JP2011130236A - Audio amplifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an audio amplifier capable of appropriately incorporating a built-in circuit/speaker in a TV receiver into a multichannel audio system. <P>SOLUTION: Au audio amplifier includes an audio signal obtaining part for inputting a video signal and a multichannel audio signal, a TV connection part to which a TV receiver is connected, a speaker connection part to which a speaker is connected, and a signal processing part outputting the audio signal and the video signal of a center channel from the TV connection part, delaying the audio signal of other channels by the time required for the TV receiver to decode the video signal, and outputting it from the speaker connection part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an audio amplifier that reproduces a multi-channel audio signal.

  With the widespread use of multichannel audio sources such as digital television broadcasts, DVDs, and BluRay discs, audio systems that reproduce multichannel audio signals have become widespread. When configuring a multi-channel audio system, usually, speakers for the corresponding channels are arranged in the listening room.

  On the other hand, the multi-channel audio source as described above is an audio / video (AV) source accompanied by a video signal (video). Therefore, in a multi-channel audio system, a monitor is installed together with the plurality of speakers. As the monitor, a television receiver is usually used. The television receiver includes a display such as a liquid crystal and an audio circuit and a speaker. Therefore, an audio system has been proposed in which a built-in speaker of a television receiver can be incorporated into a part of a multichannel audio signal (for example, Patent Documents 1 and 2).

JP 2004-104715 A

JP 2006-50195 A

  By the way, the decoding of the digital audio signal requires only about several milliseconds, whereas the decoding of the digital video signal requires about 50 milliseconds to 100 milliseconds. When the audio signal signal section is operated independently, the video is output with a delay from the sound, and the movement of the speech and the performer's mouth is shifted. Therefore, recent television receivers are provided with a function (lip sync function) for delaying an audio signal by a time required for decoding a video signal and outputting it to a speaker.

  However, in the systems of Patent Documents 1 and 2, the multi-channel audio signal is simply distributed to the speaker and the television receiver, so that the sound emitted from the speaker and the television receiver are output after being delayed. There was a problem that the audio and video were out of sync.

  An object of the present invention is to provide an audio amplifier capable of appropriately incorporating an audio circuit and a speaker built in a television receiver into a multi-channel audio system.

  The invention of claim 1 is an audio signal acquisition unit for reproducing or inputting a video signal and a multi-channel audio signal, a television connection unit to which a television receiver is connected, a speaker connection unit to which a speaker is connected, and a part thereof The audio signal of the channel and the video signal are output from the television connection unit, and the audio signal of the other channel is delayed by the time required for the television receiver to process the audio signal and video signal of the partial channel. And a signal processing unit that outputs from the speaker connection unit.

  According to a second aspect of the present invention, the signal processing unit controls the volume of the other channel and outputs a volume control command of the partial channel from the television connection unit.

  According to a third aspect of the present invention, the partial channel is a center channel.

  According to a fourth aspect of the present invention, the signal processing unit installs a microphone at a listening point, and the microphone collects the test sound emitted from the speaker of the television receiver connected to the television connection unit. The audio signal of the other channel is delayed by a time difference between the required time and the required time until the microphone picks up the test signal emitted from the speaker connected to the speaker connection unit. And

  According to the audio amplifier of the present invention, since the audio signal emitted from the speaker is output after being delayed by the time required for processing the video signal and the audio signal in the television receiver, the directly connected speaker and the television receiver are output. Even when an audio signal is configured in combination with the built-in speaker, it is possible to perform synchronized playback without shifting audio and video.

Configuration diagram of an AV system according to an embodiment of the present invention Schematic block diagram of AV amplifier and TV in AV system The figure explaining the flow of the audio signal in AV amplifier The figure which shows the example of the parameter table memorize | stored in AV amplifier Flow chart showing the procedure of sound field optimization processing The figure explaining the delay time set to each channel of audio Flow chart showing mode switching operation of AV amplifier

  FIG. 1 is a configuration diagram of an AV system according to an embodiment of the present invention. A listening point 8 where the user sits is set at the approximate center of the listening room 9. A rack 5 is arranged in front of the listening point 8, a television receiver (TV) 2 is installed on the rack 5, and an AV amplifier 1 and a source device 4 are installed inside the rack 5. The source device 4 is, for example, a DVD playback device or a set top box.

