JPH10191203A - Audio playback circuit - Google Patents

Abstract

(57) [PROBLEMS] To effectively use a bass enhancement circuit and a subwoofer built in a television receiver when L and R speakers incorporated in the television receiver are used as Dolby Pro Logic or Dolby Digital center speakers. To provide a sound reproduction circuit. SOLUTION: A change-over switch circuit 2 has a center channel signal input terminal 1 side or L, R audio signal input terminals 10,
Regardless of which of the 11 sides is selected, the L and R audio signals (second reproduced L and R audio signal outputs) reproduced by the reproduction means 21 are output from a bass enhancement circuit 40 built in the television receiver 24. , And is added to the audio output signals from the output terminal a and the output terminal d of the changeover switch circuit 2, and the amplifier built in the television receiver 24 via the amplifiers 5 and 6. 7 and 8
And output as audio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio reproducing circuit in electronic equipment such as a television receiver and a stereo reproducing apparatus, and more particularly to an audio reproducing circuit using left and right speakers in the electronic equipment as center speakers of Dolby Pro Logic. About.

[0002]

2. Description of the Related Art In recent years, with the development and spread of high-quality audio multiplex broadcasting, digitized high-quality video software, and their recording / reproducing devices, audio signals used in electronic devices such as television receivers have been developed. Processing circuits have been reviewed, and circuits for sound field reproduction, such as pseudo-stereo circuits and surround circuits (prologic decoders), have been proposed in addition to higher output and higher sound quality. Also, among the above-described audio signal processing circuits, the surround circuit gives the listener a sense of enclosing and a sense of spreading in the reproduced sound field while the sense of direction of the sound source of the source signal is preserved, thereby allowing the listener to Therefore, it is possible to easily enjoy a sound with a three-dimensional effect and a sense of reality. Therefore, there is a very strong request from a listener (market).

Such a surround circuit electrically generates a reverberation component of an audio output of a TV receiver and an output of a stereo playback device and the like, and outputs the reverberation component at the same time as the original audio output, thereby increasing a sense of realism. Circuit. Various surround systems have been proposed. In this proposal, the following description will be made by taking the Dolby stereo surround system, which is the mainstream of current cinema sound, as an example.

FIG. 6 is a diagram showing the configuration (outline view) of a conventional surround system using analog audio signals using left and right speakers built into a television receiver as center channel speakers of a Dolby stereo surround circuit. In FIG. 6, LD (laser disk) and VCR
A video signal output terminal V provided on a reproducing means 21 such as a (video cassette recorder) is connected to a television receiver 24.
L and R audio signal output terminals L and R provided on the reproducing means 21 are connected to, for example, the L and R audio signals of a pro logic decoder (a Dolby stereo surround circuit having a pro logic configuration) 22. Connected to input terminal. The L and R audio signal output terminals and the surround signal output terminal of the pro logic decoder 22 are connected to the L and R audio signal input terminals and the surround signal input terminal of the AV amplifier 23, and the center channel signal output terminal of the pro logic decoder 22 is connected. Is connected to the center channel signal input terminal of the television receiver 24. The audio signal (L) output terminal of the AV amplifier 23 is connected to the L-side speaker 25,
The audio signal (R) output terminals are connected to the R-side speakers 26, respectively, and the surround signal output terminals of the AV amplifier 23 are connected to the surround speakers 27 and 28, respectively.

Next, the operation of the surround system configured as described above will be described. The video signal output V reproduced by the reproducing means 21 is input to a television receiver 24 and displayed on a screen. Further, the reproduced L and R audio signal outputs in the encoded state are decoded by the prologic decoder 22 and restored as the audio signal L, the audio signal R, the center channel signal C and the surround signal S. Among them, the audio signal L, the audio signal R, and the surround signal S are driven by the AV amplifier 23, and the L speaker 25, the R speaker 26, and the surround speakers 27 and 2, respectively.
8 and output as audio.

On the other hand, audio signal input switching means as shown in FIG. 7 is provided in the television receiver 24, and the center channel signal C and the L and R audio signals from the external audio signal input terminal 38 are provided. The signals are respectively supplied to the changeover switch circuits 2. This changeover switch circuit 2
The audio signal selected in is amplified by the amplifiers 5 and 6 at the subsequent stage and output to the speakers 7 and 8.

Next, a description will be given of a surround system in a case where the stereo sound signal output from the reproducing means 21 is a digital signal. FIG. 8 is a diagram showing a configuration (outline view) of a conventional surround system using digital audio signals using left and right speakers built in a television receiver as center channel speakers of a Dolby stereo surround circuit. In FIG. 8, a video signal output terminal V provided on a reproducing means 31 such as an LD (laser disc) or a DVD (digital video disc) is
A digital audio signal output terminal provided on the reproduction means 31 is connected to a digital audio signal input terminal of a Dolby digital decoder (stereo surround circuit) 33, which is connected to a video signal input terminal of the television receiver 24.

The L and R audio signal output terminals, the surround L and R audio signal output terminals of the Dolby digital decoder 33, and the woofer audio signal output terminal are connected to the L and R audio signal input terminals of the AV amplifier 34 and the surround L and R audio signals. An audio signal input terminal and a woofer audio signal input terminal are connected. A center channel signal output terminal of the Dolby digital decoder 33 is connected to a center channel signal input terminal of the television receiver 24.

Then, the audio signal (L
The output terminal of the AV amplifier 34 is connected to the L-side surround speaker 35, and the output terminal of the audio signal (R side) is connected to the L-side surround speaker 35. The signal (R side) output end is R
Woofer audio signal output terminal of the AV amplifier 34 is connected to the sub woofer 32.
Connected to each other. Next, the operation of the surround system will be described.

