JPH10313223A - Av amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AV amplifier that conducts substantial multi-channel reproduction and drives a bi-wiring speaker with high sound quality stereo. SOLUTION: In the case of 4-channel reproduction, signals 3L, 3C, 3R, 3S of each channel outputted from a decoder 2 are respectively amplified by amplifiers 4A, 4B, 4C, 4D, and given to speakers of corresponding channels respectively. A 1st bi-wiring speaker 6L is connected to output terminals 5A, 5B, a 2nd bi-wiring speaker 6R is connected to output terminals 5D, 5E, and in the case of conducting 2-channel reproduction, an L channel signal 3L outputted from the decoder 2 is amplified by the amplifiers 4A, 4B in parallel and the amplified signal is given to the 1st bi-wiring speaker 6L in a bi-wiring connection form, and an R channel signal 3R outputted from the decoder 2 is amplified by the amplifiers 4C, 4D in parallel and the amplified signal is given to the 2nd biwiring speaker 6R in a bi-wiring connection form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an AV amplifier, and more particularly, to an AV amplifier capable of selectively switching between a multi-channel reproduction mode and a two-channel stereo reproduction mode.

[0002]

2. Description of the Related Art In recent years, with the penetration of home theaters,
AV amplifiers that perform multi-channel reproduction of video and audio are rapidly spreading. This type of AV amplifier decodes audio information obtained from various sources (DVD, digital broadcasting, etc.) (this audio information is obtained by encoding multi-channel audio information into two-channel audio information). Perform multi-channel playback. On the other hand, bi-amps that emphasize sound quality
There is a strong demand for stereo reproduction using a single high-end speaker that supports bi-wiring (hereinafter referred to as bi-wiring speaker). Purchasing and installing amplifiers separately for home theater and stereo playback involves a large burden both economically and in terms of space. Therefore, one AV
It is desired to perform multi-channel reproduction using an amplifier and stereo-drive a bi-wiring speaker.

A method of driving a bi-wiring speaker using a conventional multi-channel AV amplifier will be described below with reference to the drawings. FIG. 14 is a block diagram showing a state where a bi-wiring speaker is connected to a conventional AV amplifier. In FIG. 14, signals of two channels (signals obtained by encoding information of multiple channels (here, four channels)) obtained from a source (DVD, digital broadcast, etc.) not shown are input from input terminals 1L and 1R, The signal is decoded by the decoder 2 into the original 4-channel signal. L-channel signal 3 output from decoder 2
L is amplified by the L-channel amplifier 4A, and then amplified to the high-frequency terminal HF of the L-channel bi-wiring speaker 6L.
And the low-frequency terminal LF. Similarly, the R-channel signal 3R output from the decoder 2 is amplified by the R-channel amplifier 4C, and then connected in parallel to the high-frequency terminal HF and the low-frequency terminal LF of the R-channel bi-wiring speaker 6R. Is entered. The C channel (center channel) signal 3C output from the decoder 2 is
After being amplified by the channel amplifier 4B, it is input to the center speaker 11. Also, S output from the decoder 2
The channel (surround channel) signal 3S is amplified by the S-channel amplifier 4D and then input to the surround speaker 12.

[0004]

As described above, when the bi-wiring speakers 6L and 6R are driven in the two-channel stereo reproduction mode using the conventional AV amplifier, an L-channel amplifier 4A and an R-channel amplifier are used as amplification circuits. Since only two amplifiers 4C and 4C are used, it is used in a normal mode in which the high-frequency terminal HF and the low-frequency terminal LF are short-circuited, as shown in FIG. There was a problem that it was not possible to realize high-quality sound reproduction by use.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an AV amplifier capable of performing multi-channel reproduction and driving a bi-wiring speaker at high sound quality by bi-wiring connection during two-channel stereo reproduction.

