JP3065439B2 - Sound field control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound field control device, and more particularly to a sound field control device having a sound field adding function by a DSP and a direction emphasis function.

[0002]

2. Description of the Related Art Conventionally, as a sound field adding circuit for adding a desired sound field to a sound having a stereo configuration, for example, FIG.
The circuit shown in FIG. In this circuit, based on the Lch input Lin and the Rch input Rin, the reflected sound generation circuit 11 generates reflected sound components LA and RA and surround components SL and SR as sound fields, and outputs an output signal together with Lout and Rout. You.

Further, a circuit for adding a sound field to the 4-channel output of the directionality emphasizing circuit as shown in FIG. 8 is also used. The direction emphasis circuit 21 generates four-channel signals C (center), L, R, and S whose directions are emphasized from the inputs Ltin and Rtin, and outputs the signals through the center mode control circuit 22. The reflected sound generation circuit 23 generates a reflected signal L based on an output signal from the direction enhancement circuit 21.
A, RA, SL and SR are output.

[0004]

As described above, various device circuits are used as a conventional sound field control device. However, in the circuit shown in FIG.
Since the sound field is applied to the R signal and the R signal, there is a problem that the pronunciation of the vocal of the music source or the speech of the movie source becomes unclear. In the circuit shown in FIG. 8, C, L,
Since the R and S four-channel output signals and the reflected sound components generated based on the four-channel output signals are output together, not only are the vocals and lines unclear, but also the C
There is a problem that the smoothness when the sound moves between the L and R signals and between the L and R signals is often impaired by the reflected sound component.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sound field control apparatus for automatically separating a signal to which a sound field is to be added and a signal to which a sound field is not to be added and appropriately controlling the sound field.

[0006]

In order to solve the above-mentioned problems, a sound field control device according to the present invention comprises a direction emphasis circuit for generating a signal whose directionality is emphasized from an input signal, and the direction emphasis circuit. Field control device that generates a predetermined sound field by including a center mode control circuit that performs predetermined processing on a signal from the device and outputs the signal, and a reflected sound generation circuit that generates a reflected signal based on the signal from the directionality emphasizing circuit A signal separation circuit that outputs a signal obtained by adding and subtracting the input signal and a signal whose directionality is enhanced generated by the directionality enhancement circuit, and outputs the signal from the signal separation circuit as a type of the input signal. Is controlled to increase or decrease the amount sent to the reflected sound generation circuit in accordance with Here, if the input signal is a speech component or the directionality is emphasized, the amount sent to the reflected sound generation unit is reduced, and otherwise, the amount sent to the reflected sound generation unit is increased. .

[0007]

According to the present invention, an output signal is generated by increasing / decreasing an amount to be sent to a generation unit of a reflected sound according to the type of the input signal, such as when the input signal is a serif component or the direction is emphasized. By doing so, an appropriate sound field signal is generated.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration block diagram showing one embodiment of a sound field control device according to the present invention. This embodiment includes the direction emphasis circuit 21, the center mode control circuit 22, and the constituent circuits 1, 2, and 3 corresponding to the reflected sound generation circuit 23 having the structure shown in FIG. The input signals Ltin, Rtin of the circuit 1 and the output signals C, L, R, S are mixed using the configuration shown in FIG. 2, separated, and the corresponding signals CA, LA, RA, SA are reflected to the reflected sound generation circuit 3. Has been sent to. Based on the output signal from the signal separation circuit 4, the reflected sound generation circuit 3 outputs LB, RB, SLB and SLA as reflected sound components.

Therefore, according to the configuration shown in FIG. 1, the reflected sound component and the direct sound component are Ltout and Rtout, or the outputs Cout, Lout, Rout and Sout with the directional enhancement applied, or an output combining these. The signal can be arbitrarily selected and output. The center mode control circuit 2
A mode in which the signals C, L, and R from the directivity emphasizing circuit 1 are passed as they are; a mode in which the signal C is added to the signals L and R by -3 dB (attenuation);
A signal passed through a high-pass filter (HPF) of dB / oct is set as C out, and the mode is added to the signals L and R that are -3 dB (attenuated) by a low-pass filter (LPF) of 100 Hz and -6 dB / oct and added to the three modes. This is a possible configuration.

