjusted by adjusting the gain of the audio amplifier circuit 2 so as to keep the adjustment level difference. Volume control instruction means for instructing to lower the volume.

  FIG. 2 is a flowchart for explaining the sound volume control operation in this embodiment. The operation of volume control will be described with reference to this flowchart and FIG.

  First, when the power of the television receiver is turned on (step S1), ambient noise is received from the noise microphone 7 and the initial noise signal level is detected by the noise level detection circuit 11 (step S2). That is, in a preset state where no sound is generated from the speaker 4, the noise microphone 7 receives noise around the television receiver, and the noise signal from the noise microphone 7 is amplified by the microphone amplification circuit 8, and the noise is reduced. Input to the extraction circuit 10. Since only the noise signal from the microphone amplifier circuit 8 is input to the noise extraction circuit 10 at this time, the noise signal is output from the noise extraction circuit 10 as it is. The noise signal is input to the noise level detection circuit 11 and the level is detected. This level signal is further converted into a digital noise signal level by the A / D conversion circuit 12, and this digital noise signal level is temporarily stored. Is stored in the memory 14.

  Thereafter, the system controller 17 operates the audio amplifier circuit 2, whereby the audio signal from the audio amplifier circuit 2 is amplified by the audio output circuit 3 and supplied to the speaker 4, and the audio is output from the speaker 4. Is done. Along with this, the user operates the volume 16a of the remote controller 16 to adjust it to the desired volume (step S3). Then, when a predetermined time (for example, 2 seconds) elapses after the user stops touching the volume 16a, the system controller 17 sets the adjusted volume (step S4). The sound is output from the speaker 4 at the set volume, and the sound level detection circuit 5 detects the level of the sound signal from the sound amplification circuit 2, and the A / D conversion circuit 6 further detects the sound signal. Is converted to a digital audio signal level.

  Next, the adjustment level difference calculation circuit 13 calculates the audio signal level (digital audio signal level from the A / D conversion circuit 6) in a state where the sound of the volume set by the user operation is output from the speaker 4. The difference between the initial noise signal level from the noise level detection circuit 11 (digital initial noise signal level from the A / D conversion circuit 12) in the preset state when no sound is output from the speaker 4 is the adjustment level difference. Further, the adjustment level difference storage control means of the system controller 17 temporarily stores the adjustment level difference in the memory 14 (step S5). This adjustment level difference is updated when the user adjusts the volume again by operating the volume 16a.

  Incidentally, the adjustment level difference calculation circuit 13 sets the sound signal level output from the speaker 4 (corresponding to the sound signal level output from the sound level detection circuit 5) to X [dB], for example, and is received by the noise microphone 7. The initial noise signal level (corresponding to the initial noise signal level output from the preset noise level detection circuit 11) is Y [dB], and the difference between the audio signal level and the initial noise signal level is 40 [dB]. In this case, the formula XY = 40 [dB] is calculated as the adjustment level difference. The initial noise signal level output from the noise level detection circuit 11 at the time of presetting is stored in the memory 14 in advance as a digital initial noise signal level at the time of presetting. The adjustment level difference can be calculated from the digital audio signal level obtained by digitally converting the signal level by the A / D conversion circuit 6 and the digital initial noise signal level in the memory 14.

  Sound is output from the speaker 4 at the volume set by such processing. The noise signal level in this state is detected. That is, the sound output state noise level detection control means of the system controller 17 causes the noise level detection circuit 11 to detect the noise signal level when sound is output from the speaker 4 at the set volume (step S6). . Next, the noise level determination means of the system controller 17 has a digital noise signal level obtained by digitally converting the noise signal level detected by the noise level detection circuit 11 by the A / D conversion circuit 12 based on the digital initial noise signal level. Is also determined (step S7).

  When it is determined that the digital noise signal level in a state where the sound is being output is higher than the digital initial noise signal level, the volume control instruction means of the system controller 17 causes the timer 15 to perform time measurement, When the measured time elapses for a predetermined time (for example, 3 seconds) (step S8), the volume circuit 1 is controlled so as to maintain the adjustment level difference, and the gain of the audio amplification circuit 2 is increased and output from the speaker 4. An instruction to increase the volume of the voice is given (step S9). For example, when the noise increases due to surrounding voices and the average value of the noise signal level Y (for example, the average value for 2 seconds) increases by 10 [dB], the initially set adjustment level difference of 40 [dB] is maintained. Thus, the audio signal level X is increased by 10 [dB]. Thereby, the volume of the sound output from the speaker 4 is increased.

  Therefore, while the user is watching a TV program, the volume is automatically increased even if the surrounding noise increases, so that the hearing sensitivity is kept constant for the user. This eliminates the need for remote control operations to increase the volume, which is convenient. In addition, the volume is increased after a predetermined time (for example, after 3 seconds), for example, when the external car horn rings and reacts immediately, the volume increases suddenly and enters the room. This is to prevent the existing user from being surprised and uncomfortable.

  On the other hand, when it is determined that the digital noise signal level in a state where sound is output from the speaker 4 is lower than the digital noise signal level after the increase, or from the digital initial noise signal level. When it is determined that the volume has also decreased (step S7), the volume control instruction means of the system controller 17 controls the volume circuit 1 so as to maintain the adjustment level difference, thereby lowering the gain of the audio amplification circuit 2 to reduce the speaker 4 Is instructed to lower the volume of the sound output from (step S10). For example, when the noise due to the surrounding speech is quiet and the noise signal level Y is reduced by 10 [dB], the audio signal level X is lowered by 10 [dB] so as to maintain the initially set adjustment level difference of 40 [dB]. . As a result, the volume of the sound output from the speaker 4 is reduced to the original volume.