[0006]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the present invention has the following features. A first invention is an AV amplifier capable of selectively switching between a multi-channel reproduction mode and a two-channel stereo reproduction mode.
A decoder for decoding a multi-channel encoded input signal to output a multi-channel signal and outputting the input two-channel stereo signal as it is in a two-channel stereo reproduction mode, and a plurality of decoders for amplifying the output signal of the decoder Amplifiers and speakers are connected to each,
A plurality of output terminals for transmitting an output signal of the amplifier to a connected speaker; a mode selection unit for selecting a multi-channel playback mode or a two-channel stereo playback mode; A switching circuit for switching a connection relationship between the decoder, the plurality of amplifiers, and the plurality of output terminals, wherein the switching circuit has a plurality of speakers for multi-channel reproduction connected to the output terminal, and a multi-channel reproduction circuit. When the mode is selected, the connection relation is switched so that the multi-channel signal output from the decoder is amplified for each channel by the plurality of amplifiers, and the signal output from each amplifier is supplied to the speaker of the corresponding channel. A pair of bi-wiring speakers is connected to the output terminal, and the 2-channel stereo playback mode is When selected, among the two-channel stereo signals output from the decoder, the L-channel signal is amplified in parallel by the first and second amplifiers among the plurality of amplifiers, and the R-channel signal is amplified by the plurality of amplifiers. The third in
And the amplifiers are amplified in parallel by the fourth amplifier, and the output signals of the first and second amplifiers are provided to one of the pair of speakers in a bi-wiring connection manner, and the output signals of the third and fourth amplifiers are The connection relation is switched so as to be provided to the other of the pair of speakers in a bi-wiring connection mode.

As described above, according to the first aspect of the invention, a bi-wiring speaker can be driven with high sound quality by bi-wiring connection by a multi-amplifier during two-channel stereo reproduction without changing the speaker connection. Therefore, the user does not need to purchase and install a new amplifier device for the bi-wiring speaker, and a low-cost and space-saving multi-function amplifier can be realized.

[0008] In a second aspect based on the first aspect, the first aspect is the first aspect.
And a first gain correction circuit for correcting a gain difference between the third and fourth amplifiers, and a second gain correction circuit for correcting a gain difference between the third and fourth amplifiers. The circuit switches the connection so that the first and second gain correction circuits are activated when a pair of bi-wiring compatible speakers are connected to the output terminal and the two-channel stereo playback mode is selected. It is characterized by.

Since the first and second amplifiers are originally prepared for driving speakers of different channels, the gains are often different from each other. This is the same for the third and fourth amplifiers. On the other hand, in principle, the bi-wiring speaker is driven by a multi-amplifier having the same gain. Therefore, in the second invention, the gain difference between the first and second amplifiers is corrected by the first gain correction circuit, and the third and fourth gains are corrected by the second gain correction circuit.
By compensating for the gain difference between the amplifiers, amplifying circuits with different gains prepared for the multi-channel
It can be used in a form suitable for driving a bi-wiring speaker.

[0010] A third invention is the first invention according to the second invention.
The gain correction circuit of the above is such that the gain of the output signal of the first amplifier with respect to the L-channel signal is substantially equal to the gain of the output signal of the second amplifier with respect to the L-channel signal. The gain is corrected, and the second gain correction circuit includes:
Correcting the gain so that the gain of the output signal of the third amplifier with respect to the signal for the R channel and the gain of the output signal of the fourth amplifier with respect to the signal for the R channel are substantially equal. Features.

As described above, according to the third aspect, when the bi-wiring speaker is driven in the two-channel stereo reproduction mode, the gain is adjusted so that the gain difference between the first and second amplifiers becomes almost zero. Since the gain is corrected and the gain is corrected so that the gain difference between the third and fourth amplifiers becomes substantially zero, ideal biwiring reproduction can be performed.

[0012] In a fourth aspect based on the third aspect, the first aspect.
And the second gain correction circuit includes fine adjustment means for finely adjusting the gain correction amount.

