JP3281181B2 - Speaker system for sound field reproduction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound field reproduction speaker system (surround speaker) for reproducing a sound field based on a sound field signal (surround signal).

[0002]

2. Description of the Related Art When enjoying a movie at home, most of the dubbing by terrestrial television broadcasting has been performed until recently. However, in recent years, with the spread of rental videos, laser disks, satellite broadcasting, and the like, it has become possible to enjoy the sound of movies as they are.

[0003] The sound of these movies is increasingly Dolby encoded. Dolby-encoded movie sound is provided to the listener as a two-channel signal. The sound of this movie can be enjoyed through conventional stereo playback, but it can be restored to a left, center, right, and surround four-channel signal by a dedicated Dolby decoder, and by using four-channel playback, it becomes more realistic. Enjoy the sound with a sense.

In a high-definition television or the like, there is also a mode in which 4-channel signals of left, center, right, and surround are discretely sent to a listener, and the channels are well separated, so that higher quality sound can be heard. . Among these four-channel signals, the center signal plays a role of obtaining clarity and clear localization of the speech, and the surround signal plays a role of enhancing the sense of realism due to a moving sound, an environmental sound, a reverberant sound, and the like.

Here, the features of the surround sound accompanying the video will be described a little. Surround sounds are roughly classified into three types: moving sounds, environmental sounds, and reverberant sounds. The moving sound is used when moving the sound from front to back of the listener or from back to front. The environmental sound is used when creating the atmosphere of the scene, such as the sound of a wind or the noise of a crowd. Reverberation is used when expressing spatial characteristics such as halls and caves.
In order to achieve the above-mentioned effect, it is desirable that the moving sound is located behind the listener. On the other hand, it is desirable that the environmental sound and the reverberant sound are not localized at a specific place but spread naturally throughout the room.

[0006] The sound reproduction system associated with these movies and videos is herein referred to as a video sound reproduction system. FIG. 32 shows an example of the video and audio reproduction system. A video signal and a two-channel audio signal are supplied from a video / audio signal supply device 31 such as a video, laser disk, or satellite broadcast receiver. The video signal is reproduced by a display device (video equipment such as a television) 21. The two-channel sound signal is converted into a left, center, right, and surround four-channel signal by a matrix decoder 32 such as a Dolby decoder, and amplified by an amplifier 33. Then, the left speaker 22, the center speaker 23, the right speaker 24, The sound is reproduced by sound field reproduction speakers (surround speakers) 29.

FIG. 33 shows an example of a speaker arrangement that has been most commonly performed conventionally. The left speaker 22, the center speaker 23, and the right speaker 24
6 are arranged in order from the left, and surround speakers 2
9 are arranged behind the listener 26. By arranging the surround speakers 29 behind the listener 26, a feeling of movement can be obtained.

In the above-mentioned conventional video and audio reproduction system, a small speaker system generally used is generally used as the surround speaker 29 in most cases. Further, as a surround speaker, a speaker system excellent in diffusivity called a dipole speaker may be used.

FIG. 34 shows an example of a dipole type speaker. This dipole type speaker is composed of speaker units 1a and 1b attached to one baffle surface of a cabinet 5 and a baffle surface facing the baffle surface. The two speaker units 1a and 1b are driven in opposite phases to each other.
Connected to input terminal 6. As shown in FIG. 35, the radiation characteristic is a figure-eight dipole characteristic in which the sound pressure is maximum on the axis of the two speaker units 1a and 1b and the sound pressure is minimum in the direction equidistant from the two speaker units 1a and 1b. Become.

FIG. 36 shows an example of a speaker arrangement of a video and audio reproduction system using this dipole type speaker as a surround speaker. The dipole surround speaker 30 is installed on the side of the listener 26 such that the direction of the minimum sound pressure faces the listener 26 as shown in FIG. The sound radiated from the dipole surround speaker 30 is
Since the indirect sound component from the wall surface reaches the listener 26 more predominantly than the direct sound, the surround sound is not localized at a specific place, and a natural feeling of spread can be obtained. Other arrangements are the same as in FIG.

[0011]

However, using a general speaker system as a surround speaker,
In the video and audio reproduction system in which the speakers are arranged as shown in FIG. 33, the surround speakers 29 are installed at the rear, so that a sense of movement can be obtained. However, environmental sounds and reverberation sounds are localized at the rear, A natural feeling of spreading cannot be obtained.

In a video / audio reproduction system in which a dipole speaker having excellent diffusibility is used as a surround speaker and speakers are installed as shown in FIG. 36, the surround sound is more indirect from a wall than direct sound from a dipole surround speaker. Since the sound is dominant, a natural feeling of spreading can be obtained, but since the sound is not localized at a specific place, it is difficult to obtain a feeling of movement.

[0013] Another problem which is completely different from the above-mentioned problem is the problem of installation. As shown above, the surround speakers are installed at least from the side of the listener 26 to the rear, and in order to install them at the rear, a space that can be installed at the rear is necessary, and the wiring and the like are very troublesome. is there. Considering the current housing situation in Japan, it is easy to imagine that there are many cases where it is difficult to install surround speakers behind,
It is considered that the trouble has slowed the spread of the audiovisual reproduction system.

The present invention solves the above-mentioned conventional problems. When installed from the side to the rear of the listener, both the feeling of movement and the feeling of spreading are excellent, and even if the apparatus is installed forward of the listener. It is an object of the present invention to provide a sound field reproduction speaker system which can provide a natural feeling of spreading and can improve the installation property.

[0015]

[0016]

[0017]

Means for Solving the Problems] claim 1 sound field reproducing speaker system described, a speaker unit for reproducing an input signal, the rear-side opening and the front side opening of the speaker unit speaker unit is attached is It has a rear open cabinet that is opened in substantially the same shape, and an acoustic equalizer that is attached to the rear opening of the speaker unit and attenuates reproduced sound at a frequency fb or higher.

According to a second aspect of the present invention, there is provided a speaker system for reproducing a sound field, wherein a cutoff frequency f for passing a high frequency band of an input signal.
a high-pass filter mounted on one baffle surface of a cabinet for reproducing the output of the high-pass filter
And a low-pass filter having a cut-off frequency fb which is set higher than the cut-off frequency fa of the high-pass filter and allows a low frequency band of the input signal to pass therethrough, and a first speaker unit having the same characteristics as the first speaker unit. And a second speaker unit attached to the baffle surface facing the attached baffle surface and reproducing the output of the low-pass filter in a phase opposite to that of the first speaker unit.

According to a third aspect of the present invention, there is provided a speaker system for sound field reproduction, wherein the first speaker unit is mounted on one baffle surface of a cabinet and reproduces an input signal as it is, and a band from a frequency fa to a frequency fb of the input signal. A band-pass filter to be passed, and a first speaker unit having the same characteristics as the first speaker unit and attached to a baffle surface facing the baffle surface to which the first speaker unit is attached, and outputting the output of the band-pass filter to the first speaker unit And a second speaker unit for reproducing in opposite phase.

According to a fourth aspect of the present invention, there is provided a speaker system for reproducing a sound field, wherein a cutoff frequency f for passing a low frequency band of an input signal.
b, a first high-pass filter having a cut-off frequency fa for passing the high frequency of the output of the low-pass filter, and a first high-pass filter mounted on one baffle surface of the cabinet to reproduce the output of the first high-pass filter. A speaker unit, mounted on a baffle surface having the same characteristics as the first speaker unit and facing the baffle surface on which the first speaker unit is mounted, reproduces the output of the low-pass filter in a phase opposite to that of the first speaker unit. A second speaker unit, a second high-pass filter having a cut-off frequency fb 'for passing a high frequency band of the input signal, and an output of the second high-pass filter mounted on the same baffle surface as the first speaker unit. A third speaker unit for high-frequency reproduction for reproduction, and mounted on the front of the third speaker unit Its dependent and a horn directivity becomes narrow above frequency fb.

