JPH1013999A - Sound field controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound field controller with a simplified structure. SOLUTION: Digital signal for fundamental tones of a right-channel and a left-channel are provided with an audio signal processing part 24. The audio signal processing part 24 processes signals with respect to digital audio signal respectively and outputs a digital audio signal, including a high-tone digital audio signal reproduced by a center loudspeaker SC and a low-tone digital audio signal reproduced by a woofer WO. The digital audio signal is converted into an analog audio signal by a single D/A converter 27SW. The analog audio signal is changed into sound by the woofer WO, via an analog LPF 29 with the first cut-off frequency, e.g. 200Hz, and analog audio signal is changed into sound by the center loudspeaker SC, via an analog HPF 28 with a second cut-off frequency e.g. 300Hz.

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 suitably used as an indoor or on-vehicle sound reproducing device constituted by using a so-called digital signal processor or the like.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing an electrical configuration of a conventional sound field control device 1. 2. Description of the Related Art Conventionally, a sound signal provided from one of an analog sound signal source 2 such as a radio receiver and a magnetic tape reproducing device and a digital sound signal source 3 such as a compact disk reproducing device has been used as a basic sound in a vehicle-mounted sound reproducing device. A sound field control device 1 that adds an acoustic signal of an initial reflection sound or a reverberant sound to the sound signal of the basic sound and reproduces a realistic sound is used.

In a vehicle cabin, a driver side door 4 is provided.
A speaker FR of the right front channel is provided in R, and a speaker FL of the left front channel is provided in the passenger seat side door 4L. A center speaker SC is provided at the center of the instrument panel 5 arranged in front of the driver's seat and the passenger's seat. The rear tray 6 disposed behind the driver's seat and the passenger seat is provided with a right rear channel RR, a woofer WO, and a left rear channel RL.

An analog audio signal source 2 derives analog audio signals of right and left channels, respectively. These analog audio signals are converted into digital audio signals by analog / digital converters 7R and 7L, respectively, and provided to the audio signal processing unit 8. Similarly, digital audio signals of the right channel and the left channel are derived from the digital audio signal source 3, and these signals are supplied to the audio signal processing unit 8.

[0005] The acoustic signal processing section 8 is constituted by a so-called digital signal processor. A control device 10 that controls the arithmetic processing operation of the acoustic signal processing unit 8 in response to a listener's input operation from the input unit 9 is provided. When a digital audio signal is given from one of the analog audio signal source 2 and the digital audio signal source 3, the audio signal processing unit 8
The arithmetic processing is performed in response to a control signal from the control device 10.

From the acoustic signal processing unit 8, digital audio signals of the right front, right rear, left front and left rear channels, which have been subjected to the arithmetic processing, a digital audio signal to the center speaker SC, and a woofer WO are output. Are derived. These digital acoustic signals are respectively converted into digital / analog converters (hereinafter, referred to as D / A converters) 11FR, 11RR; 11FL, 11RL;
1SC, 11WO, after conversion, power amplifier 12F
R, 12RR; 12FL, 12RL; 12SC, 12W
After being amplified by O, the speaker F of each corresponding channel
R, RR; FL, RL; SC, WO and acoustic.

[0007]

In the above-mentioned conventional sound field control device, the sound signal control section 7 outputs digital sound signals for each of the six channels. Thereby, the conventional D / A converters 11FR, 1FR are provided in the conventional sound field control device.
Since 1RR; 11FL, 11RL; 11SC, and 11WO are provided, and the D / A converter is expensive, the cost is high. Further, by providing six D / A converters, the circuit scale of the entire sound field control device 1 is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sound field control device whose configuration is simplified by reducing the number of digital / analog converters and using analog LPFs and analog HPFs.

