JP3683131B2 - Audio signal control apparatus and playback apparatus having the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an audio signal control device that controls the sound quality of an audio signal in an audiovisual device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a stereo audio device having visuals, a technique of expanding a sound by providing a matrix surround circuit in order to give a sense of reality is employed. FIG. 6 shows a stereo audio device including the matrix surround circuit 1. When the switch 2 is turned on, the control unit 3 turns on the field effect transistor 4 to turn on the surround effect. Reference numerals 5 and 6 are a resistor for adjusting the surround effect and a capacitor for direct current cut. The frequency characteristics of the right channel amplifiers 7R, 8R, 9R and the speaker 10R are as flat as possible, and the frequency characteristics of the left channel amplifiers 7L, 8L, 9L and the speaker 10L are as flat as possible.
[0003]
In addition, in order to clarify the speech spoken by the characters, there is one in which a voice near the human voice band is added using a center speaker. In addition, in the audio signal, a passband filter that matches the low frequency range and human voice band to each frequency is provided, and the result of comparing the output is used to control the volume of each band, so that it can be used for scenes such as movie sources. There are things that have a corresponding effect.
[0004]
Furthermore, DVD (Digital Versatile Disc) -Video with dramatically improved recording capacity has begun to spread, and many movie titles have been released. Audio data recorded together with video data on this DVD is, for example, Dolby Digital (AC-). 3) 5.1-channel multi-channel audio data is recorded after being compressed, and when this is reproduced, the front speakers L, R, rear speakers L, R, center speakers, subwoofer speakers 6 It is possible to listen to the surround sound along with the video by playing back with the speaker of the stand. In addition, as this audio data, there is dts (Digital Theater System) audio data recorded on a DVD as 5.1 channel multi-channel audio data as in the case of Dolby AC-3 audio data. Usually, it is performed in the same manner as Dolby AC-3.
[0005]
[Problems to be solved by the invention]
However, in the matrix surround circuit, if the sound effect is expanded while watching a movie with a battle scene, the volume of the dialogue will be relatively lowered and the dialogue will be difficult to hear, or the localization of the dialogue sound image will be behind the image Tend to be in position.
In addition, in a device to which a center speaker is added, the localization of the sound image moves closer to the center speaker and does not match the position of the sound source in the image, resulting in a sense of discomfort. For example, when a center speaker is installed on the cabinet of a television receiver, the sound image is localized above the image and does not match the image. Further, in the case of this center speaker, a center speaker and an amplifier for driving the center speaker are required.
[0006]
In addition, even devices using passband filters and comparators require a system for controlling them, and tend to be expensive and complicated.
Furthermore, since the sound quality in movie theaters tends to have many overtone components and is different from the sound quality for playing music, in the case of a home compound device that can play music and play movies on a single unit, There is a problem that the atmosphere of the movie theater cannot be reproduced in the reproduction.
[0007]
Furthermore, the reproduction of Dolby AC-3 and dts audio data requires six speakers.
The present invention uses a simple circuit configuration and two stereo speakers, and in a stereo movie source, can provide a sound with a clear outline and a wide sound effect as obtained in a movie theater, It is an object to provide an audio signal control device that achieves positional matching with an image by locating a dialogue at the center and obtaining a sound quality as usual in a music source.
[0008]
In addition, a DVD in which multi-channel audio data such as Dolby AC-3 or dts audio data is recorded together with video data is played, 5.1 channels are downmixed, and output using two stereo speakers. However, it is an object of the present invention to provide a reproducing apparatus that can output in the same manner and can automatically switch a surround circuit and a bandpass circuit to an on state by determining multi-channel.
[0009]
[Means for Solving the Problems]
The audio signal control device of the present invention is A bandpass on state that has two channels of input and output and outputs the midrange of the audio signal frequency band with a higher gain than the low and high ranges, and a bandpass off state in which the frequency characteristics are flat from low to high. Two band-pass circuits that can be switched, a surround circuit that inputs the outputs of the two band-pass circuits and can switch the surround effect between an on state and an off state and obtains two-channel output, and the surround circuit And a control unit that switches the band pass circuit to the on state or the off state at the same time, and when the control unit sets the surround state, the band pass circuit is switched to reduce the midrange of the audio signal frequency band. Output with high gain compared to high and low frequencies It is characterized by comprising.