  In addition, the speaker 3 is arranged so as to surround the listening point 8. A front left (FL) speaker and a front right (FR) speaker are arranged on the front left and right of the listening point 8, and a surround left (SL) speaker and a surround right (SR) speaker are arranged on the left and right of the listening point 8, respectively. A subwoofer (SW) is arranged on the left side of FIG.

  The source device 4 reproduces and outputs an audio / video signal having a video signal and an audio signal of 5.1 channel. Here, the 5.1 channel is a center (C) channel, front left (FL) channel, front right (FR) channel, surround left (SL) channel, surround right (SR) channel, and subwoofer (SW) channel. . The audio / video signal reproduced by the source device 4 is input to the AV amplifier 1 via the HDMI cable.

  The AV amplifier 1 operates in a normal mode in which an audio source is reproduced only by a speaker 3 directly connected by a switching operation, and an extended mode in which a multichannel audio system is configured by the speaker 3 and the built-in speaker 24 of the television 2. .

  In the extension mode, the video signal is output to the downstream television 2 as it is (after being delayed) in the AV amplifier 1. Of the input audio signals, the signals of the FL channel, FR channel, SL channel, SR channel, and SW channel are output to the corresponding speaker 3 after being subjected to signal processing for delay, sound quality adjustment, and volume adjustment. The center channel signal is subjected to signal processing for delay and sound quality adjustment, and then output to the television 2 together with the volume control command (CEC command) and the video signal. The AV amplifier 1 and the television 2 are connected via an HDMI cable.

  In the extended mode, the television 2 reproduces the input video signal and displays it on the display, and reproduces the input center channel audio signal using the built-in speaker (stereo speaker) 24. The playback volume of the audio signal is controlled by an audio control command input from the AV amplifier 1.

  As a result, in the extended mode, the built-in speaker 24 of the television 2 is incorporated in the audio system centered on the AV amplifier 1, and a lean speaker configuration is possible. In addition, the center channel on which the speech of the performer is reproduced can be heard from the front of the television 2, so that there is no sense of incongruity in the direction of voice arrival.

  FIG. 2 is a schematic block diagram of the AV amplifier 1 and the television 2. The AV amplifier 1 includes a control unit 10, a memory 11, an operation / display unit 12, an HDMI receiving unit (Rx) 13, an HDMI transmitting unit (Tx) 16, an audio processing unit 14, and a video buffer 15. The control unit 10 controls the operation of the entire AV amplifier 1. The memory 11 is a flash memory, and stores a program for controlling the operation of the apparatus, set parameters, and the like in a nonvolatile manner. The operation / display unit 12 receives a user operation and displays a current operation state. The HDMI receiving unit 13 receives an audio / video signal from the HDMI transmitting unit 41 of the source device 4. The HDMI transmitting unit 16 transmits an audio / video signal to the HDMI receiving unit 21 of the television 2. The HDMI cable can transmit a command signal (CEC command) for controlling a downstream device in addition to a digital audio / video signal.

  The audio processing unit 14 is configured by a DSP, processes the audio signal input from the HDMI receiving unit 13, outputs the processed signal to the speaker 3 through the speaker connection unit 17, and transmits the processed signal to the television through the HDMI transmission unit 16. Output to 2. The buffer 15 delays the video signal by the time required for the audio processing unit 14 to process the audio signal and outputs the delayed video signal to the HDMI transmission unit 16.

  In FIG. 2, the speaker 3 is directly connected to the speaker connection unit 17, but a separate device such as a power amplifier may be inserted between the speaker connection unit 17 and the speaker 3.

  Here, with reference to FIG. 3 and FIG. 4, the audio signal processing in the audio processing unit 14 in the extended mode will be described. FIG. 3 is a diagram illustrating the flow of audio signals before and after the sound field processing unit 14 of the AV amplifier 1. FIG. 4 is a diagram showing an example of a parameter table set in the memory 11. The 5.1 channel audio signal input from the HDMI receiving unit 13 is input to the audio processing unit 14. The audio processing unit 14 functionally includes a delay unit 14A, an equalizer 14B, and a volume control unit 14C. A delay parameter (see FIG. 4) for determining the delay time of the audio signal of each channel is input to the delay unit 14A from the control unit 10 (memory 11). The delay time is an adjustment time for canceling the difference in arrival time due to the time required for signal processing or the installation position of the speaker so that the audio signals of the respective channels reach the listening point 8 at the same time. The delay unit 14A delays the audio signal of each channel by a time determined by a delay parameter and inputs the delayed signal to the equalizer 14B.