[0009]

According to the present invention, there is provided a right front speaker provided on the right front with respect to a listening position in a listening space;
A left front speaker provided at the left front with respect to the listening position of the listening space, a center speaker provided near the center of the right speaker and the left speaker, a woofer provided facing the listening space, and the right front speaker and To the left front speaker, an acoustic signal source that outputs each digital acoustic signal of a fundamental sound of a right channel and a left channel, and each digital acoustic signal of the right channel and the left channel from the acoustic signal source at a first cutoff frequency. First to cut off
A low-pass filter, a first high-pass filter that cuts off each digital audio signal of the right and left channels from the audio signal source at a second cut-off frequency exceeding a first cut-off frequency, and an output from the first high-pass filter. A processing means for performing at least one of a calculation processing for localizing the sound image in front of the listening position and a calculation processing for creating a sound effect signal giving a sense of realism; and an output from the first low-pass filter. An adder for adding the output from the processing means; a digital / analog converter provided with an output of the adder, for converting a digital audio signal from the adder into an analog audio signal; A second step of cutting off an analog sound signal from an analog converter at the first cutoff frequency and outputting the cutoff frequency to the woofer;
A sound field control device comprising: a low-pass filter; and a second high-pass filter that cuts off an analog sound signal from the digital / analog converter at the second cut-off frequency and outputs the cut-off signal to the center speaker. According to the present invention, digital audio signals of fundamental sounds of the right channel and the left channel from the audio signal source are output to the right front speaker and the left front speaker corresponding to each channel. The right front speaker and the left front speaker sound the digital sound signal of each provided channel. Each digital sound signal of the fundamental sounds of both channels is provided to a first low-pass filter and a second high-pass filter. In the first low-pass filter, a given digital audio signal is subjected to arithmetic processing to obtain a first cutoff frequency, for example, 20
Cut off at 0 Hz and output to adder. In the first high-pass filter, the applied digital audio signal is subjected to arithmetic processing, cut off at a second cut-off frequency, for example, 300 Hz, and output to the processing means. The processing unit performs at least one of a first process and a second process described below in response to an output from the first high-pass filter. The first process is based on a relationship between a right front speaker that acousticizes a digital sound signal of a fundamental sound of a right channel, a left front speaker that acousticizes a digital acoustic signal of a fundamental sound of a left channel, and a listening position. This is processing for localizing the sound image in the front direction of the listener at the listening position. The second process is a process of generating a sound effect signal such as an initial reflected sound in response to a digital sound signal from the first high-pass filter. The adder adds the output from the first low-pass filter and the output from the processing means and outputs the result to the digital / analog converter. The digital audio signal from the adder is converted to an analog audio signal by a digital / analog converter.
The converted analog audio signal is output to a second low-pass filter and a second high-pass filter. The second low-pass filter blocks the applied analog audio signal at a first cut-off frequency. This analog sound signal is provided to the woofer and is sounded. The second high-pass filter is
The applied analog sound signal is cut off at the second cut-off frequency. This analog sound signal is provided to a center speaker and is sounded. Therefore, the number of low-pass filters and high-pass filters having a simple configuration increases, but the number of digital / analog converters having a complicated and large circuit scale can be reduced by one, so that the cost can be reduced and the circuit scale can be reduced. Can be.

Further, the present invention is characterized by comprising a level processing means for performing signal processing on each digital audio signal of the right channel and the left channel from the audio signal source to a sound pressure level corresponding to the frequency characteristic of the listening space. . In accordance with the present invention, the level processing means includes a reference sound pressure level determined in accordance with a listening space such as a cabin of an automobile, for example, each of the right channel and the left channel from the acoustic signal source so as to be averaged. Signal processing for reducing the sound pressure level of the digital sound signal to a predetermined level is performed. Therefore, since signal processing is performed according to the frequency characteristics of the listening space, a sound field for reproducing realistic sound can be created.

