JP2002345095A - Sound image magnification processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound image magnification processing device that uses a monaural signal source and provides an image rather as if the sound source itself are magnified in front of a speaker position with high articulation to a listener without causing a sensor of fatigue. SOLUTION: The sound image magnification processing device is provided with; all pass filters 11a-11c that divide the monaural signal source into a fist channel signal, a second channel signal advanced by a prescribed angle from the first channel signal, and a third channel signal lagged by a prescribed angle from the first channel signal; and a delay unit 13 that delays the first channel signal by as prescribed time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sound image enlargement processing device for enlarging a sound image of a monaural signal source.

[0002]

2. Description of the Related Art When reproducing monaural sound, if a single speaker is used for reproduction, a perceived sound image is located at the position of the speaker. A phantom sound image is perceived in the center of the two speakers.

[0003] If the reflected sound or reverberant sound is synthesized and mixed with the original sound and reproduced, or reproduced by changing the respective arrival times at the listener with a plurality of speakers, a sense of spaciousness can be realized. The sound source is perceived as one location far from the speaker.

On the other hand, if the arrival time difference from each speaker or the arrival time difference of the reflected sound combined with the original sound is too large, the sound source is perceived as a multiplex sound source having a plurality of different places, and the clarity is reduced.

On the other hand, as shown in FIG. 8, two speakers 51 and 52 are arranged in front of a listener L, and multiplication circuits 53 and 5 are provided.
When the speakers 51 and 52 are driven from the monaural signal source using the driving signals of the opposite phases, the perceived sound image is near the occipital region of the listener L. It has been conventionally known that the sound image greatly fluctuates due to the movement of the head of the listener, and gives a certain feeling of spaciousness.

[0006]

That is, in the conventional sound image enlargement processing device, a monaural signal source is used to form an image in which the sound source itself is enlarged in front of the loudspeaker position with high clarity. I couldn't give it to the listener without feeling tired.

The present invention has been conceived in view of such circumstances, and uses a monaural signal source to provide high clarity and to expand the sound source itself rather ahead of the speaker position. It is an object of the present invention to provide a sound image enlargement processing device capable of giving a listener such an image without fatigue.

[0008]

DISCLOSURE OF THE INVENTION In order to solve the above-mentioned problems, the present invention takes the following technical means.

According to a first aspect of the present invention, a first and a second speaker arranged at an interval from each other, and a third speaker arranged between the first and the second speakers. A sound signal enlargement processing device for generating, from a monaural signal source, a drive signal for driving each of the speakers separately, wherein the monaural signal source is a signal of a first channel and a signal of the first channel. Phase-shift means for dividing the signal of the second channel into a signal of the second channel which is advanced by a predetermined angle and a signal of the third channel which is delayed by a predetermined angle with respect to the signal of the first channel. Delay means for delaying a predetermined time, the output of the delay means,
A signal for generating a drive signal for driving the third speaker is output, and one of the signal of the second channel and the signal of the third channel is output to the first speaker and the second channel.
And outputs a signal for generating a drive signal for driving one of the speakers, and outputs the other of the second channel signal and the third channel signal to the first channel.
A sound signal enlargement processing device characterized in that it is configured to output as a signal for generating a drive signal for driving the other of the speaker and the second speaker.

According to a preferred embodiment, there is provided a level ratio varying means for varying the level ratio between the output of the delay means and the signals of the second and third channels.

According to a second aspect of the present invention, a first and a second speaker arranged at a distance from each other, and a third speaker arranged between the first and the second speakers. A sound signal enlargement processing device for generating, from a monaural signal source, a drive signal for driving each of the speakers separately, wherein the monaural signal source is a signal of a first channel and a signal of the first channel. A phase shifter for dividing the signal of the second channel into a signal of the second channel, which is advanced by a predetermined angle, and a signal of the third channel, which is delayed by a predetermined angle with respect to the signal of the first channel; Third
Subtracting means for calculating the difference between the signal of the first channel, phase inverting means for inverting the phase of the output of the subtracting means, and delay means for delaying the signal of the first channel by a predetermined time. , A driving signal for driving the third speaker, and outputting one of the output of the subtracting means and the output of the phase inverting means to one of the first speaker and the second speaker. It outputs as a signal for generating a drive signal for driving one, and outputs the other of the output of the subtraction means and the output of the phase inversion means to the other of the first speaker and the second speaker. A sound image enlargement processing device is provided, which is configured to output a drive signal for driving as a signal for generating the drive signal.

According to a preferred embodiment, there is provided a level ratio varying means for varying the level ratio between the output of the delay means and the outputs of the subtraction means and the phase inversion means.

