JPH0292200A - Stereophonic sound reproducing device - Google Patents

Abstract

PURPOSE:To correct the change of a voice in a band when a vocal exists at a center by adding a signal, which is obtained by frequency-correcting the specific band of a right/left sum signal component where an image is fixedly positioned at the center of a stereo signal, to a left signal, a left corrective signal, a right signal and a right corrective signal. CONSTITUTION:For right and left signals RIN and LIN inserted from input terminals 1 and 2, the right/left sum signal component is detected by a detecting circuit 15, a correction by means of a corrective curve 1 is executed by a equalizer circuit 16, the signals are added to a left signal LIN and to a left corrective signal C1 by an adder circuit 11, pass through an equalizer circuit 12, and they are outputted as a characteristic C after the correction. In the same way, the right signal RIN and a right corrective signal C2 are added to the signal obtained by correcting the right/left sum signal components by an adder circuit 13, pass through the equalizer circuit 14, and they are outputted as a characteristic (c) after the correction. Thus, in the frequency characteristic (c) of the output signal, a trough part is excellently corrected.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is a stereoscopic system that can produce good stereoscopic sound and reproduce a sound field when reproducing stereo audio signals with an audio player, a television receiver, etc. The present invention relates to a sound reproduction device.

<Prior Art> Conventionally, when reproducing a stereo audio signal with an audio player, television receiver, etc., as shown in FIG.

■Sound is output. However, the listener hears four sounds ■, ■', ■, and ■' as shown in (a). For example, when the original signal ■ should enter the right ear, the component ■' from the left speaker actually enters, so this interferes with ■ and becomes a so-called crosstalk component, which is extra information. arise. Similarly, for the left ear, in addition to ■, the right speaker component ■' is included. This losstalk component changes the localization of the sound image, (a)
It feels like the sound image is located at the position of the two-dot chain line, and the stereo effect is reduced.

``Apparatus and method for creating 3D sound'' described in Japanese Patent Application Laid-Open No. 500477/1983 is known as a means for eliminating such a phenomenon and creating good 3D sound.

The content described in this publication is to create signals CI and C2 (referred to as compensation signals) that cancel the crosstalk components of As a result, ■' and C2° and ■' and C1 cancel each other out at the listener's ears, so that only ■ is heard in the left ear and only ■ is heard in the right ear.

FIG. 5 is a block diagram schematically showing a three-dimensional sound reproduction device to which the device described in the above-mentioned publication is applied in order to eliminate crosstalk. In this figure, numerals 1 and 2 are input terminals for the left signal LIN and right signal RIN supplied as input, and 3 and 4 are the left signal L taken out as output.
OUT, which is the output terminal for the right signal ROUT. The above-mentioned compensation signal C2 is obtained by passing the left signal LIN through a bypass filter (HP
F)5. The right signal RIN is passed through the N extension circuit 61 and the inversion circuit 7.
Similarly, the above compensation signal C1
The right signal RIN is set to HPF8. Delay circuit 92 Inversion circuit 10
It is created in a path that is added to the left signal LIN through the signal LIN.

Then, the left signal LIN is added to the left compensation signal C1 obtained by inverting and delaying the right signal RIN in an adder circuit 11, and the left signal is outputted through an equalizer circuit 12 and becomes OUT, and is supplied to a left speaker (not shown). Further, the right signal RIN is combined with the right compensation signal C2, which is an inverted version of the left signal LAN, and the addition circuit 13.
The signals are added together in the equalizer circuit 14 to become a right signal output R011T, which is supplied to a right speaker (not shown).

In this way, a substantial amount of the left sound component coming to the right ear position is canceled by the right compensation signal C2. Similarly,
A substantial amount of the right sound component coming to the left ear position is canceled by the left compensation signal C1.