  Further, even when the noise is further lower than the noise received by the noise microphone 7 at the preset time and the noise signal level is lower than the initial noise signal level, the volume control means of the system controller 17 starts with The audio signal level X is further lowered so as to maintain the adjustment level difference 40 [dB] set to. For example, when the noise due to surrounding speech is quieted, the ambient noise is further reduced, and the noise signal level Y is reduced by 15 [dB], the audio signal is maintained so as to maintain the initially set adjustment level difference of 40 [dB]. Lower the level X by 15 [dB]. As a result, the volume of the sound output from the speaker 4 is further reduced, and the sound of the user-preferred volume corresponding to the quietness of the surroundings is output from the speaker 4.

  As described above, according to the present embodiment, it is possible to adjust the sound volume to a user's preferred volume according to the ambient noise level, so that the ambient noise is large while watching a TV program. Even if it becomes, since the volume automatically increases, the sensitivity of hearing is kept constant for the user, which makes it unnecessary for the user to perform a remote control operation for increasing the volume. In addition, it does not react immediately to sudden and loud noises so that the volume does not increase suddenly. For example, even if an external car horn sounds, the volume does not increase suddenly, Users who are present are not surprised or uncomfortable.

  The present invention can be used for volume control of sound output from a speaker in a television receiver.

It is a block diagram which shows the component relevant to volume control in the television receiver which concerns on one Embodiment of this invention. 4 is a flowchart for explaining an operation of volume control in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Voice amplification circuit 4 Speaker 5 Voice level detection circuit 7 Noise microphone 8 Microphone amplification circuit 10 Noise extraction circuit 11 Noise level detection circuit 13 Adjustment level difference calculation circuit 14 Memory 17 System controller

Claims (3)

From an audio level detection circuit for detecting the level of an audio signal from the audio amplifier circuit, a noise microphone for receiving ambient noise, a microphone amplifier circuit for amplifying a microphone signal from the noise microphone, and the microphone amplifier circuit A noise extraction circuit that extracts a noise signal by subtracting the audio signal output from the audio amplification circuit from the output microphone signal, a noise level detection circuit that detects the level of the noise signal from the noise extraction circuit, and a user operation The sound signal level from the sound level detection circuit when the sound having the volume set by the sound is output from the speaker and the initial state from the noise level detection circuit in the preset state where the sound is not output from the speaker An adjustment level difference calculation circuit for calculating a difference from the noise signal level as an adjustment level difference;
After the power is turned on and the initial noise signal level is detected by the noise level detection circuit, when the volume is adjusted based on the user operation and the volume is set, the adjustment level difference is temporarily stored in the memory. Adjustment level difference storage control means, sound output level noise level detection control means for detecting a noise signal level by the noise level detection circuit in a state where sound is output from a speaker at the set volume, and the sound Noise level determination means for determining whether the noise signal level in the output state is greater than the initial noise signal level; and the noise signal level in the state in which the sound is output is greater than the initial noise signal level When it is determined that the gain has also increased, the gain of the audio amplifier circuit is adjusted so that the difference in the adjustment level is maintained after a predetermined time has elapsed. An instruction to increase the sound volume is given, and when it is determined that the noise signal level in the state where the sound is output is lower than the noise signal level after the increase, or lower than the initial noise signal level And a volume controller for instructing to lower the volume by adjusting the gain of the audio amplifier circuit so as to maintain the difference in adjustment level when it is determined that the system controller has been set. John receiver.   After the power is turned on and the initial noise signal level is detected by the noise level detection circuit, the sound of the volume set by the user operation is output from the speaker when the volume is set based on the user operation. An adjustment level difference, which is a difference between a sound signal level from the sound level detection circuit in a state where the sound is detected and an initial noise signal level from the noise level detection circuit in a preset state where the sound is not output from the speaker. Adjustment level difference storage control means for temporarily storing in a memory, and sound output state noise level detection in which the noise level detection circuit detects a noise signal level when sound is output from a speaker at the set volume. The noise level in the state where the sound is output with the control means is greater than the initial noise signal level And a noise level determination means for determining whether the noise level in the state where the sound is output is greater than the initial noise signal level so that the difference between the adjustment levels is maintained after a predetermined time has elapsed. To adjust the gain of the audio amplifier circuit to increase the volume, and it is determined that the noise signal level in a state where the audio is being output is lower than the noise signal level after the increase. Or a volume control instruction means for instructing to lower the volume by adjusting the gain of the audio amplifier circuit so as to keep the adjustment level difference when it is determined that the level is lower than the initial noise signal level. A television receiver comprising a system controller.   From an audio level detection circuit for detecting the level of an audio signal from the audio amplifier circuit, a noise microphone for receiving ambient noise, a microphone amplifier circuit for amplifying a microphone signal from the noise microphone, and the microphone amplifier circuit A noise extraction circuit that extracts a noise signal by subtracting the audio signal output from the audio amplification circuit from the output microphone signal, a noise level detection circuit that detects the level of the noise signal from the noise extraction circuit, and a user operation The sound signal level from the sound level detection circuit when the sound having the volume set by the sound is output from the speaker and the initial noise from the noise level detection circuit in the preset state where the sound is not output from the speaker 3. An adjustment level difference calculating circuit for calculating a difference from the signal level as an adjustment level difference. Television receiver of the mounting.

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