  The equalizer 14B is formed of, for example, a 7-band parametric equalizer. The equalizer 14B receives sound field control parameters for each channel from the control unit 10 (memory 11). The sound field control parameter is a combination of the user-set sound field parameter and the sound field compensation parameter (see FIG. 4). The user-set sound field parameter is an equalization parameter for realizing a sound field such as a hall or live performance. The sound field compensation parameter is an equalization parameter for compensating the difference in sound quality depending on the performance of the speakers of each channel and the installation conditions so that the signals of all channels reach the listening point 8 with the same sound quality. The equalizer 14B adjusts the sound quality of the audio signal of each channel with the sound field control parameter, and outputs it. The signals of the FL channel, FR channel, SL channel, SR channel, and SW channel are input to the volume control unit 14C. The center channel signal is input to the HDMI transmission unit 16. Note that the sound processing unit 14 may apply effects such as reverberation to the audio signal in order to form a more realistic sound field.

  Volume control parameters for the FL channel, FR channel, SL channel, SR channel, and SW channel are input to the volume control unit 14C from the control unit 10 (memory 11). Further, the volume control parameter of the center channel is input to the HDMI transmission unit 16. The volume control parameter is a combination of the user-set volume control value and the volume compensation parameter (see FIG. 4). The user set volume control value is a volume value set by a user operation. The volume compensation parameter is a parameter for compensating for the difference in volume caused by the size of the speaker of each channel, the distance from the listening point 8 and the like so that the signals of all the channels can be heard at the same volume at the listening point 8. . The volume control unit 14C adjusts the sound quality of the FL channel, FR channel, SL channel, SR channel, and SW channel audio signals with the volume control parameter, and outputs the audio signal to the speaker 3 of the corresponding channel.

  The center channel audio signal and the volume control parameter are output from the HDMI transmission unit 16 to the television 2 together with the video signal. The audio signal of the center channel is controlled in volume by the audio processing unit 22 of the television 2 and is emitted from the built-in speaker 24 of the television 2.

  The television 2 includes a control unit 20, an HDMI receiving unit 21, an audio processing unit 22, a video processing unit 23, a built-in speaker 24, and a display 25. The HDMI receiving unit 21 receives an audio / video signal from the AV amplifier 1. Of the audio / video signals received by the HDMI receiving unit 21, the audio signal is input to the audio processing unit 22, and the video signal is input to the video processing unit 23. The command signal sent via the HDMI cable is input to the control unit 20. The video processing unit 23 decodes the input video signal and displays it on the display 25. The audio processing unit 22 controls the volume of the input audio signal and delays the audio signal and then emits the sound from the speaker 24. The delay time for the audio processing unit 22 to delay the audio signal is approximately the same as the time required for the video processing unit 23 to decode the video signal. This delay time is about 50 milliseconds. As a result, the video and audio are synchronized so that the movement of the performer's mouth does not deviate from the speech of the speech.

  When a volume control command is input from the AV amplifier 1, the control unit 20 controls the sound processing unit 22 with the volume control command, and performs volume control according to the command. The control unit 20 does not accept a volume adjustment operation from the user when performing volume control according to the volume control command. However, if the user performs a volume adjustment operation on the AV amplifier 1, the volume of the speaker 3 is controlled, and a volume control command corresponding to this operation is transferred from the AV amplifier 1 to the television 2, so that the built-in television 2 The volume of the entire AV system including the speaker 24 is controlled.

  The audio processing unit 14 of the AV amplifier 1 is connected to a microphone 6 for executing sound field optimization processing for determining the delay parameter, sound field compensation parameter, and volume compensation parameter.