[0021]

[0022]

The sound field reproducing speaker system according to claim 5, in claim 1, 2 or 3, and sets the frequency fb at about 2 kHz. Sound field reproducing speaker system of claim 6, Oite to claim 4, the frequency fb, f
b 'is set to about 2 kHz. Sound field reproducing speaker system according to claim 7, wherein the claim 2 or 3
At the frequency fb on the front of the first speaker unit.
A horn whose directivity narrows at the above frequency is attached.

[0024] In the loudspeaker system for reproducing a sound field according to the eighth aspect , the frequency fa may be set to be the same as that of the second, third or fourth aspect .
At the observation point on the front axis of the first speaker unit, the distance until the sound emitted from the first speaker unit 1 reaches the observation point and the distance until the sound emitted from the second speaker unit reaches the observation point. The frequency is set so that the difference in distance is a half wavelength.

[0025]

The loudspeaker system for sound field reproduction according to the ninth aspect is characterized in that, in the second, third or fourth aspect , the frequency fa is set to:
It is set between 500 Hz and 1 kHz.

[0027]

[0028]

SUMMARY OF] According to the sound field reproducing speaker system of claim 1, since the sound pressure of the front and rear faces of the speaker units in the following frequency fb is approximately equal and opposite phase, the radiation pattern becomes shaped dipole characteristics of the 8 . Above the frequency fb, the acoustic equalizer lowers the sound pressure on the rear side, causing only radiation from the front side, and since the frequency is high, the radiation pattern becomes almost unidirectional.

According to the sound field reproducing speaker system according to claim 2, below the frequency fa is the action of the filter,
Since the signal is reproduced only from one of the speaker units that constitute it, and its frequency is low, its radiation pattern is almost omnidirectional. Above the frequency fa and below the frequency fb, signals are reproduced in opposite phases from two speaker units having the same performance.
Characteristic dipole characteristics. Above the frequency fb, a signal is reproduced from only one of the loudspeaker units by the action of the filter, and since the frequency is high,
The radiation pattern is almost unidirectional.

According to the loudspeaker system for reproducing a sound field according to the third or fourth aspect , the operation is substantially the same as that of the loudspeaker system for reproducing a sound field according to the second aspect . According to the speaker system for reproducing a sound field according to claim 5 or 6 , at a frequency of about 2 kHz or less, a figure-eight dipole characteristic, about 2
At frequencies above kHz, the radiation pattern can be changed for each frequency band, such as unidirectionality.
The environmental sound and reverberation sound whose frequency components below kHz are dominant can give the listener a feeling that the sound has spread in the room, and the moving sound which contains the frequency components above 2 kHz abundantly,
The sense of direction can be given. Therefore, it is possible to achieve both a sense of spreading of the environmental sound and the reverberant sound and a sense of movement of the moving sound. In addition, even when installed in front of the listener, the component of 2 kHz or more that greatly contributes to the localization of the sound image is
If the sound image is installed so that the reflected sound can be obtained only from the left and right wall surfaces, the sound image is hardly localized in front, and a good feeling of spread can be obtained.

According to the loudspeaker system for reproducing a sound field according to the seventh aspect, a horn whose directivity becomes narrower at the frequency fb or higher is attached to the front surface of the speaker unit that radiates the band at the frequency fb or higher, thereby localizing the sound image. It is possible to reduce the direct sound from the speaker of the frequency fb or higher that greatly contributes to the sound, and to increase the ratio of the indirect sound component from the wall surface. When installed in front of the vehicle, the feeling of spreading can be further increased.

According to the loudspeaker system for sound field reproduction according to the eighth aspect, the sound emitted from the first speaker unit 1 reaches the observation point at the observation point on the front axis of the first speaker unit with the frequency fa. By setting the difference between the distance to the observation point and the distance from the sound emitted from the second speaker unit to the observation point to a frequency having a half wavelength, a low reproduction band can be secured. In other words, if the dipole characteristic is used up to the low frequency range, the distance between the two loudspeakers becomes too narrow with respect to the wavelength, and the cancellation due to the opposite phase becomes excessive, so that the level suddenly drops, but this is prevented.
Since the direct sound in this band has a small sense of localization, the direct sound hardly impairs the spaciousness.

According to the loudspeaker system for reproducing a sound field according to the ninth aspect , it is easy to give a feeling of spreading by the phase control.
Since the sound from 0 Hz to 1 kHz or less can be directly given to the listener, the sense of spaciousness can be further increased by the phase control. In particular, the speaker system for sound field reproduction according to the present invention is used by the listener. When installed in front, a sense of spread is further emphasized, and a good surround feeling can be obtained even in the case of a front place where it is difficult to obtain a sense of spread.

[0034]

[First Reference Example ]

First, a sound field reproducing speaker system according to a first reference example will be described with reference to FIG. As shown in FIG. 1, this speaker system for reproducing a sound field has a diameter of 8 with the same performance.
cm-shaped loudspeaker units 1a and 1b are attached to the facing baffle surfaces of the cabinet 5, respectively. A reproduction signal is directly input to the loudspeaker unit 1a, and a cutoff frequency fb is input to the loudspeaker unit 1b.
The reproduction signal is input through the low-pass filter 3 of FIG.
Below the frequency fb, the speaker units 1a and 1b are connected so as to be driven in mutually opposite phases. 6 is an input terminal.

FIG. 2 shows the sound pressure characteristics of each of the speaker units 1a and 1b of the sound field reproducing speaker system of the second reference example . In FIG. 2, reference numeral 8a denotes a speaker unit 1a.
8b is the sound pressure characteristic of the speaker unit 1b. Since the reproduction signal is directly input to the speaker unit 1a, the entire band is reproduced. Speaker unit 1
Since b is connected to the low-pass filter 3 having the cut-off frequency fb, the frequency fb or higher is hardly reproduced. Therefore, below the frequency fb, the speaker units 1a and 1b are connected so as to emit substantially the same sound pressure and to be driven in opposite phases, so that the radiation pattern is as shown in the characteristic (B) of FIG. It has a figure eight dipole characteristic. Above the frequency fb, sound is emitted only from one speaker unit 1a, and above the frequency fb,
Since the aperture of the speaker unit 1a cannot be neglected with respect to the wavelength, the directivity becomes narrow, and the radiation pattern becomes almost unidirectional as shown in the characteristic (C) of FIG. The symbols (B) and (C) in FIG. 2 correspond to the characteristics (B) and (C) in FIG. 3, respectively.

FIG. 4 shows an example of a speaker arrangement of a video / audio reproduction system using the sound field reproduction speaker system of the first reference example . As shown in FIG. 4, the speaker system 25 for sound field reproduction of the first reference example is configured such that the direction of the minimum sound pressure of the figure-eight dipole characteristic up to the frequency fb is the direction of the listener 26 and the speaker unit. The speaker unit 1b is placed on the side of the listener 26 such that the speaker unit 1a is at the rear and the speaker unit 1b is at the front. Other arrangements are the same as in FIG.

The sound field reproducing speaker system of the first reference example has a figure-eight dipole characteristic below the frequency fb, and the listener 26 is located in the direction of the minimum sound pressure.
6 mainly receives reflected sounds from the front and rear walls rather than the direct sound. Above the frequency fb, the sound is radiated backward from the listener 26, so that the reflected sound from the rear wall mainly reaches the listener 26.