The video signal output V reproduced by the reproducing means 31 (LD, DVD, etc.)
4 and displayed on the screen. The digital audio signal output is supplied to the Dolby digital decoder 33 and decoded, and output as an audio signal L, an audio signal R, a surround signal S _L , a surround signal S _R , and a center channel signal C. The audio signal L, the audio signal R, the surround signal S _L , the surround signal S _R , and the woofer audio signal output W are driven by an AV amplifier 34, and are respectively driven by an L-side speaker 25, an R-side speaker 26, and an L-side surround. The signal is supplied to the speaker 35, the R-side surround speaker 36, and the subwoofer 32, and is output as sound.

On the other hand, the center channel signal C is supplied to the center channel signal input terminal 39 of the television receiver as shown in FIG. 7 and supplied to the amplifiers 5 and 6 via the switch circuit 2. Driven and supplied to speakers 7 and 8 built in the television receiver 24,
The built-in speakers 7 and 8 are output as center speakers.

In the input switching means for switching between the center channel signal and the external audio input signal shown in FIG. 7, the L terminal of the external audio signal input terminal 38 is connected to the input terminal c of the switch circuit 2 and the R terminal. The terminal is connected to the input terminal f of the changeover switch circuit 2 and also connected to the bass enhancement circuit 40, and the center channel signal input terminal 39 is connected to the input terminals b,
e. On the other hand, the output terminal a of the switch circuit 2 is connected to one input terminal of the adder circuit 15, and the output terminal d of the switch circuit 2 is connected to one input terminal of the adder circuit 16. The other input terminals of the circuits 15 and 16 are connected to the bass enhancement circuit 40, respectively. Further, the output terminal of the addition circuit 15 is connected to the L-side speaker 7 of the television receiver 24 via the amplifier 5, and the output terminal of the addition circuit 16 is connected to the R side of the television receiver 24 via the amplifier 6. The speaker 8 is connected to each of them.

In the conventional television receiver having the audio signal input switching means constructed as described above, when the changeover switch circuit 2 selects the external audio signal input terminal 38 side, the input terminal 38 is used. The input L and R audio signals are output through the switch circuit 2 and input to the bass enhancement circuit 40, and the outputs of the bass amplification circuit 40 are added in the addition circuits 15 and 16, The audio is output from the speakers 7 and 8 via the amplifiers 5 and 6 as emphasized sound in a lower frequency range.

When the changeover switch circuit 2 selects the center channel signal input terminal 39 side, the input terminal 3
The center channel signal input from 9 is output as sound from the speakers 7 and 8 via the changeover switch circuit 2, the adding circuits 15 and 16, and the amplifiers 5 and 6. That is, in this case, the bass enhancement circuit 40
Is vacant (cannot contribute to bass enhancement). In addition, when the surround system is applied to a television receiver having a built-in subwoofer, the subwoofer built in the television receiver is not used and is wasted.

[0015]

As described above, in a surround system using L and R speakers built in a television receiver as center speakers of Dolby Pro Logic or Dolby Digital, a bass enhancement circuit becomes empty (low range). The bass enhancement circuit was idle and wasted. Further, when the surround system is applied to a television receiver having a built-in subwoofer, there is a problem (defect) that the subwoofer built in the television receiver is wasted without being used.

Therefore, the present invention has been made in view of such a problem,
Provided is a sound reproduction circuit that can effectively use a bass enhancement circuit and a subwoofer built in a television receiver in a surround system using L and R speakers incorporated in a television receiver as Dolby Pro Logic or Dolby Digital center speakers. It is intended for.

[0017]

According to a first aspect of the present invention, there is provided an audio reproducing circuit for reproducing various kinds of video software.
Reproducing means for outputting the L and R audio signals of the first and second signals, and decoding the first L and R audio signals reproduced by the reproducing means;
A decoder for outputting a center channel signal and a second L, R audio signal;
A bass enhancement circuit for extracting components and extracting only low-frequency components thereof; a changeover switch circuit for selecting and outputting one of the first L and R audio signal outputs and the center channel audio signal output; First and second adders for adding the L and R audio signal outputs from the changeover switch circuit and the signal output from the bass enhancement circuit; and the first and second adders.
And two or more speakers provided in the television receiver for converting the signal output from the adder circuit into a sound wave and outputting the sound wave.

According to the first aspect of the present invention, the switch circuit selects either a center channel audio signal or an L or R audio signal. The L and R audio signals reproduced by the reproducing means (first reproduced L and R audio signal outputs)
Is emphasized in a low frequency range by a bass enhancement circuit built in the television receiver, added to an output audio signal of the changeover switch circuit, supplied to two or more speakers incorporated in the television receiver, and output as audio. The bass enhancement circuit is free and is not used and is not wasted and can be effectively utilized.

An audio reproducing circuit according to a second aspect of the present invention reproduces various kinds of video software and outputs first L and R audio signals, and a first L reproduced by the reproducing means. , R audio signal, and a decoder for outputting a center channel audio signal and a second L, R audio signal, and one of the first L, R audio signal output and the center channel audio signal output And a changeover switch circuit for selecting and outputting the first L, R sound output signal or the center channel sound signal output selected by the changeover switch circuit to sound waves and outputting the sound waves to a television receiver. Extracting two or more speakers provided and an L + R component of the first L and R audio signals;
A low-frequency sound enhancement circuit for extracting only the low-frequency component, and a low-frequency sound output speaker provided in the television receiver for converting an audio output signal from the low-frequency sound enhancement circuit into a sound wave and outputting the sound wave. I do.

According to the second aspect of the present invention, the switch circuit selects either the center channel audio signal or the L and R audio signals. Even if there are L and R audio signals reproduced by the reproduction means (first L and R audio signal outputs)
Since the bass enhancement is performed by a bass enhancement circuit built in the television receiver, the bass is supplied to a bass output speaker built in the television receiver and output as audio.
There is no waste of the bass enhancement circuit and no use of the bass output speaker, and both can be effectively utilized.