According to the present invention, a simple circuit configuration and two stereo speakers are installed on both sides of a TV monitor, so that a stereo movie source has a clear sound and a sense of spaciousness that can be obtained in a movie theater. A two-channel stereo audio signal control device that can obtain sound, has a localized position in the center of the image and achieves positional matching with the image, and can obtain sound quality as usual in a music source is obtained. It is done.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The audio signal control apparatus according to the present invention has two channels having a surround circuit. Input / output An audio signal control device , Interchanged between the band pass on state that outputs the high frequency gain of the audio signal frequency band interspersed with each channel and the band pass off state where the frequency characteristics are flat from low to high. Is possible Two A bandpass circuit; A surround circuit for inputting the outputs of the two band pass circuits and switching the surround effect between an on state and an off state to obtain a two-channel output; The surround circuit and the bandpass circuit When In conjunction with Simultaneously on or off And a controller for switching.
[0011]
Also, the audio signal control apparatus of the present invention has two channels having a surround circuit. Input / output An audio signal control device , Switch between the bandpass on state that outputs the middle frequency of the audio signal frequency band with low gain compared to the low and high frequencies, and the bandpass off state that has a flat frequency characteristic from low to high. Is possible Two A bandpass circuit; A surround circuit for inputting the outputs of the two band pass circuits and switching the surround effect between an on state and an off state to obtain a two-channel output; Said Via surround circuit It is connected to the output of each channel and performs electro-acoustic conversion, and the mid-range performs electro-acoustic conversion more efficiently than low and high frequencies. Two In conjunction with a speaker, the surround circuit and the bandpass circuit When the bandpass circuit is on, the surround circuit is off. When the bandpass circuit is off, the surround circuit is on. And a controller for switching.
[0012]
Specifically, the middle range of the audio signal frequency band is set to a band of 400 Hz to 7 kHz.
The reproduction apparatus of the present invention includes any one of the above audio signal control apparatuses, and reproduces audio data from a recording medium on which audio data is recorded together with video data. Audio data And input to the audio signal control device Having a reproducing means, Voice signal control device The control unit Said Based on the audio data read from the recording medium by the reproducing means, Voice signal control device Surround circuit When Bandpass circuit of On state and off state In conjunction with It is characterized by being configured to switch.
[0013]
When the control unit determines that the audio data is audio-compressed multi-channel audio data, the surround circuit and the bandpass circuit On and off Linked The switching , Raise the mid-range playback level It is configured as described above.
The multi-channel audio data is Dolby Digital (AC-3) audio data or dts audio data.
[0014]
The playback device of the present invention can play back a DVD on which multi-channel audio data is recorded together with at least video data as a recording medium. 2 channels A disc player for discriminating whether the disc of the recording medium is a DVD or another disc, and a multi-channel audio data from the recording medium, and two channels regardless of the number of channels of the original data A decoder for downmixing and outputting, and a discriminating means for discriminating the type of the extracted multi-channel audio data; , Interchanged between the band pass on state that outputs the high frequency gain of the audio signal frequency band interspersed with each channel and the band pass off state where the frequency characteristics are flat from low to high. Is possible Two A bandpass circuit; A surround circuit for inputting the outputs of the two band pass circuits and switching the surround effect between an on state and an off state to obtain a two-channel output; The surround circuit and the bandpass circuit When In conjunction with Simultaneously on or off A control unit for switching, the control unit, The disc is a DVD disc and When it is determined that the audio data is multi-channel audio data, the surround circuit and the band pass circuit are linked to each other. at the same time It is characterized by being configured to switch to the on state.
[0015]
Embodiments of the present invention will be described below with reference to FIGS.
In addition, the same code | symbol is attached | subjected and demonstrated to the thing which performs the same effect | action as FIG. 6 which shows a prior art example.