  Here, the sound field optimization process for determining the delay parameter, the sound field compensation parameter, and the volume compensation parameter will be described with reference to the flowchart of FIG. The sound field optimization processing is based on the timing, frequency spectrum, and volume of the test sound collected by the microphone 6 by installing the microphone 6 at the listening point 8 and emitting the test sound individually from each of the speakers 3 and 24. Then, parameters that eliminate the difference between the speakers 3 and 24 are determined. That is, the delay parameter is determined so that the difference in sound emission timing is eliminated, the sound field compensation parameter is determined so that the difference in frequency spectrum is eliminated, and the volume compensation parameter is determined so that the volume difference is eliminated To do.

  When the user installs the microphone 6 at the listening point 8 and performs an operation for starting the sound field optimization process, the operation of FIG. 5 starts. First, one channel to which the speaker 3 is connected is selected (S1). A pulse sound is output and emitted from the speaker 3 of the selected channel (S2), and the time until the pulse sound reaches the microphone 6 and is collected is measured (S3). After the measurement of the arrival times of all channels is completed, the delay parameters of each channel are determined by comparing them. Next, white noise is output and emitted from the speaker 3 of the selected channel (S4). White noise is a signal that uniformly includes all frequency components. The frequency component is measured by performing FFT on the signal picked up by the microphone 6 (S5). Based on this measurement result, a sound field compensation parameter for adjusting the frequency characteristics of the sound reaching the listening point 8 from the speaker 3 of the selected channel to be flat is determined (S6). Next, a maximum volume (0 dB) sound is output and emitted from the speaker 3 of the selected channel (S7), and the sound is picked up by the microphone 6 and the sound pressure level is measured (S8). After the measurement of the sound pressure levels of all the channels is completed, the volume compensation parameters for each channel are determined by comparing them.

  Thereafter, it is determined whether or not the processing of S2 to S8 has been completed for all channels to which the speaker 3 is connected (S9). If all channels have not been processed (NO in S9), the next channel is selected (S10) and the process returns to S2. If all channels have been processed (YES in S9), the process proceeds to S11 and the above processing is executed for the built-in speaker 24 of the television 2.

  In S11, a command (CEC command) with a content that prohibits the user's operation while fixing the volume to the maximum (0 dB) is transmitted to the television 2. At the same time, the volume value set at the time of the television 2 is sucked up and stored. Then, a pulse sound is output to the television 2 and emitted from the built-in speaker 24 (S12), and the time until the pulse sound reaches the microphone 6 and is collected is measured (S13). Next, white noise is output to the television 2 and emitted from the built-in speaker 24 (S4), and the frequency component is measured by performing FFT on this signal collected by the microphone 6 (S15). Based on the measurement result, the sound field compensation parameter for adjusting the frequency characteristics of the sound reaching the listening point 8 from the built-in speaker 24 of the television 2 to be flat is determined (S16). Next, a maximum volume (0 dB) sound is output to the television 2 and emitted from the built-in speaker 24 (S17). This sound is collected by the microphone 6 and the sound pressure level is measured (S18). After the above processing, the volume value sucked in the television 2 is set, and the operation by the user is permitted (S19).

  This completes all measurement processes, and the delay parameter and volume control parameter are determined below. First, delay parameters for each channel are set (S20). After the test sound is output to each channel, the arrival time until the sound reaches the listening point 8 is compared, and the delay time of the channel having the longest sound arrival time (latest channel) is set to zero. The delay time of the other channel is the difference between the arrival time of the sound of that channel and the arrival time of the sound of the latest channel. The delay parameter is determined so that the delay time of each channel is set in this way.

  The delay time of each channel will be described in detail with reference to FIG. As described above, since the TV 2 requires about 50 ms for decoding the video signal, the audio signal is also as long as the decoding of the video signal so that there is no deviation between the reproduced and output video and audio ( Delayed internally (about 50 ms) Accordingly, the arrival time until the listening point 8 is reached after outputting the test signal is usually that the center channel (speaker 24) delayed by the 50 ms signal on the television 2 is significantly longer than the other channels. is there.

  As shown in FIG. 6A, the spatial propagation time from when the test sound is emitted from the speaker until reaching the listening point 8 is not very different for each channel, but only for the center (C) channel, the test signal is transmitted. Since it is transmitted to the television 2 via the HDMI connector and further internally delayed by the decoding time of the video signal inside the television 2, the arrival time is significantly longer than other channels. Therefore, the delay time (delay parameter) of the center channel is normally 0.