By the way, the frequency characteristics of the left output from the adder circuit 11 (or the right output from the adder circuit 13) in the device shown in FIG. 5 are as shown by the solid line a in FIG. 6, and the left compensation signal C
A peak and valley portion is generated at a frequency corresponding to the delay time of I (or right compensation signal C2).

Since this is a characteristic different from the substantially flat frequency characteristic of the left signal LIN (or right signal RIM), the equalizer circuit 12 (or 14) is provided as shown in FIG. ), it is possible to correct the frequency characteristic as shown in 1 by the - dotted chain line C. However, depending on the delay time of the compensation signal, the frequency characteristic becomes as shown by the solid line a in FIG. 7, and a large-area valley (shaded area) occurs in the middle and low range. This trough cannot be completely corrected by an equalizer circuit having the characteristics as shown by the broken line C, and the frequency characteristic after correction becomes as shown by the dashed-dotted line C. Having such a large-area valley has a great effect on the sound components in this band.

Therefore, for the characteristic shown by the solid line a in Figure 8(a) (same as the solid line a in Figure 7), the equalizer characteristic is corrected by giving the opposite characteristic (indicated by the dashed line) in the shaded area. By doing so, it is possible to improve the characteristics after correction as shown by the dashed line C. However, in the case of the above equalizer characteristics, it is assumed that only the left signal LIN or only the right signal RIN is input to the device shown in FIG.
or the compensation signal C1 or C2 added to RIN is not created). At this point, the left signal LIN or right signal R
If the frequency characteristic of the IN input is as shown by the broken line d in Figure 9, after correction by the equalizer characteristic of the opposite characteristic described above, the characteristic will be as shown by the dashed dotted line e, and in the mid-low range, the diagonal line This ends up emphasizing only the components of the original sound, resulting in a sound that is far away from the original sound. Note that the solid line C in FIG. 9 indicates the left signal LIN and right signal RI similarly to C in FIG.
If there is N, the left signal output L OUT or right signal output ROUT corrected by the equalizer characteristic of the above-mentioned inverse characteristic
It shows the characteristics of

Therefore, if a trough occurs in the mid-low range of the output signal due to the delay time of the compensation signal, it cannot be corrected by the equalizer circuit. Especially the left and right stereo signals.

It is not possible to correct the change in sound caused by the valley of the L+R component localized at the center of R, and when the vocal is located at the center of J:U, the voice of the center vocal changes.

(Problems to be Solved by the Invention) As described above, in the conventional device, depending on the delay time of the compensation signal, the frequency characteristics of the left and right output signals have valleys in the mid-low range, which cannot be fully corrected by the equalizer circuit. The problem was that there was no. In particular, with respect to the L+R components localized at the center, there is no means to correct this valley, and if there is a vocal at the center of the music source, the voice of the center vocal will change.

Therefore, the present invention is aimed at eliminating the above problems.
The object of the present invention is to provide a three-dimensional sound reproducing device capable of correcting valleys occurring in the middle and low range of the output L + R components.

[Configuration of the Invention (Means for Solving the Problems) The three-dimensional sound reproduction device of the present invention includes a first compensation signal generation circuit that generates a right compensation signal by inverting and delaying a left signal supplied as an input. , a second compensation signal generation circuit that generates a left compensation signal by inverting and delaying the right signal supplied as an input; and a left and right summation circuit that detects a sum signal component of the left and right signals supplied as input. a signal component detection circuit; a first equalizer circuit that corrects a predetermined frequency characteristic band of the sum signal component detected by the left and right sum signal component detection circuit; a first addition circuit that adds the left compensation signal from the second compensation signal generation circuit and the frequency-corrected sum signal component from the first equalizer circuit; a second addition circuit that adds the right compensation signal from the first compensation signal generation circuit and the frequency-corrected sum signal component from the first equalizer circuit; A second equalizer circuit that corrects the frequency characteristics and obtains a left signal output; and a third equalizer circuit that corrects the frequency characteristics of the signal added by the second addition circuit and obtains a right signal output. It is composed of

(Operation) In the present invention, the sum signal (
The L+R) component is extracted and added to the left and right output signals through a first equalizer circuit that has an inverse characteristic to the mid-low range valley, thereby correcting the valley. did. According to the present invention, the input signal of the R component is the left;
Since the signal does not pass through the right sum signal (L+R) component detection circuit and the first equalizer circuit, the frequency characteristics can be improved without over-emphasizing the middle and low frequencies as shown in FIG. 9e.