(Embodiment 1)
FIG. 1 shows an audio signal control apparatus according to (Embodiment 1) of the present invention. Since the right channel and the left channel have the same configuration, the right channel will be described as an example.
[0016]
A band pass circuit 11R is provided in the previous stage of the matrix surround circuit 1. This band-pass circuit 11R includes an amplifier 7R, a first feedback circuit 12 composed of a resistor and a capacitor for high-frequency cut, and a second feedback circuit 13 composed of a resistor and a capacitor for low-frequency cut. The band-pass characteristics are switched by turning on / off the transistor 14R.
[0017]
FIG. 2 shows the frequency characteristics of the bandpass circuit 11R.
In the band-pass off state in which the transistor 14R is turned off, the frequency characteristic is flat from low to high as shown by the solid line 15, and in the band-pass on state in which the transistor 14R is turned on, as shown by the broken line 16 Compared with the low and high bands, the mid band centered around 1 kHz is output with a high gain of +5 dB.
[0018]
Specifically, in the bandpass on state, as shown in FIG. 2, the gain increases by 5 dB at 1 kHz as compared with the frequency characteristic having a flat frequency characteristic from the low band to the high band in the bandpass off state, and the bandpass off state. The bandwidth having a gain increased by 3 dB from the flat frequency characteristic of the filter has a lower limit frequency of 400 Hz and an upper limit frequency of 7 kHz, and the frequency characteristic of the bandpass circuit 11R has a low frequency and a high frequency in the middle range of 400 Hz to 7 kHz. It can be said that it outputs at a higher gain than that.
[0019]
The transistor 14R is turned on / off by the control unit 3 that turns on / off the surround effect.
The control unit 3 is configured as follows.
When the switch 2 is turned off as a normal music signal reproduction state, the field effect transistor 4 is turned off, the surround effect of the matrix surround circuit 1 is turned off, and the transistor 14R is turned off. The frequency characteristic of the pass circuit 11R shows a flat frequency characteristic indicated by a solid line 15. Therefore, the music signal input to the amplifier 7R is amplified in a flat manner from low to high and is acoustically converted by the speaker 10R with the same frequency characteristics.
[0020]
When reproducing a visual stereo signal such as a movie source, if the switch 2 is turned on, the field effect transistor 4 is turned on, the surround effect of the matrix surround circuit 1 is turned on, and the transistor 14R is turned on. Thus, as shown by the broken line 16 in the frequency characteristics of the band pass circuit 11R, only the middle band is output with a high gain of 5 dB. Therefore, the bandpass circuit 11R increases the harmonic components of the sound of explosions and bullets in the battle scenes in dialogue and movies, resulting in a sound with a clear outline like a movie theater. It sounds like the sound image is localized in front of the listener who is in front, and it has powerful sound quality in the battle scene, and the surround effect is applied in the matrix surround circuit 1, but the sound image is localized at the position where the dialogue is drawn in the back of the screen. The sound field is expanded to the above listeners, and the sound of explosions and helicopters is powerful.
[0021]
As described above, according to the present embodiment, by providing a simple circuit configuration and two stereo speakers on both sides of the TV monitor, in a stereo movie source, a sound with a clear outline as obtained in a movie theater can be obtained. A sound effect with a sense of breadth can be obtained, and the dialogue is localized in the center of the image to achieve positional coincidence with the image, and the sound quality as in the past can be obtained in a music source.
[0022]
(Embodiment 2)
(Embodiment 2) differs from (Embodiment 1) in the frequency characteristics of speakers 10R and 10L and the frequency characteristics of bandpass circuits 11R and 11L. Others are the same as (Embodiment 1).
The speakers 10R and 10L in (Embodiment 1) are preferably as flat as possible in the frequency characteristics from low to high, but the acoustic frequency characteristics of the speakers 10R and 10L in (Embodiment 2) are as follows. As shown by a broken line 17 in FIG. 3, the electro-acoustic conversion is performed with high efficiency in the middle range centered on 1 kHz as compared with the low range and the high range.