[0013] According to another preferred embodiment, the phase shift means, when dividing the monaural signal source, advances and retards angles of the second and third channel signals with respect to the first channel signal. Is set to a predetermined angle of about 80 to 100 degrees.

According to another preferred embodiment, the phase shifting means comprises a monaural signal source of approximately 100 Hz to 3 kHz.
The signal of the second channel is obtained by applying a phase advance of a predetermined angle to the frequency range of, and the signal of the third channel is obtained by applying a phase delay of a predetermined angle.

According to another preferred embodiment, the phase shifting means comprises a monaural signal source of approximately 200 Hz to 2 kHz.
The signal of the second channel is obtained by applying the phase advance of the predetermined angle to the frequency range of, and the signal of the third channel is obtained by applying the phase delay of the predetermined angle.

[0016] According to another preferred embodiment, the delay means comprises means for reducing the signal of the first channel from approximately 2 ms to 20 ms.
About a delay.

According to the present invention, using a monaural signal source, it is possible to give an image to a listener with high clarity and an image in which the sound source itself is enlarged rather ahead of the speaker position without feeling tired. it can.

That is, the present invention utilizes the fact that the sound source is expanded by driving the first and second speakers with driving signals having phases opposite to each other, and the reproduction is performed by the first and second speakers. The sound image first perceived near the listener is changed to a diffuse sound image by the reproduced sound from the third speaker having a correlation of 0 which arrives immediately after the delay, so that the sound image position is difficult to locate the sound image. To the listener. Moreover, since the sound source is not a multiple sound source, the clarity is high, and since the sound source is not a critical sound source, the listener does not feel tired.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an acoustic device having a sound image enlargement processing device according to an embodiment of the present invention. This acoustic device includes a sound image enlargement processing device 1, a D / A converter 2a
To 2c, amplifiers 3a to 3c, and speakers 4a to 4c
It has.

The sound image enlargement processing apparatus 1 includes all-pass filters 11a to 11c, multipliers 12a to 12c, and a delay unit 13.

The sound image enlargement processing apparatus 1 is a DSP (digital s
The digital signal is generated by a monaural signal source and generates a digital signal corresponding to a drive signal for individually driving the speakers 4a to 4c.

The D / A converters 2a to 2c convert the output of the sound image enlargement processing device 1 into analog signals.

The amplifiers 3a to 3c are provided with D / A converters 2a to 2c.
The output of 2c is amplified.

The speakers 4a to 4c are connected to the amplifiers 3a to 3c
The output of the drive signal is converted into sound. The speaker 4a and the speaker 4c are arranged at a predetermined interval,
A speaker 4b is arranged at the center of the two. The listening position of the listener L is in front of the speaker 4b,
The distance from the speaker 4a and the distance from the speaker 4c are set to be equal.

The all-pass filter 11a shifts the phase of the monaural signal source by +90 degrees.

The all-pass filter 11b shifts the phase of the monaural signal source by φ degrees.

The all-pass filter 11c shifts the phase of the monaural signal source by -90 degrees.

The multiplier 12a includes an all-pass filter 11
The output of a is multiplied by a constant k2. The constant k2 is variable.

The multiplier 12b includes an all-pass filter 11
The output of b is multiplied by a constant k1. The constant k1 is variable.

The multiplier 12c includes an all-pass filter 11
The output of c is multiplied by a constant k2. The constant k2 is variable.

The delay unit 13 includes an all-pass filter 11b
Is delayed for 10 ms.

FIG. 2 is a configuration diagram of the all-pass filter 11b. The all-pass filter 11b includes an adder 21,
Multipliers 22a to 22c and delay units 23a and 23b are provided. The all-pass filter 11a and the all-pass filter 11c have the same configuration.

Digital data from a monaural signal source is supplied to all-pass filters 11a to 11a as phase shift means.
The channel is divided into first to third channels by c. That is, the signal phase-shifted by φ degrees by the all-pass filter 11b is the signal of the first channel, the signal phase-shifted by φ + 90 degrees by the all-pass filter 11a is the signal of the second channel, and φ- is shifted by the all-pass filter 11c. The signal shifted by 90 degrees is the signal of the third channel. FIG. 3 shows the phase characteristics of each of these channels.

The output of the all-pass filter 11b, that is, the signal of the first channel is supplied to the delay unit 1 as a delay unit.
3 is multiplied by k1 by a multiplier 12b constituting a part of the level ratio varying means,
The signal is converted into an analog signal by the A converter 2b, amplified by the amplifier 3b, and drives the speaker 4b, that is, the third speaker.

The output of the all-pass filter 11a, that is, the signal of the second channel, is multiplied by k2 by a multiplier 12a constituting a part of the level ratio varying means, and is subjected to D / A
The signal is converted into an analog signal by the converter 2a,
a, and drives the speaker 4a, that is, the first speaker.