As described above, according to the fourth aspect, the first aspect
And the second gain correction circuit can be fine-tuned, so that the constant variation between the first and second gain correction circuits can be improved.
Deterioration of frequency characteristics caused by differences in the type of speaker used and the acoustic characteristics of the room to be viewed can also be corrected.

According to a fifth aspect based on the first aspect, the switching circuit includes a plurality of switches appropriately arranged between the decoder, each amplifier and each output terminal, and a mode selection unit according to the mode selection. And a computer device for controlling the on / off state of each switch.

As described above, according to the fifth aspect of the present invention, since the switch is on / off controlled by the computer device, it is possible to easily cope with a change in the connected speaker group caused by an upgrade of the AV system or the like. it can.

[0016]

FIG. 1 is a block diagram showing a configuration of an AV amplifier according to a first embodiment of the present invention. FIG.
, A two-channel signal (a signal obtained by encoding information of multiple channels (here, four channels)) obtained from a source (DVD, digital broadcast, etc.) not shown
Are input from the input terminals 1L and 1R, and are decoded by the decoder 2 into the original 4-channel signal. After being amplified by the L-channel amplifier 4A, the L-channel signal 3L output from the decoder 2 is supplied to the output terminal 5A via the switch S11 and to the output terminal 5B via the switch S1. Further, the C-channel (center channel) signal 3C output from the decoder 2 is amplified by the C-channel amplifier 4B via the switch S2, and then applied to the output terminal 5B via the switch S3. The signal is supplied to the output terminal 5C via S4. Further, the R-channel signal 3R output from the decoder 2 is amplified by the R-channel amplifier 4C and then supplied to the output terminal 5D via the switch S12.
The signal is supplied to the output terminal 5E via the switch S6. The S-channel (surround channel) signal 3S output from the decoder 2 is amplified by the S-channel amplifier 4D via the switch S7, and then applied to the output terminal 5E via the switch S8. The signal is supplied to the output terminal 5F via S9. The L-channel signal 3L output from the decoder 2 is supplied to the C-channel amplifier 4B via the switch S5 and the gain correction circuit 7.
Also given. The R-channel signal 3R output from the decoder 2 is also supplied to the S-channel amplifier 4D via the switch S10 and the gain correction circuit 8.

The CPU 101 controls on / off of the switches S1 to S12 according to the selection information given from the mode selection unit 104 and the channel selection unit 105. These mode selection unit 104 and channel selection unit 105
It is provided on the operation panel of the AV amplifier and is operated by the user. The mode selection unit 104 selects a speaker to be used. The channel selection unit 105 selects between a 2-channel stereo playback mode and a 4-channel playback mode. R
The OM 102 stores an operation program for the CPU 101. The CPU 101 operates according to the operation program. The RAM 103 functions as a working memory that stores various work data generated when the CPU 101 performs a program operation.

FIG. 2 is a block diagram showing a first connection example of the speaker unit to the AV amplifier of FIG. In FIG. 2, a first L-channel speaker 9L is connected to the output terminal 5A, a second L-channel speaker 10L is connected to the output terminal 5B, a center speaker 11 is connected to the output terminal 5C, The first R is connected to the output terminal 5D.
The channel speaker 9R is connected, the output terminal 5E is connected to the second R-channel speaker 10R, and the output terminal 5F is connected to the surround speaker 12. First
Speaker set 9L, 9R and second speaker set 10L, 10R may be driven simultaneously, or only one of them may be driven. The first speaker set 9L, 9R and the second speaker set 10L,
When 10R and 10R are arranged in the same room, both speaker sets are often driven simultaneously. On the other hand, when the first speaker sets 9L and 9R and the second speaker sets 10L and 10R are arranged in different rooms, the respective speaker sets are often driven individually. To be arranged in another room, for example, assumes a situation in which one speaker set is arranged in a living room together with a center speaker 11 and a surround speaker 12, and the other speaker set is arranged in a bedroom.