(Example) The present invention will be described below based on the example shown in the drawings.

FIG. 1 is a block diagram showing a three-dimensional sound reproduction apparatus according to an embodiment of the present invention.

In this figure, the same components as in FIG. 5 are designated by the same reference numerals. That is, the left signal LIN input terminal 1. Input terminal 2 for right signal RIN. Output terminal of left signal 10UT3.
The output terminal 4 of the right signal ROUT is arranged, and the left signal L
l-I for creating the right compensation signal C2 based on IN
P F 5 , the path of the delay circuit 6 and the inversion circuit 7,
HPF8. for creating the left compensation signal C1 based on the right signal RIN. A delay circuit 9 and an inversion circuit 10 are configured. Furthermore, the left signal LIN and right signal RIM are detected by the left and right sum signal component detection circuit (L + R component detection circuit) 1.
Enter 5 and left.

The sum signal component of both right signals is detected, and the signal component is shown in Fig. 2 f.
A path is provided through which the frequency is corrected and output through an equalizer circuit 16 that adjusts the equalizer characteristics of the signal. Then, the left signal LIN, the left compensation signal C1 and the equalizer circuit 1
Addition circuit 11 adds the frequency-corrected sum signal component from 6 to
The added signal is further frequency-corrected by the equalizer circuit 12 having the equalizer characteristics shown in FIG. 2 to produce the left signal output L0LIT. Further, the right signal RIM, the right compensation signal C2, and the frequency-corrected sum signal component from the equalizer circuit 16 are added in the adder circuit 13, and the added signal is further added to the equalizer circuit 14 which adjusts the equalizer characteristics shown in FIG. The frequency is corrected and the right signal output ROυT is obtained.

In FIG. 2, the solid line a is the frequency characteristic of the output obtained by adding the left signal L IN (or right signal RIN) and the left compensation signal C1 (or right compensation signal C2) in the conventional circuit shown in FIG. This figure shows a valley in the mid-low range due to the delay time of the compensation signal.

The broken line indicates the equalizer circuit 12 (or equalizer circuit 14)
) does not show the equalizer characteristics. Furthermore, the broken line d is the left signal LIN or the right signal RIM in the conventional circuit shown in FIG.
It also shows the frequency characteristics of the addition output when only the N or right signal RIN is input. This is because the input signal of the left signal LIN or the right signal RIN does not pass through the left and right sum signal component detection circuit 15, so that the frequency characteristics are the same as before. A broken line f indicates the equalizer characteristic of the equalizer circuit 16, and has a characteristic opposite to that of the valley in the middle and low range. - Dotted chain line C indicates the left signal output LOUT (or right signal output ROO) output from output terminal 3 (or 4)
T) shows the frequency characteristics.

In the above device, the left and right signals LIN and RIN input from the input terminal 1.2 are detected as left and right sum signal components by the detection circuit 15, and are corrected by the correction curve f in the equalizer circuit 16. At addition port 11, left signal LIN
is added to the left compensation signal c1, passes through the equalizer circuit 12, and is output as the corrected characteristic C. Similarly, the adder circuit 13 adds the right signal RIN and the right compensation signal C2 to the signal obtained by correcting the left and right sum signal components, passes through the equalizer circuit 14, and outputs the corrected characteristic C.

As a result, in the frequency characteristic C of the output signal, the troughs shown in the shaded areas shown in FIG. 7 are corrected.

