JP2000023300A - Automatic sound system setting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic sound system setting device which can automatically set an optimum mode in response to the connection or non-connection of a speaker and also to the reproducing capability of low-pitched sounds. SOLUTION: A test signal is produced by a test signal generator, and the current flowing to a speaker 9 is detected by a current detector 14a that is placed between a power amplifier 7 and a speaker connecting terminal 8. A deciding device 14b generates a deciding signal to decide the presence or absence and the reproducing capability of low-pitched sounds of the speaker 9 based on the detection output of the detector 14a. A control part 10 detects the connection or non-connection and the reproducing capability of low-pitched sounds of the speaker 9 by the deciding signal. Thus, an optimum mode is automatically set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound system which includes a plurality of speakers and reproduces an audio signal in a surround manner, and reproduces the audio signal in an optimum reproduction method (mode) according to the number and performance of the speakers. The present invention relates to a sound system automatic setting device that can be automatically set so that the sound system can be set.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand to enjoy a realistic sound and powerful sound at home, such as in a movie theater, so that a plurality of speakers are provided to reproduce an audio signal in surround. Sound systems are beginning to spread. This type of sound system may be used only as an audio device, or may be used like a so-called home theater in combination with a video display device such as a television receiver.

Here, a conventional sound system will be described. FIG. 6 is a first example of a conventional sound system, and is a block diagram showing a 4-channel multi-surround system.

In FIG. 6, left and right audio signals Lt and Rt, which are analog signals, are input to a matrix circuit 1. The matrix circuit 1 converts the left and right audio signals L and R (hereinafter, left signal L) from the audio signals Lt and Rt. , Right signal R)
Then, a center audio signal C (hereinafter abbreviated as center signal C) and a surround audio signal S (hereinafter abbreviated as surround signal S) are generated. Left and right signals L, R
And the center signal C are input to the mode selection unit 2, and a mode described later is selected. The surround signal S is supplied to a delay circuit 3, a low-pass filter 4, a noise reduction circuit 5,
Are sequentially input.

The left and right signals L and R and the center signal C output from the mode selector 2 are input to volume / tone controllers 6L, 6R and 6C, respectively, and the surround signals output from the noise reduction circuit 5 are input. S is input to the volume / sound quality adjuster 6S, and the volume and sound quality are adjusted, respectively. Note that, depending on the mode, the center signal C may not be directly output from the mode selection unit 2. Volume·
The signals output from the sound quality adjusters 6L, 6R, 6C, 6S are input to power amplifiers 7L, 7R, 7C, 7S, respectively, where the power is amplified.

The signals output from the power amplifiers 7L, 7R, 7C, 7S are respectively connected to speaker connection terminals 8L, 8L.
The signals are input to the left speaker 9L, the right speaker 9R, the center speaker 9C, and the two surround speakers 9S via R, 8C, and 8S, and the respective audio signals are reproduced.

A control unit 10 composed of a microcomputer
Controls the mode selection unit 2 so as to select an optimal mode according to the presence or absence and size of the center speaker 9C (bass sound reproduction capability), as described later. This mode is selected by the user.

Here, the mode selected by the mode selector 2 will be described. The mode selection unit 2 is configured as shown in FIGS.
There are three modes shown in (C), which are selected according to the presence or absence of the center speaker 9C and the bass reproduction capability.

In FIG. 7, (A) is a mode called a normal mode, and this normal mode is used when the center speaker 9C is relatively small and does not have much bass reproduction capability. In FIG. 7, (B) is a mode called a phantom mode, and this phantom mode is used when the center speaker 9C is not connected. In FIG. 7, (C) is a mode called a wide mode, and this wide mode is used when the center speaker 9C is relatively large and has sufficient bass reproduction capability.

Hereinafter, each mode will be described in detail. First, in the normal mode shown in FIG.
The center signal C is input to the low-pass filter 21 and the high-pass filter 22. The output of the low-pass filter 21 is attenuated by the attenuator 23 and input to the adders 24 and 25. The output of the high-pass filter 22 is output as it is as the center signal C. The left and right signals L and R are input to adders 24 and 25. Adders 24 and 25 add the left and right signals L and R and the output of the attenuator 23, and add the left and right signals L and R, respectively.
Output as right signals L and R.

As can be understood from this description, in the normal mode shown in FIG. 7A, the low-frequency component of the center signal C to be reproduced from the center speaker 9C is added to the left and right signals L and R. Thus, the sound is reproduced by the left and right speakers 9L and 9R having a relatively large size and low sound reproduction capability. Therefore, the frequency characteristics of the audio signals reproduced by the left and right speakers 9L and 9R and the center speaker 9C have the characteristics shown in FIGS. 8A and 8B, respectively.

In the phantom mode shown in FIG.
The center signal C is input to the attenuator 23, attenuated, and input to the adders 24 and 25. The left and right signals L and R are input to adders 24 and 25. Adders 24 and 25 add the left and right signals L and R and the output of the attenuator 23, and add the left and right signals L and R, respectively.
Output as right signals L and R.