[0023]
The frequency characteristics of the bandpass circuits 11R and 11L are the first and second feedback so that the middle band centered on 1 kHz is output with a lower gain than the low band and the high band as shown by the broken line 18 in FIG. The constants of the capacitors and resistors of the circuits 12 and 13 are changed.
With this configuration, when a normal music signal is reproduced, the control unit 3 keeps the transistor 14R on and the field effect transistor 4 off. At this time, the music signal input to the amplifier 7R is output with a low gain in the mid range compared to the low range and the high range, but the acoustic frequency characteristic of the single speaker 10R is for converting the mid range with high efficiency. The acoustic frequency characteristic coming out of the speaker 10R becomes a flat combined frequency characteristic from low to high as shown by the solid line 19 in FIG.
[0024]
When reproducing a visual stereo signal such as a movie source, if the switch 2 is turned on and the transistor 14R is turned off by the control unit 3 and the field effect transistor 4 is turned on, the music signal has a midrange of 5 dB. It comes out of the speakers 10R and 10L with a raised frequency characteristic.
This increases the harmonic growth of dialogue and movie battle scene explosions and bullet sounds, and it becomes a well-defined sound like a cinema, and in the human voice the listeners in the center front of the left and right speakers Sounds like moving forward, and powerful sound quality in battle scenes. Furthermore, the surround effect is applied in the matrix surround circuit 1, but the sound is localized in the position where it is retracted in the back of the screen, and the sound field is expanded to the above-mentioned listeners, without being localized according to the image, and Power is produced in the sound of explosions and helicopters.
[0025]
In this way, by installing a simple circuit configuration and two stereo speakers on both sides of a TV monitor, a stereo movie source can produce a sound with a clear outline and a spacious sound effect that can be obtained in a movie theater. The dialogue is localized at the center of the image to achieve positional coincidence with the image, and the sound quality as in the past can be obtained in the music source.
[0026]
(Embodiment 3)
4 and 5 show (Embodiment 3).
FIG. 4 shows a recording / reproducing apparatus having the audio signal control apparatus of (Embodiment 1). In (Embodiment 1), the switch 2 is manually operated, but in this (Embodiment 3), such manual operation is not required.
[0027]
In addition, the same code | symbol is attached | subjected and demonstrated to the same thing as (Embodiment 1).
The recording / reproducing apparatus shown in FIG. 4 is an apparatus capable of reproducing an optical disc 20 such as a DVD, VIDEO-CD (hereinafter referred to as VCD), CD-DA or the like as a recording medium. VCD and CD-DA are CD standards having a common physical structure, and the generic name of both is described as CD.
[0028]
The optical disk 20 rotated by the spindle motor 21 is irradiated with light on the recording surface of the optical disk 20 through an objective lens built in the optical pickup 22, and the reflected light from the recording surface is detected to detect the reflected light from the recording surface. Read the information data recorded in.
The detection signal of the optical pickup 22 is amplified by the RF amplifier 23, and the servo / disc discriminating means 24 discriminates whether the optical disc 20 is a DVD or a CD from the output signal of the RF amplifier 23, and controls the focus of the optical pickup 22, Each control of the tracking servo and the spindle servo of the spindle motor 21 is performed.
[0029]
Reference numeral 25 denotes a decoder, which has an audio decoder 26 together with a video decoder (not shown). When the audio data input from the RF amplifier 23 is multi-channel audio data, the audio decoder 26 downmixes and outputs it as an L and R two-channel stereo signal.
Here, in the case where the decoder 25 determines that the disc is a DVD when the disc is discriminated as described above, in order to discriminate what kind of audio data is recorded together with the video data, the data input to the audio decoder 26 is used as a control unit 27. This is performed by discriminating the identification code of the control information recorded on the DVD from the read information. That is, the type of recording method for audio compression of MPEG2 audio data, Dolby AC-3 audio data, and dts audio data is determined.
[0030]
The data of the L and R channels output from the audio decoder 26 after being downmixed into two channels are input to the bandpass circuits 11R and 11L.
The band-pass circuits 11R and 11L have a band-pass on state in which the mid-range of the audio signal frequency band is output with a higher gain than the low-frequency and high-frequency ranges, and is flat from the low-frequency to the high-frequency. It is possible to switch to a band pass off state that outputs with a good frequency characteristic.
