JP3422296B2 - Directional loudspeaker - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional loudspeaker capable of listening to sounds of different signal sources in different regions for a pair of loudspeakers, and more specifically to a certain signal source in a predetermined listening area. Make it difficult to hear the sound of
The present invention relates to a directional loudspeaker capable of transmitting different sound information to a plurality of listening areas so that different sounds can be heard in different listening areas.

[0002]

2. Description of the Related Art Conventionally, as a device for simultaneously listening to different sounds in different areas of the same space, the directivity of sounds emitted from a speaker is controlled in two or more desired directions. There was something. For example, JP-A-6
No. 205496 (“Speaker Device”) discloses FIG.
As shown in (1), each input signal (IN1, IN2) supplied to an array speaker (AS) in which a plurality of speakers are linearly arranged is converted into digital filters (DF1 to DF1).
m), the digital signal processing for differentiating the delay time and the like is individually performed, whereby the array speaker (A
Directivity (D1, D of each input signal sound emitted from S)
Although the technique of controlling 2) is described, this technique has a drawback that the device becomes large-scale.

Further, in general, array speakers physically arranged in an array form, when acoustic signal power is applied in phase,
The sound pressure outside the front becomes very low due to the sound wave interference, and the directivity becomes very sharp. However, in order to obtain a sufficiently sharp directivity, the longitudinal direction of the array speaker (arrangement direction)
For the dimension, several wavelengths of sound waves are required. For this reason, it is difficult to fit within a practical size in the low and middle tone range. For example, one wavelength of a sound wave having a frequency of 1 kHz is 34c
Therefore, in order to obtain sufficient directivity at a frequency lower than m, a large size of 1 m to several m is required.

As shown in FIG. 1 (2), Japanese Patent Application Laid-Open No. 5-344579 ("Speaker System and Television Receiver Using the Speaker System")
The acoustic partition plate (P) is attached to the acoustic tube (ST) that guides the sound waves emitted from the speaker diaphragms of the two speaker units (SU).
P) and a sound absorbing panel (AP) are provided to structurally give the directivity of the speaker in an arbitrary direction, this technique has a small suppression ratio effect and can switch the directivity direction. It has the drawback of not being easy.

On the other hand, the inventors of the present invention cancel two predetermined sound wave components radiated from two loudspeakers arranged close to each other by digital signal processing, so that two persons (or two persons) located in different areas of the same space. Group of two)
In Japanese Patent Application No. 10-39378, a speaker device was proposed in which listeners of the same can hear sounds of different sound sources at the same time (hereinafter, this proposal is referred to as "the above-mentioned proposal"). There is a drawback that the frequency band is narrow, and in particular, the controllable region in the high frequency range is narrow.

[0006]

In view of such inconvenience, the present invention makes it difficult to hear the sound emitted from the speakers in a space where the sound emitted from the pair of left and right speaker systems is heard. Or, in different areas, it is possible to listen to sounds of different sound sources at the same time, and such areas that are difficult to hear or areas that can be heard individually are expanded regardless of the frequency band, and high frequencies It is an object of the present invention to provide an improved directional loudspeaker capable of further improving the controllable area, and having a simple structure and a small size.

[0007]

According to the present invention, the first and second mid-low range speakers (5a, 5b) are arranged at intervals of 1/8 to 1 wavelength of the sound wave in the control frequency band.
And the acoustic signal sources (A, B) and the mid-low range speaker, and cancels the mid-low range sound for canceling the sound waves emitted from the mid-low range speaker by the interference of the sound waves in the listening space. A directional loudspeaker comprising a control means (SC) and a directional treble speaker (9a, 9b) for emitting a sound based on a treble range acoustic signal from the acoustic signal source,
Alternatively, the first and second mid- and low-range speakers (5a, 5b) arranged at intervals of ⅛ wavelength to 1 wavelength of the sound wave in the control frequency band, and the first and second acoustic signal sources (A ，
B) and a mid- and low-pitched sound speaker, and a mid-and-low-pitched cancellation control means (SC) for canceling sound waves emitted from the mid-and-low-pitched speaker by interference between the sound waves in different regions in the listening space. And a first and second directional treble loudspeakers (9a, 9b) for emitting a sound based on the treble range acoustic signal from the acoustic signal source.