As can be understood from this description, in the phantom mode shown in FIG. 7B, the left and right speakers 9L are added by adding the center signal C to be reproduced from the center speaker 9C to the left and right signals L and R. , 9R. Therefore, the left and right speakers 9L, 9R
FIG. 8B shows the frequency characteristics of the audio signal reproduced by
The characteristics are as shown in FIG.

In the wide mode shown in FIG.
The right signals L and R and the center signal C are output as they are,
The left and right speakers 9L and 9R and the center speaker 9C are independently reproduced. Therefore,
The frequency characteristics of the audio signals reproduced by the left and right speakers 9L and 9R and the center speaker 9C are as shown in FIGS. 8A and 8B, respectively.

The relationship between the presence or absence of the center speaker 9C or the bass reproduction capability and the mode is shown in Table 1.

[0016]

[Table 1]

Next, FIG. 9 is a block diagram showing a second example of a conventional sound system, which is a six-channel multi-surround system. 9, parts having the same functions as those in FIG. 6 are denoted by the same reference numerals.

In FIG. 9, a 5-channel audio signal S5, which is a digital signal, is input to a surround decoder 11. The surround decoder 11 converts the audio signal S5 into left and right audio signals L and R (hereinafter, a left signal L and a right signal). R), a center audio signal C (hereinafter abbreviated as center signal C), and left and right surround audio signals S.
L and SR (hereinafter abbreviated as left surround signal SL and right surround signal SR) and a low-frequency sound reproduction signal LFE (hereinafter abbreviated as low-frequency signal LFE).

The left and right signals L and R, the center signal C, the left and right surround signals SL and SR, and the bass signal LFE are input to a mode selection section 2 to select a mode described later. Although all signals are shown to be output from the mode selection unit 2 here, the center signal C and the bass signal LFE are not directly output from the mode selection unit 2 depending on the mode, as described later. In some cases.

The left and right signals L and R output from the mode selector 2, the center signal C, and the left and right surround signals S
The L and SR and the bass signal LFE are input to the volume / sound quality adjusters 6L, 6R, 6C, 6SL, 6SR and 6LFE, respectively, and the volume and sound quality are adjusted respectively. Volume and sound quality adjusters 6L, 6R, 6C, 6SL, 6SR, 6LFE
The output signals are respectively power amplifiers 7L and 7L.
The power is input to R, 7C, 7SL, 7SR, and 7LFE and amplified.

Power amplifiers 7L, 7R, 7C, 7SL, 7
The signals output from the SR and 7LFE are respectively speaker connection terminals 8L, 8R, 8C, 8SL, 8SR, 8L
Through the FE, a left speaker 9L and a right speaker 9
R, the center speaker 9C, the left surround speaker 9SL, the right surround speaker 9SR, and the subwoofer 9LFE are input, and respective audio signals are reproduced.

A control unit 10 comprising a microcomputer
The size of the left and right speakers 9L and 9R (bass reproduction capability), the presence or absence of the center speaker 9C (bass reproduction capability), and the sizes of the left and right surround speakers 9SL and 9SR (bass reproduction), as described later. Ability), the mode selection unit 2 is controlled so as to select an optimal mode according to the presence or absence of the subwoofer 9LFE. The choice of this mode is
Done by the user.

Here, the mode selected by the mode selector 2 will be described. The mode selection unit 2 is configured as shown in FIG.
(B), FIGS. 11A to 11C, and FIGS.
(C), FIGS. 13 (A) to 13 (C), and FIGS.
There are 11 modes shown in (C), which are selected according to the above conditions.

In FIG. 10, the first mode shown in FIG. 10A includes left and right speakers 9 L and 9 R, and a center speaker 9.
C, all of the left and right surround speakers 9SL and 9SR are relatively small, have low bass reproduction capability, and are used when the subwoofer 9LFE is connected.

Left and right signals L and R, center signal C,
The left and right surround signals SL and SR are input to the adder 26 and added to the bass signal LFE. Left and right signals L, R
, Center signal C, left and right surround signals SL, S
R is output through the high-pass filter 22, and the output of the adder 26 is output through the low-pass filter 21. In the first mode, the entire bass is reproduced by the subwoofer 9LFE.

In FIG. 10, the second mode shown in FIG. 10B is a mode in which the center speaker 9C is eliminated from the first mode. Left and right signals L and R and center signal C
And the left and right surround signals SL and SR are input to the adder 26 and added to the bass signal LFE. Left, right signal L,
R, center signal C, left and right surround signals SL,
The SR is output via the high-pass filter 22, and the output of the adder 26 is output via the low-pass filter 21.

The center signal C is further attenuated by the attenuator 23 and input to the adders 24 and 25. Adder 2
4 and 25 add the left and right signals L and R and the output of the attenuator 23, and output them as left and right signals L and R, respectively. In this second mode, the whole bass is transferred to the subwoofer 9LFE.
Then, the high frequency component of the center signal C to be reproduced from the center speaker 9C is added to the left and right signals L and R, so as to be reproduced by the left and right speakers 9L and 9R.