Here, the features of the surround sound such as the moving sound, the environmental sound, and the reverberant sound will be described. 5 to 7,
Moving sounds, environmental sounds, reverberation sounds from several movies,
The result of the frequency component analysis is shown. FIG. 5 shows the result of analyzing the frequency component of the moving sound. The moving sound is 4 from the low range
It can be seen that there are many that include frequency components almost even up to a high frequency range exceeding kHz. FIG. 6 shows the result of analyzing the frequency components of the environmental sound. It can be seen that the environmental sound has various low-frequency components, but many high-frequency components are rapidly attenuated at about 2 kHz. FIG. 7 shows the result of analyzing the frequency components of the reverberation sound. It can be seen that many reverberation sounds are gradually attenuated at 1 kHz or more.

Therefore, regarding the environmental sound and the reverberant sound,
When the cut-off frequency fb of the low-pass filter 3 is set to about 2 kHz, the sound reaching the listener is dominated by the reflected sound from the front and rear walls below the frequency fb, since the component below 2 kHz is dominant. The sound is not localized at a specific place, and the sound can be felt as if it is spreading naturally throughout the room.

On the other hand, the moving sound contains abundant components of 2 kHz or more, and if the cut-off frequency fb of the low-pass filter 3 is set to about 2 kHz, the reflected sound from the rear wall surface of the components of 2 kHz or more is reduced. Become dominant. The component of 2 kHz or less spreads over the whole room like the environmental sound and the reverberant sound, but the component of 2 kHz or more can be heard only from behind. When the band including the band of 2 kHz or more is included, the direction of the sound source is easily sensed, so that the sound image is drawn backward, and the listener can feel as if he / she is hearing from the rear.

Therefore, it is most effective to set the cut-off frequency fb of the low-pass filter to about 2 kHz. Next, FIG. 8 shows an example of a speaker arrangement of a video / audio reproduction system in which the sound field reproduction speaker system of the first reference example is installed in front of a listener. FIG first as 8
The sound field reproduction speaker system 25 of the reference example has a frequency f
b so that the direction of the minimum sound pressure of the figure-eight dipole characteristic below b is the direction of the listener 26 and the speaker unit 1
The speaker unit 1b is placed on the left speaker 22 and the right speaker 24 in front of the listener 26 such that the speaker unit 1b is on the left and right wall surfaces and the speaker unit 1b is on the display device 21 side.
Other arrangements are the same as in FIG.

Below the frequency fb, the figure has a figure eight dipole characteristic, and since the listener 26 is in the direction of the minimum sound pressure, the reflected sound from the wall in front of the direct sound reaches the listener 26 mainly. . Above the frequency fb, sound is radiated to the left and right wall surfaces of the listener 26, so that the reflected sound from the left and right wall surfaces mainly reaches the listener 26. The component below the frequency fb mainly receives the reflected sound from the wall in front of the direct sound and reaches the listener 26, so that a good spread feeling can be obtained. In addition, the component that makes it easier to perceive the direction of the sound source of the frequency fb or higher is radiated only toward the left and right wall surfaces, and there is no reflected sound from the front wall surface. You can feel it.

As shown in FIG. 9, the speaker unit 1a
Horn 7 whose directivity becomes narrower at frequency fb or higher
By installing the, the direct sound component to the listener of the frequency fb or higher is reduced, the ratio of the indirect sound component from the wall surface is increased, and the above-mentioned effect (a feeling of spreading right and left without being localized in front is obtained. Can be increased). In this reference example, the diameter is 8 cm.
A horn 7 having an opening diameter of 12 cm and a depth of 3 cm is mounted on the front surface of the speaker unit 1a, thereby limiting the directivity of 2 kHz or more.

[ Second Reference Example] Next, a sound field reproducing speaker system according to a second reference example will be described with reference to FIG. As shown in FIG. 10, this speaker system for sound field reproduction has cone-shaped speaker units 1a and 1b having the same performance and a diameter of 12 cm.
Are attached to the facing baffle surfaces of the cabinet 5, respectively. A reproduction signal is input through the low-pass filter 3 having the cutoff frequency fb, and the speaker units 1 a and 1 b are connected to be driven in opposite phases. ing. A dome-shaped speaker unit 1c having a diameter of 2.5 cm for high-frequency reproduction is mounted on the same baffle surface as the speaker unit 1a, and has a cut-off frequency fb.
The reproduced signal is input through the high-pass filter 2 of FIG. Also, a horn 7 'having an opening diameter of 12 cm is attached to the front surface of the speaker unit 1c so that the directivity becomes narrower at the frequency fb or higher. 6 is an input terminal.

FIG. 11 shows the sound pressure characteristics of each of the speaker units 1a, 1b, and 1c of the sound field reproducing speaker system of the second reference example . In FIG. 11, 8a is a sound pressure characteristic of the speaker unit 1a, and 8b is a speaker unit 1b.
8c is a sound pressure characteristic of the speaker unit 1c. Since the low-pass filter 3 having the cut-off frequency fb is connected to the speaker units 1a and 1b, a band lower than the frequency fb is reproduced. Since the high-pass filter 2 is connected to the speaker unit 1c, a band equal to or higher than the frequency fb is reproduced. Therefore,
The following frequency fb is the speaker units 1a, almost the same sound pressure also 1b is emitted, because it is connected to be driven in phase opposition, the radiation pattern first reference example as well as the characteristics of FIG. 3 ( As shown in B), it has a figure eight dipole characteristic. The frequency fb or higher, are only sound radiation from a single speaker unit 1c, since the horn 7 which directivity is narrowed above frequency fb 'is mounted, its radiation pattern is similar to the first reference example 3 As shown in the characteristic (C) of FIG. The symbols (B) and (C) in FIG. 11 correspond to the characteristics (B) and (C) in FIG. 3, respectively.

The cut-off frequency fb of the low-pass filter 3 and the high-pass filter 2, as in the first cut-off frequency fb of the low-pass filter 3 of the reference example, about 2k
Setting to Hz is effective. Since the radiation pattern of the sound field reproduction speaker system of the second reference example is almost the same as the sound field reproduction speaker system of the first reference example,
The method of use and the effect are almost the same.

In the second embodiment, the speaker unit 1c for high-frequency reproduction is mounted on the same baffle surface as the speaker unit 1a. However, the effect is not changed even if it is mounted on the same baffle surface as the speaker unit 1b. First embodiment; corresponding to claim 1 Next, a first embodiment the sound field reproducing speaker system of the present invention will be described with reference to FIG. 12. As shown in FIG. 12, this speaker system for sound field reproduction has an aperture of 8 mm.
cm speaker unit 11 and an acoustic equalizer 13 are attached to a rear open cabinet 12 provided with a horn-type sound path such that a front opening 14a and a rear opening 14b of the speaker unit 11 have substantially the same shape. Have been.

The horn-type sound path of the rear open cabinet 12 has an opening diameter of 12 cm so that directivity can be restricted at a frequency of about 2 kHz or more. In this embodiment, the horn is a straight horn. However, any other horn may be used as long as the directivity is limited to about 2 kHz or more. The high-frequency attenuation start frequency of the acoustic equalizer 13 is set to about 2 kHz. The acoustic equalizer 13 is disposed on the back of the speaker unit 11 so as to cover the magnet and the frame of the speaker unit 11, and the rear open cabinet 1 is provided.
A gap of about 5 mm to 1 cm is provided between the horn 2 and the horn sound path, and sound is emitted from this gap. When the frequency becomes higher than about 2 kHz, the wavelength becomes shorter.
3 becomes an obstacle, and the sound pressure from the back drops.