The present invention also provides a rear right speaker provided at the rear right with respect to the listening position of the listening space, a rear left speaker provided at the left rear with respect to the listening position of the listening space, and a right channel from the acoustic signal source. In response to each of the digital audio signals of the left and right channels, a sound effect signal is generated, and the sound effect signal is added to the digital audio signals of the right and left channels, and the right rear speaker and the left rear speaker respectively. And sound effect generating means for outputting. According to the present invention, the sound effect generating means generates a sound effect signal such as a reverberation sound that gives a sense of realism to the listening space. The sound effect signal is created by performing arithmetic processing on the basis of digital sound signals of fundamental sounds of the right and left channels from the sound signal source. The created sound effect signal is added to the digital sound signal of the fundamental sound of the right channel and the left channel from the sound signal source, respectively, and output to the right rear speaker and the left rear speaker corresponding to each channel. Therefore, since the sound including the sound effect is reproduced from behind the listening position, a sound field having a more realistic feeling can be reproduced.

[0012]

FIG. 1 is a block diagram showing an electrical configuration of a sound field control device 13 according to an embodiment of the present invention. An instrument panel 17 is installed in front of a driver's seat 15 and a passenger's seat 16 in the cabin 14 of the automobile. A center speaker SC, which will be described later, is provided near the center of the instrument panel 17. In addition, a right door 18R in the front right of the driver's seat 15 has
A speaker FR for the right front channel is provided, and a passenger seat 16 is provided.
The left front door 18L is provided with a left front channel speaker FL. Further, on a rear tray 19 provided behind the driver's seat 15 and the passenger seat 16, a speaker RR of a right rear channel, a woofer WO, and a left rear channel RL are provided. The speakers FR, RR, FL, FL,
The RL is configured by a full-range speaker for acoustically converting an analog audio signal in a frequency band of, for example, 200 Hz to 20 kHz.

An analog audio signal source 20 such as a magnetic tape reproducing device derives a left channel analog audio signal and a right channel analog audio signal. Each analog sound signal of the fundamental sound of both these channels is analog /
Digital (hereinafter, referred to as A / D) converters 21R, 21
At L, each is converted into a digital sound signal of a fundamental sound. From the digital audio signal source 22 such as a compact disk player, each digital audio signal of the fundamental sound of the right channel and the left channel is derived. Switch 30
Selects the analog sound signal source 20, the digital sound signals of the basic sounds from the A / D converters 21R and 21L are provided to the sound signal processing unit 24. When the switch 30 selects the digital sound signal source 22, digital sound signals of fundamental sounds of the right and left channels derived from the digital sound signal source 22 are given to the sound signal processing unit 24. The analog audio signal source 20, the digital audio signal source 22, the A / D converters 21R and 21L, and the switch 30 can be considered as an audio signal source that derives a digital audio signal.

The acoustic signal processing section 24 is realized by a so-called digital signal processor or the like. Input unit 25
Signal processing unit 2 in response to a listener's input operation from the
4 is provided. Control device 26
Outputs a control signal to control the acoustic signal processing unit 24. The sound signal processing unit 24 is controlled by the control device 26.
Generates a sound effect signal including a reflected sound, a reverberation sound, and the like, based on each digital sound signal of the fundamental sound of the right channel and the left channel from the sound signal source. The created sound effect signal is added to each digital sound signal of the fundamental sound of both channels from the sound signal source. Also, the acoustic signal processing unit 2
4 is also controlled by the control device, and also processes the sound pressure level of each digital sound signal of the given fundamental sounds of both channels.

The audio signal processing section 24 derives digital audio signals obtained by performing the above-described processing for the right front, right rear, left front, and left rear channels. The digital sound signals of the respective channels are respectively converted into digital / analog (hereinafter, referred to as D / A) converters 23FR, 23RR;
After being converted into analog audio signals by FL, 23RL, and then amplified by power amplifiers 27FR, 27RR; 27FL, 27RL, the corresponding speakers FR, RR; FL, R
L and is acousticized.

The acoustic signal processing section 24 derives one digital acoustic signal for two speakers, a center speaker SC and a woofer WO, separately from the digital acoustic signals of the respective channels. The digital audio signal is converted into an analog audio signal by the D / A converter 23SW, and then converted to an analog high-pass filter (hereinafter, referred to as HPF) 28 and an analog low-pass filter (hereinafter, L).
PF) 29.

