JP3074813B2 - Crosstalk cancellation circuit and sound image localization 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 image localization device for providing a stable sound image localization feeling in a stereo reproduction device or an electronic musical instrument.

[0002]

2. Description of the Related Art A stereo reproducing apparatus has two left and right channel output systems. A left channel speaker outputs a musical sound reaching a left ear of a listener (listener) from a sound source, and a right channel speaker outputs a musical sound. Outputs the musical sound that reaches the listener's right ear from the sound source. Thereby, the sound source can be localized at a predetermined position. However, the musical sound output from the speaker also reaches the ear opposite to the listener. This is called crosstalk. Due to this crosstalk, the sound image localization of the musical sound becomes unclear, and the sound image can be localized only in the space between the left and right speakers, and there is a defect that the sound field does not expand.

A crosstalk canceling circuit as shown in FIG. 6 has been proposed to solve this problem. This circuit delays the signal of the left channel with a delay circuit,
The signal is attenuated by a gain a (less than 1) by an amplifier and then subtracted from the signal of the right channel, and the signal of the right channel is similarly delayed and attenuated and then subtracted from the signal of the left channel. It is.
In this way, the tone heard by the crosstalk is subtracted from the tone signal of the opposite channel in advance, and the listener can cancel both by listening to this signal and the crosstalk sound together.

[0004]

However, the configuration of the crosstalk canceling circuit shown in FIG. 6 is effective when the correlation between the left and right stereo signals is small, for example, when the left and right channels are musical sounds of completely different musical instruments. However, when the left and right signals are highly correlated, such as when playing a tone localized near the center, the circuit configuration has the same characteristics as the comb filter as shown in FIG. However, there is a disadvantage that the metal is deteriorated. Also, regarding the expansion of the sound field, the case where crosstalk cancellation is not performed (FIG. 8A)
Although it can be expanded as shown in FIG.
There was a disadvantage that the localization itself was also spread and the localization was unclear.

The present invention provides a crosstalk canceling circuit for canceling crosstalk according to localization, and a sound image localization apparatus for separating a plurality of types of musical sounds using this circuit and canceling crosstalk according to the respective localizations. The purpose is to do.

[0006]

According to the first aspect of the present invention, a musical tone of one channel of a stereo is delayed,
A crosstalk canceling circuit for attenuating and inverting the phase and outputting from the other channel, wherein control means for controlling at least the attenuation is provided according to the localization of a tone signal input in stereo. I do.

According to a second aspect of the present invention, there is provided a plurality of crosstalk canceling circuits according to the first aspect, wherein a plurality of musical sounds input in stereo are input to different ones of the crosstalk canceling circuits, respectively. Is provided with means for synthesizing the output of (1) into one system of stereo signals.

[0008]

The crosstalk canceling circuit of the present invention controls the level (attenuation) of the signal input to the opposite channel according to the localization. When the localization is near the center, there is no adverse effect due to the crosstalk, so the level is reduced (the attenuation is increased), and when the localization is swung right and left, the level is increased. This enables appropriate crosstalk cancellation according to the localization.

Further, in the sound image localization apparatus of the present invention, the crosstalk canceling circuit is provided for each of a plurality of musical tones, and the crosstalk is canceled according to the localization of each musical sound. As a result, it is possible to appropriately localize each musical tone even with a set of musical tones having a spread (like an orchestra).

[0010]

FIG. 1 is a block diagram of a crosstalk canceling circuit according to an embodiment of the present invention. The stereo input signals Lin and Rin (same as the terminal names) are
Output from Lout and Rout via 6L and 16R. Also, a bypass circuit is configured from Lin to the subtractor 16R and from Rin to the subtractor 16L.

A bypass circuit from Lin to the subtractor 16R is composed of a delay circuit 13L and amplifiers 14L and 15L. The bypass circuit from Rin to the subtractor 16L includes a delay circuit 13R, amplifiers 14R and 15R.
It is composed of The delay time of the delay circuit 13 (R, L) is set to the time difference until one sound of the stereo speaker reaches the listener's right and left ears. The gain a of the amplifier 14 is set to an appropriate value less than 1. This value is a value sufficient to cancel crosstalk when the localization of the input musical sound is largely swung right and left. The gain of the amplifier 15 is input from a cancellation amount determination unit 12 described later. Amplifier 15L,
The bypass signal output from R is subtracted from the signal (Rin, Lin) of the opposite channel by the subtractors 16R, 16L. That is, the phase is inverted and added. Therefore, when the bypass signal has the same level as the phase opposite to the crosstalk, the crosstalk is completely canceled.

On the other hand, the left and right inputs Lin and Rin are also input to a subtractor 11. The subtracter 11 calculates the level difference between the two channels and inputs the result to the cancellation amount determination unit 12. The input / output relationship table of FIG. The output of this table is output to amplifiers 15R and 15L as a gain instruction signal.

Since the maximum gain of the amplifier 15 is 1 from FIG. 1B, the total gain of the amplifiers 14 and 15 is less than 1.

From FIG. 1B, when the sound image is near the center (when the Lin level and the Rin level are the same), the value is 0, and approaches 1 as the localization shifts right and left.
By configuring the table in this manner, crosstalk is completely canceled when the localization is largely shifted to the left or right, and when the localization of the sound image is near the center, crosstalk does not adversely affect the sense of localization. From
The amount of crosstalk cancellation is reduced so that the sense of localization is not spread too much.