In the third mode shown in FIG. 11A, the left and right speakers 9L and 9R are relatively large and have sufficient bass reproduction capability, and the center speaker 9C and the left and right surround speakers 9SL and 9SR are compared. This mode is used when the subwoofer 9LFE is not connected because of its extremely small size and low bass reproduction capability.

The center signal C and the left and right surround signals SL and SR are input to the adder 26 and added to the bass signal LFE. The center signal C and the left and right surround signals SL and SR are output via the high-pass filter 22, respectively. The output of the adder 26 is the low-pass filter 21
Are input to the adders 24 and 25 via. Adder 24,
25 adds the left and right signals L and R and the output of the attenuator 23, and outputs them as left and right signals L and R, respectively. In the third mode, the center signal C, the low frequency components of the left and right surround signals SL and SR, and the low sound signal LFE are to be reproduced by the left and right speakers 9L and 9R.

In FIG. 11, the fourth mode shown in FIG. 11B is a mode in which the center speaker 9C is eliminated from the third mode. The left and right surround signals SL and SR are input to the adder 26 and added to the bass signal LFE.
The left and right signals L, R are output via a high-pass filter 22. The center signal C is attenuated by the attenuator 23 and input to the adders 24 and 25. The output of the adder 26 is input to the adders 24 and 25 via the low-pass filter 21.

The adders 24 and 25 add the left and right signals L and R, the output of the attenuator 23 and the output of the adder 26 input through the low-pass filter 21, and add the left and right signals L and R, respectively. , R. In the fourth mode, the low frequency components of the left and right surround signals SL and SR and the low sound signal LF
E and the center signal C are to be reproduced by the left and right speakers 9L and 9R.

In FIG. 11, the fifth mode shown in FIG. 11 (C) includes left and right speakers 9L and 9R and a center speaker 9R.
This mode is used when C is relatively large and the bass reproduction capability is sufficient, the left and right surround speakers 9SL and 9SR are relatively small and the bass reproduction capability is not so large, and the subwoofer 9LFE is not connected.

The left and right surround signals SL and SR are input to the adder 26 and added to the bass signal LFE. The center signal C is output as it is, and the left and right surround signals S
L and SR are output via the high-pass filter 22, respectively. The output of the adder 26 is input to the adders 24 and 25 via the low-pass filter 21.

The adders 24 and 25 add the left and right signals L and R to the output of the adder 26 input via the low-pass filter 21 and output the left and right signals L and R, respectively. In the fifth mode, the left and right surround signals S
The low frequency components of L and SR and the low sound signal LFE are to be reproduced by the left and right speakers 9L and 9R.

Further, in the sixth mode shown in FIG. 12A, the left and right speakers 9L and 9R and the left and right surround speakers 9SL and 9SR are relatively large and have sufficient bass reproduction capability, and the center speaker 9C Is a mode that is used when the subwoofer 9LFE is not connected and the bass reproduction capability is relatively small, and the bass reproduction capability is not so large.

The center signal C is output as a center signal C via a high-pass filter 22 and is added via adders 24 and 2 via a low-pass filter 21 and an attenuator 23.
5 is input. The bass signal LFE is added to adders 24 and 2
5, 27 and 28.

The adders 24 and 25 provide left and right signals L and R, respectively.
And a center signal C input via the attenuator 23,
The left and right signals L and R are added by adding the bass signal LFE.
Output as The adders 27 and 28 add the left and right surround signals SL and SR and the bass signal LFE, and output them as left and right surround signals SL and SR, respectively. In the sixth mode, the low frequency component of the center signal C is reproduced by the left and right speakers 9L and 9R, and the low sound signal LFE is reproduced by the left and right speakers 9L and 9R and the left and right surround speakers 9R.
SL, 9SR.

In FIG. 12, the seventh mode shown in FIG. 12B is a mode in which the center speaker 9C is eliminated from the sixth mode. The center signal C is attenuated by the attenuator 23 and input to the adders 24 and 25. Bass signal L
The FE is input to the adders 24, 25, 27, and 28.
The adders 24 and 25 provide the left and right signals L and R and the attenuator 23.
Signal C inputted through the center signal C and the bass signal LFE
And outputs as left and right signals L and R, respectively. The adders 27 and 28 provide left and right surround signals SL,
SR and the bass signal LFE are added and output as left and right surround signals SL and SR, respectively.

In the seventh mode, the center signal C is reproduced by the left and right speakers 9L and 9R, and the bass signal LFE is reproduced.
Is reproduced by the left and right speakers 9L and 9R and the left and right surround speakers 9SL and 9SR.

In the seventh mode shown in FIG. 12C, the left and right speakers 9L and 9R, the center speaker 9C, and the left and right surround speakers 9SL and 9SR are all relatively large and have sufficient bass reproduction capability. This mode is used when the subwoofer 9LFE is not connected.