The analog LPF 29 is formed by a capacitor and a resistor (not shown). Analog LPF29
Filters a frequency component of the analog sound signal converted by the D / A converter 23SW that is equal to or lower than a first cutoff frequency of 200 Hz, which will be described later. The filtered analog audio signal is amplified by a power amplifier 27WO, and then applied to a woofer WO to be acousticized. The low-frequency sound signal given to the woofer WO has no directivity. Therefore, the woofer WO that reproduces the low-frequency sound signal without directivity may be installed at any position as long as it faces the vehicle interior 14.

The analog HPF 28 is formed by a capacitor and a resistor (not shown). Analog HPF28
Filters a second cut-off frequency, for example, a frequency component of 300 Hz or more of the analog audio signal converted by the D / A converter 23SW. The filtered analog audio signal is amplified by the power amplifier 27SC and provided to the center speaker SC to be acousticized.

FIG. 2 is a block diagram showing an electrical configuration inside the acoustic signal processing unit 24. As shown in FIG. Sound signal processing unit 24
Are a front processing unit 31, a rear processing unit 32, a digital HPF 33, a center processing unit 34, a digital LPF
35. The acoustic signal processing unit 24 includes:
As described above, the digital sound signal of the fundamental sound of the right channel and the left channel is provided from one of the analog sound signal source 21 and the digital sound signal source 22.

The front processing section 31 is controlled based on a control signal generated by the control device 26 in response to the output of the input section 25. In the input unit 25, the sound in the cabin 14
It is captured as a digital signal detected by a microphone (not shown). The control signal of the control device 26 is created based on this digital signal. The front processing unit 31 responds to the control signal from the control device 26, and performs the digital sound of each of the right and left channel fundamental sounds from the acoustic signal source so as to be averaged with respect to a preset reference sound pressure level. The sound pressure level of the signal is reduced by a predetermined level. As a result, the sound pressure level of the middle frequency of the acoustic signal to be acousticized can be set to a substantially constant level in the passenger compartment 14, so that a sound field for reproducing realistic sound can be created. it can. The preset reference sound pressure level may be set by the input unit 25 for the listener.

The rear processing unit 32 creates a sound effect signal such as a reverberation sound based on each digital sound signal of the fundamental sound of the right channel and the left channel of the sound signal source. In the rear processing unit 32, when each digital sound signal of the fundamental sound of both channels is given, each digital sound signal of the fundamental sound of the right channel and the left channel is delayed by a predetermined time by a delay circuit (not shown), and The determined coefficient is multiplied, fed back to an adder (not shown), and added to each digital audio signal. As a result, a reverberant sound effect signal is created which attenuates by a coefficient multiplied every time a predetermined time elapses. The sound effect signals are added to the digital sound signals of the fundamental sounds of both channels, and are added to the D / A converters 23RR and 23R.
Output to L. The two-channel digital sound signal to which the sound effect signal has been added is converted into an analog sound signal by D / A converters 23RR and 23RL, respectively.
The signal is amplified by RR and 27RL, and is sounded by the right rear speaker RR and the left rear speaker RL. The sound effect signal may include an initial reflection sound created based on digital sound signals of fundamental sounds of both channels. In another embodiment in which the rear speaker is omitted, the rear processing unit 32 that creates a sound effect signal may be omitted.

The adder 36 adds the digital control signals of the fundamental sounds of both channels from the acoustic signal source to generate a digital L signal.
Output to PF35. The digital LPF 35 has a first cutoff frequency of the analog LPF 29, for example, 200H.
It has the same cutoff frequency as z. This digital LPF3
5 performs arithmetic processing based on the applied digital audio signal, and provides the adder 37 with a digital audio signal including a first cutoff frequency, for example, a frequency component of 200 Hz or less.
In addition, one digital LPF may be formed instead of the adder 36, and a digital sound signal of a fundamental sound of the right channel and the left channel may be provided.