The output of the all-pass filter 11c, that is, the signal of the third channel, is multiplied by k2 by a multiplier 12c constituting a part of a level ratio varying means, and is subjected to D / A.
The signal is converted into an analog signal by the converter 2c,
c to drive the speaker 4c, that is, the second speaker.

Accordingly, the reproduced sound having a phase difference of ± 90 degrees relative to the reproduced sound of the speaker 4b as the third speaker located in front of the listener L is located on the left and right sides of the listener L. The sound is reproduced by the speakers 4a and 4c as the first and second speakers, and the reproduced sound of the speaker 4b as the third speaker is reproduced with a delay of 10 ms. As a result, the listener L perceives as a sound image that spreads from near the front side of the front speaker 4b to near both sides of the listener L and whose position is difficult to specify.

That is, the sound image reproduced by the speakers 4a and 4c and first perceived near the listener L is
Since the sound is immediately changed to a diffused sound image due to the reproduced sound from the loudspeaker 4b having a correlation degree of 0 that arrives late, the listener L is given a perceived sound image in which the sound image position is difficult to identify. Moreover, since the sound source is not a multiple sound source, the clarity is high, and since the sound source is not a critical sound source, the listener L does not feel tired.

The ratio of the reproduced sound pressure level between the center speaker 4b and the left and right speakers 4a and 4c is determined by the multiplier 1
By adjusting by changing the constants 2a to 12c, the effect of expanding the sound image can be changed. The practical range of this variable range is about -6 dB to +6 dB.

As described above, using a monaural signal source, an image in which the clarity is high and the sound source itself is rather enlarged in front of the speaker position can be obtained.
It can be given to listeners without feeling tired. Therefore, by utilizing the feeling that the sound source has spread to the listener L, it can be effectively used for pseudo-stereo reproduction for monaural music, for example.

Also, in the case of multi-channel surround playback including a left channel signal, a center channel signal, a right channel signal, a surround left channel signal, a surround right channel signal, and the like, the center channel signal is handled as the monaural signal source. The sound image can be enlarged. Therefore, in a source such as a movie, the central channel signal, in which dialogue is concentrated, can be expanded without giving the viewer a feeling of fatigue,
Can be emphasized.

FIG. 4 is a schematic configuration diagram of an acoustic device having a sound image enlargement processing device according to another embodiment. In this embodiment, a subtracter 14 is provided as subtraction means for calculating the difference between the output of the all-pass filter 11a and the output of the all-pass filter 11c, and the output of the subtracter 14 is multiplied as a level ratio variable means and phase inversion means. And a multiplier 12a and a multiplier 12c. Then, the multiplier 12a
By setting the constant to be multiplied by -k2, the output of the multiplier 12a and the output of the multiplier 12c are in opposite phases.

In this embodiment, as shown in FIG. 5, the all-pass filter 11a and the all-pass filter 11
The frequency band in which the relative phase difference is given by c is set to about 100 Hz to 3 kHz, which is the band of human speech, and the output of the all-pass filter 11a is subtracted from the output of the all-pass filter 11c, so that the volume of the speech portion and the size of the sound source Is emphasized.

FIG. 6 is a configuration diagram of the all-pass filters 11a to 11c according to another embodiment. Thus, the adder 31, the multipliers 32a to 32e, and the delay unit 33a
The order of the digital filter may be set to the second order using ３３33d.

FIG. 7 is a configuration diagram of the all-pass filters 11a to 11c according to another embodiment. As described above, an analog filter using the operational amplifier OP1, the resistors R1 to R3, and the capacitor C1 may be employed.

In each of the above embodiments, the relative phase difference between the signal of the second channel and the signal of the third channel with respect to the signal of the first channel is made exactly 90 degrees. However, this is not always necessary. For example, from 80 degrees to 1
There is no practical problem as long as it falls within about 00 degrees.

In the second embodiment, the all-pass filter 11a and the all-pass filter 11a
According to c, the frequency band of the speech is 100 Hz to 3 kHz.
Although the relative phase difference is given to the signal of the order, the first embodiment also has a large influence on the sense of localization of the sound image.
A relative phase difference may be given to a signal of about 0 Hz to 2 kHz. Of course, a frequency band of about 100 Hz to 3 kHz may be adopted in the first embodiment, and 200 Hz to 2 kHz in the second embodiment.
A frequency band of about kHz may be employed.

In each of the above embodiments, the delay time of the delay unit 13 is set to 10 ms. However, it is not always necessary to set the delay time to, for example, 2 ms to 20 ms.
It is sufficient if it is on the order. If the delay time is shorter than about 2 ms, the spread of the sound image is insufficient, and the delay time is 20 ms.
If the length is longer than the degree, the listener L perceives as a double sound, and the clarity is reduced.