An audio reproducing circuit according to a third aspect of the present invention reproduces various kinds of video software and outputs at least a Dolby Digital 5.1-channel digital signal and a one-channel analog signal.
A decoder for decoding the 5.1-channel Dolby digital signal from the reproducing means and outputting a center channel audio signal, a subwoofer audio signal, and second L and R audio signals; A bass enhancement circuit for extracting an L + R component of the audio signal and extracting only a low-frequency component thereof; an output of the first L and R audio signals and an audio signal output from the bass enhancement circuit; or an output of the center channel audio signal And a changeover switch circuit for selecting one of the subwoofer sound signal outputs, and converting the first L, R sound signal output or the center channel sound signal output selected by the changeover switch circuit into a sound wave. Two or more loudspeakers provided in a television receiver for conversion and output, and Is selected, characterized by comprising a bass output speaker provided in the television receiver converts the signal output or the subwoofer audio signal output from the bass enhancing circuit to sound waves.

According to the third aspect of the present invention, either the case where the changeover switch circuit selects the center channel audio signal or the case where the L and R audio signals are selected. Even so, the low sound output speaker built into the television receiver is always driven and can be used effectively. Further, the bass enhancement circuit built in the television receiver is driven when the changeover switch circuit selects the first L, R audio signal (the changeover switch circuit selects the center channel audio signal). In this case, it is unnecessary), and it can be effectively used similarly.

A sound reproducing circuit according to a fourth aspect of the present invention reproduces various video software and outputs at least a Dolby Digital 5.1-channel digital signal and a one-channel analog signal.
A decoder for decoding the 5.1-channel Dolby digital signal from the reproducing means and outputting a center channel audio signal, a subwoofer audio signal, and second L and R audio signals; and a center channel audio signal from the decoder. An addition circuit for adding a signal and a subwoofer audio signal; a changeover switch circuit for selecting one of the first L and R audio signal outputs or an audio signal output from the addition circuit; and the changeover switch Two or more speakers provided in a television receiver for converting the first L, R audio signal output or the audio signal output from the adding circuit into a sound wave and outputting the sound wave selected by a circuit; Selected by the changeover switch circuit,
A bass enhancement circuit for extracting a sum component of two-channel audio signals from the first L and R audio signal outputs or the adder circuit and extracting only low-frequency components thereof; and an audio signal output from the bass enhancement circuit. And a bass output speaker provided in the television receiver for converting the sound into a sound wave and outputting the sound wave.

According to the fourth aspect of the present invention, when the changeover switch circuit 2 selects the adder circuit, or selects the first L and R audio signals. In any case, the first L and R audio signals reproduced by the reproduction means are always emphasized in a low frequency range by a bass enhancement circuit built in the television receiver, and are transmitted to the television receiver. It is supplied to the built-in bass output speaker. As a result, the bass enhancement circuit does not become vacant, and the subwoofer is not wasted without being wasted, and both can be effectively utilized.

According to a fifth aspect of the present invention, in the audio reproduction circuit according to the fourth aspect, the two-channel audio signal output from the changeover switch circuit is sound quality controlled by a sound quality control circuit, and the sound volume is controlled. After the sound volume is controlled by the control circuit, the sound signal output from the two or more speakers provided in the television receiver is output from the bass enhancement circuit. The sound is output from the bass output speaker provided in the John receiver.

According to a sixth aspect of the present invention, in the audio reproduction circuit according to any one of the first to fifth aspects, the changeover switch circuit is arranged so that the audio signal reproduced by the reproducing means is a Dolby signal. In the case of stereo, the audio signal output from the decoder is selected, and when the audio signal is not Dolby stereo, the first L, R audio signal output from the reproducing means is selected.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an audio reproduction circuit of a surround system according to the present invention using L and R speakers of a television receiver as center speakers of Dolby Pro Logic.

In FIG. 1, an LD (laser disk)
Means 21 such as a VCR or a video cassette recorder
Is connected to the video signal input terminal 2 of the television receiver 24 similar to that shown in FIG.
The first audio signal output terminals L and R provided in the reproduction means 21 are connected to, for example, the L and R audio signal input terminals of a pro logic decoder (a Dolby stereo surround circuit having a pro logic) 22. The second audio signal output terminals L and R are connected to L and R audio signal input terminals (external audio signal input terminals) 10 and 11 of the audio processing circuit 9 in the television receiver 24, respectively.

The L and R of the prologic decoder 22
The audio signal output terminal and the surround signal output terminal are connected to the L and R audio signal input terminals and the surround signal input terminal of the AV amplifier 23, and the center channel signal output terminal C of the prologic decoder 22 is connected to the center of the audio processing circuit 9. Connected to channel signal input terminal 1. The audio signal (L side) output terminal of the AV amplifier 23 is connected to the L side speaker 25.
The audio signal (R side) output terminal is connected to the R side speaker 26, respectively, and the surround signal output terminal of the AV amplifier 23 is connected to the surround speakers 27 and 28, respectively.

On the other hand, an audio signal input terminal 10 of the audio processing circuit 9 is connected to an input terminal c of the changeover switch circuit 2,
The audio signal input terminal 11 is connected to the input terminal f of the switch circuit 2.
Connected to Further, the L and R audio signal input terminals 1
Reference numerals 0 and 11 denote an L + R component extraction circuit of a bass enhancement circuit 40 composed of an L + R component extraction circuit 12, a low-pass filter 13 that passes only low-frequency components, and a bass level controller 14 that controls the output level of the low-frequency components. 12 is connected. L + R component extraction circuit 12
Is connected to a low-pass filter 13, and the low-pass filter 13 is connected to a bass level controller 14. The bass level controller 14 is connected to a first input terminal of an addition circuit 15 and a first input terminal of an addition circuit 16.

The center channel signal input terminal 1
Is connected to the input terminals b and e of the switch circuit 2, the output terminal a of the switch circuit 2 is connected to the second input terminal of the adder circuit 15, and the output terminal c of the switch circuit 2 is connected to The second input terminal of the adder circuit 16 is connected. Further, the output terminal of the addition circuit 15 is connected to the L-side speaker 7 via the amplifier 5, and the output terminal of the addition circuit 16 is connected to the R-side speaker 8 via the amplifier 6.