The digital HPF 33R receives a digital sound signal of a fundamental sound of the right channel from the sound signal source. Similarly, the digital HPF 33L is provided with a digital sound signal of the fundamental sound of the left channel from the sound signal source.
These digital HPFs 33R and 33L have the same cutoff frequency as the second cutoff frequency of the analog HPF 28 described above. These digital HPFs 33R and 33L perform arithmetic processing based on a given digital acoustic signal to filter a frequency component having a second cutoff frequency, for example, 300 Hz or more, and filter the filtered digital acoustic signal into a center processing unit 3
Give to 4.

In the center processing unit 34, the digital HPF 3
Each digital sound signal of the fundamental sound of both channels filtered by 3R and 33L is provided. The center processing unit 34 performs first processing and second processing, which will be described later, based on the given digital sound signals of the fundamental sounds of the right and left channels.
At least one of the processes is performed.

The first process is a process of localizing the sound image in the front direction of the listener based on the riding state of the driver's seat 15 and the passenger seat 16 input from the input unit 25. this is,
Each digital sound signal of the fundamental sound of the right channel and the left channel is attenuated by a certain amount by an attenuator (not shown),
This is performed by changing the phase by a phase shifter.

The second process is a process for creating a sound effect signal such as an initial reflected sound based on digital sound signals of fundamental sounds of the right channel and the left channel. Each digital audio signal of the right channel and the left channel is delayed by a predetermined time by a plurality of delay circuits (not shown). The output of each delay circuit is multiplied by a predetermined coefficient. The multiplied digital audio signals are all added by an adder (not shown). As a result, after the digital sound signals of the fundamental sounds of the right channel and the left channel are output, a sound effect signal that outputs an initial reflected sound every time a predetermined time elapses is created. The level of the initial reflected sound is determined by a coefficient to be multiplied. Also, this sound effect signal
It may include sound effects such as reverberation. Center processing unit 34
Outputs the digital audio signal subjected to these two processes to the adder 37. In the adder 37, the digital audio signal from the center processing unit 34 and the digital audio signal from the digital LPF 35 are added. The added digital sound signal is output to the D / A converter 23SW.

FIG. 3 is a diagram showing frequency characteristics of the digital LPF 35 and the analog LPF 29 and the digital HPFs 33R and 33L and the analog HPF 28. The vertical axis indicates gain (dB), and the horizontal axis indicates frequency (Hz). Curve 41 represents digital LPF 35 and analog L
4 shows the frequency characteristics of the PF29. Curve 42 is digital H
The frequency characteristics of PF33R, 33L and analog HPF28 are shown.

Digital LPF 35 and analog LPF 2
9 has the same frequency characteristic and has a pass band of 200 Hz or less as shown by the curve 41. Digital L
The PF 35 and the analog LPF 29 filter the applied acoustic signal at a first cutoff frequency of 200 Hz. The filtered acoustic signal is supplied to the woofer WO and is converted into an acoustic field, thereby forming a realistic sound field.

The digital HPFs 33R and 33L and the analog HPF 28 have the same frequency characteristic,
Has a pass band of 300 Hz or more.
The digital LPF 35 and the analog LPF 29
The applied acoustic signal is filtered at a second cut-off frequency of 0 Hz. The filtered acoustic signal is provided to a center speaker SC and is acoustically converted.

As described above, the digital HPFs 33R, 3
The second cutoff frequencies of the 3L and the analog HPF 28 are higher than the first cutoff frequencies of the digital LPF 35 and the analog LPF. As a result, the audio signal processing unit 24 outputs the digital audio signal filtered by the digital LPF 35 and the digital audio signal filtered by the digital HPFs 33R and 33L and processed by the center processing unit 34.
The digital audio signal added by the adder 37 is output. Even if this digital audio signal is converted into an analog audio signal by one A / D converter SW, the analog HPF 28
And the analog LPF 29 are configured,
An analog sound signal corresponding to the digital sound signal processed by the center processing unit 34 is given to a center speaker SC,
An analog sound signal corresponding to the digital sound signal filtered by the digital LPF 35 is provided to the woofer WO.