The material of the acoustic equalizer 13 may be anything as long as the sound does not pass through, and may be any thickness as long as it is difficult to resonate. In this embodiment, a molding resin having a thickness of about 2 mm is used, but a resin like a metal cover may be used. FIG. 13 shows the sound pressure characteristics of the front opening 14a and the rear opening 14b of the speaker unit 11 of the speaker system for sound field reproduction according to the present invention. In FIG. 13, reference numeral 8a denotes the sound pressure characteristic of the front opening 14a of the speaker unit 11, and 8b denotes the sound pressure characteristic of the rear opening 14b of the speaker unit 11. Since the front side opening 14a of the speaker unit 11 has nothing to block, the entire band is reproduced. The rear opening 14b of the speaker unit 11 is provided with the acoustic equalizer 13 for attenuating the frequency band of about 2 kHz or more, so that the band of about 2 kHz or less is reproduced. Therefore, in the following about 2 kHz, substantially the same sound pressure is also a front-side opening 14a and the rear-side opening 14b of the speaker unit 11 is emitted, since the sound of the opposite phase is emitted, the radiation pattern first reference example As shown in FIG. 3, the characteristic becomes a figure-eight dipole characteristic as shown in FIG. About 2
In kHz or more, the front side for viewing the sound from the opening 14a is emitted, the radiation pattern first reference example as well as substantially unidirectional as indicated by the characteristic shown in FIG. 3 (C) of the speaker unit 11 Becomes The symbols (B) and (C) in FIG. 13 correspond to the characteristics (B) and (C) in FIG. 3, respectively.

FIG. 14 shows an example of a speaker arrangement of a video and audio reproduction system using the sound field reproduction speaker system according to the first embodiment of the present invention. As shown in FIG. 14, the speaker system for sound field reproduction 28 of the present invention is arranged such that the direction of the minimum sound pressure of the figure-eight dipole characteristic of about 2 kHz or less is the direction of the listener 26 and the front of the speaker unit 11. It is installed on the side of the listener 26 such that the side opening 14a is at the rear and the back opening 14b of the speaker unit 11 is at the front. Other arrangements are the same as in FIG.

Next, FIG. 15 shows an example of a speaker arrangement of a video and audio reproduction system in which the sound field reproduction speaker system according to the first embodiment of the present invention is installed in front of a listener 26. As shown in FIG. 15, the sound field reproducing speaker system 28 of the present invention is arranged such that the direction of the minimum sound pressure of the figure-eight dipole characteristic of about 2 kHz or less is the direction of the listener 26 and the speaker unit 11 The front opening 14a is provided on the left and right wall surfaces, and the rear opening 14 of the speaker unit 11 is provided.
The listener 26 is set so that b is on the display device 21 side.
Above the left speaker 22 and the right speaker 24. Other arrangements are the same as in FIG.

[0052] emission pattern of the sound field reproducing speaker system of the first embodiment, since the first reference example is substantially the same as the sound field reproducing speaker system, also its use and effect the first reference example Is almost the same as The speaker system for reproducing a sound field according to the first embodiment is characterized in that it can be made very inexpensive because only one speaker unit is used.

[ Second Embodiment: Corresponding to Claim 2 ] Next, a sound field reproducing speaker system according to a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 16, this speaker system for reproducing sound fields has a cone-shaped speaker unit 1 having the same performance and a diameter of 8 cm.
a and 1b are respectively attached to the facing baffle surfaces of the cabinet 5, and a reproduction signal is input to the speaker unit 1a via the high-pass filter 2 having a cutoff frequency fa, and the cutoff frequency fb is input to the speaker unit 1b. The reproduction signal is input through the low-pass filter 3 of FIG. Cutoff frequency fb of low-pass filter 3
Is set higher than the cutoff frequency fa of the high-pass filter 2, and the speaker units 1a and 1b are connected so as to be driven in opposite phases from the frequency fa to the frequency fb. 6 is an input terminal.

FIG. 17 shows the sound pressure characteristics of each of the speaker units 1a and 1b of the speaker system for reproducing a sound field according to the present invention. In FIG. 17, 8a is a speaker unit 1a.
8b is the sound pressure characteristic of the speaker unit 1b. Below the frequency fa, the input to the speaker unit 1a is cut by the high-pass filter 2, so that sound is emitted almost only from the speaker unit 1b. Since the wavelength is sufficiently longer than the aperture of the speaker unit below the frequency fa, the radiation pattern becomes almost non-directional as shown in the characteristic (A) of FIG. Frequency f
Since the high-pass filter 2 and the low-pass filter 3 are in the pass band from a to the frequency fb, almost the same sound pressure is emitted from both the speaker units 1a and 1b. Since the speaker units 1a and 1b are connected so as to be driven in opposite phases between the frequency fa and the frequency fb, the radiation pattern has a figure-eight dipole characteristic as shown in the characteristic (B) of FIG. . Above the frequency fb, the input to the speaker unit 1b is cut by the low-pass filter 3, so that sound is almost emitted only from the speaker unit 1a. Above the frequency fb, the aperture of the speaker unit cannot be neglected with respect to the wavelength, so the directivity becomes narrow, and the radiation pattern becomes almost unidirectional as shown in the characteristic (C) of FIG. The symbols (A),
(B) and (C) show the characteristics (A), (B) and (C) of FIG.
Respectively.

Cut-off frequency f of low-pass filter 3
It is effective that b is set to about 2 kHz, similarly to the cutoff frequency fb of the low-pass filter 3 of the first reference example. The cutoff frequency fa of the high-pass filter 2 is
At the observation point on the front axis of the speaker unit 1a, the difference between the distance until the sound emitted from the speaker unit 1a reaches the observation point and the distance until the sound emitted from the speaker unit 2 reaches the observation point is defined as a half wavelength. Set the frequency to be used. For example, regarding the size of the cabinet 5 of this embodiment,
The size of the baffle surface to which the speaker units 1a and 1b are attached is 20 cm square, and the speaker units 1a and 1b are
If the distance between the two baffle surfaces with 1b is 25cm and the observation point is 1m from the speaker unit 1a,
The difference in distance to the observation point is about 35 cm, and the frequency at which this distance is a half wavelength is about 490 Hz. This frequency decreases as the size of the cabinet 5 increases. The purpose is mainly to secure a low-frequency reproduction band. If the dipole characteristic is used up to the low frequency range, the interval between the two loudspeakers becomes too narrow with respect to the wavelength, and the cancellation due to the opposite phase becomes excessive, so that the level suddenly drops. Since the direct sound in this band has a small sense of localization, the direct sound hardly impairs the spaciousness.

FIG. 19 shows an example of a speaker arrangement of a video and audio reproduction system using the sound field reproduction speaker system according to the second embodiment of the present invention. As shown in FIG. 19, the speaker system 27 for sound field reproduction according to the present invention is configured such that the direction of the minimum sound pressure of the figure-eight dipole characteristic from the frequency fa to the frequency fb is the direction of the listener 26, and the speaker unit The speaker unit 1b is placed on the side of the listener 26 such that the speaker unit 1a is at the rear and the speaker unit 1b is at the front. Other arrangements are the same as in FIG.

Since the sound is almost omnidirectional below the frequency fa, the direct sound from the speaker mainly reaches the listener 26. Between the frequency fa and the frequency fb, there is a figure-eight dipole characteristic, and since the listener 26 is located in the direction of the minimum sound pressure, the listener 26 is mainly made of the reflected sound from the front and rear wall surfaces rather than the direct sound. reach. Above the frequency fb, the sound is radiated backward from the listener 26, so that the reflected sound from the rear wall mainly reaches the listener 26.

The frequency fa and below are omnidirectional, and the sound directly arrives at the listener 26 directly. However, since the frequency is low, there is almost no sense of localization, and the sense of spread is not impaired.
As for the environmental sound and the reverberant sound, as described in the first reference example, the component of 2 kHz or less is dominant, so that the sound reaching the listener 26 is the direct sound of the frequency fa or less and the frequency f
The reflected sound from the front and rear wall surfaces from a to the frequency fb becomes dominant, and the listener 26 can receive the feeling that the sound is spread naturally throughout the room without the sound being localized at a specific place.