Next, the operation of the surround system configured as described above will be described. The video signal output V reproduced by the reproducing means 21 is input to a television receiver 24 and displayed on a screen. The reproduced L and R audio signal outputs in the first encoded state are decoded by the pro-logic decoder 22, and the audio signal L, the audio signal R, the center channel signal C,
And is restored as a surround signal S. Among them, the audio signal L, the audio signal R, and the surround signal S
Driven by the amplifier 23, each of the L-side speakers 2
5, R-side speaker 26 and surround speaker 27
And 28 and output as audio.

The second reproduced L and R audio signal outputs reproduced by the reproducing means 21 are supplied to the changeover switch circuit 2 via the L and R audio signal input terminals 10 and 11, respectively. , And the L + R component extraction circuit 12 constituting the bass enhancement circuit 40. And
The L + R component extraction circuit 12 adds the L component and the R component of the audio signal, extracts only the low-frequency component by the low-pass filter 13, controls the output level of the low-frequency component by the low-frequency level controller 14, and
5 and a first input of the adder 16.

On the other hand, the center channel signal C decoded by the pro logic decoder 22 is supplied to the changeover switch circuit 2 via the center channel signal input terminal 1 of the audio processing circuit 9.

When the changeover switch circuit 2 selects the center channel signal input terminal 1 side, the input center channel signal is output from the output terminals a and d of the changeover switch circuit 2. , Are supplied to the addition circuit 15 and the addition circuit 16, respectively. The addition circuit 15 adds the center channel signal C and the low frequency component from the low frequency enhancement circuit 40 to emphasize the low frequency range, and outputs the result as sound from the speaker 7 via the amplifier 5. Similarly, the addition circuit 16 adds the center channel signal C and the low-frequency component from the bass enhancement circuit 40, emphasizes the low-frequency range, and outputs the result as sound from the speaker 8 via the amplifier 6.

Further, when the changeover switch circuit 2 selects the L and R audio signal input terminals 10 and 11, the L audio signal input from the input terminal 10 is:
The signal is supplied from the output terminal a of the changeover switch circuit 2 to the addition circuit 15, added to the low frequency component from the bass enhancement circuit 40, emphasized in the low frequency range, and output as sound from the speaker 7 via the amplifier 5. . Similarly, the R-side audio signal input from the input terminal 11 is supplied from the output terminal d of the changeover switch circuit 2 to the addition circuit 16, where it is added to the low-frequency component from the bass enhancement circuit 40, and the low-frequency range is emphasized. Is output from the speaker 8 via the amplifier 6 as audio. The first reproduced L and R audio signals and the second reproduced L and R audio signals are reproduced audio signals from different output terminals provided in the reproducing means, and the contents of the signals are the same. Things.

As described above, according to the embodiment of the present invention, when the changeover switch circuit 2 selects the center channel signal input terminal 1 side, or when the L, R audio signal input terminals 10 and 11 side Is selected, the L and R audio signals (second reproduced L and R audio signal outputs) reproduced by the reproducing means 21 are output from the bass sound built in the television receiver 24. It is added to the low-frequency component from the enhancement circuit 40, supplied to the speakers 7 and 8 via the amplifiers 5 and 6, and output as sound. That is,
The bass enhancement circuit 40 is not vacant and is not wasted without being used, and both are effectively utilized.

The surround system using the speakers 7 and 8 built in the television receiver as center speakers of Dolby Pro Logic has been described above. Next, a case where a television receiver having a built-in subwoofer is applied will be described. The surround system will be described.

FIG. 2 is a block diagram showing an audio reproduction circuit of the surround system of the present invention using a television receiver with a built-in subwoofer as a center speaker of Dolby Pro Logic.

In FIG. 2, an LD (laser disk)
Means 21 such as a VCR or a video cassette recorder
Is connected to a video signal input terminal 29 of the television receiver 24, and the first audio signal output terminals L and R provided in the reproducing means 21 are connected to, for example, a professional logic. L, R of decoder (Dolby stereo surround circuit of professional logic configuration) 22
The second audio signal output terminals L and R are connected to the audio signal input terminal, and the second audio signal output terminals L and R are the L and R audio signal input terminals (external audio signal input terminals) 1 of the audio processing circuit 9 in the television receiver.
0 and 11 respectively.

The L and R of the pro logic decoder 22
The audio signal output terminal and the surround signal output terminal are connected to the L and R audio signal input terminals and the surround signal input terminal of the AV amplifier 23, and the center channel signal output terminal C of the prologic decoder 22 is connected to the center channel of the audio processing circuit 9. Connected to signal input terminal 1. The audio signal (L side) output terminal of the AV amplifier 23 is connected to the L side speaker 25.
The audio signal (R side) output terminal is connected to the R side speaker 26, respectively, and the surround signal output terminal of the AV amplifier 23 is connected to the surround speakers 27 and 28, respectively.

On the other hand, the audio signal input terminal 10 is connected to the input terminal c of the changeover switch circuit 2, and the audio signal input terminal 11 is connected to the input end f of the changeover switch circuit 2.
Further, the L and R audio signal input terminals 10 and 11 are
A low-pass filter 13 that passes only a low-frequency component, and a low-frequency level controller 14 that controls the output level of the low-frequency component. I have. The bass level controller 14 is the amplifier 1
7 and the amplifier 17 is connected to a subwoofer 18 built in the television receiver 24.

The center channel signal input terminal 1
Is connected to the input terminals b and e of the switch circuit 2, the output terminal a of the switch circuit 2 is connected to the L-side speaker 7 via the amplifier 5, and the output terminal d of the switch circuit 2 is connected to the amplifier 6 Are connected to the R-side speaker 8 respectively.