According to another feature of the present invention, the directional treble speaker can be formed of array speakers (SA, SB), and according to another feature, the mid-low range speaker and the directional treble speaker. Speaker for array speaker (S
A, SB) can be shared. Furthermore,
In the latter case, the mid-low range speaker is divided into a mid-range speaker unit (SM) and a low-range speaker unit (SL), and the mid-range speaker unit (SM) is located on the center side of the array speaker (SA, SB). The speaker for bass (S
L) can be located.

[Operation] According to the first feature of the present invention,
Two speakers (5a, 5b) are arranged close to each other with an interval of ⅛ wavelength to 1 wavelength of the sound wave in the frequency range to be controlled, and sound waves of the mid-low range acoustic signal in this frequency range are emitted. A mid-low frequency cancellation control means (SC) is interposed between the acoustic signal source (for example, A) and one speaker (5b), so that in a certain area of the listening space of both speakers, The sound waves in the middle and low range radiated from the speaker are canceled by the interference between the sound waves. For the treble sound signal of the acoustic signal source, the corresponding sound wave in the treble range is
Sound is emitted from the directional treble speaker (for example, 9a) in a direction avoiding the cancellation region. Therefore, by using a speaker device of a small size, in the cancellation area and the listening area in the vicinity thereof, both the middle and low range sounds and the high range sound are
It can be hard to hear enough.

According to the second feature of the present invention, the two speakers (5a, 5b) are arranged close to each other with the interval of ⅛ wavelength to 1 wavelength of the sound wave in the controlled frequency region, and the controlled frequency region. And each have a different content type (that is,
Sound waves in the mid-low range including the uncorrelated (first and second) channel sound signal components are emitted from both speakers. A mid-low tone cancellation control means (SC) is interposed between the second and first channel acoustic signal sources (B, A) and the first and second speakers, whereby the listening space of both speakers is within the listening space. In different first or second regions of
The second channel or first channel acoustic signal components of the sound waves in the middle and low range radiated from the respective speakers are canceled by the interference between the sound waves. Regarding the treble range acoustic signal of the first channel or the second channel acoustic signal source (A, B), the corresponding treble range sound wave is output from the directional treble speaker (9a, 9b) respectively in the middle and low range sound wave. Sound is emitted in the direction toward the region where the second channel or first channel acoustic signal component is canceled. Therefore, by using a small-sized speaker device, different sounds from the first channel or second channel acoustic signal sources (A, B) are output in the mid-low range in each cancellation area and each listening area in the vicinity thereof. Both the sound and the high-pitched sound can be effectively heard.

According to the present invention, as described above, in the middle and low range, the middle and low range cancellation control means (SC) is used.
Sounds emitted from the two speakers (5a, 5b) are mutually canceled by using sound wave interference, and in the high frequency range, sound in only a specific direction toward the listening area using the directional treble speakers (9a, 9b). By increasing the pressure level, it is possible to effectively transmit different sound information including a high frequency range to a plurality of listening areas. According to another feature of the present invention, the directional treble speaker (9a, 9)
By using a highly directional sound source such as an array speaker in b), effective transmission of separate sound information to each listening area including a high frequency range can be realized with a simple configuration.

Further, according to another feature of the present invention, a speaker for middle and low sounds is also included in the array speakers (SA, SB), and a part or all of the array speaker is controlled by a middle and low sound canceling control means (SC). The speaker structure can be further simplified by using the speaker as a mid-low range speaker driven through. In this case, the speaker for middle and low sounds is the speaker for middle sound (SM) and the speaker for low sound (SL).
The speaker unit for medium sound (SM) is located on the center side of the array speaker (SA, SB), and the speaker unit for bass (SL) is located outside the speaker unit for different sounds according to the listening environment. Any method can be adopted.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the drawings. The following embodiments are merely examples, and various modifications can be made without departing from the spirit of the present invention.