In the above embodiments, the constants of the multipliers 12a to 12c are configured to be variable. However, the constants of the multipliers 12a to 12c may be fixed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an acoustic device including a sound image enlargement processing device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an all-pass filter.

FIG. 3 is an explanatory diagram of a phase-frequency characteristic of an all-pass filter.

FIG. 4 is a schematic configuration diagram of an acoustic device including a sound image enlargement processing device according to another embodiment.

FIG. 5 is an explanatory diagram of amplification-frequency characteristics of an all-pass filter according to another embodiment.

FIG. 6 is a configuration diagram of an all-pass filter according to another embodiment.

FIG. 7 is a configuration diagram of an all-pass filter according to another embodiment.

FIG. 8 is an explanatory diagram of a conventional sound image enlargement processing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sound image expansion processing apparatus 2a-2c D / A converter 3a-3c Amplifier 4a-4c Speaker 11a-11c All-pass filter 12a-12c Multiplier 13 Delayer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuro Nakatake 2-1 Nisshinmachi, Neyagawa-shi, Osaka Onkyo Corporation F-term (reference) 5D062 BB12

Claims (8)

[Claims] 1. A drive for separately driving first and second speakers arranged at an interval from each other and a third speaker arranged between the first speaker and the second speaker. A sound image enlargement processing device for generating a signal from a monaural signal source, wherein the monaural signal source is a signal of a first channel and a second signal which is advanced by a predetermined angle with respect to the signal of the first channel. Phase-shift means for dividing the signal of the first channel into a signal of the third channel delayed by a predetermined angle with respect to the signal of the first channel, and a delay means for delaying the signal of the first channel by a predetermined time And outputting the output of the delay means as a signal for generating a drive signal for driving the third speaker. The signal of the second channel and the signal of the third channel While the the said first speaker second of
And outputs a signal for generating a drive signal for driving one of the speakers, and outputs the other of the signal of the second channel and the signal of the third channel to the first channel. A sound image enlarging processing apparatus, wherein a sound signal is output as a signal for generating a drive signal for driving the other of the speaker and the second speaker. 2. The sound image enlargement processing apparatus according to claim 1, further comprising a level ratio varying unit that varies a level ratio between an output of the delay unit and a signal of the second and third channels. 3. A drive for separately driving first and second speakers arranged at an interval from each other and a third speaker arranged between the first speaker and the second speaker. A sound image enlargement processing device for generating a signal from a monaural signal source, wherein the monaural signal source is a signal of a first channel and a second signal obtained by advancing the signal of the first channel by a predetermined angle. Phase-shifting means for dividing the signal of the first channel into a signal of the third channel delayed by a predetermined angle with respect to the signal of the first channel; and a signal of the second channel and the signal of the third channel. Subtraction means for calculating a difference from the signal; phase inversion means for inverting the phase of the output of the subtraction means; delay means for delaying the signal of the first channel for a predetermined time; An output is output as a signal for generating a drive signal for driving the third speaker. One of the output of the subtraction unit and the output of the phase inversion unit is connected to the first speaker and the second speaker. And outputs the other of the output of the subtraction means and the output of the phase inversion means to the first speaker. A sound image enlarging processing apparatus, wherein the apparatus outputs a drive signal for generating a drive signal for driving the other of the second speaker and the second speaker. 4. The sound image enlargement processing apparatus according to claim 3, further comprising a level ratio varying unit that varies a level ratio between an output of the delay unit and an output of the subtraction unit and the output of the phase inversion unit. 5. The phase shift means, when dividing the monaural signal source, sets a leading angle and a retarding angle of the signals of the second and third channels with respect to the signal of the first channel to approximately 80. The sound image enlargement processing device according to any one of claims 1 to 4, wherein the predetermined angle is about 100 degrees to 100 degrees. 6. The phase shift means for a frequency range of approximately 100 Hz to 3 kHz of the monaural signal source.
The signal according to any one of claims 1 to 5, wherein a signal of the second channel is obtained by applying a phase advance of a predetermined angle, and a signal of the third channel is obtained by applying a phase delay of a predetermined angle. Sound image enlargement processing device. 7. The phase shift means for a frequency range of approximately 200 Hz to 2 kHz of the monaural signal source.
The signal according to any one of claims 1 to 5, wherein a signal of the second channel is obtained by applying a phase advance of a predetermined angle, and a signal of the third channel is obtained by applying a phase delay of a predetermined angle. Sound image enlargement processing device. 8. The sound image enlargement processing apparatus according to claim 1, wherein said delay means delays the signal of said first channel by approximately 2 ms to 20 ms.