FIG. 3 is a block diagram showing a second connection example of the speaker unit to the AV amplifier of FIG. In FIG. 3, the output terminal 5A is connected to the high-frequency terminal HF of the L-channel bi-wiring speaker 6L, and the output terminal 5B is connected to the L-channel bi-wiring speaker 6L.
The low-frequency terminal LF of L is connected, the center speaker 11 is connected to the output terminal 5C, the high-frequency terminal HF of the R-channel bi-wiring speaker 6R is connected to the output terminal 5D, and the output terminal 5E is connected. The low-frequency terminal LF of the R-channel bi-wiring speaker 6R is connected, and the surround speaker 12 is connected to the output terminal 5F. In the present embodiment, the bi-wiring speaker sets 6L, 6L
R can be driven by two-channel stereo reproduction, which is the original use mode, or can be driven by four-channel reproduction, which is a mode for reproducing mainly audio accompanying video.

FIG. 4 is a diagram showing combinations of ON / OFF states of the switches S1 to S12 controlled by the CPU 101 of FIG. FIGS. 5 to 12 are diagrams showing operating states of the AV amplifier of FIG. 1 corresponding to the various on / off states shown in FIG. The operation of the first embodiment will be described below with reference to FIGS.

First, the operation of the decoder 2 will be described. At the time of 4-channel reproduction, a multi-channel encoded signal such as a movie is input from the input terminals 1L and 1R.
In this case, the decoder 2 separates the input signal into four signals, and outputs an L-channel signal 3L, a C-channel signal 3C, R
The signal is output as the channel signal 3R and the S channel signal 3S. On the other hand, when performing two-channel stereo reproduction, a two-channel signal that is not multi-channel encoded is input from the input terminals 1L and 1R. In this case, the decoder 2 outputs the L channel signal 3L and the R channel signal 3L.
Output only R.

Next, the operation when the mode selection by the mode selection unit 104 is off will be described. Such a state is set, for example, when listening to sound with headphones without using a speaker. In this case, as shown in FIG. 4, the CPU 101 turns off all the switches S1 to S12 (opens). Therefore, at this time, the signal output from the decoder 2 is not supplied to any speaker, but is supplied to headphones (not shown).

Next, an operation when the mode selection unit 104 selects a mode for driving the first speaker sets 9L and 9R will be described. First, when the channel selection unit 105 selects 2-channel stereo reproduction, as shown in FIG.
The CPU 101 turns ON only the switches S11 and S12 (closed state) and turns OFF the other switches. In this case, as shown in FIG. 5, after the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A, the first L-channel speaker 9L
Given to. The R-channel signal 3R output from the decoder 2 is supplied to the first R-channel speaker 9R after being amplified by the R-channel amplifier 4C.
Therefore, at this time, stereo reproduction is performed using the first speaker sets 9L and 9R. On the other hand, when the channel selection unit 105 selects the 4-channel reproduction, as shown in FIG. 4, the CPU 101 switches the switches S2, S4, S7, S
9, S11 and S12 are turned on, and the other switches are turned off. In this case, as shown in FIG. 6, after the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A, it is provided to the first L-channel speaker 9L. The C channel signal 3C output from the decoder 2 is supplied to the center speaker 11 after being amplified by the C channel amplifier 4B. Also, the R channel signal 3R output from the decoder 2
Are amplified by the R-channel amplifier 4C, and then the first R
This is provided to the channel speaker 9R. After the S channel signal 3S output from the decoder 2 is amplified by the S channel amplifier 4D, the surround speaker 12
Given to. Therefore, at this time, four-channel reproduction is performed using the first speaker sets 9L and 9R, the center speaker 11, and the surround speakers 12.