[System Configuration] FIG. 2 is a block diagram showing the configuration of a directional loudspeaker according to an embodiment of the present invention. In this example, the directional loudspeaker is supplied with the first channel and second channel acoustic signals A and B having different content types (that is, no correlation),
These two acoustic signals A and B are supplied to the acoustic signal control circuit 2 after being converted into digital signals by the analog-digital conversion circuits (ADC) 1a and 1b.

The acoustic signal control circuit 2 includes first and second delay devices 21 and 22, and first and second digital filters 2.
3, 24, and the first channel acoustic signal A is supplied to the first delay device 21 and the first digital filter 23,
The second channel acoustic signal B is supplied to the second delay device 22 and the second digital filter 24. The output signals of the first delay device 21 and the second digital filter 24 in the acoustic signal control circuit 2 pass through the digital-analog conversion circuits (DAC) 31 and 34 and the first and second attenuators AT, respectively, to obtain the first signal. The output signals of the second delay device 22 and the first digital filter 23 in the acoustic signal control circuit 2 which are added by the adding circuit AD are DACs 32 and 3, respectively.
The addition is performed in the second addition circuit AD via the third, third and fourth attenuators AT.

The addition output signals of the adder circuits AD are amplified by the first and second power amplifiers 4a and 4b, respectively, and then input to the first and second mid-low range speakers 5a and 5b. Both middle and low range loudspeakers 5a and 5b are arranged at an interval (d0) of 1/8 to 1 wavelength of the sound waves in the main control frequency regions of the first channel and second channel acoustic signals A and B, respectively. , First and second power amplifier 4
Sound waves are emitted based on the signals input from a and 4b.

The ADCs 1a and 1b, the acoustic signal control circuit 2, the DACs 31 to 34, the attenuator AT, the adder circuit AD, and the first and second power amplifiers 4a and 4b described above are crossover network type sound source control as shown in FIG. The device SC is configured, and the sound source control device SC drives the first and second mid- and low-pitched sound speakers 5a and 5b to provide a proximity sound source control (PSC: Proximate Sourse Control) method [hereinafter, referred to as a "PSC method". Is abbreviated as ] Proximity controlled sound source is realized. When the mid- and low-pitched sound speakers 5a and 5b are driven by the PSC method, two different points Pa and Pb in the listening space (not shown. For example, in FIG. 2, the first and second mid- and low-pitched sound speakers 5a and 5b are set to the back. ,
Left front and right front respectively. ), Only the first channel or second channel acoustic signal components (A, B) are heard respectively, and the second channel or first channel acoustic signal B,
The crosstalk sound originating in A can be made inaudible. Such proximity control sound source has already been described in the above proposal, but the principle thereof will be described later.

In one embodiment of the present invention, as shown in FIG. 2, first-channel and second-channel acoustic signals A and B are used.
For the sound in the mid-low range of about 100 Hz to 2500 Hz (or 3000 Hz), the sound source control device SC uses the PSC method for the first and second mid-low range speakers 5a and 5b.
Driving the first channel and the second channel acoustic signals A and B from 3 kHz (or 2.5 kHz) to 1
For sounds in the high frequency range of about 5 kHz, high frequency filters 6a and 6b, power amplifiers 7a and 7b, distribution circuits 8a and 8b, and high-direction treble speakers 9a and 9b, respectively.
b is provided to obtain a desired directivity for sounds in the high frequency range. That is, the first channel and second channel acoustic signals A and B are output to the high-pass filters 6a and 6 respectively.
The treble range signals of the first and second channels obtained through b are amplified by the power amplifiers 7a and 7b, and given a predetermined signal strength gradient by the distribution circuits 8a and 8b, and then the treble array speaker 9a. , 9b is supplied to each sounding unit.