On the other hand, since the left or right input signal does not pass through the circuits 15 and 16, it is output as before with the characteristics shown in FIG.

FIG. 3 is a block diagram showing another embodiment of the present invention.

In the embodiment shown in this figure, a delay circuit 17 is provided between the left and right sum signal component detection circuit 15 and the equalizer circuit 16 shown in FIG.

This is the circuit section 15. of FIG. ．． When adding the signal for correcting the shaded area created by 16, if the addition to the shaded area (trough) is not performed in a timely manner due to the influence of the delay time of the compensation signals CI and C2, the delay circuit 6 , 9, a delay circuit 17 is provided to perform time adjustment and addition.

[Effects of the Invention] As described above, according to the present invention, a signal obtained by frequency-correcting a specific band of left and right sum signal components in which a sound image is localized at the center of a stereo signal is converted into a conventional left signal and left compensation signal, By adding to the right signal and the right compensation signal, it is possible to correct the valleys in a specific band (for example, mid-low range) of the left signal output and right signal output caused by the delay time of the compensation signal, and also to position it to the center. The specific band of the left and right sum signal components can also be corrected. Therefore, it is possible to correct the change in the voice in the above band, especially when there is a vocal in the center, and it is possible to create a good three-dimensional sound and reproduce the sound field.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a three-dimensional sound reproduction device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram illustrating the frequency characteristics of the left signal output or right signal output of the device in FIG. 1, and FIG. FIG. 4 is a block diagram showing another embodiment of the present invention, FIG. 4 is an explanatory diagram explaining a conventional three-dimensional sound reproduction method, FIG. Explanatory diagram explaining the frequency characteristics of the left signal output or right signal output of the device shown in the figure, No. 7
The figure is an explanatory diagram illustrating the frequency characteristics when there is a trough in the middle and low range of the left signal output or right signal output of the device in Figure 5.
The figure is an explanatory diagram illustrating a method for correcting the frequency characteristic with the valley in Fig. 7 using an equalizer circuit, and Fig. 9 shows the frequency characteristic corrected by the method explained in Fig. 8. FIG. 6 is an explanatory diagram illustrating the difference between the characteristics in a normal case where there is a signal input and a right signal input, and the characteristics when there is only a left signal input or only a right signal input. 1...Left signal input terminal, 2...Right signal input terminal, 3
...Left signal output terminal, 4...Right signal output terminal, 5.
8... Bypass filter, 6.9... Delay circuit, 7, 10... Inversion circuit, 11
．． 13...Addition circuit, 12.14.16...Equalizer circuit, 15...Left and right sum signal component detection circuit. Old R fly) -)-1 center (Diagram

Claims (2)

[Claims] (1) A first compensation signal creation circuit that creates a right compensation signal by inverting and delaying the left signal supplied as an input, and creating a left compensation signal by inverting and delaying the right signal supplied as an input. a second compensation signal generation circuit; a left and right sum signal component detection circuit for detecting the sum signal components of the left and right signals supplied as input; and a sum signal detected by the left and right sum signal component detection circuits. a first equalizer circuit that corrects a predetermined band of frequency characteristics of a component; and a left compensation signal from the second compensation signal generation circuit and a left compensation signal from the first equalizer circuit for the left signal supplied as an input. a first addition circuit that adds frequency-corrected sum signal components; and a right compensation signal from the first compensation signal generation circuit and a right compensation signal from the first equalizer circuit for the right signal supplied as an input. a second adder circuit that adds the frequency-corrected sum signal components; a second equalizer circuit that corrects the frequency characteristics of the signal added by the first adder circuit to obtain a left signal output; A 3D sound reproduction device comprising: a third equalizer circuit that corrects the frequency characteristics of the signals added by the second adder circuit and obtains a right signal output. (2) The stereophonic sound reproducing apparatus according to claim 1, further comprising a delay circuit provided in series with the left and right sum signal component detection circuit and the first equalizer circuit.