Next, the operation when the mode selection unit 104 selects the mode for driving the second speaker sets 10L and 10R will be described. First, the channel selection unit 105
When the channel stereo reproduction is selected, as shown in FIG. 4, the CPU 101 turns on only the switches S1 and S6 and turns off the other switches. In this case, as shown in FIG. 7, the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A and then supplied to the second L-channel speaker 10L. After the R-channel signal 3R output from the decoder 2 is amplified by the R-channel amplifier 4C,
To the R channel speaker 10R. Therefore,
At this time, stereo reproduction is performed using the second speaker sets 10L and 10R. On the other hand, the channel selection unit 10
5 selects four-channel reproduction, the CPU 101 switches the switches S1, S2, S4, S4 as shown in FIG.
6, S7, and S9 are turned on, and the other switches are turned off. In this case, as shown in FIG. 8, the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A, and then applied to the second L-channel speaker 10L. The C channel signal 3C output from the decoder 2 is supplied to the center speaker 11 after being amplified by the C channel amplifier 4B. Also,
The R channel signal 3R output from the decoder 2
After being amplified by the channel amplifier 4C, it is given to the second R channel speaker 10R. The S-channel signal 3S output from the decoder 2 is amplified by the S-channel amplifier 4D and then supplied to the surround speakers 12. Therefore, at this time, the second speaker set 1
Four channels are reproduced using the 0L, 10R, the center speaker 11, and the surround speaker 12.

Next, the mode selection unit 104 controls the first speaker set 9L, 9R and the second speaker set 10
The operation when the mode for driving both L and 10R is selected will be described. First, when the channel selection unit 105 selects 2-channel stereo reproduction, as shown in FIG.
The PU 101 turns on the switches S1, S6, S11, and S12 and turns off the other switches. In this case, as shown in FIG. 9, after the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A, the L-channel signal 3L is connected in parallel to the first and second L-channel speakers 9L and 10L. Given. The R-channel signal 3R output from the decoder 2 is amplified in the R-channel amplifier 4C, and then supplied in parallel to the first and second R-channel speakers 9R and 10R. Therefore, at this time, the first and second speaker sets 9L,
Stereo reproduction is performed using both 9R, 10L, and 10R. On the other hand, when the channel selection unit 105 selects 4-channel reproduction, as shown in FIG.
Are switches S1, S2, S4, S6, S7, S9, S
11 and S12 are turned on, and the other switches are turned off. In this case, as shown in FIG. 10, L-channel signal 3L output from decoder 2 is amplified by L-channel amplifier 4A, and then applied to first and second L-channel speakers 9L and 10L. . After the C channel signal 3C output from the decoder 2 is amplified by the C channel amplifier 4B,
Given to. Further, the R-channel signal 3R output from the decoder 2 is amplified by the R-channel amplifier 4C, and then supplied to the first and second R-channel speakers 9R and 10R. Further, the S-channel signal 3S output from the decoder 2 is amplified by the S-channel amplifier 4D and then supplied to the surround speakers 12.
Therefore, at this time, the first and second speaker sets 9
L, 9R and 10L, 10R, center speaker 11,
Four-channel reproduction is performed using the surround speakers 12.

Next, the operation when the mode selection unit 104 selects the mode for driving the bi-wiring speaker sets 6L and 6R will be described. The speaker connection state in this case is as shown in FIG.

First, when the channel selection unit 105 selects 2-channel stereo reproduction, as shown in FIG.
U101 includes switches S3, S5, S8, S10, S1
1, S12 is turned on, and the other switches are turned off. In this case, as shown in FIG. 11, after the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A, it is applied to the high-frequency terminal HF of the L-channel bi-wiring speaker 6L. . Further, the level of the L-channel signal 3L output from the decoder 2 is adjusted by the gain correction circuit 7 and further amplified by the C-channel amplifier 4B, and then applied to the low-frequency terminal LF of the L-channel bi-wiring speaker 6L. Given. Also,
The R channel signal 3R output from the decoder 2
After being amplified by the channel amplifier 4C, it is provided to the high-frequency terminal HF of the R-channel bi-wiring speaker 6R. Further, the level of the R-channel signal 3R output from the decoder 2 is adjusted by the gain correction circuit 8 and further amplified by the S-channel amplifier 4D, and then supplied to the low-frequency terminal LF of the R-channel biwiring speaker 6R. Given. Therefore, at this time, the bi-wiring speaker sets 6L and 6R can be stereo-driven with high sound quality by bi-wiring connection using the four amplifiers 4A to 4D.