Here, the directional treble loudspeakers 9a and 9b are used.
As shown in Fig. 2, 3 kHz (or 2.5 kHz)
It is preferable to use an array speaker having a narrow (high) directivity in the band of z) to 15 kHz. However,
A speaker having an equivalent directivity (for example, a structure having a physically equivalent directivity if possible, as shown in FIG. 1A) may be used. FIG. 3 is a diagram showing the external appearance of a directional loudspeaker according to an embodiment of the present invention. The PSC system is used to drive the mid- and low-pitched sound speakers 5a and 5b so that only the first channel or the second channel acoustic signal components (A and B) can be heard at the listening points Pa and Pb, respectively. If so, the high-pitched array speakers 9a and 9b are tilted in the physical arrangement direction as shown in FIGS. 2 to 3 and the intensity gradient of the signal supplied to the sounding unit is adjusted, thereby Listening points Pa, P
A predetermined directional characteristic is given in the direction toward b.

[Principle of PSC System] Now, in the acoustic listening space for both the middle and low range speakers 5a and 5b, a certain point Pa (not shown. For example, in FIG. 2, the first middle and low range speaker 5a is used as a back. Considering the left front.), This point Pa
The sound heard at is the first and second mid-low range speaker 5
The sound pressures of sounds emitted from a and 5b are linearly superimposed. Therefore, the sound pressure S (ω) at the listening point Pa is equal to the voltage of the first channel acoustic signal A by X.
(Ω), where Y (ω) is the voltage of the second channel acoustic signal B (ω is the angular frequency of the sound wave signal) and can be expressed by the following equation (1): S = (αX + βY) + (γX + δY) (1) where α is a circuit element 1a → 21 → 31 → 4a → 5a
And elements 1a to 5a to Pa whose path is the space 5a to Pa
The transfer function between, β is circuit element 1b → 24 → 34 → 4a
→ 5a and space 5a → elements 1b to 5a whose path is Pa
The transfer function between γ and Pa, γ, is the circuit element 1a → 23 → 33.
→ 4a → 5b and space 5b → Pa 1a-5
The transfer function δ between b and Pa is as follows: circuit element 1b → 22 → 32
→ 1b to 5 with 4b → 5b and space 5b → Pa as routes
It is a transfer function between b and Pa.

That is, the first term on the right side represents the sound radiated from the first mid-low range speaker 5a and heard at the listening point Pa, and the second term on the right side is radiated from the second mid-low range speaker 5b. The sound is heard at the same listening point Pa. Therefore, when the digital coefficient of the second digital filter 24 is adjusted to change the coefficient β to satisfy β = −δ, Expressions (1) to (2) are obtained, and the second channel acoustic signal voltage Y is included. The term can be deleted. S = αX + γX = (α + γ) X (2)

This means that at the listening point Pa, the first
Only the sound originating from the channel acoustic signal A (signal voltage X) is heard, and the second channel acoustic signal B (signal voltage Y) is heard.
It means that the crosstalk sound [(β + δ) Y] derived from is inaudible.

Further, the same operation is performed by another point Pb (not shown. For example, in FIG. 2, the second middle and low frequency speaker is symmetrical with respect to the center line between the middle and low frequency speakers 5a and 5b at the listening point Pa. 5b as a back right front), by adjusting α = −γ even for the filter of the first digital filter 23, the second channel acoustic signal B (signal voltage Y at the listening point Pb). ), The crosstalk sound [(α + γ) X] derived from the first channel acoustic signal A (signal voltage X) is not heard.

Each digital filter 2 having such a configuration
It is only one point in the listening space that β = −δ or α = −γ can be established by 3 and 24, and the crosstalk is zero at that one point (hereinafter referred to as “cancellation point”). Become. In addition, a region with less crosstalk is generated around the cancellation point.