[0031]
The outputs of the bandpass circuits 11R and 11L are input to the matrix surround circuit 1. The matrix surround circuit 1 is configured to be switchable between an on state in which the output of the bandpass circuits 11R and 11L is output with a surround effect and an off state in which the output is performed without applying the surround effect.
The output of the band pass circuit 11R via the matrix surround circuit 1 is reproduced by the speaker 10R via the amplifier 9R, and the output of the band pass circuit 11L via the matrix surround circuit 1 is reproduced by the speaker 10L via the amplifier 9L. Is done.
[0032]
The control unit 27 collects disc discrimination result information for the servo / disc discriminating means 24 and performs reproduction control relating to the reproduction of the optical disc 20, and the decoder 25 reads the DVD from the read information as described above. By discriminating the identification code of the control information recorded in the disc, the type of audio data is discriminated, the audio data decoding method is set based on the discriminating recording method, and the band-pass circuits 11R and 11L and the matrix surround circuit 1 are set. On / off is set by control described later, and the on / off state is displayed on the display unit 28. In addition, the control unit 27 is configured to collect the pressing information of an ON switch and an OFF switch (not shown) of the operation unit 29 and switch the bandpass circuits 11R and 11L and the matrix surround circuit 1.
[0033]
Here, when the optical disc 20 is set, the servo / disc discriminating means 24 rotates the optical disc 20 by the spindle motor 21 and irradiates light through the objective lens built in the optical pickup 22 to detect the reflected light from the recording surface. Then, the optical disk 20 is discriminated as a DVD and a CD from the output amplified by the RF amplifier 23 and the discrimination result is output to the control unit 27.
[0034]
The output of the RF amplifier 23 is input to the decoder 25. When the optical disk 20 is a DVD, the input data is read from the audio decoder 26 into the control unit 27, and the control information recorded on the DVD is identified from the read information. By discriminating the code, the type of the recorded recording method is discriminated. The control unit 27 sets a decoding method in the audio decoder 26 based on the determination result of the recording method. Then, the audio decoder 26 whose decoding method is set by the control unit 27 downmixes the output of the RF amplifier 23 in the case of multi-channel, and decodes it to a 2-channel stereo audio signal.
[0035]
The output of the audio decoder 26 is input to each of the bandpass circuits 11R and 11L, and when it is set to ON by control described later of the control unit 27, the middle range of the audio signal frequency band is set with respect to the output of the audio decoder 26. Output with high gain compared to low and high frequencies. When it is set to off, the audio decoder 26 outputs with a flat frequency characteristic from the low frequency range to the high frequency range of the audio signal frequency band. The outputs of the band-pass circuits 11R and 11L are input to the matrix surround circuit 1, and when set to ON by control described later of the control unit 27, the outputs of the band-pass circuits are output with a surround effect. When set to OFF, the output of the bandpass circuits 11R and 11L is output without applying a surround effect.
[0036]
FIG. 5 shows a processing routine for controlling the band-pass circuits 11R and 11L and the matrix surround circuit 1 by the control unit 27.
In step S101, the control unit 27 determines whether the optical disk 20 is a DVD from the optical disk determination information acquired from the servo / disk determination unit 24. If the optical disc 20 is a CD, then the routine from step S102 to step S104 is executed.
[0037]
In step S102, the bandpass circuits 11R and 11L and the matrix surround circuit 1 are switched off. In step S103, the display unit 28 displays the off state. In step S104, it is detected whether or not the ON switch of the operation unit 29 is operated. If not, step S102 and step S103 are repeated. If it is detected in step S104 that the ON switch of the operation unit 29 has been operated, the routine from step S105 to step S107 is executed.
[0038]
In step S105, the bandpass circuits 11R and 11L and the matrix surround circuit 1 are switched on. In step S106, the display unit 28 displays the on state. In step S107, it is detected whether or not the off switch of the operation unit 29 is operated. If not, steps S105 and S106 are repeated. If it is detected in step S107 that the off switch of the operation unit 29 has been operated, the process returns to step S102.