  If the TV 2 does not delay the audio signal for the video decoding time, as shown in FIG. 6B, the video signal is decoded for all channels including the center channel in the AV amplifier 1. What is necessary is just to delay so that it may synchronize with timing. The time required for video decoding may be received from the TV 2 using a CEC command or the like, and an optical sensor is connected to the AV amplifier 1 and a test image is output from the AV amplifier 1 to the TV 2 to measure delay. You may make it do.

  Next, a volume control parameter for each channel is set (S21). The sound pressure level at the listening point 8 of the sound emitted from the speakers 3 and 24 of each channel is compared, and the attenuation amount of the channel (minimum channel) with the lowest sound pressure level is set to 0 dB. The difference between the sound pressure level of the sound of the channel and the sound pressure level of the sound of the minimum channel. The volume control parameter is determined so that the attenuation amount of each channel is set in this way. The parameters set in the above process are written in the parameter table (see FIG. 4) (S22), and the process is terminated.

  FIG. 7 is a flowchart showing the operation of the AV amplifier 1 when the extended mode is turned on / off. FIG. 4A shows the operation when the extended mode is on. When the user performs an operation to turn on the extended mode, a volume control prohibit command is transmitted to the television 2 to prohibit the volume adjustment operation by the user (S30). The volume setting value currently set in the television 2 is read and stored (S31). Then, various parameters are set in the audio processing unit 14 (S32), the center channel volume control parameter is transmitted to the television 2 and the speaker 3 directly connected to the AV amplifier 1 and the built-in speaker 24 of the television 2 are set. Are linked (S33). In the subsequent reproduction of the audio / video signal, only the audio signal of the center channel is transmitted to the television 2 via the HDMI transmission unit 16 (S34).

  FIG. 7B is a flowchart showing the operation when the extended mode is off. When the user performs an extension mode off operation, the volume setting value read in S31 is transmitted to the television 2, the volume is returned to the original value (S40), and a volume control permission command is transmitted to the television 2. Then, the volume adjustment operation by the user is permitted (S41). Thereby, the television 2 operates independently in the normal mode. The AV amplifier 1 operates without a center channel (for example, with two channels on the front left and right).

  In this embodiment, the center channel is assigned to the speaker of the television 2 (external device) in the expansion mode, but the channel assigned to the television 2 is not limited to the center channel. When the television 2 has a built-in speaker with a plurality of channels such as LR stereo, a plurality of channels of audio signals may be assigned to the television 2.

  In this embodiment, in the expansion mode, only the volume is adjusted by the television 2 (external device). However, the volume setting value of the television 2 is fixed to the maximum (0 dB), and the volume (signal) is set by the AV amplifier 1. (Level) may be adjusted and output.

  In this embodiment, the AV amplifier 1 inputs an audio / video signal from the source device 4, but the AV amplifier 1 has a built-in DVD playback unit, digital TV tuner, etc., and plays back the audio / video signal internally. It may be.

1 AV amplifier 2 TV 3 Speaker 4 Source device 8 Listening point

Claims (4)

An audio signal acquisition unit for playing back or inputting a video signal and a multi-channel audio signal;
A TV connection to which the TV receiver is connected;
A speaker connection part to which a speaker is connected;
The audio signal of the partial channel and the video signal are output from the television connection unit, and the audio signal of the other channel is delayed by the time required for the television receiver to process the audio signal and the video signal of the partial channel. A signal processing unit that outputs from the speaker connection unit;
Audio amplifier equipped with.   2. The audio amplifier according to claim 1, wherein the signal processing unit performs volume control of the other channel and outputs a volume control command of the partial channel from the television connection unit.   The audio amplifier according to claim 1, wherein the partial channel is a center channel.   The signal processing unit has a microphone installed at a listening point, a time required for the microphone to pick up test sound emitted from a speaker of a television receiver connected to the TV connection unit, and the speaker connection 4. The audio signal of the other channel is delayed by a time of a difference in required time until the microphone picks up a test signal emitted from a speaker connected to the unit. 5. Audio amplifier as described in.

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