For example, when the crosstalk at the listening point Pa is set to zero by adjusting the filter coefficient of the second digital filter 24 to satisfy β = −δ, the crosstalk occurs in the region near the listening point Pa. Reduced,
When the crosstalk at the listening point Pb is set to zero by adjusting the filter coefficient of the first digital filter 23, the crosstalk is reduced in a region near the listening point Pb, which is symmetrical to this. This, as explained next,
The present invention has been clarified by the present inventors, and the invention utilizing this phenomenon is described in detail in the above proposal.

Generally, when the speakers are installed sufficiently apart from each other in a diffuse sound field, the crosstalk is -10 dB.
It is said that such a space has a substantially circular shape and has a size of about 1/10 of the wavelength of the sound wave in the control band (for example, “A. David and S. J. Elliot 1993 applied.
acoustics 41, 63-79. Numerical studies of activel
y generated quiete zones ”). And vice versa,
1/8 of the wavelength of the sound wave of the control frequency between the sound source speakers
It is known that when approaching to the following, the region where the crosstalk is −10 dB or less spreads in front of both the two speakers, and in the case of the two-channel configuration, the regions for crosstalk reduction overlap each other.

As shown in FIG. 2, middle and low range speakers 5a and 5b.
The wavelength of the emitted sound is λ
Then, the crosstalk reduction region where the crosstalk becomes −10 dB when the speaker spacing is changed changes as a function of the speaker spacing for a predetermined wavelength λ.
When the speakers 5a and 5b are sufficiently separated from each other to have a relationship of "speaker interval d1> wavelength λ", crosstalk is reduced in a substantially circular small area [see FIG. 2 (A) of the above proposal]. ]. Further, when the speakers 5a and 5b are brought close to each other to satisfy the relationship of "speaker interval d2> (1/8) × wavelength λ", the crosstalk reduction region is greatly expanded, but the first channel and the second channel are reduced. The crosstalk reduction regions for the acoustic signal components overlap each other [see FIG. 2 (C) of the above proposal]. ].

However, when the speaker spacing d0 is set to (1/8) × λ <d0 <λ (3) as in the present invention, the crosstalk reduction region of each acoustic signal component is independent. It also has a large volume [see FIG. 2 (B) of the above proposal]. ]. In FIG. 2, the sound field based on such a PSC system is the first sound field generated by the sound source control device SC.
And the second mid- and low-pitched sound speakers 5a and 5b (for example, the distance d0 between the centers of the mid-and-low-pitched sound speakers 5a and 5b is approximately 40).
It can be within cm. ) Is driven by a proximity control sound source.

[Outline of formation of sound field in mid-low range and high range]
According to such a PSC system, 100 Hz to 2500
For the sound in the mid-low range of about Hz (or 3000 Hz), the sound pressure in a specific direction can be lowered, and the area where the crosstalk can be favorably reduced can be made independent to have a large volume. Alternatively, for sounds in the high frequency range of about 3000 Hz) or higher, the controllable crosstalk reduction region is narrow, and it is difficult to achieve the desired effect.

Therefore, in one embodiment of the present invention, FIG.
As shown in FIG. 1, the sound source control device SC for the sound in the mid-low range of the first and second channel acoustic signals A and B
1st and 2nd bass speaker 5 by PSC method
a and 5b are driven, and high-pass filters 6a and 6b and power amplifiers 7a and 7b are used for high-frequency sounds of the first and second channel acoustic signals A and B, respectively.
b, distribution circuits 8a and 8b, and high-directional loudspeakers 9a and 9b.

FIGS. 4 and 5 show the PSC according to the present invention.
FIG. 6 is a diagram for explaining formation of a mid-low range sound field by the mid-low range speakers 5a and 5b, and FIG. 6 illustrates formation of a high-range sound field by the directional high range speakers 9a and 9b according to the present invention. FIG. For example, it is assumed that the sound source control device SC receives the broadcast sound signal of "English" as the first channel sound signal A and the broadcast sound signal of "Spanish" as the second channel sound signal B.