[0039]
On the other hand, if it is determined in step S101 that it is a DVD, it is determined in step S108 whether or not the recording method is AC-3 from the stream ID analyzed by the decoder 25.
If it is determined in step S108 that the recording method of the optical disc 20 is AC-3, the routine from step S105 to step S107 is executed, and the bandpass circuits 11R and 11L and the matrix surround circuit 1 are automatically turned on. Switch to.
[0040]
If it is determined in step S108 that the recording method of the optical disc 20 is not AC-3, it is determined whether or not the recording method is dts from the stream ID analyzed by the recording method determination unit 25 in step S109.
If it is determined in step S109 that the recording method of the optical disc 20 is dts, the routine from step S105 to step S107 is executed, and the bandpass circuits 11R and 11L and the matrix surround circuit 1 are automatically turned on. It is done.
[0041]
If it is determined in step S109 that the recording method of the optical disc 20 is not dts, the routine from step S102 to step S104 is executed, and the bandpass circuits 11R and 11L and the matrix surround circuit 1 are automatically switched off. .
With this configuration, when it is determined that the disc 20 is a DVD and audio data is recorded in AC-3 or dts, the bandpass circuits 11R and 11L and the matrix surround circuit 1 are automatically turned on. At the same time, by displaying ON on the display unit 28, a sound with a clear outline and a sound effect with a sense of expanse as obtained in a movie theater can be obtained despite the sound output from a two-channel speaker. can get.
[0042]
Further, when the disk 20 is a CD-DA or VCD, or a DVD, but the recording method is recorded in MPEG2, the matrix surround circuit 1 and the band pass circuit 11R that display OFF on the display unit 28. , 11L is turned off, the conventional sound quality for reproducing the audio recording information of the optical disc 20 can be obtained.
[0043]
When the user desires to change the setting based on the ON or OFF display displayed on the display unit 28, the matrix surround circuit 1 and the band pass circuit 11R are pressed by pressing the ON switch or OFF switch of the operation unit 29. , 11L can be arbitrarily changed.
[0044]
【The invention's effect】
As described above, according to the present invention, The audio signal controller has two channels of input and output, and the frequency characteristics are flat from low to high, with a bandpass on state that outputs the middle frequency of the audio signal frequency band with a higher gain than the low and high frequencies. Two band-pass circuits that can be switched to the band-pass off state, and a surround circuit that receives the outputs of the two band-pass circuits and can switch the surround effect between the on-state and the off-state to obtain two-channel output And a control unit that simultaneously switches the surround circuit and the bandpass circuit to an on state or an off state, and when the control unit sets the surround state, the bandpass circuit is switched to switch the audio signal frequency band Outputs the middle frequency range with a higher gain than the low and high frequencies Because of this configuration, by installing a simple circuit configuration and two stereo speakers on both sides of the TV monitor, a stereo movie source has a clear sound and a spacious sound effect that can be obtained in a movie theater. Can be obtained, and the dialogue is localized at the center of the image to achieve positional coincidence with the image, and a two-channel stereo audio signal control device that can obtain the same sound quality as a conventional music source can be realized. Is.
[0045]
When it is determined that the audio data recorded on the recording medium is recorded as Dolby AC-3 or dts multi-channel audio data, the surround circuit and the bandpass circuit are automatically turned on to Although the sound is output from the channel speaker, it is possible to realize a playback device that can obtain a sound with a clear outline and a sound effect with a sense of breadth that can be obtained in a movie theater without performing any operation.
[0046]
Also, The disc is CD-DA or VCD or DVD, but the recording method is MPEG2. If it is recorded, turn off the surround circuit and bandpass circuit automatically so that the audio recording information Leave It is possible to obtain the same sound quality that is played back.
[Brief description of the drawings]
FIG. 1 is a block diagram of an audio signal control apparatus according to (Embodiment 1) of the present invention.
FIG. 2 is a frequency characteristic diagram of the bandpass circuit according to the embodiment;
FIG. 3 is a conceptual diagram of acoustic frequency characteristics of speaker output according to (Embodiment 2) of the present invention.