On the other hand, the moving sound contains abundant components of 2 kHz or more, and the cutoff frequency fb of the low-pass filter 3 is set to about 2 kHz.
For the component of z or more, the reflected sound from the rear wall surface becomes dominant. The component of 2 kHz or less spreads over the whole room like the environmental sound and the reverberant sound, but the component of 2 kHz or more can be heard only from behind. When the band including the band of 2 kHz or more is included, the direction of the sound source can be easily sensed, so that the sound image is drawn rearward, and the listener 26 can eventually feel as if he / she is hearing from behind.

Next, FIG. 20 shows an example of a speaker arrangement of a video and audio reproduction system in which the sound field reproduction speaker system according to the second embodiment of the present invention is installed in front of a listener 26. As shown in FIG. 20, the speaker system 27 for sound field reproduction according to the present invention is configured such that the direction of the minimum sound pressure of the figure-eight dipole characteristic from the frequency fa to the frequency fb is the direction of the listener 26, and the speaker unit Left speaker 22 in front of listener 26, so that 1a is on the left and right wall surfaces and speaker unit 1b is on display device 21 side.
It is installed on the light speaker 24. Other arrangements are the same as in FIG.

From the frequency fa to the frequency fb, there is a figure-eight dipole characteristic, and since the listener 26 is in the direction of the minimum sound pressure, the listener 26 is mainly made of the reflected sound from the wall in front of the direct sound. Will reach you. Above the frequency fb, sound is radiated to the left and right wall surfaces of the listener 26, so that the reflected sound from the left and right wall surfaces mainly reaches the listener 26. Frequency fa
The following is omnidirectional, and the direct sound reaches the listener 26 directly, but has little localization due to the low frequency.
There is no loss of spaciousness. From frequency fa to frequency f
As for the components up to b, the reflected sound from the wall mainly reaches the listener 26 rather than the direct sound, so that a good spread feeling can be obtained.
In addition, the component that makes it easier to perceive the direction of the sound source having the frequency fb or higher is emitted only toward the left and right wall surfaces.
Since there is no reflected sound from the front wall surface, it is possible to receive a feeling that the sound spreads right and left without being localized in front.

There is another method for setting the cutoff frequency fa of the high-pass filter 2. That is, the cutoff frequency fa of the high-pass filter 2 is set to 500H
That is, it is set between z and 1 kHz. Since the diameter of the speaker unit 1b is 8 cm, it is almost omnidirectional below 1 kHz, so that the listener 26 can directly hear mainly the sound. The purpose is to apply a phase process to a band lower than this frequency and make the listener 26 hear the direct sound to give a wider feeling. The simplest phase processing is to use two surround speakers and make the phases opposite to each other. It is more effective if phase processing such as crosstalk cancellation is performed. 1
When the frequency is higher than kHz, the wavelength becomes short and the service area becomes narrow, so that it is difficult to obtain the effect. Therefore, it is desirable to set the frequency to 500 Hz to 1 kHz where the effect of the phase processing is easily obtained, and to directly listen to the direct sound below that frequency. It goes without saying that the level drop in the low frequency range can be prevented at the same time.

The cutoff frequency f of the high-pass filter 2
When a is set between 500 Hz and 1 kHz as described above, the surround speakers 25 may be installed on the sides of the listener 26 as shown in FIG. 19, but as shown in FIG. It is most effective when installed in front. This is because the effect of the phase processing of the direct sound further enhances the sense of spaciousness.

Also, as shown in FIG.
By attaching a horn 7 whose directivity becomes narrower at the frequency fb or higher, a direct sound component to the listener at the frequency fb or higher is reduced, and the ratio of the indirect sound component from the wall surface is increased. The effect (the effect of being able to receive the feeling of spreading left and right without being localized in the front) can be improved. In this embodiment, an opening diameter of 12 cm and a depth of 3 c are provided in front of a speaker unit 1 a having a diameter of 8 cm.
A horn 7 of m is attached to restrict the directivity of 2 kHz or more.

[ Third Embodiment: Corresponding to Claim 3 ] Next, a speaker system for reproducing a sound field according to a third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 22, this speaker system for reproducing a sound field has a cone-shaped speaker unit 1 having the same performance and a diameter of 8 cm.
a and 1b are respectively attached to the facing baffle surfaces of the cabinet 5, and a reproduction signal is directly input to the speaker unit 1a, and a band-pass filter 4 that passes a band from the frequency fa to the frequency fb to the speaker unit 1b. A playback signal is input via the. Between the frequency fa and the frequency fb, the speaker units 1a and 1b are connected so as to be driven in mutually opposite phases. 6 is an input terminal.

FIG. 23 shows the sound pressure characteristics of each of the speaker units 1a and 1b of the speaker system for sound field reproduction according to the present invention. In FIG. 23, 8a is a speaker unit 1a.
8b is the sound pressure characteristic of the speaker unit 1b. Since the reproduction signal is directly input to the speaker unit 1a, the entire band is reproduced. Speaker unit 1
Since b is connected to the band-pass filter 4 whose pass frequency band is fa to fb, sound is radiated almost only from the speaker unit 1a below the frequency fa and above the frequency fb. Therefore, below the frequency fa, sound is radiated from only one speaker unit 1a and the frequency is low, so that the radiation pattern is almost omnidirectional as shown in the characteristic (A) of FIG. 18 similarly to the second embodiment. And sex. From the frequency fa to the frequency fb, the speaker units 1a and 1b are also connected so as to emit substantially the same sound pressure and to be driven in opposite phases, so that the radiation pattern is the same as in the second embodiment. As shown in the characteristic (B) of FIG. 18, a figure eight dipole characteristic is obtained. Above the frequency fb, sound is emitted only from one speaker unit 1a. Above the frequency fb, the aperture of the speaker unit cannot be ignored with respect to the wavelength, so that the directivity becomes narrow, and the radiation pattern is the same as that of the second embodiment. Similarly, as shown by the characteristic (C) in FIG. The symbols (A), (B), and (C) in FIG. 23 are the characteristics (A),
(B) and (C) respectively.

The upper limit frequency fb of the band pass filter 4
Is effectively set to about 2 kHz, like the cutoff frequency fb of the low-pass filter 3 of the second embodiment. The lower limit frequency fa of the band-pass filter 4 is:
Like the cut-off frequency fa of the high-pass filter 2 of the second embodiment, there duplicate the way of the setting, an effect similar to that shown in the second embodiment, respectively are obtained.

The radiation pattern of the sound field reproducing speaker system of the third embodiment is almost the same as that of the sound field reproducing speaker system of the second embodiment, so that the method of use and the effects are almost the same. Further, as shown in FIG. 24, a horn 7 whose directivity is narrowed at a frequency of fb or higher is attached to the front of the speaker unit 1a to reduce a direct sound component to a listener at a frequency of fb or higher, and to reduce an indirect sound component from a wall surface. More effect by increasing the ratio (the same as in FIG. 21)
Can be raised. This is also the same as in the second embodiment.

[ Fourth Embodiment; Corresponding to Claim 4 ] Next, a speaker system for reproducing a sound field according to a fourth embodiment of the present invention will be described with reference to FIG. In this sound field reproducing speaker system, as shown in FIG. 25, cone-shaped speaker units 1a and 1b having the same performance and having a diameter of 12 cm are attached to the facing baffle surfaces of the cabinet 5, respectively. , A reproduction signal is input through a low-pass filter 3 having a cut-off frequency fb and a high-pass filter 2a having a cut-off frequency fa, and a reproduction signal is input into the speaker unit 1b through the low-pass filter 3. The cut-off frequency fb of the low-pass filter 3 is set higher than the cut-off frequency fa of the high-pass filter 2a, and between the frequency fa and the frequency fb, the speaker unit 1
a and 1b are connected so as to be driven in opposite phases to each other. A dome-shaped speaker unit 1c having a diameter of 2.5 cm for high-frequency reproduction is mounted on the same baffle surface as the speaker unit 1a, and has a cutoff frequency fb '.
The reproduction signal is input through the high-pass filter 2b. The frequency f is provided on the front of the speaker unit 1c.
A horn 7 'having an opening diameter of 12 cm is attached so that the directivity becomes narrower than b'. 6 is an input terminal.