In the present invention, for example, 100 Hz
For mid-low range sounds up to 2500 Hz (or 3000 Hz), a pair of two mid-low range speakers 5
By applying the PSC method to a and 5b, a direction in which the sound of one channel is hard to hear (DA) is created, and similarly, a direction in which the sound of the other channel is hard to hear (DB) is created in another direction. For example, in the case of “Spanish” of the second channel acoustic signal B, the direction difficult to hear is “D” in FIG. 4 (1).
A sound field having a direction indicated by "A" is generated, and for "English" of the first channel acoustic signal A, a sound field having a direction difficult to hear is a direction indicated by "DB" in FIG. 4B. Thus, the proximity control sound source including the sound source control device SC is set. Then, when the acoustic signals A and B of these two channels are superimposed and reproduced by this proximity control sound source,
As shown in FIG. 5, two directions DA and DB in which only "English" or "Spanish" are easy to hear are generated, so that bilingual broadcasting of Spanish and English can be distributed to the two directions DA and DB.

In one embodiment of the present invention, for example,
For sounds in the high range of 2500 Hz (or 3000 Hz) or higher, the array speakers 9a and 9b physically arranged in an array are used. The array speakers 9a and 9b are sound sources with extremely sharp directivity, and have a characteristic that when electric power is applied to the same phase, sound pressure other than in the front is very low due to sound wave interference. Therefore, each array speaker 9a, 9b
As shown in FIG. 6, the directivity of the first channel is adjusted to the directions DA and DB of the mid-low range speakers 5a and 5b shown in FIG.
The channel "Spanish" can be heard only in the listening areas of the desired directions DA and DB even in the high frequency range. Therefore, according to the present invention, it is possible to effectively distribute the bilingual broadcast to the two directions DA and DB for the entire range.

In order to obtain a sufficiently sharp directivity with the array speaker, longitudinal dimensions for several wavelengths of sound waves are required,
For the mid-low range, it is difficult to fit within a practical size, but in the present invention, as described above, the PSC method is applied to the mid-low range sound, and the high-range sound is driven by the common mode of the array speaker. Therefore, the speaker mechanism can be downsized.

[Other Configuration Example] In the present invention, not only the directional treble loudspeakers 9a and 9b but also the mid and low tone loudspeakers 5a and 5b can be configured by array loudspeakers. FIG. 7 is a block diagram showing the configuration of a directional loudspeaker according to another embodiment of the present invention, and the same reference numerals as those in FIG. 2 indicate the same configurations as those of FIG. In this embodiment, the functions of the middle and low-pitched loudspeakers 5a and 5b and the directional high-pitched loudspeakers 9a and 9b are realized by the array loudspeakers SA and SB, thereby further simplifying the configuration of the loudspeaker device. You can FIG. 8 is a diagram showing the external appearance of a directional loudspeaker according to another embodiment of the present invention.

In the example shown in FIGS. 7 and 8, the array loudspeakers SA and SB are driven in-phase by the distribution circuits 8a and 8b, respectively, with the treble range acoustic signals of the first and second channels with a predetermined intensity gradient. However, some of the sounding units on the center side (in the figure, the three inner units)
The outputs of the power amplifiers 4a and 4b are supplied via the adder circuit AD, and are also driven by the PSC system. When the array speaker is also used as a PSC driving speaker, the center-side sounding unit driven by the PSC method has the eighth and the eighth sound waves in the control frequency band of the middle and low range components of the first and second channel acoustic signals A and B. It is necessary to satisfy the interval of 1 wavelength to 1 wavelength, and depending on the conditions, as shown in the development view of both speaker output surfaces in FIG. May not be used.

FIG. 9 (2) shows an example of another speaker device configuration in the case where a part or all of the array speaker used as the directional treble speaker is commonly used for the mid-low range speaker by the PSC system. Also in the array loudspeakers SA and SB shown in FIG. 9 (2), all the sounding units are driven in phase with a high-range acoustic signal with a predetermined intensity gradient, and some of the sounding units near the center are of the PSC system. The function of the speaker for middle and low frequencies is given.