FIG. 2 shows another embodiment of the crosstalk canceling circuit. In this embodiment, the same components as those in the embodiment of FIG. In this embodiment, the amplifiers 14 and 15 connected in series in two stages in FIG. 1 are reduced to one (15). further,
From the ratio of the value output by the cancellation amount determination unit to the gain a, a circuit that outputs the gain itself with the maximum value as a is used. Therefore, the cancellation amount determination unit 20 is a circuit that outputs a gain as shown in FIG. Thus, the configuration can be simplified as compared with the circuit of FIG.

FIG. 3 shows a sound image localization device in which a plurality of crosstalk canceling circuits shown in FIG. 1 or 2 are connected in parallel. This device has n crosstalk canceling circuits as shown in FIG. 1 or 2 connected in parallel. Tones of different timbres are input to the respective crosstalk cancel circuits, and the crosstalk is canceled based on the localization. The outputs of the crosstalk cancel circuits 1-1 to 1-n are added to adders 2L,
All are added in 2R and output as a 2-channel stereo signal. As a result, a plurality of timbres localized at different positions can cancel crosstalk based on the respective localizations, thereby forming a tone having a unique and clear localization for each timbre.

FIG. 4 shows an example in which the sound image localization apparatus shown in FIG. 3 has a time division structure. The n sound source devices 20 are connected to the selection unit 33. Each tone generator comprises a tone signal generator 31, a panning controller 32 and a timbre parameter supplier 30.

The tone signal generator 31 generates a tone signal based on the parameters input from the tone parameter supplier 30. The generated tone signal is input to the panning control unit 32. The panning control unit 32 separates a tone signal input at a predetermined ratio into a left channel and a right channel based on a panning control signal input from the tone color parameter supply unit. The panning control unit 32 stores a function table as shown in FIG. 5A, and determines the level of the left channel and the level of the right channel based on the input panning control signal (data corresponding to the localization angle). I do. The separated two-channel signal and the cancel amount signal C output by the tone color parameter supply unit are input to the selection unit 33, respectively. The cancellation amount signal C is shown in FIG.
It is calculated based on the same table as (B).

A counter 34 is connected to the selector 33. The first clock signal CK1 as shown in the upper part of FIG. Counter 34
Outputs the selection signals 1 to n in synchronization with the clock signal. This selection signal is input to the selection unit 33 and an accumulator unit 38 described later. The selection unit 33 converts one set of the signals L, R, and C from the plurality of (1 to n) sound source devices 20 based on the input selection signal into the subsequent cancellation circuit unit 2.
Enter 1 The cancel circuit unit 21 includes the delay circuit 3
5 (L, R), amplifier 36 (L, R) and subtractor 37
(L, R), and is configured as a crosstalk cancel circuit similar to that shown in FIG. Subtractor 37
The outputs of L and 37R are stored in the accumulator unit 38. The storage is performed in synchronization with the selection signal. n
After the first selection signal is input and before the first selection signal of the next cycle is input, the accumulator unit 3
8 clears the internal memory. The D / A converter 39 is connected to the accumulator 38. D / A converter 3
The second clock signal CK2 shown in the lower part of FIG. CK2 has n times the cycle of CK1,
It is output between the n-th clock of CK1 and the next first clock. When the tone signals of the tone generators 1 to n are stored and stored in the accumulator unit 38 by the clock signal, the tone signals are converted into analog signals and output.

As described above, by canceling the crosstalk by using a unique crosstalk canceling amount for each tone color, a sound field having a spread and clear localization is formed as shown in FIG. 8C. It is possible to do.

[0021]

As described above, according to the present invention, by controlling the amount of crosstalk cancellation in accordance with the localization of a sound image, the range in which the sound image can be localized can be expanded, and the sense of localization of the sound image can be clearly defined. Can be kept. In addition, by inputting each of the timbres to another crosstalk cancel circuit and canceling the crosstalk in accordance with the localization, even when a plurality of timbres are sounded in different localizations, all the timbres are output. It becomes possible to clarify the localization.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a crosstalk cancel circuit according to an embodiment of the present invention;

FIG. 2 is a diagram showing another embodiment of the crosstalk canceling circuit;

FIG. 3 is a diagram showing a configuration of a sound image localization apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing another embodiment of the sound image localization apparatus.

FIG. 5 is a diagram illustrating a stereo level table and a clock signal used in the sound image localization apparatus.

FIG. 6 is a configuration diagram of a conventional crosstalk cancel circuit.

FIG. 7 is a diagram showing frequency characteristics of the conventional crosstalk canceling circuit;

FIG. 8 is a diagram for explaining the spread of a sound image when the crosstalk canceling circuit according to the related art and the present application is used.

[Explanation of symbols]

11-subtractor, 12,20-cancellation amount determination unit, 15
L, 15R-amplifier.

Claims (2)

(57) [Claims] 1. The sound of one channel of a stereo is
A crosstalk canceling circuit for delaying, attenuating, inverting the phase, and outputting the inverted signal from the other channel, wherein control means for controlling at least the attenuation according to the localization of a tone signal input in stereo is provided. A crosstalk canceling circuit. 2. A plurality of crosstalk canceling circuits according to claim 1, wherein a plurality of musical sounds input in stereo are input to different crosstalk canceling circuits, respectively, and an output of each crosstalk canceling circuit is a stereo signal of one system. A sound image localization apparatus characterized by comprising means for synthesizing the sound image.