The bass signal LFE is added to adders 24, 25, 2
7, 28 and 29 are input. The adders 24 and 25 are
The left and right signals L and R are added to the bass signal LFE and output as left and right signals L and R, respectively. Adders 27 and 28
Are left and right surround signals SL and SR and a bass signal LFE
And the left and right surround signals SL and SR, respectively.
Output as The adder 29 adds the center signal C and the bass signal LFE, and outputs the result as the center signal C.

In the eighth mode, the bass signal LFE
To the left and right speakers 9L and 9R and the center speaker 9
C and the left and right surround speakers 9SL and 9SR.

In the ninth mode shown in FIG. 13A, the left and right speakers 9L and 9R and the left and right surround speakers 9SL and 9SR are relatively large and have sufficient bass reproduction capability, and the center speaker 9C is compared with the center speaker 9C. This mode is used when the subwoofer 9LFE is connected with a very small size and low bass reproduction capability.

The center signal C is output as a center signal C via a high-pass filter 22 and is added via adders 24 and 2 via a low-pass filter 21 and an attenuator 23.
5 is input. Adders 24 and 25 output left and right signals L,
R and the center signal C input via the attenuator 23 are added and output as left and right signals L and R, respectively.
The left and right surround signals SL and SR and the bass signal LFE are
Each is output as it is.

In the ninth mode, the low frequency component of the center signal C is to be reproduced by the left and right speakers 9L and 9R.

In FIG. 13, the tenth mode shown in FIG. 13B is a mode in which the center speaker 9C is eliminated from the ninth mode. The center signal C is attenuated by the attenuator 23 and input to the adders 24 and 25. Adder 2
4 and 25 add the left and right signals L and R and the center signal C input via the attenuator 23, and output them as left and right signals L and R, respectively. Left and right surround signals SL,
The SR and the bass signal LFE are output as they are.

In the tenth mode, the center signal C
Is to be reproduced by the left and right speakers 9L and 9R.

In the eleventh mode shown in FIG. 13 (C), the left and right speakers 9L and 9R, the center speaker 9C, and the left and right surround speakers 9SL and 9SR are all relatively large and have sufficient bass reproduction capability. This mode is used when the subwoofer 9LFE is connected. In this case, the left and right signals L and R and the center signal C
, Left and right surround signals SL and SR, and bass signal LF
E are all output as they are.

Table 2 shows the relationship between the presence / absence of each speaker or the bass reproduction capability and the mode in the above-described six-channel multi-surround system.

[0050]

[Table 2]

[0051]

As described above,
In a sound system with a multi-surround system, the user may or may not connect speakers.
Further, when a speaker is connected, it is necessary to select the most suitable mode in consideration of the size of the speaker (bass reproduction capability).

However, this is extremely difficult for the user, and there is a problem that it is not easy to select an optimal mode.

The present invention has been made in view of the above problems, and provides an automatic sound system setting device capable of automatically setting an optimum mode in accordance with the presence or absence of a speaker connection and bass reproduction capability. The purpose is to do.

[0054]

According to the present invention, in order to solve the above-mentioned problems of the prior art, a plurality of audio signals to be reproduced by a plurality of speakers are input, and at least one of the plurality of speakers is input. A plurality of modes for outputting at least a part of frequency components of an audio signal to be supplied to the speaker to another speaker different from the speaker according to the presence or absence of connection of one speaker to the speaker connection terminal or bass reproduction capability A sound system provided with a mode selection section (2) for selecting any one of the following. In a sound system automatic setting device for automatically setting the mode, the sound system automatic setting device has a connection to a speaker connection terminal or a bass reproduction capability. A first test for detecting whether or not the speaker to be determined is connected to the speaker connection terminal And a test signal generator (12) for generating at least one of a signal and a second test signal for detecting a lowest resonance frequency of the speaker; a test signal generator (12) connected to the speaker connection terminal; 1 to detect a current flowing when the test signal is supplied, output a determination signal for determining whether or not the speaker is connected to the speaker connection terminal based on the detection output, and output the determination signal to the speaker connection terminal. A current detector / determiner (14) for detecting a current flowing when the second test signal is supplied, and outputting a determination signal for determining a lowest resonance frequency of the speaker based on the detected output; A determination signal from a detector / determiner determines whether or not the speaker is connected to the speaker connection terminal, and determines whether or not the speaker is connected to the speaker connection terminal. A control unit (10) for detecting at least one of the lowest resonance frequencies of the speaker when connected, and automatically setting a mode selected by the mode selection unit according to the detection result; And a sound system automatic setting device characterized by the following.

[0055]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sound system automatic setting device according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a block diagram showing a first embodiment of the sound system automatic setting device of the present invention, FIG. 2 is a block diagram showing a second embodiment of the sound system automatic setting device of the present invention, and FIG. 3 is a sound system of the present invention. FIG. 4 is a block diagram for explaining the principle of the automatic setting device, FIG. 4 is a characteristic diagram for explaining the principle of the sound system automatic setting device of the present invention, and FIG. It is a flowchart for the. 1 and 2, the same parts as those in FIGS. 6 and 9 are denoted by the same reference numerals.