Since the gain of the L-channel amplifier 4A and the gain of the C-channel amplifier 4B are not necessarily equal, the gain of the L-channel amplifier 4A and the gain of the C-channel amplifier by the gain correction circuit 7 during two-channel stereo reproduction. It is necessary to make the gain of 4B the same and make the frequency characteristic of the L-channel bi-wiring speaker 6L flat. Similarly, the gain of the R-channel amplifier 4C and the gain of the S-channel amplifier 4D are not necessarily equal to each other.
And the gain of the S-channel amplifier 4D need to be the same, and the frequency characteristics of the R-channel bi-wiring speaker 6R need to be flat. Usually, since the amplifiers 4A and 4C have higher gains than the amplifiers 4B and 4D, the gain correction circuits 7 and 8 have a positive gain (that is, increase the level of the input signal). When the gains of the amplifiers 4B and 4D are higher,
It is necessary to attenuate the negative gain, that is, the level of the input signal.

On the other hand, when the channel selection unit 105 selects 4-channel reproduction, as shown in FIG.
Are switches S1, S2, S4, S6, S7, S9, S
11 and S12 are turned on, and the other switches are turned off. In this case, as shown in FIG. 12, after the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A, the high-frequency terminal HF and the low-frequency terminal of the L-channel bi-wiring speaker 6L are used. Terminal LF
Are given in parallel. The C channel signal 3C output from the decoder 2 is supplied to the center speaker 11 after being amplified by the C channel amplifier 4B. Also,
The R channel signal 3R output from the decoder 2
After being amplified by the channel amplifier 4C, it is supplied in parallel to the high-frequency terminal HF and the low-frequency terminal LF of the R-channel bi-wiring speaker 6R. The S-channel signal 3S output from the decoder 2 is amplified by the S-channel amplifier 4D and then supplied to the surround speakers 12. Therefore, at this time, four-channel reproduction is performed using the bi-wiring speakers 6L and 6R, the center speaker 11, and the surround speakers 12.

The bi-wiring speakers 6L, 6
In principle, an amplifier having the same gain is connected to the high-frequency terminal HF and the low-frequency terminal LF of R. for that reason,
In the first embodiment described above, the gains of the amplifiers 4A to 4D are made uniform by providing the gain correction circuits 7 and 8. However, in some cases, it is necessary to further correct the variation in the constants of the gain correction circuits 7 and 8 and the deterioration of the frequency characteristics caused by the difference in the acoustic characteristics of the type of speaker used and the room to be viewed. An embodiment capable of coping with such a correction will be described below.
This will be described below.

FIG. 13 is a block diagram showing a configuration of an AV amplifier according to a second embodiment of the present invention. 13 differs from the first embodiment shown in FIG. 1 in that first and second variable resistors 13 and 14 are connected in series to the input sides of gain correction circuits 7 and 8, respectively. . Other configurations are the same as those of the first embodiment. Corresponding portions have the same reference characters allotted, and description thereof will not be repeated. By previously setting the gain correction amounts of the gain correction circuits 7 and 8 to be high, the gain correction circuit 7 and the C channel for when the attenuation amounts of the first and second variable resistors 13 and 14 are minimized. The sum of the gain with the amplifier 4B and the sum of the gain with the gain correction circuit 8 and the S-channel amplifier 4D are represented by L-channel amplifiers 4A and R
The gain is set to be higher than the gain of the channel amplifier 4C.

The operation of the AV amplifier according to the second embodiment configured as described above for performing two-channel stereo reproduction will be described. The switching state of each switch is the same as in the first embodiment. That is, as shown in FIG.
3, S5, S11 are turned on, and switches S1, S2, S
4 is off. Therefore, the L-channel signal 3L output from the decoder 2 is amplified by the L-channel amplifier 4A, and then applied to the high-frequency terminal HF of the L-channel bi-wiring speaker 6L. Further, the level of the L-channel signal 3L is adjusted by the gain correction circuit 7 via the first variable resistor 13 and then further amplified by the C-channel amplifier 4B. It is provided to the area terminal LF.