FIG. 26 shows the sound pressure characteristics of each of the speaker units 1a, 1b and 1c of the speaker system for sound field reproduction according to the present invention. In FIG. 26, 8a is the sound pressure characteristic of the speaker unit 1a, 8b is the sound pressure characteristic of the speaker unit 1b, and 8c is the sound pressure characteristic of the speaker unit 1c. Since the low-pass filter 3 and the high-pass filter 2a are connected to the speaker unit 1a, the frequency fa
To the frequency fb. Since the low-pass filter 3 is connected to the speaker unit 1b, a band lower than the frequency fb is reproduced. Since the high-pass filter 2b is connected to the speaker unit 1c, a band equal to or higher than the frequency fb 'is reproduced. Therefore, since the sound is radiated from only one speaker unit 1b below the frequency fa and the frequency is low, the radiation pattern is almost omnidirectional as shown in the characteristic (A) of FIG. 18 similarly to the second embodiment. Becomes From the frequency fa to the frequency fb, the speaker units 1a and 1b are also connected so as to emit substantially the same sound pressure and to be driven in opposite phases, so that the radiation pattern is the same as in the second embodiment. 18
As shown in the characteristic (B) of FIG. At the frequency fb 'or higher, one speaker unit 1
Since the horn 7 'which emits sound only from the point c and whose directivity becomes narrower at the frequency fb' or higher is attached, the radiation pattern is as shown in the characteristic (C) of FIG. 18 similarly to the second embodiment. Almost unidirectional. Symbols (A),
(B) and (C) show the characteristics (A), (B) and (C) of FIG.
Respectively.

It is effective to set the cut-off frequencies fb and fb 'of the low-pass filter 3 and the high-pass filter 2b to about 2 kHz, similarly to the cut-off frequency fb of the low-pass filter 3 of the second embodiment. Note that the frequencies fb and fb 'need not be the same value. Further, the cut-off frequency fa of the high-pass filter 2a, like the cut-off frequency fa of the high-pass filter 2 of the second embodiment, There are two ways in how the set, shown in the second embodiment each effect The same effect can be obtained.

The radiation pattern of the sound field reproducing speaker system of the fourth embodiment is almost the same as that of the sound field reproducing speaker system of the second embodiment, so that the method of use and the effect are almost the same. Further, in this embodiment, the speaker unit 1c for high-frequency reproduction is mounted on the same baffle surface as the speaker unit 1a, but the effect is not changed even if it is mounted on the same baffle surface as the speaker unit 1b.

Third Embodiment Next, a sound field reproducing speaker system according to a third embodiment will be described with reference to FIG. As shown in FIG. 27, this speaker system for sound field reproduction has cone-shaped speaker units 1a and 1b having the same performance and a diameter of 8 cm.
Are mounted on the facing baffle surfaces of the cabinet 5, respectively. A reproduction signal is input to the speaker unit 1a via the high-pass filter 2 having a cutoff frequency fa, and the speaker unit 1b is connected to the high-pass filter 2, and A reproduction signal is input via the low-pass filter 3a. The cut-off frequency fb of the low-pass filter 3a is set higher than the cut-off frequency fa of the high-pass filter 2, and the speaker units 1a and 1b are driven in opposite phases from the frequency fa to the frequency fb. It is connected. Also, a cone-shaped speaker unit 1d having a diameter of 10 cm for low-frequency reproduction is mounted on the same baffle surface as the speaker unit 1b, and a reproduction signal is input via a low-pass filter 3b having a cutoff frequency fa '. 6 is an input terminal.

Since the speaker unit 1d only emits omnidirectional bass, it may be mounted on any baffle surface of the cabinet 5. FIG. 28 shows speaker units 1a and 1 of a sound field reproducing speaker system according to a third reference example.
The sound pressure characteristics of each of b and 1c are shown. In FIG. 28, 8
a is the sound pressure characteristic of the speaker unit 1a, 8b is the sound pressure characteristic of the speaker unit 1b, and 8d is the sound pressure characteristic of the speaker unit 1d. Since the high-pass filter 2 is connected to the speaker unit 1a, a band higher than the frequency fa is reproduced. Since the high-pass filter 2 and the low-pass filter 3a are connected to the speaker unit 1b, the band from the frequency fa to the frequency fb is reproduced. The speaker unit 1d has a low-pass filter 3b
Is connected, the band below the frequency fa 'is reproduced. Accordingly, since the sound is radiated from only one speaker unit 1d below the frequency fa 'and the frequency is low, the radiation pattern is almost omnidirectional as shown in the characteristic (A) of FIG. 18 similarly to the second embodiment. And sex. Frequency f
a and the frequency fb, the speaker units 1a, 1
Since b is connected so as to emit almost the same sound pressure and to be driven in the opposite phase, the radiation pattern has a figure eight shape as shown in the characteristic (B) of FIG. 18 similarly to the second embodiment. It has dipole characteristics. Above the frequency fb, sound is radiated only from one speaker unit 1a. Above the frequency fb, since the aperture of the speaker unit 1a cannot be ignored with respect to the wavelength, the directivity becomes narrow, and the radiation pattern is the second embodiment. As shown in the characteristic (C) of FIG. The symbols (A), (B),
(C) corresponds to the characteristics (A), (B), and (C) in FIG. 18, respectively.

It is effective to set the cut-off frequency fb of the low-pass filter 3a to about 2 kHz, like the cut-off frequency fb of the low-pass filter 3 of the second embodiment. Further, the cut-off frequency fa of the high-pass filter 2 and the low-pass filter 3b, fa ', like the cut-off frequency fa of the high-pass filter 2 of the second embodiment, There are two ways the way of the setting, the second, respectively The same effect as the effect shown in the embodiment can be obtained. Frequency f
a and fa 'need not be the same.

Since the radiation pattern of the sound field reproducing speaker system of the third embodiment is almost the same as that of the sound field reproducing speaker system of the second embodiment, the method of use and the effects are almost the same. Further, as shown in FIG. 29, a horn 7 whose directivity is narrowed at a frequency of fb or more is attached to the front of the speaker unit 1a, thereby reducing a direct sound component to a listener having a frequency of fb or more, and an indirect sound component from a wall surface. More effect (same effect as in FIG. 21)
Can be raised. This is also the same as in the second embodiment.

[ Fourth Reference Example ] Next, a sound field reproducing speaker system according to a fourth reference example will be described with reference to FIG. As shown in FIG. 30, this speaker system for reproducing a sound field has cone-shaped speaker units 1a and 1b having the same performance and a diameter of 8 cm.
Are attached to the facing baffle surfaces of the cabinet 5, respectively, and a reproduction signal is input through a band-pass filter 4 that passes a band from a frequency fa to a frequency fb, and the speaker units 1a and 1b are in opposite phases. It is connected to be driven. A dome-shaped speaker unit 1c having a diameter of 2.5 cm for high-frequency reproduction is mounted on the same baffle surface as the speaker unit 1a, and a reproduction signal is input through a high-pass filter 2 having a cutoff frequency fb '. I have. Further, a horn 7 'having an opening diameter of 12 cm is attached to the front surface of the speaker unit 1c so that the directivity becomes narrower at the frequency fb' or higher. Further, a cone-shaped speaker unit 1d having a diameter of 10 cm for low-frequency reproduction is mounted on the same baffle surface as the speaker unit 1b, and a reproduction signal is input through a low-pass filter 3 having a cutoff frequency fa '. 6 is an input terminal.