First, the principle of the automatic sound system setting device of the present invention will be described with reference to FIG. In FIG. 3, a switch 13 is inserted between the sound quality / volume controller 6 and the power amplifier 7. The sound quality / volume controller 6
Is a general term for the sound quality / volume adjuster 6C in FIG. 6 and the sound quality / volume adjusters 6L to 6LFE in FIG.
Are the power amplifier 7C in FIG. 6 and the power amplifier 7L in FIG.
~ 7 LFE.

An audio signal from the sound quality / volume controller 6 is input to one terminal of the switch 13, and a test signal from the test signal generator 12 is input to the other terminal. Switch 1
Reference numeral 3 designates the selection of the audio signal from the sound quality / volume controller 6 and the test signal from the test signal generator 12 under the control of the control unit 10, and usually, as shown in the figure, the sound quality / volume controller 6 Is selected, and a test signal from the test signal generator 12 is selected at the time of automatic setting of the mode. Note that the test signal generator 12 has a number of outputs corresponding to the number of the switches 13 (that is, the presence or absence of connection and the number of channels of the speaker for determining the bass reproduction capability).

The power amplifier 7 and the speaker connection terminal 8
Between them, the current detector 14a is inserted. A speaker 9 is connected to the speaker connection terminal 8. The speaker connection terminal 8 is a general term for the speaker connection terminal 8C in FIG. 6 and the speaker connection terminals 8L to 8LFE in FIG. 9, and the speaker 9 is the speaker 9C in FIG. 6 and the speakers 9L to 9L in FIG. It is a generic term for 9LFE.

The current detector 14a includes a current detecting resistor R1
And resistors R2 and R3 connected in series to a connection point between the power amplifier 7 and the current detection resistor R1, and resistors R4 and R3 connected in series to a connection point between the current detection resistor R1 and the speaker connection terminal.
5, and an operational amplifier 141 whose connection point between the resistors R2 and R3 is connected to the + terminal and whose connection point between the resistors R4 and R5 is connected to the-terminal. Note that one end of the resistor R3 is grounded, and one end of the resistor R5 is connected to the output terminal of the operational amplifier 141.

The output of the current detector 14a is input to the determiner 14b. The determiner 14b includes a diode D1, a resistor R6, a capacitor C1, and a comparator 142. The output of the current detector 14a is input to one terminal of the comparator 142, and the determination voltage is input to the other terminal. The output of the comparator 142 is input to the interface 15.

The current detector 14a and the determiner 14b constitute a current detector / determiner 14, and the current detector / determiner 1
4 are required by the number corresponding to the number of channels of the speaker for determining the presence or absence of connection and the bass reproduction capability. Therefore, the output of the current detector / judgment unit 14 is input to the interface 15 in parallel. The interface 15 converts the input parallel data into serial data, and
To enter. Thereby, the number of input terminals of the control unit 10 can be reduced. The control unit 10 controls the switch 13 and the test signal generator 12 as described above.

Next, the operation of judging the presence / absence of the speaker 9 and the bass reproduction capability with the configuration of FIG. First, in order to determine the presence or absence of the speaker 9, it is sufficient to determine whether or not the speaker 9 is connected to the speaker connection terminal 8.
Under the control of the control unit 10, the switch 13 is connected to the test signal generator 12, and the test signal generator 12 generates a sine wave signal (first test signal) having a predetermined level and frequency.

At this time, if the speaker 9 is connected, the same current as the current flowing through the speaker 9 flows through the current detection resistor R1 in the current detector 14a,
a outputs a signal of a voltage proportional to the current.
The output signal of the current detector 14a is
The signal is converted into a direct current proportional to the signal level by 4b, and is compared with the judgment voltage by the comparator 142. If the voltage is higher than the determination voltage, the comparator 142 outputs a high level (or low level), and the speaker 9
Is determined to be connected.

Conversely, if the speaker 9 is not connected, no current flows through the current detection resistor R1 in the current detector 14a, and the output of the current detector 14a disappears. And
The output of the comparator 142 of the determiner 14b becomes low level (or high level), and it is determined that the speaker 9 is not connected.

As described above, it is possible to determine whether or not the speaker 9 is connected to the speaker connection terminal 8. However, the frequency of the test signal generated by the test signal generator 12 is selected around 400 Hz at which the speaker 9 has an impedance close to the nominal impedance. This is to avoid a decrease in current due to an increase in impedance near the lowest resonance frequency of the speaker 9 described later.

Next, to determine whether the speaker 9 is small or large, it is sufficient to determine the lowest resonance frequency which is a measure of the bass reproduction capability of the speaker 9. Generally, the bass reproduction capability of a speaker is determined by the lowest resonance frequency that is the bass reproduction limit. A speaker having a low minimum resonance frequency and a low bass reproduction limit has a large bass reproduction capability, and conversely,
A speaker having a high minimum resonance frequency and a high bass reproduction limit has a low bass reproduction capability.