Therefore, since the analog audio signal having a frequency lower than the first cut-off frequency is converted into a sound by the woofer WO, it is possible to form a realistic sound field in which low-frequency sounds are reproduced.
Further, since the analog sound signal having the second cut-off frequency or higher corresponding to the processed digital sound signal is converted into a sound by the center speaker SC, the sound image is localized in front of the listener. Further, the center speaker SC converts the sound effect such as the initial reflection sound into an acoustic sound, thereby forming a realistic sound field.

As described above, according to the present invention, the number of analog LPFs 29 and analog HPFs 28 having a simple configuration increases, but the D / A converter 23SW has a complicated and large circuit scale.
Can be reduced to one, so that the cost can be reduced and the circuit scale can be reduced as compared with the prior art. In addition, the sound field control device 13 having a simple configuration can provide a sound field for reproducing realistic sound.

FIG. 4 is a simplified diagram of a listening space in a room 52 of a sound field control device according to another embodiment of the present invention. In another embodiment of the present invention, the sound field control device 13 according to the embodiment of the present invention is used.

The listening position 53 in the room 52 is different from the listening position in the cabin 14 according to the above-described embodiment, and is generally installed at the center of the room 52. A front right speaker FR is provided at the front right of the listening position 53, and a front left speaker FL is provided at the front left. This right front speaker FR
A center speaker SC is provided at a central portion between the front speaker FL and the left front speaker FL. On the right rear is a right rear speaker RR.
And a rear left speaker RL is provided at the rear left. A woofer WO is provided at the center between the right rear speaker RR and the left rear speaker RL. In addition, the acoustic signal given to the woofer WO has low directivity and thus has no directivity. Therefore, if the woofer WO is at a position facing the room 52,
It may be provided anywhere.

As described above, in the cabin 52, the vehicle 1
4, since the listening position and the listening space are different, the control signal of the control device 26 for controlling the acoustic signal control device 24 is different. Front processing unit 3 of acoustic signal control device 24
1 is a digital signal of a fundamental sound of a right channel and a left channel from an acoustic signal source to be averaged with respect to a set reference sound pressure level based on a control signal generated according to the frequency characteristics of the room 52. The sound pressure level of the control signal is reduced by a predetermined level. As a result, a sound field that can reproduce sound adapted to the frequency characteristics of the room 52 can be formed. The rear processing unit 32 and the center processing unit 3
4 generates a sound effect signal such as a reverberation sound or an early reflection sound. The signal including the generated sound effect signal is sounded by the right rear speaker RR, the left rear speaker RL, and the center speaker SC. Thus, the room 52
However, it is possible to form a sound field capable of reproducing realistic sound.

[0036]

As described above, according to the present invention, the digital audio addition signal output from the audio signal control device 24 is:
One digital / analog converter converts the signal into an analog sound signal. The converted analog audio signal is filtered by a second low-pass filter for a frequency component equal to or lower than the first cutoff frequency, and applied to a woofer to be acoustically converted. The converted analog audio signal is passed through a second high-pass filter,
A frequency component equal to or higher than the second cutoff frequency is filtered and applied to a center speaker to be acoustically converted. Accordingly, although the number of low-pass filters and high-pass filters having a simpler configuration is increased as compared with the related art, one digital / analog converter having a complicated and large circuit scale can be reduced, so that the cost is reduced as compared with the related art. be able to. In addition, a digital / analog converter with a large circuit
Therefore, the circuit scale can be reduced. Further, with a sound field control device having a small circuit size and a low cost configuration, it is possible to localize a sound image in front of a listener at a listening position and form a sound field for reproducing realistic sound.

According to the present invention, the level processing means includes:
With respect to the reference sound pressure level set based on the frequency level of the listening space, signal processing for reducing the sound pressure level of each digital sound signal of the right channel and the left channel from the sound signal source to a predetermined level is performed. Therefore, since the signal processing is performed according to the frequency characteristics of the listening space, it is possible to create a sound field that reproduces realistic sound according to the listening space.