FIG. 2 shows a specific configuration example of the signal separation circuit 4 shown in FIG. The mixing circuit 41
In the C (center) signal separation circuit, the signals Rtin and Ltin are input to the + input terminal, the signals L and R are input to the-input terminal, and the output signal is level-adjusted by the volume circuit VR1. The mix circuit 45 is a second C signal separation circuit, and outputs the output from the volume circuit VR1 to the-input terminal,
The C signal is received at the + input terminal, and the signal CA is output. The mix circuit 42 is a first L signal separation circuit. Ltin is input to the + input terminal, signals C and S are input to the-input terminal, and the output signal is adjusted in level by the volume circuit VR2. The signal L is mixed with the signal L by a mix circuit 46 as a second L signal separation circuit to output a signal LA. The mix circuit 43 is a first R separation circuit. The signal S and Rtin are supplied to the + input terminal, the signal C is supplied to the-input terminal, and the output is the volume circuit VR3.
After that, the signal R is mixed with the signal R by the mixing circuit 47 as a second R signal separation circuit, and the signal RA is output. The mix circuit 44 is a first S (surround) signal separation circuit, and the signals R and Ltin are supplied to the + input terminal and the signals L and Rtin are supplied to the-input terminal.
The output is adjusted in level by a volume circuit VR4, and then a mix circuit 4 as a second S signal separation circuit is used.
8, the signal S is mixed with the signal S and the signal SA is output. The volume circuits VR1 to VR4 in FIG. 2 can be independently adjusted.

FIG. 3 shows the relationship between input and output in the directionality emphasizing circuit 1. FIG. 3 shows the frequency relationship between the input signals Ltin, Rtin and the output signals C, L, R, S for the conditions A to H, with the unit being (Hz). In FIG. 3, the input signals Ltin and Rtin have the same amplitude, and a negative sign indicates a phase shift.

FIG. 4 shows the relationship between the input signals Ltin and Rtin and the outputs of the mix circuits 41 to 44 for the conditions A to H. It can be seen from the figure that there is no output when the input has two or more frequencies.

FIG. 5 also shows input signals Ltin,
The relationship between Rtin and the outputs of the mix circuits 45 to 48 is shown. FIG. 5 shows a relationship obtained when the signals of FIGS. 3 and 4 are subtracted, and shows the volume circuits VR1 to VR4.
Is not attenuated. From FIG. 5, condition A
The output signals CA, LA, RA, and SA do not appear for the input signals Ltin, Rtin of the stages D to D, and two or more frequencies are input to the input signals Ltin, Rtin as in the conditions E to H. Output signal LA = Ltin, RA = Rtin, CA = Lt
in + Rtin, SA = Ltin-Rtin are obtained.

As described above, since the signal separation circuit 4 is arranged at the preceding stage of the reflected sound generation circuit, the input Lt and Rt signals that are strongly emphasized in the direction (conditions A to S of FIGS. 3 to 5).
In the case of D stage, the level of the reflected sound is equivalently reduced, and the input Ltin and Rtin signals (FIG. 3 to FIG.
In the case of the conditions E to H in FIG. 5, the level of the reflected sound is maximum. Therefore, input Ltin and Rtin signals (source signals)
The level of the reflected sound is automatically changed by the component of, and an appropriate sound field space can be obtained. Further, since the volume circuits VR1 to VR4 can be linearly variable as attenuators, an intermediate operation of the strength of signal separation is possible, so that the setting can be freely performed.

FIG. 3 shows the characteristics of the directivity emphasizing circuit. When the directivities of the stages A to D are emphasized, C = Ltin + Rtin, S = Ltin-Rtin, L = Ltin, R = Rtin (1), and when the signal difference C is output, the operation is performed so that the other outputs are eliminated. However, when the signals become two or more types as in the conditions E to H, (1) Expressions have the property of being output simultaneously. Utilizing this property, FIG. 4 shows the outputs of the mix circuits 41 to 44 of FIG. 2, and the output of 41 = [(Ltin + Rtin)-(L + R)] (2) The output of 42 = [Ltin− (C + S) )] (3) Output of 43 = [Rtin− (S−C)] (4) Output of 44 = [(Ltin−Rtin) − (LR)] (5) When the direction is emphasized, the terms Ltin and Rtin remain, and when the direction is not emphasized, all the terms become zero.

Next, according to FIG. 5, the outputs of the mix circuits 45 to 48 of FIG. 2 are as follows: CAout = output of C-41 = C-[(Ltin + Rtin)-(L + R)] (6) LAout = Output of L-42 = L-[Ltin-(C + S)] ... (7) RAout = output of R-43 = R-[Rtin-(SC)] ... (8) SAout = output of S-44 = S − [(Ltin−Rtin) − (LR)] (9), and the terms in [] are equivalent to C in equation (6) when the directionality is emphasized. CA out is
C- [C] = 0. Equations (7), (8), and (9) are also 0. When the direction is not emphasized, the term in [] becomes 0, and the equation (6) indicates that CAout = C−
It is output as [0] = C. The same applies to equations (7), (8) and (9).