FIG. 4 shows the frequency characteristics of the reproduced sound pressure of the speaker 9 and the frequency characteristics of the current flowing through the speaker 9. As shown in FIG. 4, the impedance of the speaker 9 has a maximum value at the lowest resonance frequency, and the current flowing through the speaker 9 at that time becomes a minimum. The electrical characteristics of the speaker 9 are shown in FIG.
Therefore, the lowest resonance frequency can be known by detecting the frequency at which the current flowing through the speaker 9 becomes minimum, and the bass reproduction capability of the speaker 9 can be known.

In order to detect the frequency (minimum resonance frequency) at which the current flowing through the speaker 9 becomes minimum, the switch 13 is switched to the test signal generator 12 in the circuit of FIG. A sine wave sweep signal (second test signal) whose frequency sequentially increases in a range of about 20 Hz to 400 Hz is generated.

Then, the current detection / judgment unit 14
What is necessary is just to detect that the current flowing through the speaker 9 has become smaller than the judgment voltage of the comparator 142, and to judge that the current has become minimal. The frequency at that time is the speaker 9
At the lowest resonance frequency. By determining this frequency by the control unit 10, it is possible to determine whether the speaker 9 is small or large. It should be noted that the criterion of small or large may be appropriately set depending on the system, and the determination voltage input to the comparator 142 may be appropriately set.
The judgment voltage input to the comparator 142 is determined by the speaker 9
It is preferable to set a voltage at which about 1/3 of the current flowing at the nominal impedance flows.

An embodiment of the present invention applying the above principle will be described.

<First Embodiment> FIG. 1 shows a first embodiment of a sound system to which the present invention is applied, and is a block diagram showing a 4-channel multi-surround system.

In FIG. 1, left and right audio signals Lt and Rt, which are analog signals, are input to a matrix circuit 1. The matrix circuit 1 converts the left and right audio signals L and R (hereinafter, left signal L) from the audio signals Lt and Rt. , Right signal R)
Then, a center audio signal C (hereinafter abbreviated as center signal C) and a surround audio signal S (hereinafter abbreviated as surround signal S) are generated. Left and right signals L, R
And the center signal C are input to the mode selection unit 2,
The mode as described in is automatically selected. The surround signal S is sequentially input to the delay circuit 3, the low-pass filter 4, and the noise reduction circuit 5.

The left and right signals L and R and the center signal C output from the mode selector 2 are input to the volume / tone controllers 6L, 6R and 6C, respectively, and the surround signals output from the noise reduction circuit 5 are output. S is input to the volume / sound quality adjuster 6S, and the volume and sound quality are adjusted, respectively. Note that, depending on the mode, the center signal C may not be directly output from the mode selection unit 2. Volume·
The signals output from the sound quality adjusters 6L, 6R, and 6S are input to power amplifiers 7L, 7R, and 7S, respectively, where the power is amplified.

The center signal output from the volume / tone controller 6C is input to the power amplifier 7C via the switch 13, and the power is amplified. The test signal from the test signal generator 12 is also input to the switch 13. The operations of the switching unit 13, the test signal generator 12, and the control unit 10 for controlling them are as described above.

The signals output from the power amplifiers 7L, 7R, and 7S are respectively connected to speaker connection terminals 8L, 8R, and 8S.
Through S, the left speaker 9L and the right speaker 9
R, which are input to the two surround speakers 9S, and the respective audio signals are reproduced. The center signal output from the power amplifier 7C is input to the speaker connection terminal 8C via the current detector / determiner 14. Speaker connection terminal 8
The output of C is input to the center speaker 9C, and a voice signal is reproduced.

As described above, the output of the current detection / judgment unit 14 is input via the interface 15 to the control unit 10 composed of a microcomputer. When the automatic setting of the mode is started, the control unit 10 determines the presence or absence and the size (bass reproduction capability) of the center speaker 9C according to the above-described principle, and automatically selects the optimum mode. 2 is controlled.

<Second Embodiment> FIG. 2 shows a second embodiment of a sound system to which the present invention is applied, and is a block diagram showing a six-channel multi-surround system.

In FIG. 2, a 5-channel audio signal S5, which is a digital signal, is input to a surround decoder 11. The surround decoder 11 outputs left and right audio signals L and R (hereinafter, left signal L and right signal) from the audio signal S5. R), a center audio signal C (hereinafter abbreviated as center signal C), and left and right surround audio signals S.
L and SR (hereinafter abbreviated as left surround signal SL and right surround signal SR) and a low-frequency sound reproduction signal LFE (hereinafter abbreviated as low-frequency signal LFE).

The left and right signals L and R, the center signal C, the left and right surround signals SL and SR, and the bass signal LFE are input to the mode selector 2 and are shown in FIGS.
The mode as described in is automatically selected. In addition,
Here, although all signals are shown to be output from the mode selection unit 2, the center signal C and the bass signal LF are output.
E may not be directly output from the mode selector 2 depending on the mode.