According to the present invention, the sound effect generating means includes:
Creates a sound effect signal such as a reverberation sound that gives a sense of realism to the listening space, and the sound effect signal is added to the digital sound signal of the fundamental sound of the right channel and the left channel from the sound signal source, each corresponding to each channel Output to the right rear speaker and the left rear speaker. Therefore, since sound including sound effects such as reverberation is reproduced from behind the listening position, a more realistic sound field can be created.

[Brief description of the drawings]

FIG. 1 shows a sound field control device 13 according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an electrical configuration of the embodiment.

FIG. 2 is a block diagram showing an electrical configuration inside the acoustic signal processing unit 24.

FIG. 3 shows a digital LPF 35 and an analog LPF 29
And digital HPF33R and 33L and analog HP
It is a figure which shows the frequency characteristic with F28.

FIG. 4 is a sound field control device 5 according to another embodiment of the present invention.
FIG. 2 is a block diagram showing an electrical configuration of FIG.

FIG. 5 is a block diagram showing an electrical configuration of a conventional sound field control device 1.

[Explanation of symbols]

Reference Signs List 13 sound field control device 14 cabin 15 driver's seat 16 passenger seat 20 analog sound signal source 21R, 21L A / D converter 22 digital sound signal source 23FR, 23RR; 23FL, 23RL; 23SW
D / A converter 24 Acoustic signal controller 26 Controller 27FR, 27RR; 27FL, 27RL; 27SC,
27WO Power amplifier 28 Analog HPF 29 Analog LPF 31 Front processing unit 32 Rear processing unit 33R, 33L Digital HPF 34 Center processing unit 35 Digital LPF 37 Adder FR Right front speaker RR Right rear speaker FL Left front speaker RL Left rear speaker SC Center Speaker WO Wha

Claims (3)

[Claims] 1. A front right speaker provided in the front right with respect to the listening position in the listening space; a front left speaker provided in the front left with respect to the listening position in the listening space; and near a center of the right speaker and the left speaker. A center speaker provided, a woofer provided facing a listening space, and an audio signal source for outputting digital sound signals of fundamental sounds of a right channel and a left channel to the right front speaker and the left front speaker, respectively, A first low-pass filter that cuts off each digital audio signal of a right channel and a left channel from an audio signal source at a first cutoff frequency, and a first cutoff of each digital audio signal of the right channel and the left channel from the audio signal source. A first high-pass filter that cuts off at a second cut-off frequency exceeding the frequency, Processing means for performing at least one of arithmetic processing for localizing a sound image in front of the listening position and arithmetic processing for creating a sound effect signal for giving a sense of realism in response to the output of the first low-pass filter; An adder that adds the output from the processing unit and the output from the processing unit; and a digital / analog converter that is provided with the output of the adder and converts a digital audio signal from the adder into an analog audio signal. A second low-pass filter that cuts off the analog sound signal from the digital / analog converter at the first cutoff frequency and outputs the signal to the woofer; and converts the analog sound signal from the digital / analog converter at the second cutoff frequency. A second high-pass filter that cuts off and outputs the signal to the center speaker. 2. The apparatus according to claim 1, further comprising a level processing unit for performing signal processing on each digital audio signal of the right channel and the left channel from the audio signal source to a sound pressure level corresponding to a frequency characteristic of a listening space. 2. The sound field control device according to claim 1. 3. A right rear speaker provided at the rear right with respect to the listening position of the listening space; a left rear speaker provided at the left rear with respect to the listening position of the listening space; and a right channel and a left channel from the acoustic signal source. In response to each digital sound signal of the above, an effect sound signal is generated, the sound effect signal is added to the digital sound signals of the right channel and the left channel, and the sound signal is output to the right rear speaker and the left rear speaker, respectively. The sound field control device according to claim 1, further comprising a sound generation unit.