In this case, by adjusting the first variable resistor 13, the total gain of the gain correction circuit 7 including the first variable resistor 13 and the C-channel amplifier 4B can be adjusted. Can be freely adjusted in the increasing direction and the decreasing direction.

On the other hand, on the R channel side, the switching state of the switches is the same as that of the first embodiment (that is, the switches S8, S10, S12 are turned on and the switches S6, S9, S12 are turned off). ing),
The adjustment of the second variable resistor 14 is also performed by the first variable resistor 1.
3 is performed in the same manner.

In the case of four-channel reproduction, the switches S1, S2, S4, S6, S
7, S9, S11, and S12 are turned on, and the other switches are turned off. Therefore, the gain correction circuits 7, 8
Is disconnected.

In the second embodiment, the first and second variable resistors 1 are connected to the input sides of the gain correction circuits 7 and 8, respectively.
Although 3 and 14 are inserted in series, they may be inserted on the output side, or may be provided in the gain correction circuits 7 and 8. Further, another method may be used instead of the variable resistor as long as the gain of the gain correction circuits 7 and 8 can be adjusted.

In each of the above embodiments, the switch for turning on or off is used. However, the switches S3 and S4 and the switches S8 and S9 are respectively set as changeover switches,
2, S5, S7, S10 are abolished, and amplifier 4
By providing input changeover switches for B and 4D, the number of switches can be reduced. In addition, it goes without saying that these switches include not only those having mechanical contacts but also those which are electronically connected.

In each of the above embodiments, when the bi-wiring speakers 6L and 6R are stereo-driven by bi-wiring connection, the outputs of the amplifiers 4A and 4C are connected to the high frequency terminals HF of the bi-wiring speakers 6L and 6R, respectively. The outputs of the amplifiers 4B and 4D are applied to the low-frequency terminals LF of the bi-wiring speakers 6L and 6R, respectively.
The outputs of B and 4D are supplied to the high frequency terminals HF of the bi-wiring speakers 6L and 6R, respectively, and the amplifiers 4A and 4C
Are output to the bi-wiring speakers 6L and 6L, respectively.
It may be provided to the low-frequency terminal LF of R.

As described above, according to the above embodiments,
By adding a simple switch switching circuit and a gain correction circuit to the AV amplifier body, an amplifier for multi-channel reproduction can be effectively used at the time of stereo reproduction to improve sound quality at the time of two-channel stereo reproduction. Also, if necessary, the first and second variable resistors 13 and 14 may
It is possible to fine-tune the gain during channel stereo reproduction, thereby correcting the variation in the constant of the gain correction circuit and the deterioration of the frequency characteristics caused by the difference in the type of speaker used and the acoustic characteristics of the room to be viewed. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an AV amplifier according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a first connection example of a speaker unit to the AV amplifier of FIG. 1;

FIG. 3 is a block diagram showing a second connection example of a speaker unit to the AV amplifier in FIG. 1;

FIG. 4 is a diagram showing a combination of on / off states of each switch controlled by a CPU in the first embodiment of the present invention.

FIG. 5 is a diagram showing a first example of an on / off state of each switch in the first embodiment of the present invention.

FIG. 6 is a diagram showing a second example of the on / off state of each switch in the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a third example of the on / off state of each switch in the first embodiment of the present invention.

FIG. 8 is a diagram showing a fourth example of the on / off state of each switch in the first embodiment of the present invention.

FIG. 9 is a diagram showing a fifth example of the on / off state of each switch in the first embodiment of the present invention.

FIG. 10 is a diagram showing a sixth example of the on / off state of each switch in the first embodiment of the present invention.

FIG. 11 is a diagram showing a seventh example of the on / off state of each switch in the first embodiment of the present invention.