Since the speaker unit 1c only emits omnidirectional low-frequency sound, it may be mounted on any baffle surface of the cabinet 5. FIG. 31 shows the speaker units 1a and 1a of the speaker system for sound field reproduction according to the fourth reference example.
The sound pressure characteristics of each of b, 1c, and 1d are shown. In FIG. 31, 8a is the sound pressure characteristic of the speaker unit 1a, 8b is the sound pressure characteristic of the speaker unit 1b, 8c is the sound pressure characteristic of the speaker unit 1c, and 8d is the speaker unit 1d.
Is the sound pressure characteristic. Since the bandpass filter 4 is connected to the speaker units 1a and 1b, the frequency fa
To the frequency fb.

Since the high-pass filter 2 is connected to the speaker unit 1c, a band of the frequency fb 'or higher is reproduced. Since the low-pass filter 3 is connected to the speaker unit 1d, a band lower than the frequency fa 'is reproduced. Therefore, since the sound is radiated from only one speaker unit 1d below the frequency fa 'and the frequency is low, the radiation pattern is the same as in the second embodiment shown in FIG.
As shown in the characteristic (A) of FIG. Between the frequency fa and the frequency fb, the speaker unit 1
Since the same sound pressure is radiated to both a and 1b and they are connected so as to be driven in opposite phases, the radiation pattern thereof is the same as that of the second embodiment as shown in the characteristic (B) of FIG. It becomes a character dipole characteristic. Above the frequency fb ', sound is emitted only from one speaker unit 1c, and the frequency fb'
Since the horn 7 'whose directivity becomes narrower than b' is attached, its radiation pattern is similar to that of the second embodiment shown in FIG.
As shown in the characteristic (C) of FIG. Symbols (A), (B), and (C) in FIG. 31 correspond to the characteristics (A), (B), and (C) in FIG. 18, respectively.

The cut-off frequency f of the high-pass filter 2
b ′ and the upper limit frequency fb of the bandpass filter 4 are
Similarly to the cutoff frequency fb of the low-pass filter 3 of the second embodiment, it is effective to set the frequency to about 2 kHz.
The frequencies fb, fb 'need not be the same. The cut-off frequency fa of the low-pass filter 3 and the lower limit frequency fa of the band-pass filter 4 are set in two ways, similarly to the cut-off frequency fa of the high-pass filter 2 of the second embodiment. The same effect as the effect shown in the second embodiment can be obtained.

Since the radiation pattern of the speaker system for reproducing a sound field of the fourth embodiment is almost the same as that of the speaker system for reproducing a sound field of the second embodiment, the method of use and the effect are almost the same. The frequencies fa and fa 'need not be the same. In the fourth reference example , the high-frequency reproduction speaker unit 1c is mounted on the same baffle surface as the speaker unit 1a. However, the effect is not changed even if the speaker unit 1c is mounted on the same baffle surface as the speaker unit 1b.

[0082]

Effects of the Invention According to the sound field reproducing speaker system according to claim 1, shaped dipole characteristics of the 8 in the following frequency fb, so on a single directivity at frequencies above fb,
Since the radiation pattern can be changed for each frequency band, environmental sounds and reverberation sounds in which the frequency components below fb are dominant can give the listener a feeling that the sound has spread in the room, and the frequency components above fb The movement sound, which includes abundant sounds, can give the sense of direction. Therefore, it is possible to achieve both a sense of spreading of the environmental sound and the reverberant sound and a sense of movement of the moving sound. Also, when installed in front of the listener,
If the component of fb or more that greatly contributes to the localization of the sound image is installed so that the reflected sound can be obtained only from the left and right wall surfaces, the sound image is hardly localized in front, and a good feeling of spread can be obtained.

According to the loudspeaker system for reproducing a sound field according to the second, third or fourth aspect , omnidirectionality is obtained at a frequency of fa or less, a figure-eight dipole characteristic is obtained at a frequency of fa or more and fb or less, and a singular shape is obtained at a frequency of fb or more. Because the radiation pattern can be changed for each frequency band, such as unidirectionality,
The environmental sound and reverberation sound in which the frequency component below fb is dominant can give the listener a feeling that the sound has spread in the room, and the moving sound which contains the frequency component above fb abundantly gives the sense of direction. be able to. Therefore, it is possible to achieve both a sense of spreading of the environmental sound and the reverberant sound and a sense of movement of the moving sound. Also, even when installed in front of the listener, components larger than fb that contribute to the localization of the sound image, if installed so that reflected sounds can be obtained only from the left and right wall surfaces, it is difficult for the sound image to be localized in front, Good spreading feeling can be obtained. Also,
A reproduction band equal to or less than fa can be secured.

According to the loudspeaker system for reproducing a sound field according to the fifth or sixth aspect , a figure eight dipole characteristic is obtained at a frequency of about 2 kHz or less, and a unidirectional pattern is obtained at a frequency of about 2 kHz or more. Since the radiation pattern can be changed, the environmental sound and reverberation sound in which the frequency component of 2 kHz or less is dominant can give the listener a feeling that the sound has spread in the room, and the frequency component of 2 kHz or more is abundant. The moving sound can give the sense of direction. Therefore, it is possible to achieve both a sense of spreading of the environmental sound and the reverberant sound and a sense of movement of the moving sound. In addition, even when it is installed in front of the listener, it contributes greatly to the localization of the sound image.
If the component of kHz or more is installed so that reflected sound can be obtained only from the left and right wall surfaces, the sound image is hardly localized in front, and a good feeling of spreading can be obtained.

According to the loudspeaker system for reproducing a sound field according to the fourth or seventh aspect, a horn whose directivity becomes narrower at the frequency fb or higher is attached to the front surface of the speaker unit that radiates the band at the frequency fb or higher. It is possible to reduce the direct sound from the speaker of the component of the frequency fb or more that greatly contributes to the localization of the sound, and to increase the ratio of the indirect sound component from the wall surface. When installed in front of the listener, the feeling of spreading can be further increased.

According to the loudspeaker system for reproducing sound fields of the eighth aspect, the sound emitted from the first speaker unit 1 reaches the observation point at the observation point on the front axis of the first speaker unit with the frequency fa. Is set to a frequency at which the difference between the distance to the observation point and the sound emitted from the second speaker unit reaches the observation point is set to a half wavelength, so that a low-frequency reproduction band can be secured. There is almost no loss of spaciousness due to the direct sound.

According to the loudspeaker system for reproducing a sound field according to the ninth aspect , it is easy to give a feeling of spreading by the phase control.
Since the sound from 0 Hz to 1 kHz or less can be directly given to the listener, the sense of spaciousness can be further increased by the phase control. When installed in front of the camera, the sense of spread is further emphasized, and a good surround feeling can be obtained even in the case of a front place where the sense of spread is difficult to obtain.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a speaker system for sound field reproduction according to a first reference example .

FIG. 2 is a sound pressure characteristic diagram of each speaker unit of the speaker system for sound field reproduction according to the first reference example .

FIG. 3 is a polar coordinate characteristic diagram of the speaker system for reproducing a sound field according to the first reference example ;

FIG. 4 is a schematic diagram showing an example of a speaker arrangement of a video and audio reproduction system using the sound field reproduction speaker system of the first reference example .

FIG. 5 is a frequency analysis diagram in which a moving sound of a movie is analyzed for a frequency component of a sound field signal.

FIG. 6 is a frequency analysis diagram in which a frequency component of a sound field signal of an environmental sound of a movie is analyzed.

FIG. 7 is a frequency analysis diagram obtained by analyzing a frequency component of a sound field signal of a reverberant sound of a movie.

FIG. 8 is a schematic diagram showing another example of the speaker arrangement of the video and audio reproduction system using the sound field reproduction speaker system of the first reference example .

FIG. 9 is a schematic diagram showing a configuration of a modified example of the sound field reproduction speaker system of the first reference example .

FIG. 10 is a schematic diagram showing a configuration of a speaker system for reproducing a sound field according to a second reference example .