In this way, both array speakers SA, SB
When PSC is driven not only by the in-phase sound signals of the first and second channels in the high range sound signal but also by the PSC drive in the middle and low range sound signals, basically, the PSC middle range sound signal is output from the inner unit of the array speaker. Used, whereas the PSC bass audio signal uses the outer unit of the array speaker. In the example of FIG. 9 (2), the function of the speaker for middle and low sounds is divided into a speaker portion for middle sound SM and a speaker portion for low sound SL, and the speaker portion for middle sound SM is located on the center side of the array speaker. The bass speaker unit SL is located outside of the above. In this case, for example, the sound source control device SC is provided in the middle sound speaker unit SM and the low sound speaker unit SL.
The outputs of the power amplifiers 4a, 4b can be supplied via suitable filters.

The function of the middle and low range speaker for the PSC system low and middle range sound signal is not limited to the above two ranges, but can be divided into a larger number of ranges. Furthermore, it is not necessary to use all the sounding units for the high-range sound signal, and some sounding units may be PSC.
It may be driven only by the method or may not be used.

[Other Embodiments] In the PSC method, the sound wave canceling region (position, direction) is controlled by, for example, filter coefficient control (Japanese Patent Application No. 11-101805, 102110) proposed by the present inventors. No.) can be adjusted, but such a filter coefficient control is adopted in the sound source control device of the present invention, and the arrangement and directional characteristics of the highly directional speakers such as the array speaker are changed accordingly. Can be configured.

Further, the directional loudspeaker according to the present invention is
For example, it is possible to intentionally create an area in the same room where the volume of television broadcast, radio broadcast, etc. is lower than the surrounding area in any direction or position. It can be used as a speaker of a receiver for multiplex audio broadcasting of television, and it is possible for two people (or two groups) to simultaneously enjoy different main audio and subchannels of multiplex audio broadcasting such as bilingual broadcasting. Regions can be intentionally created in any direction or position. Further, the present invention is not limited to broadcasting of television, radio, etc., and is used for various directional loudspeaking systems when a volume is made small in a certain area in an indoor area or when different broadcasting is performed in two areas. be able to.

[Effect of the Invention] As described above, according to the present invention, one eighth of the sound wave in the frequency region to be controlled.
Two speakers (5a, 5a via a wavelength to one wavelength interval)
b) is arranged in close proximity, the sound waves of the middle and low range sound signals in this frequency range are radiated, and the middle and low range cancellation control means is inserted between the sound signal source and one of the speakers, so that In a certain area of the listening space, the sound waves in the middle and low range radiated from both speakers are canceled by the interference between sound waves, and the treble sound signal of the acoustic signal source is canceled by the directional treble speaker. Since the sound is emitted in the direction avoiding the area, a small-sized speaker device is used, and in the cancellation area and the listening area in the vicinity thereof, both the middle and low range sounds and the high range sound are sufficiently generated. It can be difficult to hear.

Further, according to the present invention, the sonic wave in the controlled frequency region is divided into two by a distance of ⅛ wavelength to 1 wavelength.
Two loudspeakers are arranged close to each other, and sound waves in the middle and low frequency ranges, which include sound signal components of the first channel and the second channel having different content types (correlation-free) respectively, are radiated from both loudspeakers. Between the channel and the first channel acoustic signal source and the first and second speakers,
By inserting the middle-and-low-tone cancellation control means, in the different first or second regions in the listening spaces of both speakers, the second channel or the first channel of the sound waves in the middle or low range emitted from each speaker, respectively. The acoustic signal component is canceled by the interference between the sound waves, and the treble acoustic signal of the first channel or the second channel acoustic signal source is output from the directional treble speaker to the second channel or the first channel of the mid-low range acoustic wave, respectively. Since the sound is emitted in the direction toward the region where the channel acoustic signal component is canceled, a speaker device of a small size is used, and in each cancellation region and each listening area in the vicinity thereof, the first channel or the second channel. Regarding the separate sounds from the acoustic signal source, it is possible to effectively hear the sounds in the mid-low range and the high range.