FIG. 12 is a diagram showing an eighth example of the on / off state of each switch in the first embodiment of the present invention.

FIG. 13 is a block diagram showing a state in which a bi-wiring speaker is driven using an AV amplifier according to a second embodiment of the present invention.

FIG. 14 is a block diagram showing a configuration of a conventional AV amplifier.

[Explanation of symbols]

 1L, 1R input terminal 2 decoder 4A L channel amplifier 4B C channel amplifier 4C R channel amplifier 4D S channel amplifier 5A to 5F output terminals 7, 8 gain correction circuits S1 to S12 Switch 101 CPU 102 ROM 103 RAM 104 Mode selector 105 Channel selector 6 L L-channel bi-wiring speaker 6 R R-channel bi-wiring speaker 9 L First L-channel speaker 9 R First R-channel speaker 10L ... second L-channel speaker 10R ... second R-channel speaker 11 ... center speaker 12 ... surround speakers 13, 14 ... variable resistor

Claims (5)

[Claims] An AV amplifier capable of selectively switching between a multi-channel reproduction mode and a two-channel stereo reproduction mode. In the multi-channel reproduction mode, the multi-channel encoded input signal is decoded to decode the multi-channel signal. Output,
In the two-channel stereo reproduction mode, a decoder that outputs the input two-channel stereo signal as it is, a plurality of amplifiers for amplifying the output signal of the decoder, speakers are connected to the respective speakers, and the amplifier is connected to the connected speakers. A plurality of output terminals for transmitting an output signal of the multi-channel reproduction mode and a two-channel stereo reproduction mode; and a decoder according to a mode selection by the mode selection unit. And a switching circuit for switching a connection relationship between the plurality of amplifiers and the plurality of output terminals. The switching circuit includes a plurality of speakers for multi-channel reproduction connected to the output terminal, When the channel playback mode is selected,
The multichannel signal output from the decoder is amplified for each channel by the plurality of amplifiers, and the connection relation is switched so that the signal output from each amplifier is provided to the speaker of the corresponding channel. When a pair of bi-wiring compatible speakers is connected and the two-channel stereo playback mode is selected, the L-channel signal of the two-channel stereo signals output from the decoder is output from the plurality of amplifiers among the plurality of amplifiers. Amplified in parallel by the first and second amplifiers, R
A channel signal is amplified in parallel by third and fourth amplifiers of the plurality of amplifiers, and output signals of the first and second amplifiers are connected to one of the pair of speakers in a bi-wiring connection manner. An AV amplifier that switches the connection relationship so that output signals of the third and fourth amplifiers are supplied to the other of the pair of speakers in a bi-wiring connection manner. 2. A first gain correction circuit for correcting a gain difference between the first and second amplifiers, and a second gain correction circuit for correcting a gain difference between the third and fourth amplifiers. A gain correction circuit, wherein the switching circuit is configured to control the first and second gain correction when a pair of bi-wiring compatible speakers is connected to the output terminal and a two-channel stereo playback mode is selected. 2. The AV amplifier according to claim 1, wherein the connection relation is switched so that a circuit is activated. 3. The first gain correction circuit comprises: a gain of an output signal of the first amplifier with respect to the L-channel signal; and an output of the second amplifier with respect to the L-channel signal. The second gain correction circuit corrects the gain so that the gain of the signal becomes substantially equal to the gain of the output signal of the third amplifier with respect to the signal for the R channel. 3. The AV amplifier according to claim 2, wherein the gain is corrected such that a gain of the output signal of the fourth amplifier with respect to the use signal is substantially equal. 4. The first and second gain correction circuits,
4. The AV amplifier according to claim 3, further comprising fine adjustment means for finely adjusting the gain correction amount. 5. The switching circuit, comprising: a plurality of switches appropriately arranged between the decoder, the plurality of amplifiers, and the plurality of output terminals; The AV amplifier according to claim 1, further comprising: a computer device that controls an on / off state of a switch.