In FIG. 2, if the directionality emphasizing circuit is basically set as in the following equations (10) and (11), Lt = L + 0.7C + J0.7S (10) Rt = R + 0 0.7C-J0.7S (11) (0.7 is -3 dB, J is 90 degrees in phase shift) (1) When Lt = Rt = 0.7C, the output of 41 is 0.7.
7C, 0 otherwise, (2) 42 when Lt = L, Rt = 0
Is L, others are 0, (3) When Lt = 0, Rt = R, the output of 43 is R, others are 0, (4) Lt = -Rt = 0.
In the case of 7S, the output of 44 may be set to 0.7S, and the others may be set to 0. In the second-stage mix circuit, V
Assuming that R1 to VR4 are not attenuated, (1) to
It is desirable to set so that the outputs of 45 to 48 become 0 under any condition of (4).

The output of FIGS. 1 and 2 is an embodiment in which full-channel output is enabled. Four channels CAout to SAout are added to LAout and RAout to add three channels, and SAout is added to LAout and RAout. LA out and RA out are further added to two channels, and CA out is added to LA out and RA out to form one signal, and SA out and two channels are used to match the input of the reflected sound generation circuit. Will be possible.

This signal separating circuit can also change the degree of signal separation by changing the setting of the depth of emphasis of the directionality emphasizing circuit. One directionality emphasis circuit can be used independently for direct sound, and one operation can be combined for signal separation. If it is desired to control only a certain band, a filter may be formed on the outputs of the mix circuits 41 to 44 in FIG. At this time, as the output of the mix circuits 45 to 48, the band outside the control can be an output with the directionality emphasized. If it is not desired to output a band outside the control, this can be realized by passing the outputs of the mox circuits 45 to 48 through a filter in the band.

The signals of Ltin and Rtin in FIG. 2 can be generated in reverse from the four signals of C, L, R and S which are the outputs of the directional enhancement in FIG. 1, and as shown in FIG. -3 dB attenuators 5A and 5B and adder 6 for obtaining Le and Re
A, Le = Lt and Re = Rt can be used by adding a mix circuit composed of A and the adder / subtractor 6B.

The reflected sound generation section provided at the subsequent stage of the signal separation includes:
It refers to anything that has the function of sound field reproduction. Also, the reflected sound generation unit is configured to include the mix circuits 41 to 41 in FIG.
It is also possible to add a reflected sound generation unit independent of the output of 44 (the output to which only the directionality is applied).

[0022]

As described above, according to the present invention,
If the source is composed of stereo, an effective sound field can be expressed. In addition, the vocal component in the musical sound component is hardly affected by the sound field, and the musical sound component sounding around the vocal is affected by the sound field, and the vocal clarity is improved and the sense of localization is improved. Furthermore, in the reproducibility of a source such as a movie, a sound field is applied in a music scene, and when the scene is suddenly changed to a scene talking in a quiet room, the sound field is not applied, and from the front of an airplane, etc. In the scene moving backward, the sound field is not applied, so the feeling of movement is smooth. Therefore, natural expressive power suitable for the scene increases. Also, C (center), L,
For each of the four channels of R and S (surround), separate output can be obtained for each of the four channels, and the degree of separation can be freely set, so that the range of design variations in the reflected sound generation circuit is widened. .

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a sound field control device according to an embodiment of the present invention.

FIG. 2 is a specific configuration circuit diagram of a signal separation circuit according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating an input / output relationship of a directionality emphasizing circuit according to an embodiment of the present invention.

FIG. 4 is a diagram showing operation characteristics of the signal separation circuit shown in FIG. 2;

FIG. 5 is a diagram showing an input / output relationship of a signal separation circuit according to the embodiment of the present invention.

FIG. 6 is a configuration block diagram of a sound field control device according to another embodiment of the present invention.

FIG. 7 is a configuration block diagram of a conventional sound field control device.

FIG. 8 is a diagram showing an example in which a conventional direction emphasis circuit is used.

[Explanation of symbols]

Reference Signs List 1 directional emphasis circuit 2 center mode control circuit 3 reflected sound generation circuit 4 signal separation circuit

Claims (2)

(57) [Claims] (1)Generates a signal with enhanced directivity from the input signal
Direction emphasizing circuit to generate and the signal from this direction emphasizing circuit.
Center mode control that processes and outputs signals
Circuit, and reflection based on a signal from the direction emphasis circuit.
Produces a predetermined sound field with a reflected sound generation circuit that generates signals
In the resulting sound field control device, The input signal and the one generated from the direction emphasis circuit
A signal that outputs a signal obtained by adding or subtracting a signal with emphasized directivity
No. separation circuit, The output from the signal separation circuit is determined according to the type of the input signal.
The reflected sound generation circuit To control the amount sent to
Characteristic sound field control device. 2. The amount sent to the reflected sound generator when the input signal is a serif component or when the directionality is emphasized, and otherwise the amount sent to the reflected sound generator. The sound field control device according to claim 1, wherein