Next, the operation of the surround system configured as described above will be described. The video signal output V reproduced by the reproducing means 21 is input to a television receiver 24 and displayed on a screen. The reproduced L and R audio signal outputs in the first encoded state are decoded by the pro-logic decoder 22, and the audio signal L, the audio signal R, the center channel signal C,
And is restored as a surround signal S. Among them, the audio signal L, the audio signal R, and the surround signal S
Driven by the amplifier 23, each of the L-side speakers 2
5, R-side speaker 26 and surround speaker 27
And 28 and output as audio.

The second reproduced L and R audio signal outputs reproduced by the reproducing means 21 are supplied to the switch circuit 2 via the L and R audio signal input terminals 10 and 11, respectively. , The L + R component extraction circuit 12 constituting the bass enhancement circuit 40. The L + R component extraction circuit 12 adds the L component and the R component of the audio signal, extracts only the low-frequency component by the low-pass filter 13, controls the output level of the low-frequency component by the low-frequency level controller 14, and controls the amplifier 17. Is supplied to the subwoofer 18 via the subwoofer and output as audio.

On the other hand, the center channel signal C decoded by the pro logic decoder 22 is supplied to the changeover switch circuit 2 via the center channel signal input terminal 1.

Further, when the changeover switch circuit 2 selects the center channel signal input terminal 1 side,
The center channel signal input from the input terminal 1 is output from the output terminal and the output terminal b of the changeover switch circuit 2, and is output as sound from the L-side speaker 7 and the R-side speaker 8 via the amplifiers 5 and 6. .

The changeover switch circuit 2 is connected to the L,
When the R audio signal input terminals 10 and 11 are selected,
The L-side audio signal input from the input terminal 10 is output from the output terminal a of the changeover switch circuit 2, and is output as audio from the L-side speaker 7 via the amplifier 5. Similarly, the R-side audio signal input from the input terminal 11 is output from the output terminal d of the changeover switch circuit 2 and
Is output from the R-side speaker 8 as audio.

As described above, according to the embodiment of the present invention, when the changeover switch circuit 2 selects the center channel signal input terminal 1 side, or when the L and R audio signal input terminals 10 and 11 side In either case, the L and R audio signals reproduced by the reproduction means 21 are subjected to bass enhancement by the bass enhancement circuit 40 and supplied to the subwoofer 18 via the amplifier 17. Output as audio. That is, the bass enhancement circuit 40 is not vacant and the subwoofer is not wasted without being wasted, and both are effectively used.

Next, a surround system using left and right speakers built into a television receiver as Dolby Digital center speakers will be described.

FIG. 3 shows that the left and right speakers included in the television receiver are used as center channel speakers of a Dolby stereo surround circuit (Dolby Digital), and a subwoofer built in the television receiver is used as a subwoofer in the Dolby stereo surround circuit. FIG. 2 is a diagram illustrating an example of a configuration (outlook) of a surround system using digital audio signals.

In FIG. 3, an LD (laser disk)
Means 3 such as DVD and digital video disk (DVD)
A video signal output terminal V provided at 1 is connected to a video signal input terminal of the television receiver 24, and a digital audio signal output terminal provided at the reproduction means 31 is connected to a Dolby digital decoder (stereo surround circuit).
33 digital audio signal input terminals.

The L and R audio signal output terminals of the Dolby digital decoder 33 and the surround L and R audio signal output terminals are connected to the L and R audio signal input terminals of the AV amplifier 34 and the surround L and R audio signal input terminals. The center channel signal output terminal C of the Dolby digital decoder 33 is connected to the center channel signal input terminal of the television receiver 24, and the woofer audio signal output terminal W is connected to the woofer audio signal output terminal of the television receiver 24. Connected.

Then, the audio signal (L
The output terminal of the AV amplifier 34 is connected to the L-side surround speaker 35, and the output terminal of the audio signal (R side) is connected to the L-side surround speaker 35. The signal (R side) output end is R
It is connected to the side surround speakers 36, respectively.

In the surround system configured as described above, the video signal output V reproduced by the reproducing means 31 (LD, DVD, etc.) is input to the television receiver 24 and displayed on a screen. The digital audio signal output is from the Dolby digital decoder 33.
, And are decoded and output as an audio signal L, an audio signal R, a surround signal S _L , a surround signal S _R , a woofer audio signal W, and a center channel signal C. And among these, the audio signal L, the audio signal R,
The surround signal S _L and the surround signal S _R
The L-side speakers 2 are driven by the amplifiers 34, respectively.
5, R side speaker 26, L side surround speaker 35,
In addition, the sound is supplied to the R-side surround speakers 36 and output as sound.

FIG. 4 is a block diagram showing a configuration inside a television receiver having a subwoofer in FIG.

In FIG. 4, an LD (laser disk)
Means for reproducing a DVD or a digital video disk (DVD) having at least a 5.1-channel digital output and a 2-channel analog output.
The video signal output terminal provided at 1 is connected to a video signal input terminal 29 in the television receiver 24 (not shown). The digital audio signal output terminal provided in the reproducing means 31 is connected to, for example, a digital audio signal input terminal of the Dolby digital decoder 33, and outputs the L and R audio signal output terminals and the surround L and R of the Dolby digital decoder 33. The audio signal output terminals are the L, R audio signal input terminals of the AV amplifier 34 and the surround L, R
The Dolby digital decoder 33 is connected to the center channel signal input terminal 1 of the audio processing circuit 9 in the television receiver, and the woofer audio signal output terminal is connected to the woofer audio signal input terminal. Connected to terminals 45 respectively.

Further, the audio signal (L) of the AV amplifier 34
An output terminal is connected to the L-side speaker 25, and an audio signal (R) output terminal is connected to the R-side speaker 26.
The surround signal (L) output terminal is connected to the L side surround speaker 35, and the surround signal (R) output terminal is connected to the R side surround speaker 36. The L and R audio signal (analog) output terminals provided on the reproduction means 31 are connected to the L and R audio signal input terminals 10 and 11 provided on the audio processing circuit 9, respectively.