FIG. 11 is a sound pressure characteristic diagram of each speaker unit of the speaker system for sound field reproduction according to the second reference example .

FIG. 12 is a schematic diagram showing a configuration of a speaker system for reproducing a sound field according to the first embodiment of the present invention.

FIG. 13 is a sound pressure characteristic diagram of each speaker unit of the sound field reproduction speaker system according to the first embodiment of the present invention.

14 is a schematic diagram showing an example of a speaker arrangement audiovisual reproduction system using the sound field reproducing speaker system of the first embodiment of the present invention.

FIG. 15 is a schematic diagram showing another example of the speaker arrangement of the video and audio reproduction system using the sound field reproduction speaker system according to the first embodiment of the present invention.

FIG. 16 is a schematic diagram showing a configuration of a speaker system for reproducing a sound field according to a second embodiment of the present invention.

FIG. 17 is a sound pressure characteristic diagram of each speaker unit of the speaker system for sound field reproduction according to the second embodiment of the present invention.

FIG. 18 is a polar coordinate characteristic diagram of the speaker system for reproducing a sound field according to the second embodiment of the present invention.

FIG. 19 is a schematic diagram showing an example of a speaker arrangement of a video and audio reproduction system using a sound field reproduction speaker system according to a second embodiment of the present invention.

FIG. 20 is a schematic diagram showing another example of the speaker arrangement of the video and audio reproduction system using the sound field reproduction speaker system according to the second embodiment of the present invention.

FIG. 21 is a schematic diagram showing a configuration of a modification of the speaker system for reproducing a sound field according to the second embodiment of the present invention.

FIG. 22 is a schematic diagram showing a configuration of a speaker system for reproducing a sound field according to a third embodiment of the present invention.

FIG. 23 is a sound pressure characteristic diagram of each speaker unit of the speaker system for reproducing a sound field according to the third embodiment of the present invention.

FIG. 24 is a schematic diagram showing a configuration of a modified example of the sound field reproduction speaker system according to the third embodiment of the present invention.

FIG. 25 is a schematic diagram showing a configuration of a sound field reproduction speaker system according to a fourth embodiment of the present invention.

FIG. 26 is a diagram showing a sound pressure characteristic of each speaker unit of the speaker system for reproducing a sound field according to the fourth embodiment of the present invention.

FIG. 27 is a schematic diagram illustrating a configuration of a speaker system for reproducing a sound field according to an embodiment of a third reference example ;

FIG. 28 is a diagram illustrating a sound pressure characteristic of each speaker unit of the speaker system for reproducing a sound field according to the third embodiment;

FIG. 29 is a schematic diagram showing a configuration of a modification of the sound field reproduction speaker system of the third reference example .

FIG. 30 is a schematic diagram showing a configuration of a speaker system for sound field reproduction according to a fourth reference example .

FIG. 31 is a sound pressure characteristic diagram of each speaker unit of the speaker system for reproducing a sound field according to the fourth reference example .

FIG. 32 is a block diagram illustrating an example of a video and audio reproduction system.

FIG. 33 is a schematic diagram showing an example of a speaker arrangement of a video and audio reproduction system using a conventional sound field reproduction speaker system.

FIG. 34 is a schematic diagram showing a configuration of a dipole type speaker system.

FIG. 35 is a polar coordinate characteristic diagram of the dipole speaker system.

FIG. 36 is a schematic diagram showing an example of a speaker arrangement of a video and audio reproduction system using a dipole type speaker system.

[Explanation of symbols]

 1a, 1b, 1c, 1d Speaker unit 2, 2a, 2b High pass filter 3, 3a, 3b Low pass filter 4 Band pass filter 5 Cabinet 6 Input terminal 7 Horn 7 'Horn 11 Speaker unit 12 Rear open cabinet 13 Acoustic equalizer 14a Front side Opening 14 b Backside opening 21 Display device 22 Left speaker 23 Center speaker 24 Right speaker 25 Surround speaker 26 Listener 27 Surround speaker 28 Surround speaker 31 Video / audio signal supply device 32 Matrix decoder 33 Amplifier

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-227198 (JP, A) JP-A-51-123137 (JP, A) JP-A-3-54991 (JP, A) 137994 (JP, A) JP-A-62-226799 (JP, A) JP-A-4-318800 (JP, A) JP-A-64-18398 (JP, A) JP-B-51-16724 (JP, B1) Special table 1986-500644 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04R 1 / 02,1 / 22,1 / 40 H04R 3 / 00,5 / 02 H04S 1 / 00,5 / 02

Claims (9)

(57) [Claims] 1. A speaker unit for reproducing an input signal.
And the speaker unit is attached to the speaker.
The front and rear openings of the unit are almost the same
A rear open cabinet opened in a shape, and the speaker
The frequency fb or lower is attached to the back side opening of the unit.
A sound field reproduction speaker system including an acoustic equalizer for attenuating a reproduction sound . 2. A cutoff for passing a high frequency band of an input signal.
A high-pass filter with a frequency fa and a
The output of the high-pass filter is mounted on the full surface.
A first speaker unit for reproduction;
Set higher than the cut-off frequency fa of the filter
The cutoff frequency fb that allows the low-pass of the input signal to pass
-Pass filter and the same as the first speaker unit
The first speaker unit having characteristics
Attached to the baffle surface facing the baffle surface
-Pass filter output with the first speaker unit
Is a speaker system for sound field reproduction, comprising: a second speaker unit for reproducing in opposite phase . 3. A cabinet attached to one baffle surface of a cabinet.
The first speaker unit that reproduces the input signal
Between the frequency fa of the input signal and the frequency fb.
A band-pass filter for passing a band;
The first speaker unit having the same characteristics as the speaker unit.
On the baffle surface facing the baffle surface where the knit is attached
The output of the band-pass filter
The second speaker that plays back in phase opposite to that of the first speaker unit
Sound field reproduction for a speaker system that includes a Kayunitto. 4. A cutoff for passing a low frequency band of an input signal.
A low-pass filter having a frequency fb;
Of the cut-off frequency fa that passes the high band of the output of the
One high-pass filter and one baffle side of the cabinet
Attached to restart the output of the first high-pass filter
A first loudspeaker unit, and the first loudspeaker
The first speaker unit having the same characteristics as the unit.
Attach to the baffle surface facing the baffle surface where the
And outputs the output of the low-pass filter to the first
The second speaker unit that plays back in phase opposite to that of the speaker unit
And a cutoff frequency for passing a high frequency band of the input signal.
A second high-pass filter having a wave number fb ';
It is mounted on the same baffle surface as the
No. 2 for high-frequency reproduction that reproduces the output of the high-pass filter 2
3 speaker unit and the third speaker unit
Is mounted on the front of the unit and the directivity is narrow at frequencies fb and higher.
A speaker system for sound field reproduction including a horn . 5. The method according to claim 1, wherein the frequency fb is set to about 2 kHz.
Item 4. A speaker system for reproducing a sound field according to Item 1, 2, or 3 . 6. Each of the frequencies fb and fb 'is about 2 kHz.
The speaker system for sound field reproduction according to claim 4, wherein z is set to z . 7. A frequency display on the front of the first speaker unit.
Attaches a horn that reduces the directivity at frequencies above fb
The speaker system for sound field reproduction according to claim 2 or 3 . 8. A first speaker unit for transmitting a frequency fa to a first speaker unit.
At the observation point on the front axis of the first speaker unit 1
The distance from the sound coming out of the
Before the sound from the speaker unit reaches the observation point
4. A frequency set to a half-wavelength difference in distance.
Or the speaker system for sound field reproduction according to 4 . 9. A frequency fa of 500 Hz to 1 kHz.
5. The speaker system for reproducing a sound field according to claim 2 , wherein the speaker system is set in between .