According to the present invention, for middle and low tones, the sounds emitted from the two speakers are mutually canceled by using the middle and low tones canceling control means by using the interference of sound waves, and the treble range is used for the directional treble. By increasing the sound pressure level only in a specific direction toward the listening area using the speaker, it is possible to effectively transmit different sound information including a high frequency range to a plurality of listening areas. Further, this directional treble speaker uses a highly directional sound source such as an array speaker to effectively transmit separate sound information to each listening area including the treble range with a simpler configuration. Can be realized.

Further, according to the present invention, a speaker for middle and low sounds is also included in the array speaker, and a part or all of the array speaker is driven as a speaker for middle and low sounds through the medium and low sound cancellation control means. By using it, the speaker structure can be further simplified. In this case, the middle and low range speakers are divided into a middle range speaker part and a low range speaker part, the middle range speaker part is located on the center side of the array speaker, and the low range speaker part is located outside thereof. Various effective methods can be adopted depending on the situation.

[Brief description of drawings]

FIG. 1 is a diagram showing a conventional technique relating to a directional loudspeaker.

FIG. 2 is a block diagram showing a system configuration of a directional loudspeaker according to an embodiment of the present invention.

FIG. 3 is an external view of a directional loudspeaker according to an embodiment of the present invention.

FIG. 4 is a part of a diagram for explaining sound field formation by the proximity control sound source in the present invention.

FIG. 5 is another part of the diagram for explaining the sound field formation by the proximity control sound source in the present invention.

FIG. 6 is a diagram for explaining sound field formation by a directional sound source according to the present invention.

FIG. 7 is a block diagram showing a system configuration of a directional loudspeaker according to another embodiment of the present invention.

FIG. 8 is an external view of a directional loudspeaker according to another embodiment of the present invention.

FIG. 9 is a diagram showing another example of the array speaker array in another embodiment of the present invention.

[Explanation of symbols]

2 acoustic signal control circuit, 5a, 5b mid-low range speaker, 9a, 9b treble speaker, ADC analog-digital conversion circuit, AT attenuator, AD addition (mixing) circuit, DAC digital-analog conversion circuit, SC sound source control device, SA, SB array speaker. SM mid-range speaker section, SL Bass speaker section.

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Claims (5)

(57) [Claims] 1. A one-eighth wavelength to 1 of a sound wave in a control frequency band
The first and second mid- and low-pitched sound speakers arranged at wavelength intervals are interposed between the acoustic signal source and the mid- and low-pitched sound speaker, and sound waves emitted from the mid- and low-pitched sound speaker are heard in the listening space. A directional loudspeaker comprising: a mid-low tone cancellation control means for canceling by interference of sound waves, and a directional treble speaker that emits a sound based on a treble range acoustic signal from the acoustic signal source. apparatus. 2. One-eighth wavelength to 1 of a sound wave in a control frequency band
The first and second mid- and low-pitched loudspeakers arranged at wavelength intervals, and the first and second acoustic signal sources and the mid- and low-pitched loudspeakers are interposed between the mid and low-pitched loudspeakers. Mid-and-low-range cancellation control means for canceling sound waves emitted from the bass speaker by interference between sound waves, and first and second directivities for emitting sounds based on the high-range sound signal from the sound signal source. A directional loudspeaker comprising a high-frequency speaker. 3. The directional loudspeaker according to claim 1, wherein the directional treble speaker comprises an array speaker. 4. The directional loudspeaker according to claim 1, wherein the speaker for middle and low sounds and the speaker for directional treble sound are array speakers. 5. The mid-low range speaker comprises a mid-range speaker unit and a low-range speaker unit, the middle-range speaker unit is located on the center side of the array speaker, and the low-range speaker unit is located outside thereof. The directional loudspeaker according to claim 4.