On the other hand, the audio signal input terminal 10 is connected to the input terminal c of the switch circuit 2 ', and the audio signal input terminal 11 is connected to the input terminal f of the switch circuit 2'. The audio signal input terminals 10 and 11 are provided with an L + R component extraction circuit 12, a low-pass filter 13 that passes only low-frequency components, and a low-frequency sound enhancement circuit 14 that controls the output level of the low-frequency components. The low tone level controller 14 is connected to the input terminal i of the changeover switch circuit 2 '.

The center channel signal input terminal 1
Are input terminals b and e of the changeover switch circuit 2 '.
The woofer audio signal input terminal 45 is connected to the input terminal h of the changeover switch circuit 2 '. Further, the output terminal a of the changeover switch circuit 2 'is connected to the L-side speaker 7 via the amplifier 5, and the output end d of the changeover switch circuit 2' is connected to the R-side speaker 8 via the amplifier 6.
The output terminal g of the changeover switch circuit 2 ′ is connected to the woofer 18 via the amplifier 17.

Next, the operation of the surround system configured as described above will be described. The video signal output V reproduced by the reproducing means 31 (LD, DVD, etc.) is input to the television receiver 24 and displayed on the screen. The digital audio signal output is decoded by the Dolby digital decoder 33 and output as an audio signal L, an audio signal R, a surround signal S _L , a surround signal S _R , a woofer audio signal W, and a center channel signal C. The audio signal L, the audio signal R, the surround signal S _L , and the surround signal S _R are driven by an AV amplifier 34, and are respectively connected to the L-side speaker 25, the R-side speaker 26, the L-side surround speaker 35, and the R-side surround speaker 35. Side surround speakers 36
And output as audio.

The reproduced L and R audio signal outputs reproduced by the reproducing means 31 are supplied to the changeover switch circuit 2 'via the L and R audio signal input terminals 10 and 11, respectively. L constituting the enhancement circuit 40
It is supplied to the + R component extraction circuit 12. The L + R component extraction circuit 12 adds the L component and the R component of the audio signal, extracts only the low-frequency component by the low-pass filter 13, controls the output level of the low-frequency component by the low-frequency level controller 14, and selects the switch. Circuit 2 '
Supplied to

On the other hand, the Dolby digital decoder 3
3. The woofer audio signal W decoded by the woofer audio signal W is supplied to the woofer audio signal input terminal 45 through the switch circuit 2 '.
The center channel signal C is supplied to the switch circuit 2 'via the center channel signal input terminal 1, respectively.

Here, when the changeover switch circuit 2 ′ selects the center channel signal input terminal 1 side and the woofer audio signal input terminal 45 side, the center channel signal input from the input terminal 1 is The signal is output from the output terminal a and the output terminal d of the changeover switch circuit 2 ', supplied to the L-side speaker 7 and the R-side speaker 8 via the amplifiers 5 and 6, and output as sound. The woofer audio signal input from the input terminal 45 is output from the output terminal g of the changeover switch circuit 2 ', and
Is supplied to the subwoofer 18 and output as audio.

Further, when the changeover switch circuit 2 'selects the L and R audio signal input terminals 10 and 11, the L audio signal input from the input terminal 10 is
The signal is output from the output terminal a of the changeover switch circuit 2 ′, supplied to the L-side speaker 7 via the amplifier 5, and output as sound. Similarly, the R-side audio signal input from the input terminal 11 is output from the output terminal d of the changeover switch circuit 2 ', supplied to the R-side speaker 8 via the amplifier 6, and output as audio. The L and R components from the input terminals 10 and 11 are input to the bass enhancement circuit 40, and the L + R signal for which the bass is enhanced is transmitted between the input end i and the output end g of the switch circuit 2 '. The signal is supplied to the subwoofer 18 via the amplifier 12 and output as audio.

As described above, according to the embodiment of the present invention, when the changeover switch circuit 2 ′ selects the center channel signal input terminal 1 side and the woofer audio signal input terminal 45 side, When the L / R audio signals reproduced / supplied by the means 21 are Dolby digital signals, the center channel signal supplied via the center channel signal input terminal 1 is used as it is on the L side of the television receiver 24. It is supplied to the speaker 7 and the R-side speaker 8 and output as sound. The woofer audio signal supplied via the woofer audio signal input terminal 45 is supplied to the sub woofer 18 of the television receiver 24 as it is, and is output as audio.

Further, when the changeover switch circuit 2 'selects the L and R audio signal input terminals 10 and 11, that is, when the signal reproduced and supplied by the reproducing means 21 is a normal L and R audio signal, Signal (not Dolby Digital signal)
In the case of, the normal L and R audio signals supplied from the reproduction means 21 via the L and R audio signal input terminals 10 and 11 are used as they are in the L-side speakers 7 and R-side of the television receiver 24. It is supplied to the speaker 8 and output as sound. Also, the L + R signal for which the bass range has been enhanced is supplied from the bass enhancement circuit 40 to the subwoofer 18 and output as audio.

That is, whether the switch circuit 2 selects the center channel signal input terminal 1 or the L, R audio signal input terminals 10 and 11 is selected. , Television receiver 24
The sub woofer 18 built in is always driven and used effectively. In the bass enhancement circuit 40, the changeover switch circuit 2 is connected to the L and R audio signal input terminals 1
It is driven when the 0, 11 side is selected (not necessary when the changeover switch circuit 2 selects the center channel signal input terminal 1 side), and is effectively used.

Next, a description will be given of an audio reproducing circuit in a surround system using digital audio signals according to the present invention in a case where the position of the changeover switch circuit 2 in FIG.