The left and right signals L and R output from the mode selection unit 2, the center signal C, and the left and right surround signals S
The L and SR and the bass signal LFE are input to the volume / sound quality adjusters 6L, 6R, 6C, 6SL, 6SR and 6LFE, respectively, and the volume and sound quality are adjusted respectively. Volume and sound quality adjusters 6L, 6R, 6C, 6SL, 6SR, 6LFE
The output signals are respectively output from the switches 13L and 13L.
R, 13C, 13SL, 13SR, 13LFE are input.

The switches 13L, 13R, 13C, 13
SL, 13SR, and 13LFE correspond to the switch 13 in FIG. Switches 13L, 13R, 13C, 13SL,
A test signal from the test signal generator 12 is also input to 13SR and 13LFE. Switches 13L, 13R, 13C,
13SL, 13SR, 13LFE and test signal generator 12
The operation of the control unit 10 for controlling them is as described above.

Switchers 13L, 13R, 13C, 13S
The signals output from L, 13SR, and 13LFE are power amplifiers 7L, 7R, 7C, 7SL, 7SR,
The power is input to the 7LFE and amplified.

Power amplifiers 7L, 7R, 7C, 7SL, 7
Signals output from SR and 7LFE are current detectors / determiners 14L, 14R, 14C, 14SL, and 14 respectively.
SR, input to 14LFE. Current detector / determiner 14
L, 14R, 14C, 14SL, 14SR, 14LFE
Corresponds to the current detection / determination unit 14 in FIG.

Current detectors / determiners 14L, 14R, 14
Signals output from C, 14SL, 14SR, and 14LFE are speaker connection terminals 8L, 8R, 8C,
Speaker 9 for the left through 8SL, 8SR, 8LFE
L, the right speaker 9R, the center speaker 9C, the left surround speaker 9SL, the right surround speaker 9SR, and the subwoofer 9LFE, and the respective audio signals are reproduced.

As described above, the current detector / determiner 14L,
Outputs of 14R, 14C, 14SL, 14SR, and 14LFE are input to a control unit 10 including a microcomputer via an interface 15. When the automatic setting of the mode is activated, the control unit 10 determines the size of the left and right speakers 9L and 9R (bass sound reproduction capability) and
A mode for automatically selecting an optimum mode by judging the presence or absence or size of the center speaker 9C (bass reproduction capability), the sizes of the left and right surround speakers 9SL and 9SR (bass reproduction capability), and the presence or absence of the subwoofer 9LFE. Controls the selection unit 2.

The operation of the automatic sound system setting apparatus of the present invention described above will be further described with reference to the flowchart of FIG. In FIG. 5, when the automatic setting of the mode is started, the presence or absence of the speaker 9 is detected by the current detection / determination device 14 in step S1, and the control unit 1 is determined in step S2.
“0” determines the presence or absence of the speaker 9 based on the detection output from the current detection / determination device 14. As a result of this determination, the speaker 9 is not connected in step S5, or
Determines that the speaker 9 is connected, and terminates.

In step S3, the control unit 10 detects the lowest resonance frequency, and in step S4, for example, determines whether the lowest resonance frequency is equal to or higher than 100 Hz or lower than 100 Hz. If the lowest resonance frequency is equal to or higher than 100 Hz, the size is determined to be small in step S7. If the minimum resonance frequency is less than 100 Hz, the size is determined to be large in step S8, and the process ends.

When there are a plurality of target channels,
The above processing is executed for each channel. FIG.
In the example of (1), only the presence / absence of the connection of the center speaker 9C is detected, so that the determination processing of only steps S1 and S2 in FIG. 5 is performed.

In the example shown in FIG. 2, the subwoofer 9LFE
For, only the presence or absence of the connection is determined, so the determination processing of only steps S1 and S2 in FIG. Left and right speakers 9L and 9R and left and right surround speakers 9S
For L and 9SR, only the size (low sound reproduction ability) is determined, and therefore only the steps S3 and S4 in FIG. 5 are determined. Of course, there is no problem even if the determination processes of steps S1 and S2 are performed together. For the center speaker 9C, both the presence or absence of connection and the size (bass sound reproduction capability) are determined, so that steps S1, S2 and S3 in FIG.
S4 Both determination processes are performed.

As described above, the optimum mode can be determined according to the state of the speaker 9. In the case of FIG. 1, the mode is automatically set to any of the normal mode, phantom mode, and wide mode shown in Table 1. I do. In the case of FIG. 2, the mode is automatically set to any of the first to eleventh modes shown in Table 1.

Incidentally, in the embodiment of FIG. 2, the left and right speakers 9L and 9R and the left and right surround speakers 9S
L and 9SR are all assumed to be connected. Therefore, if any one of the left and right speakers 9L and 9R and the left and right surround speakers 9SL and 9SR is in a state equivalent to no connection, It is desirable to stop the automatic setting of the mode as an error and notify the user of the error.