FIG. 4 is a block diagram of a playback apparatus according to (Embodiment 3) of the present invention.
FIG. 5 is a flowchart of the control unit according to the embodiment;
FIG. 6 is a configuration diagram of a conventional audio device including a surround circuit.
[Explanation of symbols]
1 Matrix surround circuit
3 Control unit
4 Field effect transistors
7R, 7L, 8R, 8L, 9R, 9L Amplifier
10R, 10L speaker
11R, 11L bandpass circuit
12 First feedback circuit
13 Second feedback circuit
14R transistor
20 Optical disc
21 Spindle motor
22 Optical pickup
23 RF amplifier
24 Servo / disk discriminating means
25 Decoder
26 Audio decoder
27 Control unit
28 Display section
29 Operation unit

Claims (7)

A two-channel input / output audio signal control device having a surround circuit ,
Interchanged between the band pass on state that outputs the high frequency gain of the audio signal frequency band interspersed with each channel and the band pass off state where the frequency characteristics are flat from low to high. Two bandpass circuits capable of
A surround circuit for inputting the outputs of the two band pass circuits and switching the surround effect between an on state and an off state to obtain a two-channel output;
The surround circuit and the control unit in conjunction with a band-pass circuit for switching the on or off simultaneously and the audio signal control apparatus provided with. A two-channel input / output audio signal control device having a surround circuit ,
Switch between the bandpass on state that outputs the middle frequency of the audio signal frequency band with low gain compared to the low and high frequencies, and the bandpass off state that has a flat frequency characteristic from low to high. Two bandpass circuits capable of
A surround circuit for inputting the outputs of the two band pass circuits and switching the surround effect between an on state and an off state to obtain a two-channel output;
Two speakers that are connected to the output of each channel via the surround circuit and perform electro-acoustic conversion, and perform mid-range electro-acoustic conversion more efficiently than low and high frequencies;
A sound provided with a control unit that links the surround circuit and the bandpass circuit to switch the surround circuit to an off state when the bandpass circuit is in an on state, and to switch the surround circuit to an on state when the bandpass circuit is in an off state Signal control device. The audio signal control device according to claim 1 or 2, wherein a middle range of the audio signal frequency band is set to a band of 400 Hz to 7 kHz. A playback device that has the audio signal control device according to claim 1 and plays back audio data from a recording medium on which audio data is recorded together with video data,
Reproducing means for reproducing audio data read from a recording medium and inputting the audio data to the audio signal control device ;
Control unit of the audio signal controller, configured to switch in conjunction with on and off states of the surround circuit and a bandpass circuit of the audio signal control device based on the read audio data from the recording medium by said reproducing means Playback device. Wherein, when the audio data is determined to be a multi-channel audio data audio compression, it switched in conjunction with on and off states of said bandpass circuit and the surround circuit,
5. The playback apparatus according to claim 4 , wherein the playback level is configured to increase the playback level of the mid range . 6. The playback apparatus according to claim 5, wherein the multi-channel audio data is Dolby Digital (AC-3) audio data or dts audio data. A two-channel playback device capable of playing a DVD in which multi-channel audio data is recorded together with at least video data as a recording medium,
Disc discriminating means for discriminating whether the disc of the recording medium is a DVD or other disc;
A decoder for extracting multi-channel audio data from a recording medium and down-mixing it to two channels regardless of the number of channels of the original data;
Determining means for determining the type of the extracted multi-channel audio data ;
Interchanged between the band pass on state that outputs the high frequency gain of the audio signal frequency band interspersed with each channel and the band pass off state where the frequency characteristics are flat from low to high. Two bandpass circuits capable of
A surround circuit for inputting the outputs of the two band pass circuits and switching the surround effect between an on state and an off state to obtain a two-channel output;
Wherein in conjunction with surround circuit and said bandpass circuit and a control unit for turning on or off at the same time,
The control unit is configured to simultaneously turn on the surround circuit and the bandpass circuit in conjunction with each other when it is determined that the disk is a DVD disk and the audio data is multi-channel audio data. Playback device.

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