In FIG. 5, an LD (laser disk)
Means for reproducing a DVD or a digital video disk (DVD) having at least a 5.1-channel digital output and a 2-channel analog output.
Is connected to a video signal input terminal 29 provided in the television receiver 24. The digital audio signal output terminal provided in the reproducing means 31 is connected to, for example, a digital audio signal input terminal of the Dolby digital decoder 33, and outputs the L and R audio signal output terminals and the surround L and R of the Dolby digital decoder 33. The audio signal output terminal is an AV amplifier 34
Are connected to the L and R audio signal input terminals and the surround L and R audio signal input terminals of the
The center channel signal output terminal is connected to the center channel signal input terminal 1 of the audio processing circuit 9 in the television receiver 24, and the woofer audio signal output terminal is connected to the woofer audio signal input terminal 45.

Further, the audio signal (L) of the AV amplifier 34
An output terminal is connected to the L-side speaker 25, and an audio signal (R) output terminal is connected to the R-side speaker 26.
The surround signal (L) output terminal is connected to the L side surround speaker 35, and the surround signal (R) output terminal is connected to the R side surround speaker 36. The L and R audio signal (analog) output terminals provided on the reproducing means 31 are connected to the L and R audio signal input terminals 10 and 11 provided on the audio processing circuit 9 (not shown), respectively.

On the other hand, the audio signal input terminal 10 is connected to the input terminal c of the switch circuit 2, and the audio signal input terminal 1
1 is connected to the input terminal f of the changeover switch circuit 2. The center channel signal input terminal 1 is connected to an adder circuit 44.
The woofer audio signal input terminal 45 is connected to the other input terminal of the addition circuit 44, and the output terminal of the addition circuit 44 is connected to the changeover switch circuit 2.
Are connected to the input terminal b and the input terminal e.

Further, the output terminal a and the output terminal d of the changeover switch circuit 2 are connected to the L-side speaker 7 of the television receiver 24 via the sound quality control circuit 42, the sound control circuit 43, and the amplifiers 5 and 6, respectively. Each is connected to the R-side speaker 8. An output terminal a and an output terminal d of the changeover switch circuit 2 are connected to the sound quality control circuit 42, and L + R
A low-pass filter 13 that passes only low-frequency components, and a low-frequency level controller 14 that controls the output level of the low-frequency components; The level controller 14 is connected to the woofer 18 of the television receiver 24 via the audio control circuit 43 and the amplifier 17.

Next, the operation of the surround system configured as described above will be described. The video signal output V reproduced by the reproducing means 31 (LD, DVD, etc.) is input to the television receiver 24 and displayed on the screen. The digital audio signal output is decoded by the Dolby digital decoder 33 and output as an audio signal L, an audio signal R, a surround signal S _L , a surround signal S _R , a woofer audio signal W, and a center channel signal C. The audio signal L, the audio signal R, the surround signal S _L , and the surround signal S _R are driven by an AV amplifier 34, and are respectively connected to the L-side speaker 25, the R-side speaker 26, the L-side surround speaker 35, and the R-side surround speaker 35. Side surround speakers 36
And output as audio.

The reproduced L and R audio signal outputs reproduced by the reproducing means 31 are supplied to the changeover switch circuit 2 via the L and R audio signal input terminals 10 and 11, respectively. The woofer audio signal W decoded by the above is added via the woofer audio signal input terminal 45, the center channel signal C is added via the center channel signal input terminal 1 by the adding circuit 44, and supplied to the changeover switch circuit 2. .

Here, when the changeover switch circuit 2 has selected the adder circuit 44 side, that is, the reproducing means 21
If the L and R audio signals to be reproduced / supplied are Dolby digital signals, the sum signal of the woofer audio signal W and the center channel signal C (the output of the adder circuit 44) is output from the switch circuit 2 Are output from an output terminal a and an output terminal d, are supplied to a sound quality control circuit 42, are controlled in sound quality, are controlled in volume by a volume control circuit 43, and are connected to L-side speakers 7 and R through amplifiers 5 and 6. It is supplied to the side speaker 8 and output as sound. Further, the changeover switch circuit 2
Of the output terminal a and the output terminal d of the
4) is supplied to the sound quality control circuit 42 and supplied to the L + R component extraction circuit 12 for addition. The low-pass filter 13 extracts only low-frequency components. The output level of the low-frequency component is controlled and supplied to the volume control circuit 43 to control the volume. Thereafter, the signal is supplied to the subwoofer 18 via the amplifier 17 and output as audio.

Further, when the changeover switch circuit 2 has selected the L and R audio signal input terminals 10 and 11, that is, when the signal reproduced and supplied by the reproducing means 21 is a normal L and R audio signal ( LOL audio signal input terminal 10 (L side audio)
The input L-side audio signal is supplied from the input terminal c to the output terminal a of the changeover switch circuit 2 to the sound quality control circuit 42, where the sound quality is controlled, and the volume control circuit 43 controls the volume. Are supplied to the L-side speaker 7 via the amplifier 5 and output as sound. Also, L and R audio signal input terminals 11 (R side audio)
The input R-side audio signal is supplied to the sound quality control circuit 42 through the portion between the input end f and the output end d of the changeover switch circuit 2 to control the sound quality, and the volume control circuit 43 controls the volume. Are supplied to the R-side speaker 8 via the amplifier 6 and output as audio. On the other hand, the output (the L and R audio output) signals from the output terminals a and d of the switch circuit 2 are
The sound signal is supplied to the sound quality control circuit 42 and also to the L + R component extraction circuit 12 constituting the bass enhancement circuit 40, where the L component and the R component of the audio signal are added. Is extracted, the output level of the low frequency component is controlled by the bass level controller 14, supplied to the volume control circuit 43, and the volume is controlled, and then supplied to the subwoofer 18 via the amplifier 17 and output as audio. You.

As described above, according to the embodiment of the present invention, when the changeover switch circuit 2 selects the adder circuit 44 side, or when the L, R audio signal input terminal 1
Regardless of whether the 0 or 11 side is selected, the L and R audio signals reproduced by the reproduction means 31 are emphasized in a low frequency range through a bass enhancement circuit 40 built in the television receiver 24. Is supplied to the subwoofer 18 via the amplifier 17 and output as audio. That is, the bass enhancement circuit 40 is not vacant and the subwoofer is not wasted without being wasted, and both are effectively used.