In the embodiment shown in FIG. 2, when the magnitude judgment of the left and right speakers 9L and 9R and the magnitude judgment of the left and right surround speakers 9SL and 9SR are different from each other, the state of each of the judged speakers 9 is different. Even in the case where the mode is not included in the mode shown in Table 2, it is desirable to notify the user of the error. This is shown in Table 2
Is a practical combination of the states of the respective speakers 9, and other than those described in Table 2 are not practical. However, when another practical mode exists, the mode may be added to Table 2, and the mode to be automatically set is not limited to Table 2.

The above-mentioned error is displayed by an LED or a liquid crystal display element, or, when the system is incorporated in a television receiver, an on-screen display using a well-known technique. do it. Also,
The error may be notified by voice using the speaker 9.

The automatic setting of the mode according to the present invention is described below.
Convenience is improved if the operation is performed when the power of the sound system is turned on.

[0095]

As described above in detail, in the sound system automatic setting device according to the present invention, the presence or absence of the connection to the speaker connection terminal or the speaker for which the bass reproduction capability is determined is connected to the speaker connection terminal. A test signal generator for generating at least one of a first test signal for detecting whether or not the test has been performed and a second test signal for detecting the lowest resonance frequency of the speaker; and a speaker connection terminal. Detecting a current flowing when the first test signal is supplied to the speaker connection terminal, and outputting a determination signal for determining whether or not the speaker is connected to the speaker connection terminal based on the detected output; Detecting a current flowing when the second test signal is supplied to the speaker connection terminal, and determining a lowest resonance frequency of the speaker based on the detected output. A current detection / judgment unit that outputs a constant signal, and a judgment signal from the current detection / judgment unit, based on whether or not the speaker is connected to the speaker connection terminal, and when the speaker is connected to the speaker connection terminal And a control unit that detects at least one of the lowest resonance frequencies of the speaker and automatically sets the mode selected by the mode selection unit according to the detection result. The optimum mode can be automatically set according to the condition. Therefore, the user needs to perform a complicated operation of connecting or not connecting a speaker or selecting the most suitable mode in consideration of the size of the speaker (bass reproduction capability) when connecting the speaker. Thus, it is possible to provide an extremely convenient sound system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a block diagram for explaining the principle of the present invention.

FIG. 4 is a characteristic diagram for explaining the principle of the present invention.

FIG. 5 is a flowchart for explaining the operation of the present invention.

FIG. 6 is a block diagram showing a first conventional example.

FIG. 7 is a block diagram showing a mode according to a first conventional example.

FIG. 8 is a diagram showing frequency characteristics in the mode shown in FIG. 7;

FIG. 9 is a block diagram showing a second conventional example.

FIG. 10 is a block diagram showing a mode according to a second conventional example.

FIG. 11 is a block diagram showing a mode according to a second conventional example.

FIG. 12 is a block diagram showing a mode according to a second conventional example.

FIG. 13 is a block diagram showing a mode according to a second conventional example.

[Explanation of symbols]

1 Matrix circuit 2 Mode selector 6, 6L, 6R, 6C, 6S, 6SL, 6SR, 6LF
E Volume / Sound Quality Adjuster 7, 7L, 7R, 7C, 7S, 7SL, 7SR, 7LF
E Power amplifier 8, 8L, 8R, 8C, 8S, 8SL, 8SR, 8LF
E Speaker connection terminals 9, 9L, 9R, 9C, 9S, 9SL, 9SR, 9LF
E speaker 10 control unit 11 surround decoder 12 test signal generator 13, 13L, 13R, 13C, 13SL, 13SR,
13LFE switch 14, 14L, 14R, 14C, 14SL, 14SR,
14LFE current detector / determiner 15 interface

Claims (1)

[Claims] A plurality of audio signals to be reproduced by a plurality of speakers are inputted, and at least one of the plurality of speakers is connected to a speaker connection terminal or according to bass reproduction capability. A sound system including a mode selection unit that selects any one of a plurality of modes for outputting at least some frequency components of an audio signal to be supplied to a speaker to another speaker different from the speaker, In a sound system automatic setting device for automatically setting a mode, detecting whether or not a speaker is connected to a speaker connection terminal or whether or not the speaker for which bass reproduction capability is to be determined is connected to the speaker connection terminal. The first to do
A test signal generator that generates at least one of a test signal for detecting a lowest resonance frequency of the speaker and a second test signal for detecting a lowest resonance frequency of the speaker; A current flowing when the test signal is supplied is detected, and a detection signal for determining whether the speaker is connected to the speaker connection terminal is output based on the detection output, and the determination signal is output to the speaker connection terminal. A current detection / determination unit that detects a current flowing when the second test signal is supplied, and outputs a determination signal for determining the lowest resonance frequency of the speaker based on the detection output; Is determined whether or not the speaker is connected to the speaker connection terminal, and whether the speaker is connected to the speaker connection terminal. And a control unit for detecting at least one of the lowest resonance frequencies of the speaker and automatically setting a mode selected by the mode selection unit according to the detection result. System automatic setting device.