[0079]

As described above, according to the present invention, the subwoofer or the bass enhancement circuit built in the television receiver can be effectively used at the time of Dolby Pro Logic and Dolby Digital reproduction, and can be newly provided to the outside. There is no need to install a subwoofer in the car.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an audio reproduction circuit of a surround system according to the present invention.

FIG. 2 is a block diagram showing a specific configuration of an audio reproduction circuit of the surround system according to the present invention.

FIG. 3 is a diagram showing a configuration of a surround system according to the present invention.

FIG. 4 is a block diagram showing a specific configuration of an audio reproduction circuit.

FIG. 5 is a block diagram showing another specific configuration of the audio reproduction circuit.

FIG. 6 is a diagram showing a configuration of a conventional surround system.

FIG. 7 is a circuit diagram showing an example of a conventional input switching means.

FIG. 8 is a diagram showing a configuration of a conventional surround system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Center channel signal input terminal 2 ... Changeover switch circuit 5,6 ... Amplifier 7 ... L side speaker 8 ... R side speaker 9 ... Sound processing circuit 10 ... L, R sound signal input terminal (L side sound) 11 ... L, R audio signal input terminal (R side audio) 12 L + R component extraction circuit 13 Low pass filter 14 Low sound level controller 15, 16 Addition circuit 21 Reproduction means 22 Prologic decoder 23 AV amplifier 25 L speaker 26 … R side speaker 27… L side surround speaker 28… R side surround speaker 29… Video signal input terminal 40… Low sound enhancement circuit L… L side audio signal R… R side audio signal S… Surround audio signal C… Center channel audio signal V: Video signal

Claims (6)

[Claims] 1. An apparatus for reproducing various kinds of video software, comprising:
Reproducing means for outputting an audio signal; decoding the first L and R audio signals reproduced by the reproducing means to obtain a center channel signal and a second L and R signals;
A decoder that outputs an audio signal; a bass enhancement circuit that extracts an L + R component of the first L and R audio signals and extracts only low-frequency components; a first L and R audio signal output and the center channel A changeover switch circuit for selecting and outputting one of the sound signal outputs; a first and a second addition for adding the L and R sound signal outputs from the changeover switch circuit and the signal output from the bass enhancement circuit; An audio reproduction circuit comprising: a circuit; and two or more speakers provided in a television receiver for converting a signal output from the first and second addition circuits into a sound wave and outputting the sound wave. 2. Playing various kinds of video software, the first L, R
A reproducing unit that outputs an audio signal; a decoder that decodes the first L and R audio signals reproduced by the reproducing unit and outputs a center channel audio signal and a second L and R audio signal; A switch circuit for selecting and outputting one of the L and R audio signal outputs and the center channel audio signal output, and the first L and R audio output signals selected by the changeover switch circuit or Two or more speakers provided in the television receiver for converting the center channel sound signal output into sound waves and outputting the sound wave; extracting L + R components of the first L and R sound signals; And a bass output speaker provided in a television receiver for converting an audio output signal from the bass enhancement circuit into a sound wave and outputting the sound wave. Audio reproduction circuit, characterized in that Bei was. 3. Playing various video software, at least
Reproducing means for outputting a Dolby Digital 5.1-channel digital signal and a one-channel analog signal; decoding the 5.1-channel Dolby Digital signal from the reproducing means to obtain a center channel audio signal and subwoofer audio; A decoder that outputs a signal and second L and R audio signals; a bass enhancement circuit that extracts an L + R component of the first L and R audio signals and extracts only low-frequency components thereof; , R audio signal output and an audio signal output from the bass enhancement circuit, or one of the center channel audio signal output and the subwoofer audio signal output, and a changeover switch circuit, The selected first L, R audio signal output or the center channel audio signal output Two or more speakers provided in a television receiver for converting power into sound waves and outputting the signals; and a signal output from the bass enhancement circuit or an audio signal output for the subwoofer, also selected by the changeover switch circuit. An audio reproduction circuit, comprising: a low-frequency sound output speaker provided in the television receiver for converting the sound wave into a sound wave and outputting the sound wave. 4. Playing various video software, at least
Reproducing means for outputting a 5.1-channel Dolby Digital digital signal and a one-channel analog signal; decoding the 5.1-channel Dolby Digital signal from the reproducing means to obtain a center channel audio signal and a subwoofer audio signal; A decoder for outputting a signal and second L and R audio signals; an adding circuit for adding a center channel audio signal from the decoder and an audio signal for a subwoofer; A switch circuit for selecting any one of the audio signal outputs from the adder circuit; and a first L, R audio signal output or an audio signal output from the adder circuit selected by the switch circuit. Two or more speakers provided in a television receiver for converting into sound waves and outputting the sound waves; Selected by the axis the change-over switch circuit, the first L, of from R audio signal output or the addition circuit, 2
A bass enhancement circuit for extracting a sum component of the audio signal of the channel and extracting only a low-frequency component thereof; a bass provided in the television receiver for converting an audio signal output from the bass enhancement circuit into a sound wave and outputting the sound wave. An audio reproduction circuit comprising an output speaker. 5. A two-channel audio signal output from the changeover switch circuit is controlled in sound quality by a sound quality control circuit, and is controlled in volume by a volume control circuit. The audio signal output from the speaker, the audio signal output from the bass enhancement circuit is output from the bass output speaker provided in the television receiver after the volume is controlled by a volume control circuit. Item 5. The audio reproduction circuit according to Item 4. 6. The switch circuit selects an audio signal output from the decoder when the audio signal reproduced by the reproduction means is Dolby stereo, and selects the reproduction signal when the audio signal is not Dolby stereo. 6. The audio reproducing circuit according to claim 1, wherein the first L and R audio signal outputs are selected.